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TableofContents
ZabbixNetworkMonitoringEssentials
Credits
AbouttheAuthors
AbouttheReviewers
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Supportfiles,eBooks,discountoffers,andmore
Whysubscribe?
FreeaccessforPacktaccountholders
Preface
Whatthisbookcovers
Whatyouneedforthisbook
Whothisbookisfor
Conventions
Readerfeedback
Customersupport
Downloadingtheexamplecode
Errata
Piracy
Questions
1.InstallingaDistributedZabbixSetup
Zabbixarchitectures
UnderstandingZabbixdataflow
UnderstandingtheZabbixproxies’dataflow
InstallingZabbix
Installingfrompackages
SettingupaZabbixagent
CreatingaZabbixagentpackagewithCheckInstall
Serverconfiguration
Installingadatabase
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Consideringthedatabasesize
MySQLpartitioning
InstallingaZabbixproxy
InstallingtheWebGUIinterface
Summary
2.ActiveMonitoringofYourDevices
UnderstandingZabbixhosts
Hostsandhostgroups
Hostinterfaces
Hostinventory
GoingbeyondZabbixagents
Simplechecks
KeepingSNMPsimple
GettingSNMPdataintoZabbix
FindingtherightOIDstomonitor
MappingSNMPOIDstoZabbixitems
Gettingdatatypesright
SNMPtraps
Snmptrapd
TransformingatrapintoaZabbixitem
Gettingnetflowfromthedevicestothemonitoringserver
Receivingnetflowdataonyourserver
MonitoringalogfilewithZabbix
Summary
3.MonitoringYourNetworkServices
MonitoringtheDNS
DNS–responsetime
DNSSEC–monitoringthezonerollover
Apachemonitoring
NTPmonitoring
NTP–whatarewemonitoring?
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Squidmonitoring
Summary
4.DiscoveringYourNetwork
FindinghoststheZabbixway
Definingactionconditions
Choosingactionoperations
Remotecommands
Low-leveldiscovery
Summary
5.VisualizingYourTopologywithMapsandGraphs
Creatingcustomgraphs
Maps–aquicksetupforalargetopology
Maps–automatingtheDOTcreation
DraftingZabbixmapsfromDOT
Puttingeverythingtogetherwithscreens
Summary
A.PartitioningtheZabbixDatabase
MySQLpartitioning
Thepartition_maintenanceprocedure
Thepartition_createprocedure
Thepartition_verifyprocedure
Thepartition_dropprocedure
Thepartition_maintenance_allprocedure
Housekeepingconfiguration
B.CollectingSquidMetrics
Squidmetricscript
Index
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ZabbixNetworkMonitoringEssentialsCopyright©2015PacktPublishing
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Firstpublished:February2015
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PublishedbyPacktPublishingLtd.
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ISBN978-1-78439-976-4
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CreditsAuthors
AndreaDalleVacche
StefanoKewanLee
Reviewers
RaviBhure
NicholasPier
NicolaVolpini
CommissioningEditor
AmarabhaBanerjee
AcquisitionEditor
NikhilKarkal
ContentDevelopmentEditor
SiddheshSalvi
TechnicalEditor
HumeraShaikh
CopyEditor
SarangChari
ProjectCoordinator
KrantiBerde
Proofreaders
SimranBhogal
LindaMorris
Indexer
HemanginiBari
Graphics
DishaHaria
ProductionCoordinator
AparnaBhagat
CoverWork
AparnaBhagat
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AbouttheAuthorsAndreaDalleVaccheisahighlyskilledITprofessionalwithover14yearsofexperienceintheITindustryandbanking.HegraduatedfromUniversitàdegliStudidiFerrarawithaninformationtechnologycertification.ThislaidthetechnologyfoundationthatAndreahasbuiltoneversince.Andreahasacquiredvariousindustry-respectedaccreditations,whichincludeCisco,Oracle,RHCE,ITIL,andofcourse,Zabbix.Throughouthiscareer,hehasworkedinmanylarge-scaleenvironments,ofteninrolesthathavebeenverycomplex,onaconsultantbasis.Thishasfurtherenhancedhisgrowingskillset,addingtohispracticalknowledgebaseandincreasinghisappetitefortheoreticaltechnicalstudying.
Andrea’sloveforZabbixcamefromhistimespentintheOracleworldasadatabaseadministrator/developer.Histimewasspentmainlyonreducingownershipcosts,specializinginmonitoringandautomation.ThisiswherehecameacrossZabbixandtheflexibilityitoffered,bothtechnicallyandadministratively.Withthisasalaunchpad,AndreawasinspiredtodevelopOrabbix,thefirstopensourcesoftwaretomonitorOracle’scompleteintegrationwithZabbix.HehaspublishedanumberofarticlesonZabbix-relatedsoftware,suchasDBforBIX.Hisprojectsarepubliclyavailableathttp://www.smartmarmot.com.Currently,Andreaisworkingasaseniorarchitectforaleadingglobalinvestmentbankinaverydiverseandchallengingenvironment.HedealswithmanyaspectsoftheUnix/Linuxplatformsaswellasmanytypesofthird-partysoftware,whicharestrategicallyalignedtothebank’stechnicalroadmap.Inadditiontothistitle,AndreaDalleVaccheisacoauthorofMasteringZabbix,PacktPublishing.
StefanoKewanLeeisanITconsultantwithmorethan12yearsofexperienceinsystemintegration,security,andadministration.HeisacertifiedZabbixspecialistinlargeenvironmentsholdsaLinuxadministrationcertificationfromtheLPIandaGIACGCFWcertificationfromSANSInstitute.Whenhe’snotbusybreakingwebsites,helivesinthecountrysidewithhistwocatsandtwodogsandpracticesmartialarts.Inadditiontothistitle,StefanoKewanLeeisacoauthorofMasteringZabbix,PacktPublishing.
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AbouttheReviewersRaviBhureisbasicallyanITengineerwithnicheskills,suchasChef,CloudAnsible,SaltStack,Python,Ruby,andShell/Bash.Healsowritescodeforinfrastructure,dailyIToperations,andsoon.Inshort,heisfondofusinghisskillsandknowledgeoffault-tolerantsolutionsfortheday-to-daymaintenanceofmission-criticalproductioninfrastructure.
Ravistartedinteractingwithcomputerssince1996whenhegothisfirstcomputerathome.Thingschangedveryfast,andin1998,heenteredthemagicalworldoftheInternet☺forthefirsttimeever,whichchangedhislife!Hestartedhisowncybercafein1999.In2004,hegothisfirstjobasafieldengineer,hiredtomaintainandsupportVRIUFOsystems.After2years,hemovedtoPuneandworkedwithmanyorganizations,suchasVyomLabs,GlamIndia,Symphony,andDhingana.
Themosthappeningandinterestingfactabouthisdiverseexposureisthatheisfromanartsbackground.Yes,heholdsabachelor’sdegreeinartsfromSRTMUniversity,Nanded,Maharashtra,India.Andweallwillhavetoagreethathehasthearttosolveproblems☺,agreatinspirationforpeoplewhoarenonengineers!
Currently,RaviisassociatedwithOpexSoftwareasaseniorDevOpsengineer.
NicholasPierisanetworkengineerinthemanagedservices/professionalservicesfield.HisexperienceincludesdesigningdatacenternetworkinfrastructureswithvirtualizationandSANsolutions,webdevelopment,andwritingmiddlewareforbusinessapplications.Atthetimeofwritingthis,Nicholasholdsanumberofindustrycertifications,includingtheCiscoCCNP,VMwareVCP5-DCV,andvariousotherCiscoandCompTIAcertifications.Inhisfreetime,heindulgesinhispassionforcraftbeer,distancerunning,andreading.
I’dliketothankPacktPublishingforthisopportunity!
NicolaVolpinihasbeenplayingwithtechnologyfromayoungage,havingahardtimeresistingtheurgetodisassemblecomplextoysorkitchenappliances.
Theloveforcomputersoriginatedaroundhistenthbirthday,whenheaccidentallytoastedhisfirstCPU.Thisepisodeonlyincreasedhisfascinationforcomputers,andtheaccidents,fortunately,stopped.
Forthepast10years,he’sbeenworkingasanITprofessional,specializinginenterprisenetworkingandsystemadministration.ExperimentingwiththemostdiversetechnologiesinthefieldandbeinganavidfanoftheFOSSphilosophy,Linux,and*BSD,hedreamsofseeingthecollaborativethinkingoftheFOSSmovementhelpinspiretheworld.
He’scurrentlyworkingatStockholm,Sweden,whereheresideswithhisgirlfriend.
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PrefaceNetworkadministratorsarefacinganinterestingchallengethesedays.Ontheonehand,computernetworksarenotsomethingnewanymore.Theyhavebeenaroundforquiteawhile:theirphysicalcomponentsandcommunicationprotocolsarefairlywellunderstoodanddon’trepresentabigmysterytoanincreasingnumberofprofessionals.Moreover,networkappliancesaregettingcheaperandeasiertosetup,tothepointthatitdoesn’ttakeacertifiedspecialisttoinstallandconfigureasimplenetworkorconnectittoothernetworks.Theveryconceptofnetworkingissowidespreadandingrainedinhowusersanddevelopersthinkofacomputersystemthatbeingonlineinsomeformisexpectedandtakenforgranted.Inotherwords,acomputernetworkisincreasinglyseenasacommodity.
Ontheotherhand,theverysameforcesthatarecallingforsimpler,easier,accessiblenetworksaretheonesthatareactuallypushingthemtogrowmoreandmorecomplexeveryday.It’samatterofbothquantityandquality.Thenumberofconnecteddevicesonagivennetworkisalmostalwaysconstantlygrowingandsoistheamountofdataexchanged:mediastreams,applicationdata,backups,databasequeries,andreplicationtendtosaturatebandwidthjustasmuchastheyeatupstoragespace.Asforquality,therearedozensofdifferentrequirementsthatfactorinagivennetworksetup:fromhavingtomanagedifferentphysicalmediums(fiber,cable,radio,andsoon),totheneedtoprovidehighperformanceandavailability,bothontheconnectionandontheapplicationlevel;fromtheneedtoincreaseperformanceandreliabilityforgeographicallinks,toprovidingconfidentiality,security,anddataintegrityatalllevels,andthelistgoeson.
Thesetwocontrasting,yetintertwined,tendenciesareforcingnetworkadministratorstodomore(moreservices,moreavailability,andmoreperformance)withless(lessbudget,butalsolessattentionfromthemanagementcomparedtonewer,flashiertechnologies).Now,morethanever,asanetworkadmin,youneedtobeabletokeepaneyeonyournetworkinordertokeepitinahealthystate,butalsotoquicklyidentifyandresolvebottlenecksandoutagesofanykind—orbetteryet,findwaystoanticipateandworkaroundthembeforetheyhappen.You’llalsoneedtointegrateyoursystemswithdifferenttoolsandenvironments(bothlegacyandstrategicones)thatwillbeoutofyourdirectcontrol,suchasassetdatabases,incidentmanagementsystems,accountingandprofilingsystems,andsoon.Evenmoreimportantly,you’llneedtobeabletoshowyourworkandexplainyourneedsinclear,understandabletermstonontechnicalpeople.
Now,ifweweretosaythatZabbixistheperfect,one-size-fits-allsolutiontoallyournetworkmonitoringandmanagementproblems,wewouldclearlybelying.Tothisday,nosuchtoolexistsdespitewhatmanyvendorswantyoutobelieve.Eveniftheyhavemanyfeaturesincommon,whenitcomestomonitoringandcapacitymanagement,everynetworkhasitsownquirks,specialcases,andpeculiarneeds,tothepointthatanytoolhastobecarefullytunedtotheenvironmentorfacetheriskofbecominguselessandneglectedveryquickly.
WhatistrueisthatZabbixisamonitoringsystempowerfulenoughandflexibleenough
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that,withtherightamountofwork,canbecustomizedtomeetyourspecificneeds.Andagain,thoseneedsarenotlimitedtomonitoringandalerting,butalsotoperformanceanalysisandprediction,SLAreporting,andsoon.WhenusingZabbixtomonitoranenvironment,youcancertainlycreateitemsthatrepresentvitalmetricsforthenetworkinordertohaveareal-timepictureofwhat’shappening.However,thosesameitemscanalsoproveveryusefultoanalyzeperformancebottlenecksandtoplannetworkexpansionandevolution.Items,triggers,andactionscanworktogethertoletyoutakeanactiveroleinmonitoringyournetworkandeasilyidentifyandpre-emptcriticaloutages.
Inthisbook,we’llassumethatyoualreadyknowZabbixasageneral-purposemonitoringtool,andthatyoualsousedittoacertainextent.Specifically,wewon’tcovertopicssuchasitem,trigger,oractioncreationandconfigurationwithabasic,step-by-stepapproach.Here,wewanttofocusonafewtopicsthatcouldbeofparticularinterestfornetworkadministrators,andwe’lltrytohelpthemfindtheirownanswerstoreal-worldquestionssuchasthefollowing:
Ihavealargenumberofappliancestomonitorandhavetokeepmonitoringdataavailableforalongtimeduetoregulatoryrequirements.HowdoIinstallandconfigureZabbixsothatitisabletomanageeffectivelythislargeamountofdata?Whatarethebestmetricstocollectinordertobothhaveaneffectivereal-timemonitoringsolutionandleveragehistoricaldatatomakeperformanceanalysisandpredictions?ManyZabbixguidesandtutorialsfocusonusingtheZabbixagent.Theagentiscertainlypowerfulanduseful,buthowdoIleverageinaneffectiveandsecurewaymonitoringprotocolsthatarealreadyavailableonmynetwork,suchasSNMPandnetflow?Loadbalancers,proxies,andwebserverssometimesfallunderagrayareabetweennetworkandapplicationadministration.Ihaveabunchofwebserversandproxiestomonitor.Whatkindofmetricsaremostusefultocheck?Ihaveacomplexnetworkwithhoststhataredeployedanddecommissionedonadailybasis.HowdoIkeepmymonitoringsolutionup-to-datewithoutresortingtolong,error-pronemanualinterventionsasmuchaspossible?NowthatIhavecollectedalargeamountofmonitoringandperformancedata,howcanIanalyzeitandshowtheresultsinameaningfulway?HowdoIputtogetherthegraphsIhaveavailabletoshowhowtheyarerelated?
Inthecourseofthenextfewchapters,we’lltrytoprovidesomepointersonhowtoanswerthosequestions.Wediscussasmanypracticalexamplesandreal-worldapplicationsaswecanaroundthesubjectofnetworkmonitoring,butmorethananything,wewantedtoshowyouhowit’srelativelysimpletoleverageZabbix’spowerandflexibilitytoyourownneeds.
Theaimofthisbookisnottoprovideyouwithasetofprepackagedrecipesandsolutionsthatyoucanapplyuncriticallytoyourownenvironment.Eventhoughweprovidedsomescriptsandcodethataretestedandworking(andhopefullyyou’llfindthemuseful),therealintentionwasalwaystogiveyouadeeperunderstandingofthewayZabbixworksso
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thatyouareabletocreateyourownsolutionstoyourownchallenges.
Wehopewehavesucceededinourgoal,andthatbytheendofthebook,you’llfindyourselfamoreconfidentnetworkadministratorandamoreproficientZabbixuser.Evenifthiswillnotbethecase,wehopeyou’llbeabletofindsomethingusefulinthefollowingchapters:wetouchupondifferentaspectsofZabbixandnetworkmonitoringandalsodiscussacoupleoflessknownfeaturesthatyoumightfindveryinterestingnonetheless.
So,withoutfurtherado,let’sgetstartedwiththeactualcontentwewanttoshowyou.
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WhatthisbookcoversChapter1,InstallingaDistributedZabbixSetup,teachesyouhowtoinstallZabbixinadistributedsetup,withalargeuseofproxies.Thechapterwillguideyouthroughallthepossiblesetupscenarios,showingyouthemaindifferencesbetweentheactiveandpassiveproxysetup.ThischapterwillexplainhowtoprepareandsetupaZabbixinstallation,whichisreadytobegrownwithinyourinfrastructure,readytosupportyou,andmonitoralargeenvironmentorevenaverylargeone.
Chapter2,ActiveMonitoringofYourDevices,offersyouafewveryusefulexamplesofthedifferentmonitoringpossibilitiesZabbixcanachievebyrelyingondifferentmethodsandprotocols.You’llseehowtoqueryyournetworkfromthelinkleveluptoroutingandnetworkflowusingICMP,SNMP,andlog-parsingfacilitiestocollectyourmeasurements.Youwillalsolearnhowtoextractmeaningfulinformationfromthegathereddatausingaggregatedandcalculateditems,andconfiguringcomplextriggersthatwillalertyouaboutrealnetworkissueswhileminimizingsignalnoiseandfalsepositives.
Chapter3,MonitoringYourNetworkServices,takesyouthroughhowtoeffectivelymonitorthemostcriticalnetworkservices,suchasDNS,DHCP,NTP,Apacheproxy/reverseproxies,andproxycacheSquid.Asitiseasytounderstand,allofthemarecriticalserviceswhereasimpleissuecanaffectyournetworksetupandquicklypropagatetheissuetoyourentirenetwork.Youwillunderstandhowtoextractmeaningfulmetricsandusefuldatafromallthelistedservices,beingablethennotonlytomonitortheirownreliability,butalsotoacquireimportantmetricsthatcanhelpyoutopredictfailuresorissues.
Chapter4,DiscoveringYourNetwork,explainshowtodeeplyautomatethemonitoringconfigurationofnetworkobjects.Itwillmassivelyusethebuilt-indiscoveryfeatureinordertokeepthemonitoringsolutionup-to-datewithinanevolvingnetworkenvironment.ThischapterisdividedintotwocorepartsthatcoverthetwomainlevelsofZabbix’sdiscovery:hostdiscoveryandlow-leveldiscovery.
Chapter5,VisualizingYourTopologywithMapsandGraphs,showsyouhowtocreatecomplexgraphsfromyouritem’snumericalvalues,automaticallydrawmapsthatreflectthecurrentstatusofyournetwork,andbringitalltogetherusingscreensasatooltocustomizemonitoringdatapresentation.ThischapteralsopresentsasmartwaytoautomatetheinitialstartupofyourZabbix’ssetup,makingyouabletodrawnetworkdiagramsusingmapsinafullyautomatedway.Youwillthenlearnaproduction-readymethodtomaintainmapswhileyournetworkisgrowingorrapidlychanging.
AppendixA,PartitioningtheZabbixDatabase,containsalltherequiredsoftwareandstoredprocedurestoefficientlypartitionyourZabbixdatabase.
AppendixB,CollectingSquidMetrics,containsthesoftwareusedtomonitorSquid.
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WhatyouneedforthisbookThesoftwarethathasbeenusedandisnecessaryforthisbookis:
LinuxRedHatEnterpriseLinux6.5orhigherZabbix4.2ApacheHTTPD2.2MySQLServer-5.1Netflow1.6.12Nmap
Thisbookalsorequiresanintermediateexperienceinshellscripting,abasic-to-intermediateknowledgeofPython,andanintermediateknowledgeofZabbix.
Anyway,alltheexamplesdiscussedandproposedinthisbookareexplainedwellandcommentedupon.Thesameapproachhasbeenappliedeventothesoftwareusedonthisbookwhereitisexplained,withareasonablelevelofdetail,howtosetupandconfigureeachsoftwarecomponent.
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WhothisbookisforThisbookisintendedforexperiencednetworkadministratorslookingforacomprehensivemonitoringsolutionfortheirnetworks.ThereadermusthaveagoodknowledgeofUnix/Linux,networkingconcepts,protocols,andappliancesandabasic-to-intermediateknowledgeofZabbix.Thereaderwillbeguidedstepbysteptomanageandleadalltheimportantpointsyouwillhavetodealwith.Youwillthenbeabletostartupaneffectiveandlarge-environment-readyZabbixmonitoringsolutionthatwillbeaperfectfitwithinyournetwork.
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ConventionsInthisbook,youwillfindanumberoftextstylesthatdistinguishbetweendifferentkindsofinformation.Herearesomeexamplesofthesestylesandanexplanationoftheirmeaning.
Codewordsintext,databasetablenames,foldernames,filenames,fileextensions,pathnames,dummyURLs,userinput,andTwitterhandlesareshownasfollows:“OntheZabbixserver-side,youneedtocarefullysetthevalueofStartTrappers=.”
Ablockofcodeissetasfollows:
#FirstofallweneedtoimportcsvandNetworkx
importcsv
importnetworkxasnx
#Thenweneedtodefinewhoisourzabbixserverandsomeotherdetailto
properlyproducetheDOTfile
zabbix_service_ipaddr="192.168.1.100"
main_loop_ipaddr="10.12.20.1"
Whenwewishtodrawyourattentiontoaparticularpartofacodeblock,therelevantlinesoritemsaresetinbold:
#wecanopenourCSVfile
csv_reader=csv.DictReader(open('my_export.csv'),\
delimiter=",",\
fieldnames=("ipaddress","hostname","oid","dontcare","neighbors"))
#Skiptheheader
csv_reader.next()
Anycommand-lineinputoroutputiswrittenasfollows:
#chkconfig--level345zabbix-serveron
Newtermsandimportantwordsareshowninbold.Wordsthatyouseeonthescreen,forexample,inmenusordialogboxes,appearinthetextlikethis:“Thereisaclearwarningonthewebsitethatwarnsuswiththisstatement:TheApplianceisnotintendedforseriousproductionuseatthistime.”
NoteWarningsorimportantnotesappearinaboxlikethis.
TipTipsandtricksappearlikethis.
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Tosendusgeneralfeedback,simplye-mail<[email protected]>,andmentionthebook’stitleinthesubjectofyourmessage.
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ErrataAlthoughwehavetakeneverycaretoensuretheaccuracyofourcontent,mistakesdohappen.Ifyoufindamistakeinoneofourbooks—maybeamistakeinthetextorthecode—wewouldbegratefulifyoucouldreportthistous.Bydoingso,youcansaveotherreadersfromfrustrationandhelpusimprovesubsequentversionsofthisbook.Ifyoufindanyerrata,pleasereportthembyvisitinghttp://www.packtpub.com/submit-errata,selectingyourbook,clickingontheErrataSubmissionFormlink,andenteringthedetailsofyourerrata.Onceyourerrataareverified,yoursubmissionwillbeacceptedandtheerratawillbeuploadedtoourwebsiteoraddedtoanylistofexistingerrataundertheErratasectionofthattitle.
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Chapter1.InstallingaDistributedZabbixSetupMostlikely,ifyouarereadingthisbook,youhavealreadyusedandinstalledZabbixasanetworkmonitoringsolution.Now,inthischapter,wewillseehowtoinstallZabbixinadistributedsetup,eventuallymovingontoalargeuseofproxies.Thechapterwilltakeyouthroughallthepossiblescenariosandexplainthemaindifferencesbetweentheactiveandpassiveproxysetup.Usually,thefirstZabbixinstallationisdoneasapartoftheconcepttoseewhethertheplatformisgoodenoughforyou.Here,thecommonerroristostartusingthissetuponalargeproductionenvironment.Afterreadingthischapter,youwillbereadytoinstallandsetupalargeenvironmentreadyinfrastructure.
Inthischapter,wewillexplainhowtoprepareandsetupaZabbixinstallation,whichisreadytobegrownwithinyourinfrastructure,andreadyforalargetoaverylargeenvironment.ThisbookismainlyfocusedonZabbixfornetworkmonitoring.Thischapterwillquicklytakeyouthroughtheinstallationprocess,emphasizingonallthemostimportantpointsyouneedtoconsider.Inthenextchapter,wewillspendmoretimedescribingabetterapproachtomonitoryournetworkdevicesandhowtoretrieveallthecriticalmetricsfromthem.Afterreadingthischapter,youwillbecomeawareofthecommunicationbetweenserverandproxiesbeingabletomixtheactiveandpassivesetupinordertoimproveyourinfrastructure.YoucanextendthestrongcentralZabbixcoresetupwithmanylightweightandeffectiveZabbixproxiesactingasasatelliteinsideyournetworktoimproveyourmonitoringsystem.
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ZabbixarchitecturesZabbixwasbornasadistributednetworkmonitoringtoolwithacentralwebinterfacewhereyoucanmanagealmosteverything.Nowadays,withZabbix2.4,thenumberofpossiblearchitectureshasbeenreducedtoasingleserversetupandaZabbix-proxiesdistributedsetup.
NoteFromZabbix2.4,thenode-setupwasdiscontinued.Moreinformationisavailableathttps://www.zabbix.com/documentation/2.4/manual/introduction/whatsnew240#node-based_distributed_monitoring_removed.
Now,thesimplestarchitecture(whichisreadytohandlelargeenvironmentssuccessfully)thatyoucanimplementcomposesofthreeservers:
WebserverRDBMSserverZabbixserver
Topreparethissimplesetupforalargeenvironmentsetting,it’sbettertouseadedicatedserverforeachoneofthesecomponents.
Thisisthesimplestsetupthatcanbeeasilyextendedandisreadytosupportalargeenvironment.
Theproposedarchitectureisshowninthefollowingdiagram:
ThiskindofsetupcanbeextendedbyaddingmanyZabbixproxiesresultinginaproxy-basedsetup.Theproxy-basedsetupisimplementedwithoneZabbixserverandseveralproxies:oneproxyperbranch,datacenteror,inourcase,foreachremotenetworksegmentyouneedtomonitor.
Thisconfigurationiseasytomaintainandofferstheadvantagetohaveacentralizedmonitoringsolution.Thiskindofconfigurationistherightbalancebetweenlargeenvironmentmonitoringandcomplexity.
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TheZabbixproxy,likeaserver,isusedtocollectdatafromanynumberofhostsordevices,acquiringallthemetricsrequestedandactingasaproxy.Thismeansthatitcanretainthisdataforanarbitraryperiodoftime,relyingonadedicateddatabasetodoso.Theproxydoesn’thaveafrontendandismanageddirectlyfromthecentralserver.
NoteTheproxylimitsitselftodatacollectionwithouttriggerevaluationsoractions;allthedataisstoredinitsdatabase.Forthisreason,it’sbettertouseanefficientrobustRDBMSthatcanpreventdatalossincaseofacrash.
AllthesecharacteristicsmaketheZabbixproxyalightweighttooltodeployandoffloadsomechecksfromthecentralserver.Ourobjectiveistocontrolandstreamlinetheflowofmonitoreddataacrossnetworks,andtheZabbixproxygivesusthepossibilitytosplitandsegregateitemsanddataonthedifferentnetworks.Themostimportantfeatureisthattheacquiredmetricsarestoredinitsdatabase.Therefore,incaseofanetworkloss,youwillnotlosethem.
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UnderstandingZabbixdataflowThestandardZabbixdataflowiscomposedofseveralactorsthatsenddatatoourZabbixserver.OfallthesourcesthatcansenddatatoourZabbixserver,wecanidentifythreemaindatasources:
ZabbixagentZabbixsenderOtheragents(externalscriptsorcomponentsbuiltinhouse)
Theotheragentsrepresentedinthenextdiagramcanbeoftwomaintypes:
Customand/orthird-partyagentsZabbixproxy
Asthediagramdisplaysthedatathatgetsacquiredfrommanydifferentsourcesintheformofitems.Attheendofthediagram,youseetheGUI,whichpracticallyrepresentstheusersconnectedandthedatabasethatistheplacewhereallthevaluesarestored.
Inthenextsection,wewilldivedeepintotheZabbixproxies’dataflow.
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UnderstandingtheZabbixproxies’dataflowZabbixproxiescanoperateintwodifferentmodes,activeandpassive.Thedefaultsetupistheactiveproxy.Inthissetup,theproxyinitiatesallconnectionstotheZabbixserver,theoneusedtoretrieveconfigurationinformationonmonitoredobjects,andtheconnectiontosendmeasurementsbacktotheserver.Here,youcanchangeandtweakthefrequencyofthesetwoactivitiesbysettingthefollowingvariablesintheproxyconfigurationfile:/etc/zabbix/zabbix_proxy.conf:
ConfigFrequency=3600
DataSenderFrequency=1
Valuesareexpressedinseconds.OntheZabbixserver-side,youneedtocarefullysetthevalueofStartTrappers=.
Thisvalueneedstobegreaterthanthenumberofallactiveproxiesandnodesyoudeployed.Thetrapperprocesses,indeed,managealltheincominginformationfromtheproxies.
NotePleasenotethattheserverwillforkextraprocessesasrequired,ifneeded,butitisstronglyadvisabletopreforkalltheprocessesthatareneededduringthestartup.Thiswillreducetheoverheadduringthenormaloperation.
Ontheproxyside,anotherparametertoconsideris:
HeartbeatFrequency
Thisparametersetsasortofkeepalive,whichafterthedefinednumberofseconds,willcontacttheserveralthoughitdoesn’thaveanydatatosend.Theproxyavailabilitycanbeeasilycheckedwiththefollowingitem:
zabbix[proxy,"proxyuniquename",lastaccess]
Heretheproxyuniquename,ofcourse,istheidentifieryouassignedtotheproxyduringdeployment.Theitemwillreturnthenumberofsecondsasthelasttimethattheproxywascontacted,avalueyoucanthenusewiththeappropriatetriggeringfunctions.
TipIt’sreallyimportanttohaveatriggerassociatedtothisitem,soyoucanbewarnedincaseofconnectionloss.Lookingatthetrendofthistrigger,youcanlearnaboutaneventualreapingtimesetonthefirewall.Let’slookatapracticalexample:ifyounoticethatafter5minutesyourconnectionsaredropped,settheheartbeatfrequencyto120secondsandcheckforthelastaccesstimeabove300seconds.
Inthefollowingdiagram,youcanseethecommunicationflowbetweentheZabbixserverandtheproxy:
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Asyoucanseefromthediagram,theserverwillwaittoreceiverequestsfromtheproxyandnothingmore.
NoteTheactiveproxyisthemostefficientwaytooffloaddutiesfromtheserver.Indeed,theserverwilljustsitherewaitingtobeaskedaboutchangesinconfiguration,ortoreceivenewmonitoringdata.
Ontheotherside,proxiesareusuallydeployedtomonitorsecurenetworksegmentswithstrictoutgoingtrafficpolicies,andareusuallyinstalledonDMZs.Inthesekindofscenarios,normally,itisverydifficulttoobtainpermissionfortheproxytoinitiatethecommunicationwiththeserver.Unfortunately,it’snotjustduetopolicies.DMZsareisolatedasmuchaspossiblefrominternalnetworks,astheyneedtobeassecureastheycan.Generally,it’softeneasierandmoreacceptedfromasecuritypointofviewtoinitiateaconnectionfromtheinternalnetworktoaDMZ.Inthiskindofscenario,thepassiveproxyisveryhelpful.Thepassiveproxyisalmostamirroredimageoftheactiveproxysetup,asyoucanseeinthefollowingdiagram:
Withthisconfiguration,theZabbixserverwillcontacttheproxyperiodicallytodelivertheconfigurationchangesandtorequesttheitemvaluestheproxyisholding.
Thisistheproxyconfigurationtoenabletheproxyyouneedtoset:
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ProxyMode=1
Thisparameterspecifiesthepassiveproxy,youdon’tneedtodoanythingelse.Now,ontheserverside,youneedtosetthefollowingparameters:
StartProxyPollers=
Thiswillsetthenumberofprocessesdedicatedtothepassiveproxies
NoteTheStartProxyPollersparametershouldmatchthenumberofpassiveproxiesyouhavedeployed.
ProxyConfigFrequency=
Thisvalueexpressesthefrequencywithwhichtheserversendstheconfigurationtoitsproxy
ProxyDataFrequency=
Thisistheintervalparameterthatexpressesthenumberofsecondsbetweentwoconsecutiverequeststogettheacquiredmetricsfromtheproxy
Theitemusedtocheckapassiveproxy’savailabilityisasfollows:
zabbix[proxy,"proxyuniquename",lastaccess]
Thisisexactlythesameastheactiveone.
Thepassiveproxyenablesustogathermonitoringdatafromotherwiseclosedandlockeddownnetworkswithaslightlyincreasedoverhead.
NoteYoucanmixasmanyactiveandpassiveproxiesasyouwantinyourenvironment.Thisenablesyoutoexpandyourmonitoringsolutiontoreacheachpartofthenetworkandtohandlealargenumberofmonitoredobjects.Thisapproachkeepsthearchitecturesimpleandeasytomanagewithastrongcentralcoreandmanysimple,lightweightsatellites.
Ifyouwouldliketokeeptrackofalltheremainingitemsthattheproxyneedstosend,youcansetuptheproxytorunthisqueryagainstitsdatabase:
SELECT((SELECTMAX(proxy_history.id)FROMproxy_history)-nextid)FROMids
WHEREfield_name='history_lastid'
TipDownloadingtheexamplecode
Youcandownloadtheexamplecodefilesfromyouraccountathttp://www.packtpub.comforallthePacktPublishingbooksyouhavepurchased.Ifyoupurchasedthisbookelsewhere,youcanvisithttp://www.packtpub.com/supportandregistertohavethefilese-maileddirectlytoyou.
ThisquerywillreturnthenumberofitemsthattheproxystillneedstosendtotheZabbix
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server.ConsideringthatyouareusingMySQLasadatabase,youneedtoaddthefollowinguserparameterintheproxyagentconfigurationfile:
UserParameter=zabbix.proxy.items.sync.remaining,mysql-u<yourdbname
here>-p'<yourpasswordhere>'-e'SELECT((SELECTMAX(proxy_history.id)
FROMproxy_history)-nextid)FROMidsWHEREfield_name=history_lastid'2>&1
Now,allyouneedtodoissetanitemontheZabbixserversideandyoucanseehowyourproxyisfreeingitsqueue.
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InstallingZabbixZabbix,likealltheothersoftware,canbeinstalledintwoways:
1. Downloadthelatestsourcecodeandcompileit.2. Installitfrompackages.
Actually,thereisanotherwaytohaveaZabbixserverupandrunning:usingthevirtualappliance.TheZabbixserverappliancewillnotbeconsideredinthisbookasZabbixitselfdefinesthisvirtualapplianceasnotreadyforproductiveenvironments.Thisvirtualapplianceisnotaproductionreadysetupformanyreasons:
Itisamonolithwhereeverythingisinstalledonthesameserver.Thereisnoseparationfromthedatabaselayerandthepresentationlayer.Thismeansthateachoneofthesecomponentscanaffecttheperformanceoftheother.Thereisaclearwarningonthewebsitethatwarnsuswiththisstatement:TheApplianceisnotintendedforseriousproductionuseatthistime.
Ontheotherhand,theinstallationfrompackagesgivesussomebenefits:
ThepackagesmakeiteasytoupgradeandupdateDependenciesareautomaticallysortedout
Thesourcecodecompilationalsogivesussomebenefits:
WecancompileonlytheneededfeaturesWecanbuildtheagentstaticallyanddeployondifferentLinuxflavorsCompletecontrolonupdate
It’squiteusualtohavedifferentversionsofLinux,Unix,andMicrosoftWindowsonalargeenvironment.Thiskindofscenarioisquitediffusedonaheterogeneousinfrastructure,andifweusetheZabbix’sagentdistributionpackageoneachLinuxserver,wewillhavedifferentversionsoftheagentforsure,anddifferentlocationsfortheconfigurationfiles.
Themorethethingsarestandardizedacrossourserver,theeasieritwillbecometomaintainandupgradetheinfrastructure.The--enable-staticoptiongivesusawaytostandardizetheagentacrossdifferentLinuxversionsandrelease,whichisastrongbenefit.Theagent,staticallycompiled,canbeeasilydeployedeverywhereand,forsure,wewillhavethesamelocation(andwecanusethesameconfigurationfileapartfromthenodename)fortheagentandhis/herconfigurationfile.Theonlythingthatmightvaryisthestart/stopscriptandhowtoregisteritontherightinitrunlevel,butatleastthedeploymentwillbestandardized.
ThesamekindofconceptcanbeappliedtothecommercialUnix,bearinginmindtocompileitonthetargetenvironmentsothatthesameagentcanbedeployedondifferentUnixreleasesofthesamevendor.
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InstallingfrompackagesThefirstthingtodotoinstallZabbixfromrepoistoaddtheyumrepositorytoourlist.Thiscanbedonewiththefollowingcommand:
$rpm-Uvhhttp://repo.zabbix.com/zabbix/2.4/rhel/6/x86_64/zabbix-release-
2.4-1.el6.noarch.rpm
Retrievinghttp://repo.zabbix.com/zabbix/2.4/rhel/6/x86_64/zabbix-release-
2.4-1.el6.noarch.rpm
warning:/var/tmp/rpm-tmp.dsDB6k:HeaderV4DSA/SHA1Signature,keyID
79ea5ed4:NOKEY
Preparing…###########################################[100%]
1:zabbix-release###########################################[100%]
Oncethisisdone,wecantakeadvantageofallthebenefitsintroducedbythepackagemanagerandhavethedependenciesautomaticallyresolvedbyyum.
ToinstalltheZabbixserver,yousimplyneedtorun:
$yuminstallzabbix-server-mysqlzabbix-agentzabbix-javagateway
Now,youhaveyourserverreadytostart.Wecan’tstartitnowasweneedtosetupthedatabase,whichwillbedoneinthenextheading,anyway,whatyoucandoissetupthestart/stoprunlevelforourzabbix_serverandzabbix_agentdaemons:
$chkconfig--level345zabbix-serveron
$chkconfig--level345zabbix-agenton
Pleasedoublecheckifthepreviouscommandransuccessfullywiththefollowing:
$chkconfig--list|grepzabbix
zabbix-agent0:off1:off2:off3:on4:on5:on6:off
zabbix-server0:off1:off2:off3:on4:on5:on6:off
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SettingupaZabbixagentNow,asusuallyhappensinalargeserverfarm,itispossiblethatyouhavemanydifferentvariantsofLinux.Here,ifyoucan’tfindthepackageforyourdistribution,youcaneventhinktocompiletheagentfromscratch.Thefollowingarethestepsforthesame:
1. DownloadthesourcecodefromtheZabbixwebsite.2. Unpackthesoftware.3. Satisfyallthesoftwaredependencies,installingalltherelated-develpackages.4. Runthefollowingcommand:$./configure--enable-agent.
TipHere,youcanstaticallylinktheproducedbinarywiththe--enable-staticoption.Withthis,thebinaryproducedwillnotrequireanyexternallibrary.ThisisreallyusefultodistributetheagentacrossdifferentversionsofLinux.
Compileeverythingwith$make.
Now,beforeyourun$makeinstall,youcandecidetocreateyourownpackagetodistributewithCheckInstall.
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CreatingaZabbixagentpackagewithCheckInstallTheadviceistonotrunmakeinstall,butuseCheckInstalltoproducetherequiredpackageforyourLinuxOSfromhttp://asic-linux.com.mx/~izto/checkinstall/.
NoteWecanalsouseaprebuiltCheckInstall;thecurrentreleaseischeckinstall-1.6.2-20.2.i686.rpmonRedHat/CentOS.Thepackagewillalsoneedtherpm-buildpackage:
rpm-buildyuminstall
Also,weneedtocreatethenecessarydirectories:
mkdir-p~/rpmbuild/{BUILD,RPMS,SOURCES,SPECS,SRPMS}
Thissoftwareenablesyoutocreateapackageformanydifferentversionsofthepackagemanager,namely,RPM,deb,andtgz.
NoteCheckInstallwillproducepackagesforDebian,Slackware,andRedHat,helpingustopreparetheZabbix’sagentpackage(staticallylinked)anddistributeitaroundourserver.
Now,weneedtoswitchtotherootaccountusing$sudosu–.Also,usethecheckinstallfollowedbytheseoptions:
$checkinstall--nodoc--install=yes-y
Ifyoudon’tfaceanyissue,youshouldgetthefollowingmessage:
******************************************************************
Done.Thenewpackagehasbeensavedto
/root/rpmbuild/RPMS/i386/zabbix-2.4.0-1.i386.rpm
Youcaninstallitinyoursystemanytimeusing:
rpm-izabbix-2*.4.0-1.i386.rpm
******************************************************************
Rememberthattheserverbinarieswillbeinstalledin<prefix>/sbin,utilitieswillbein<prefix>/bin,andthemainpagesunderthe<prefix>/sharelocation.
TipTospecifyadifferentlocationforZabbixbinaries,weneedtouse--prefixontheconfigureoptions(forexample,--prefix=/opt/zabbix).
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ServerconfigurationFortheserverconfiguration,weonlyhaveonefiletocheckandedit:
/etc/zabbix/zabbix_server.conf
Alltheconfigurationfilesarecontainedinthefollowingdirectory:
/etc/zabbix/
Allyouneedtochangefortheinitialsetupisthe/etc/zabbix/zabbix_server.confconfigurationfileandwritetheusername/passwordanddatabasenamehere.
NotePleasetakecaretoprotecttheaccesstotheconfigurationfilewithchmod400/etc/zabbix/zabbix_server.conf.
Thedefaultexternalscriptslocationis:
/usr/lib/zabbix/externalscripts
Also,thealertscriptdirectoryis:
/usr/lib/zabbix/alertscripts
Thiscanbechangedbyeditingthezabbix_server.conffile.
Theconfigurationontheagentsideisquiteeasy;basically,weneedtowritetheIPaddressofourZabbixserver.
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InstallingadatabaseThedatabasewewilluseonthisbook,asalreadyexplained,isMySQL.
Now,consideringthatyouhaveaRedHatserver,theproceduretoinstallMySQLfromtheRPMrepositoryisquiteeasy:
$yuminstallmysqlmysql-server
Now,youneedtosetuptheMySQLservicetostartautomaticallywhenthesystemboots:
$chkconfig--levels235mysqldon
$/etc/init.d/mysqldstart
TipRemembertosetapasswordfortheMySQLrootuser
Tosetapasswordfortheroot,youcanrunthesetwocommands:
/usr/bin/mysqladmin-urootpassword'new-password'
/usr/bin/mysqladmin-uroot-hhostname-of-your.zabbix.dbpassword'new-
password'
Alternatively,youcanrun:
/usr/bin/mysql_secure_installation
Thiswillalsohelpyoutoremovethetestdatabasesandanonymoususerdatathatwascreatedbydefault.Thisisstronglyrecommendedforproductionservers.
Now,it’stimetocreatetheZabbixdatabase.Forthis,wecanusethefollowingcommands:
$mysql-uroot-p
$mysql>CREATEDATABASEzabbixCHARACTERSETUTF8;
QueryOK,1rowaffected(0.00sec)
$mysql>GRANTALLPRIVILEGESonzabbix.*to'zabbixuser'@'localhost'
IDENTIFIEDBY'zabbixpassword';
QueryOK,0rowsaffected(0.00sec)
$mysql>FLUSHPRIVILEGES;
$mysql>quit
Next,weneedtorestorethedefaultZabbixMySQLdatabasefiles:
$mysql-uzabbixuser-pzabbixpasswordzabbix</usr/share/doc/zabbix-
server-mysql-2.4.0/create/schema.sql
$mysql-uzabbixuser-pzabbixpasswordzabbix</usr/share/doc/zabbix-
server-mysql-2.4.0/create/images.sql
$mysql-uzabbixuser-pzabbixpasswordzabbix</usr/share/doc/zabbix-
server-mysql-2.4.0/create/data.sql
Now,ourdatabaseisready.Beforewebegintoplaywiththedatabase,it’simportanttodosomeconsiderationaboutdatabasesizeandheavytasksagainstit.
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ConsideringthedatabasesizeZabbixusestwomaingroupsoftablestostoreitsdata:
HistoryTrends
Now,thespaceconsumedbythesetablesisinfluencedby:
Items:Thisisthenumberofitemsyou’regoingtoacquireRefreshrate:ThisisthemeanaveragerefreshrateofouritemsSpacetostorevalues:ThisdependsonRDBMS
Thespaceusedtostoredatacanvaryduetothedatabase,butwecanresumethespaceusedbythesetablesinthefollowingtable:
Typeofmeasure Retentionindays Spacerequired
History 30 10.8G
Events 1825(5years) 15.7GB
Trends 1825(5years) 26.7GB
Total NA 53.2GB
Thiscalculationis,ofcourse,doneconsideringtheenvironmentafter5yearsofretention.Anyway,weneedtohaveanenvironmentreadytosurvivethisperiodoftimeandretainthesameshapethatithadwhenitwasinstalled.Wecaneasilychangethehistoryandtrendsretentionpolicyperitem.Thismeansthatwecancreateatemplatewithitemsthathaveadifferenthistoryretentionbydefault.Normally,thehistoryissetto30days,butforsomekindofmeasure(suchasinwebscenarios)orotherparticularmeasures,weneedtokeepallthevaluesformorethanaweek.Thispermitsustochangethisvalueoneachitem.
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MySQLpartitioningNowthatweareawareofhowbigourdatabasewillbe,it’seasytoimaginethathousekeepingwillbeaheavytaskandthetime,CPU,andresourceconsumedbythisonewillgrowtogetherwiththedatabasesize.
Housekeepingisinchargetoremovetheoutdatedmetricsfromthedatabaseandtheinformationdeletedbyauser,andaswe’veseenthehistory,trends,andeventstablesare,aftersometime,hugetables.Thisexplainswhytheprocessissoheavytomanage.
Theonlywaywecanimproveperformancesoncewehavereachedthisvolumeofdataisbyusingpartitioninganddisablingthehousekeeperaltogether.
Partitioningthehistoryandtrendtableswillprovideuswithmanymajorbenefits:
Allhistorydatainatableforaparticulardefinedwindowtimeareself-containedinitsownpartition.Thisallowsyoutoeasilydeleteolddatawithoutimpactingthedatabaseperformance.WhenyouuseMySQLwithInnoDB,andifyoudeletedatacontainedinatable,thespaceisnotreleased.Thespacefreedismarkedasfree,butthediskspaceconsumedwillnotchange.Whenyouusepartition,andifyoudropapartition,thespaceisimmediatelyfreed.Queryperformancecanbeimproveddramaticallyinsomesituations,inparticular,whenthereisheavyaccesstothetable’srowsinasinglepartition.Whenaqueryupdatesahugeamountofdataorneedsaccesstoalargepercentageofthepartition,thesequentialscanisoftenmoreefficientthantheindexusagewitharandomaccessorscatteredreadsagainstthisindex.
Unfortunately,Zabbixisnotabletomanagethepartitions.So,weneedtodisablehousekeeping,anduseanexternalprocesstoaccomplishhousekeeping.
Whatweneedtohaveisastoredprocedurethatdoesalltheworkforus.
Thefollowingisthestoredprocedure:
DELIMITER$$
CREATEPROCEDURE`partition_maintenance`(SCHEMA_NAMEVARCHAR(32),
TABLE_NAMEVARCHAR(32),KEEP_DATA_DAYSINT,HOURLY_INTERVALINT,
CREATE_NEXT_INTERVALSINT)
BEGIN
DECLAREOLDER_THAN_PARTITION_DATEVARCHAR(16);
DECLAREPARTITION_NAMEVARCHAR(16);
DECLARELESS_THAN_TIMESTAMPINT;
DECLARECUR_TIMEINT;
Untilhere,wehavedeclaredthevariableweneedafter.Now,onthenextline,wewillcallthestoredprocedureresponsibletocheckwhetherapartitionisalreadypresentandifnot,wewillcreatethem:
CALLpartition_verify(SCHEMA_NAME,TABLE_NAME,HOURLY_INTERVAL);
SETCUR_TIME=UNIX_TIMESTAMP(DATE_FORMAT(NOW(),'%Y-%m-%d
00:00:00'));
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IFDATE(NOW())='2014-04-01'THEN
SETCUR_TIME=UNIX_TIMESTAMP(DATE_FORMAT(DATE_ADD(NOW(),
INTERVAL1DAY),'%Y-%m-%d00:00:00'));
ENDIF;
SET@__interval=1;
create_loop:LOOP
IF@__interval>CREATE_NEXT_INTERVALSTHEN
LEAVEcreate_loop;
ENDIF;
SETLESS_THAN_TIMESTAMP=CUR_TIME+(HOURLY_INTERVAL*@__interval
*3600);
SETPARTITION_NAME=FROM_UNIXTIME(CUR_TIME+HOURLY_INTERVAL*
(@__interval-1)*3600,'p%Y%m%d%H00');
Nowthatwehavecalculatedalltheparametersneededbythecreate_partitionprocedure,wecanrunit.Thisstoredprocedurewillcreatethenewpartitiononthedefinedschema:
CALLpartition_create(SCHEMA_NAME,TABLE_NAME,
PARTITION_NAME,LESS_THAN_TIMESTAMP);
SET@__interval=@__interval+1;
ENDLOOP;
SETOLDER_THAN_PARTITION_DATE=DATE_FORMAT(DATE_SUB(NOW(),INTERVAL
KEEP_DATA_DAYSDAY),'%Y%m%d0000');
Thesectionthatfollowsisresponsibletoremovetheolderpartitions,usingtheOLDER_TAN_PARTITION_DATEprocedure,whichwehavecalculatedonthelinesbefore:
CALLpartition_drop(SCHEMA_NAME,TABLE_NAME,
OLDER_THAN_PARTITION_DATE);
END$$
DELIMITER;
Thisstoredprocedurewillbethecoreofourhousekeeping.Itwillbecalledwiththefollowingsyntax:
CALLpartition_maintenance('<zabbix_db_name>','<table_name>',
<days_to_keep_data>,<hourly_interval>,<num_future_intervals_to_create>)
Theprocedureworksbasedon1hourintervals.Next,ifyouwanttopartitiononadailybasis,theintervalwillbe24hours.Instead,ifyouwant1hourpartitioning,theintervalwillbe1.
Youneedtospecifythenumberofintervalsthatyouwantcreatedinadvance.Forexample,ifyouwant2weeksintervaloffuturepartitions,use14.Ifyourintervalis1(forhourlypartitioning),thenthenumberofintervalstocreateis336(24*14).
Thisstoredprocedureusessomeotherstoresprocedures:
partition_create:Thiscreatesthepartitionforthespecifiedtablepartition_verify:Thischeckswhetherthepartitionisenabledonatable,ifnot,thencreateasinglepartitionpartition_drop:Thisdropspartitionsolderthanatimestamp
Forallthedetailsaboutthesestoredprocedures,seeAppendixA,PartitioningtheZabbix
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Database.
Onceyou’vecreatedalltherequiredstoredprocedures,youneedtochangetwoindexestoenabletheminordertobereadyforapartitionedtable:
mysql>Altertablehistory_textdropprimarykey,addindex(id),drop
indexhistory_text_2,addindexhistory_text_2(itemid,id);
QueryOK,0rowsaffected(0.49sec)
Records:0Duplicates:0Warnings:0
mysql>Altertablehistory_logdropprimarykey,addindex(id),dropindex
history_log_2,addindexhistory_log_2(itemid,id);
QueryOK,0rowsaffected(2.71sec)
Records:0Duplicates:0Warnings:0
Oncethisisdone,youneedtoschedulethepartition_maintenance_allstoredprocedurewithacronjob.Formoredetailsaboutthepartition_maintenance_allprocedure,pleasechecktheinstructionscontainedinAppendixA,PartitioningtheZabbixDatabase.Thecronjobneedstoexecutethefollowingcommand:
mysql-h<zabbix_db_host>-u<zabbixuser>-p<zabbixpassword>zabbixdatabase
-e"CALLpartition_maintenance_all('zabbix');"
Oncethishasbeenset,youneedtobearinmindtodisablethehousekeepingforhistoryandtrends.VerifythattheOverrideitem<trend/history>periodZabbixconfigurationischeckedforbothhistoryandtrends.Here,youneedtosettheDatastorageperiod(indays)boxforhistoryandtrendstothevalueyou’vedefinedinyourprocedure,ourexampleinAppendixA,PartitioningtheZabbixDatabaseisof28and730.
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InstallingaZabbixproxyInstallationoftheZabbixproxyfrompackagesisaquitesimpletask.Onceyou’veaddedtheZabbixrepository,youonlyneedtorunthefollowingcommand:
$yuminstallzabbix-proxy-mysql
Thiswillinstalltherequiredpackages:
Installation:
zabbix-proxy-mysqlx86_642.4.0-1.el6zabbix390k
Installingfordependencies:
zabbix-proxyx86_642.4.0-1.el6zabbix21k
TheZabbixproxyinstallationisquitesimilartotheserverone.Onceyou’veinstalledtheserver,youneedtoinstallMySQL,createthedatabase,andimporttheDBschema:
$mysql-uroot-p
$mysql>CREATEDATABASEzabbixCHARACTERSETUTF8;
QueryOK,1rowaffected(0.00sec)
$mysql>GRANTALLPRIVILEGESonzabbix.*to'zabbixuser'@'localhost'
IDENTIFIEDBY'zabbixpassword';
QueryOK,0rowsaffected(0.00sec)
$mysql>FLUSHPRIVILEGES;
$mysql>quit
Next,weneedtorestorethedefaultZabbixMySQLdatabasefiles:
$mysql-uzabbixuser-pzabbixpasswordzabbix</usr/share/doc/zabbix-
proxy-mysql-2.4.0/create/schema.sql
Now,weneedtostartthedatabase,configuretheproxy,andstarttheservice.Inthisexample,wehaveconsideredtouseaZabbixproxythatreliesonaMySQLwithInnoDBdatabase.Thisproxycanbeperformedintwodifferentways:
Lightweight(andthenuseSQLite3)Robustandsolid(andthenuseMySQL)
Here,wehavechosenthesecondoption.Inalargenetworkenvironmentwheretheproxy,incaseofissue,needstopreserveallthemetricsacquireduntiltheserveracquiresthemetrics,it’sbettertoreduce,attheminimum,theriskofdataloss.Also,ifyouconsiderthisscenarioinalargenetworkenvironment,youmostlikelywillhavethousandsofsubnetworksconnectedtotheZabbixserverwithallthepossiblenetworkdevicesin-between.Well,exactly,thisisnecessarytouseadatabasethatcanpreventanydatacorruptions.
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InstallingtheWebGUIinterfaceTheWebGUIinterfacewillbedoneoncemoreusingtheRPMs.
Toinstallthewebinterface,youneedtorunthefollowingcommand:
$yuminstallzabbix-web-mysql
Yumwilltakecaretoresolveallthedependencies.Onceyou’redone,theprocessofthiscomponentisquiteeasy:weneedtoopenawebbrowser,pointatthefollowingURL:http://your-web-server/zabbix,andfollowtheinstructions.
OnthestandardRedHatsystem,yousimplyneedtochangetheseparametersonyour/etc/php.inifile:
php_valuemax_execution_time300
php_valuememory_limit128M
php_valuepost_max_size16M
php_valueupload_max_filesize2M
php_valuemax_input_time300
Also,setyourtimezoneonthesamefile(forexample,php_valuedate.timezoneEurope/Rome).
Now,it’stimetostartupApache,butbeforethis,weneedtocheckwhetherwehaveSELinuxenabledandonwhichmode?TocheckyourSELinuxstatus,youcanrun:
#sestatus
SELinuxstatus:enabled
SELinuxfsmount:/selinux
Currentmode:permissive
Modefromconfigfile:permissive
Policyversion:24
Policyfromconfigfile:targeted
Now,youneedtocheckwhetheryouhavethehttpddaemonenabledtousethenetworkwiththefollowingcommand:
#getseboolhttpd_can_network_connect
httpd_can_network_connect-->off
Mostlikely,youwillhavethesamekindofresult,thenallweneedtodoisenablethehttpd_can_network_connectoptionusingthenextcommandwith–Ptopreservethevalueafterareboot:
#setsebool–Phttpd_can_network_connecton
#getseboolhttpd_can_network_connect
httpd_can_network_connect-->on
Now,allthatwestillhavetodoisenablethehttpddaemonandstartourhttpdserver:
#servicehttpdstart
Startinghttpd:[OK]
Next,enablethehttpdserverasaservice:
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#chkconfighttpdon
Wecancheckthechangedonewiththenextcommand:
#chkconfig--listhttpd
httpd0:off1:off2:on3:on4:on5:on6:off
Onceyou’vedonethis,youonlyneedtofollowthewizard,andinafewclicks,youwillhaveyourwebinterfacereadytostartup.
TipIfyouknowthattheloadagainstthewebserverwillbehigh,duetoahighnumberofaccountsthatwillaccessit,probably,it’sbettertoconsiderusingNginx.
Now,youcanfinallystartyourZabbixserverandthefirstentryinthe/var/log/zabbix/zabbix_server.logfilewilllooksomethinglikethefollowingcode:
37909:20140925:091128.868StartingZabbixServer.Zabbix2.4.0(revision
48953).
37909:20140925:091128.868******Enabledfeatures******
37909:20140925:091128.868SNMPmonitoring:YES
37909:20140925:091128.868IPMImonitoring:YES
37909:20140925:091128.868WEBmonitoring:YES
37909:20140925:091128.868VMwaremonitoring:YES
37909:20140925:091128.868Jabbernotifications:YES
37909:20140925:091128.868EzTextingnotifications:YES
37909:20140925:091128.868ODBC:YES
37909:20140925:091128.868SSH2support:YES
37909:20140925:091128.868IPv6support:YES
37909:20140925:091128.868******************************
37909:20140925:091128.868usingconfigurationfile:
/etc/zabbix/zabbix_server.conf******************************
Next,youcanstarttoimplementandacquirealltheitemscriticalforyournetwork.
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SummaryInthischapter,wecoveredalargenumberofcomponents.Westartedwithdefiningwhatalargeenvironmentis.Wealsosawhowthenetworksetupcanbedesignedandhowitcanevolvewithinyourinfrastructure.Wesawtheheaviesttaskontheserverside(housekeeping)andhowtoavoidperformancedegradationduetothis.WediscussedMySQLpartitioningin-depth.Wealsobrieflydiscussedthedifferencesbetweenactiveandpassiveproxies;youwillnowbeabletodecidehowtosetthemupandwhichonetochooseonceyouknowyournetworktopology.Also,wesawhowtoacquiresomecriticalmetricstomonitortheZabbixproxyconnectionandtheamountofitemsthatitstillneedstosendus.
Asyoucansee,wecoveredalotofargumentsinjustonechapter;wedidthisbecausewewouldliketousemorespaceintheupcomingchapters.Inthenextchapter,wewillexplorethedifferentappliancesandprotocolsatlayer2andlayer3oftheISO/OSIstack.Also,youwillseehowtobestextrapolatemeaningfulmonitoringdatafromthecollectedmeasurefortheprotocollayers2and3.
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Chapter2.ActiveMonitoringofYourDevicesNowthatyouhaveaworkingZabbixsetup,it’stimetotakealookatyournetworkandfigureoutthecomponentsthatyouwanttomonitor,thekindofdatayouwanttocollect,andtheconditionsunderwhichyouwanttobenotifiedaboutproblemsandstatechanges.
Itwouldbeimpossibleforanybookonthistopictofullycoverallthedifferentkindsofnetworkappliancesandtopologiesandallthedifferentmonitoringscenariosthatanetworkadministratormightneedaseveryenvironmenthasitsownspecificquirksthatagoodmonitoringsolutionhastoaccountfor.ThischapterwillofferyouafewexamplesofthedifferentmonitoringpossibilitiesZabbixcanachievebyrelyingondifferentmethodsandprotocols.You’llseehowtoqueryyournetworkfromthedatalinklayeruptoroutingandnetworkflowusingICMP,SNMP,andlogparsingfacilitiestocollectyourmeasurements.
You’lllearnhowtoextractmeaningfulinformationfromthedatayougatheredusingaggregatedandcalculateditemsandhowtoconfigurecomplextriggersthatwillalertyouaboutrealnetworkissueswhileminimizinguninterestingornonrelevantdata.
Bytheendofthechapter,you’llhaveagoodoverviewofZabbix’snetworkmonitoringpossibilities,andyou’llbereadytoadaptwhatyoulearnedforyourspecificrequirements.Butlet’sfirsthaveaquickoverviewofhowZabbixorganizesmonitoringdatawithhosts,templates,items,andtriggers.
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UnderstandingZabbixhostsOneofZabbix’sgreatstrengthsisitsflexibilitywhenitcomestoorganizingmonitoringdata.Evenwithoutconsideringitspowerfultemplatinganddiscoveryfeatures,whichwillbecoveredinChapter4,DiscoveringYourNetwork,thereisalotthatyoucandowithstandardhosts,items,andtriggers.Hereareafewtipsonhowyoucanusethemeffectively.
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HostsandhostgroupsZabbixhostsusuallyrepresentasingle,specificboxorapplianceinyournetwork.Theycanalsobeapartofoneormorehostgroups.
HostgroupsareveryusefulastheymakeiteasytonavigateZabbix’sinterface,separatinghostsintocategoriesandallowingyoutoorganizeandmanageahugeamountofapplianceswithouthavingtodealwithimpossiblylonglistsofhostnames.Thesamehostcanbepartofdifferenthostgroups,andthiscanbeveryusefulasyoumightwant,forexample,tohaveagroupforallyourrouters,agroupforallyourswitches,andagroupforeverysubnetyoumanage.So,asinglerouterwillbepartoftheroutersgroupandallthesubnetgroupsithasaninterfaceon,whileaswitchwillbepartoftheswitchesgroupandofthesubnetit’spartof,andsoon.
Whilethisiscertainlyagoodwaytoorganizeyourhosts,bothtovisualizeandtomanageyourmonitoringdata,thereareacoupleofnot-too-obviouspitfallsyoushouldbeawareofifyoudecidetoputthesamehostinmultiplegroups:
Calculateditemsshowaggregatemonitoringdatabasedonhostgroupmembership.Ifyouconfigureanaggregateditemthatusesmorethanonecalculateditemfromdifferenthostgroups,youcanendupusingthesamehost’sdatamorethanonce,introducingasignificanterrorinyourcalculations.Actionsareusuallyfilteredbasedonhostgroups.Thismeansthatthesametriggereventcouldfireupmorethanoneactionifthehostispartofmorethanonehostgroup,leadingtopotentiallyduplicatemessagesandalerts.Useraccesspermissionsarehost-group-based.Thismeansthatsomeuserscouldbeabletoseemorehostsandmonitoringdatathantheyactuallyneedtoifahostendsupinahostgrouptheyhaveaccessto.
Thisisbynomeansanattempttodiscouragethepracticeofassigningmultiplehostgroupstothesamehost.Justbeawareoftheramificationsofsuchapracticeanddon’tforgettotakeintoconsiderationtheaddedcomplexitywhenyouconfigureyouritems,actions,andaccesspermissions.
HostinterfacesEachhostiscomposedofacollectionofitemsthatrepresenttherawmonitoringdata,andtriggers,whichrepresentZabbix’smonitoringintelligencebasedonthedatagathered.It’salsocomposedofaseriesofinterfacesthattelltheZabbixserverorproxyhowtocontactthehosttocollecttheaforesaidmonitoringdata.Mostnetworkapplianceshavemorethanoneinterface,soyouwouldwanttomakesurethatallhoststhatrepresentrouters,firewalls,proxies,gateways,andwhatnot,arelistingallthoseappliances’interfacesandtheiraddresses.Theadvantagesareobvious:
You’llbeabletoquicklyreviewwhataddressesareconfiguredonaspecifichostwhilelookingatmonitoringdataYou’llbeabletodifferentiateyourchecksbyqueryingdifferentaddressesorportsofthesamehostbasedonyourneeds
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Yourmapsandtopologieswillbemoreconsistentwithwhat’sactuallydeployed
Addinginterfacestoahostisfairlystraightforward.AllyouneedtodoisnavigatetoConfiguration|Hostsandthenselectthehostyouwanttoedit.Theinterfacessectionisinthemainconfigurationtab,asshowninthefollowingscreenshot:
Asyoucanseeintheaboveexample,therearethreeagentinterfacesthatshowallthenetworkstherouterisconnectedtoandjustoneSNMPinterface.AgentinterfacesareusednotonlyforZabbixagentitems,butalsoforsimpleandexternalchecks.Ontheotherhand,you’lluseSNMPinterfacestosendSNMPqueriestoyourhost.Theprecedingexampleassumesthatyou’llonlyuseSNMPontherouter’sinterfacethatisconnectedtoamanagementnetwork(192.168.1.0inthisexample),whileyou’llalsouseICMP,TCP,andexternalchecksonitstwoproductioninterfaces.Ofcourse,youarefreetoconfiguredifferentIPaddressesforAgentandSNMPinterfacesdependingonwhatprotocolsandchecksyouplantoactivateonwhichinterfaces.
HostinventoryHavinginventorydatadirectlyavailableinyourmonitoringsolutionhasalotofobviousadvantageswhenitcomestoattachingusefulinformationtoyouralertsandalarms.Unfortunately,themorehostsyouhavetomanage,themoreessentialitistohaveup-to-dateinventoryinformation,andtheharderitistomaintaintheaforesaidinformationinareliableandtimelymanner.Manuallyupdatingahost’sinventorydatacanquicklybecomeanimpossibletaskwhenyouhavetensorhundredsofhoststomanage,andit’snotalwayspossibletowriteautomatedscriptsthatwilldothejobforyou.Fortunately,Zabbixoffers
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anautomaticinventoryfeaturethatcanatleastpartiallyfillininventorydatabasedonactualmonitoringdata.Toactivatethisfeature,firstyou’llneedtoselectAutomaticintheHostinventorytabofahostconfigurationpageandthenmovetotheitemsthatyou’llusetopopulatetheinventorydata.
Whenconfiguringanitem,youshouldassignitsdatatoaspecificinventoryfieldsothattheaforesaidfield’svaluewillbesetandautomaticallyupdatedbasedontheitem’smeasurements,asshowninthefollowingscreenshot:
Asyoucanseeintheprecedingexample,ahost’slocationinventoryvaluewillbepopulatedbasedonthecorrespondingSNMPquery.Thismeansthatifyouchangeadevice’slocationinformation,thatchangewillbereflectedinZabbixassoonastheitem’svalueispolledonthedevice.Dependingonthedataavailableonthedevice,you’llbeabletopopulateonlyafewinventoryfieldsormostofthem,whilefallingbackonmanualupdatesofthefieldsthatfalloutsideofyourdevice’sreportingpossibilities.
Speakingofitems,let’snowfocusonthedifferentmonitoringpossibilitiesthatZabbixitemsofferandhowtoapplythemtoyourenvironment.
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GoingbeyondZabbixagentsTherearecertainlymanyadvantagesinusingZabbix’sownagentsandprotocolwhenitcomestomonitoringWindowsandUnixoperatingsystemsortheapplicationsthatrunonthem.However,whenitcomestonetworkmonitoring,thevastmajorityofmonitoredobjectsarenetworkappliancesofvariouskinds,whereit’softenimpossibletoinstallandrunadedicatedagentofanytype.Thisbynomeansimpliesthatyou’llbeunabletofullyleverageZabbix’spowertomonitoryournetwork.Whetherit’sasimpleICMPechorequest,anSNMPquery,anSNMPtrap,netflowlogging,oracustomscript,therearemanypossibilitiestoextractmeaningfuldatafromyournetwork.Thissectionwillshowyouhowtosetupthesedifferentmethodsofgatheringdata,andgiveyouafewexamplesonhowtousethem.
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SimplechecksLet’sstartwiththesimplestcase.Atfirstglance,simplechecksdon’tlookthatinteresting:excludingalltheVMwareHypervisorchecksthatareincludedinthiscategory,simplechecksarereducedtoacoupleofgenericTCP/IPconnectionchecksandthreeICMPechochecks,asfollows:
Checkname Description
Icmpping Thisreturns1ifthehostrespondstoanICMPping;0otherwise
Icmppingloss ThisreturnsthepercentageoflostICMPpingpackets
Icmppingsec ThisreturnstheICMPresponsetimeinseconds
Net.tcp.service Thisreturns1ifthehostacceptsconnectionsonaspecifiedTCPport;0otherwise
Net.tcp.service.perf ThisreturnsthenumberofsecondsspenttoobtainaconnectiononaspecifiedTCPport
Generallyspeaking,thesechecksprovemoreusefulasthedistancebetweenthemonitoringprobeandthemonitoredhostincreases,bothintermsofphysicaldistance(ageographicallinktoanothercityforexample)andintermsofhopsapackethastogothrough.Thismeansthatifyouareinterestedinyournetwork’sperformance,itwouldmakesensetoassignhostswithsimplecheckstoZabbixproxiesthatarenotinthesamesubnet,butaresituatedwheretheywillmimicascloselyaspossibleyouractualnetworktraffic.Net.tcp.serviceisparticularlyusefulfromthispointofview,notjusttocheckthestatusoftheavailabilityofspecificserviceswhenyoucannotuseZabbixagents,butalsotocheckgeneralhostavailabilityacrossrestrictivefirewallsthatblockICMPtraffic.
TipInordertoreducenetworktrafficandtomakemoreefficientICMPchecks,Zabbixusesfpinginsteadoftheregularpingwhenexecutingicmpping,icmppingloss,andicmppingsecitemchecks.
MakesureyouhavefpinginstalledonyourZabbixserverandalsoonalltheZabbixproxiesthatmightneedit.Ifyoudon’thaveit,asimpleyuminstallfpingwillusuallybeenoughfortheZabbixdaemonstofinditanduseit.
Whilebothnet.tcp.serviceandnet.tcp.service.perfdosupportsomewell-knownprotocols,suchasSSH,FTP,HTTP,andsoon,thesetwoitems’mostusefuloptionisprobablytheonethatallowsyoutoperformasimpleTCPhandshakeconnectionandcheckwhetheraspecificIPisreachableonaspecificport.Thesekindofchecksareusefulbecause,justlikeICMPpings,theywillmostlyinvolvethenetworkstack,reducingapplicationoverheadtoaminimum,thusgivingyoudatathatmorecloselymatchesyouractualnetworkperformance.Ontheotherhand,unlikeICMPpings,theywillallowyoutocheckforTCPportavailabilityforagivenhost.Obvioususecasesincludemakinglightweightservicechecksthatwillnotimpactverybusyhostsorappliancestoomuch,
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andmakingsurethatagivenfirewallisallowingtrafficthrough.
Aslightlylessobvioususecaseisusingoneormorenet.tcp.serviceitemstomakesurethatsomeservicesarenotrunningonagiveninterface.Takeforexample,thecaseofaborderrouterorfirewall.Unlessyouhavesomeveryspecialandspecificneeds,you’lltypicallywanttomakesurethatnoadminconsolesareavailableontheexternalinterfaces.Youmighthavedouble-checkedtheappliance’sinitialconfiguration,butasystemupdate,acarelessadmin,orasecuritybugmightchangetheaforesaidconfigurationandopenyourappliance’sadmininterfacestoafarwideraudiencethanintended.AsecuritybreachlikethisonecouldpassunobservedforalongtimeunlessyouconfigureafewsimpleTCP/IPchecksonyourappliance’sexternalinterfacesandthensetupsometriggersthatwillreportaproblemifthosechecksreportanopenandresponsiveport.
Let’staketheexampleoftherouterwithtwoproductioninterfacesandamanagementinterfaceshowninthesectionabouthostinterfaces.Iftherouter’sHTTPSadminconsoleisavailableonTCPport8000,you’llwanttoconfigureasimplecheckitemforeveryinterface:
Itemname Itemkey
management_https_console net.tcp.service[https,192.168.1.254,8000]
zoneA_https_console net.tcp.service[https,10.10.1.254,8000]
zoneB_https_console net.tcp.service[https,172.16.7.254,8000]
Allthesecheckswillreturn1iftheserviceisavailable,and0iftheserviceisnotavailable.Whatchangesishowyouimplementthetriggersontheseitems.Forthemanagementitem,you’llhaveaproblemiftheserviceisnotavailable,whilefortheothertwo,you’llhaveaproblemiftheserviceisindeedavailable,asshowninthefollowingtable:
Triggername Triggerexpression
Managementconsoledown {it-1759-r1:net.tcp.service[http,192.168.1.254,8000].last()}=0
ConsoleavailablefromzoneA {it-1759-r1:net.tcp.service[http,10.10.1.254,8000].last()}=1
ConsoleavailablefromzoneB {it-1759-r1:net.tcp.service[http,172.16.7.254,8000].last()}=1
Thisway,you’llalwaysbeabletomakesurethatyourdevice’sconfigurationwhenitcomestoopenorclosedportswillalwaysmatchyourexpectedsetupandbenotifiedwhenitdivergesfromthestandardyouset.
Tosummarize,simplechecksaregreatforallcaseswhereyoudon’tneedcomplexmonitoringdatafromyournetworkastheyarequitefastandlightweight.Forthesamereason,theycouldbethepreferredsolutionifyouhavetomonitoravailabilityforhundredstothousandsofhostsastheywillimpartarelativelylowoverheadonyour
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overallnetworktraffic.
Whenyoudoneedmorestructureandmoredetailinyourmonitoringdata,it’stimetomovetothebreadandbutterofallnetworkmonitoringsolutions:SNMP.
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KeepingSNMPsimpleTheSimpleNetworkMonitoringProtocol(SNMP)isanexcellent,generalpurposeprotocolthathasbecomewidelyusedbeyonditsoriginalpurpose.Whenitcomestonetworkmonitoringthough,it’salsooftentheonlyprotocolsupportedbymanyappliances,soit’softenaforced,albeitnaturalandsensible,choicetointegrateitintoyourmonitoringscenarios.Asanetworkadministrator,youprobablyalreadyknowallthereistoknowaboutSNMPandhowitworks,solet’sfocusonhowit’sintegratedintoZabbixandwhatyoucandowithit.
Firstofall,we’llneedtotalkaboutSNMPgetsandSNMPtrapsintwodifferentdiscussionsastheyareimplementedandusedindifferentwaysbyZabbix.ThereasonforthisseparationisintheverynatureofSNMPgetsasopposedtoSNMPtraps.AnSNMPgetrepresentsasingle,discretepieceofinformationthatrepresentsthecurrentstatusofametric,andit’snottiedtoanyspecificevent.Whetherit’sacounterwiththetotalnumberofbytesthatpassedthroughaninterface,aBooleanvaluethatwilltellifalinkisupordown,orastringwithanappliance’slocationorcontactinformation,anSNMPvaluewillbeavailableatanymoment,anditwillbepossibletopollitwithanarbitraryfrequency.
ThismapsnicelytoZabbixitems.JustlikeSNMPgetvalues,theyalsorepresentsingle,discretevaluesthatcanbepolledwitharbitraryfrequency.ThismakesitreallystraightforwardtouseregularSNMPqueriestopopulateZabbixitemssincetheonlythingsyouhavetoworryaboutaretheSNMPOID,thedatatype,andthecommunitystringorauthenticationinformation.We’llseeafewexamplesinthenextparagraph.
AnSNMPtraprepresentsaspecificeventthathappensataspecificpointintime.Itmightrepresentalinkstatechange,arebootevent,orauserlogin.Inanycase,youcannotquerythestateofanSNMPtrap;youjusthavetowaittoreceiveone,anditwillnotrepresentasingle,discretevaluebutachangefromonevaluetoanother.Theyresemble,inmanyways,Zabbixeventsinsteadofrawdata.ThiscomplicatesthingsalittlesinceZabbixeventsaretheresultofevaluatingtriggersagainstcollecteddata,whileSNMPtrapscanonlyenterZabbixasitemvalues,thatis,ascollecteddata.Sowe’llneedtoresolvethisapparentmismatchinordertofullyleveragetheinformationcontainedinSNMPtraps.We’llseehowinashortwhile,butfirstlet’slookatafewdetailsconcerningregularSNMPqueriesexecutedfromZabbix.
GettingSNMPdataintoZabbixAZabbixserverusuallycomeswithgoodSNMPsupportoutofthebox.Notonlydoesitsupportthequeryingprotocolnatively,butitalsocomesequippedwithanumberofSNMPtemplatesthatcangetyoustartedintherightdirection.ThismeansthatformostdevicesyouonlyhavetolinktheTemplateSNMPDevicetemplate,andyou’llimmediatelybeabletogetsomebasicinformationaboutit,asshowninthefollowingscreenshot:
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We’vealreadyseenhowtheDevicelocationitemcanbeusedtopopulateahost’sinventorylocationrecord,butthereareacoupleofotherusefulbitsofinformationintheabovepicture.
Firstofall,there’salow-leveldiscoveryruletoexplore.We’lldelvemoredeeplyintodiscoveryrulesinChapter4,DiscoveringYourNetwork,butfornow,we’lljustseethatit’saboutdynamicallycreatingnetworkinterfaceitems:
Foreveryinterface,eightitemswillbecreated,includingtheinterfacename,operationalstatus,incomingandoutgoingtraffic,andsoon.Thismeansthatthesametemplatewillbeusefulforthebasicmonitoringofnetworkapplianceswithanynumberofnetworkinterfaces.
Thesecondthingtonotice,lookingatbothimages,istheupdateinterval,andhistoryandtrendretentionperiodsfortheitems.Zabbixtriestosetsomesensibledefaults,butyou’llprobablyneedtoupdatesomeofthosevaluesbasedonthenumberofmonitoredhostsyouhaveinyourenvironment,yourstoragespaceavailability,andthenetworkloadofyourmonitoringtraffic.
NoteAnotherparameterthatisrelatedtoZabbix’sperformanceistheinitial(andminimum)numberofpollersthattheserverkeepsactiveatanygiventime.Ifyoufindthatyourpollingqueueisgettinglonger,youmightwanttoincreasethenumberofpollersinzabbix_server.conf.Theavailabledefaultoptionsare:
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#StartPollers=5
#StartIPMIPollers=0
#StartPollersUnreachable=1
#StartTrappers=5
#StartPingers=1
#StartDiscoverers=1
#StartHTTPPollers=1
Workyourwayupslowly,oryou’lljustendupwithunnecessaryprocessesbeingcreatedwhenZabbixisstarted.
Ifyouhavehundredsofhoststomonitor,andforeveryhost,youcollecttensofsinglemeasurementseveryminute,youwouldreachapointwhereyourZabbixserver’snetworkloadorCPUloadwillstarttoimpactontheserver’sperformance,leadingtodelaysinitempollingordroppedconnections.Ifyoucannotjustupgradetomorepowerfulhardware,youmighthavetotweakthepollingintervalofyourtemplatessothattheystrikeagoodbalancebetweengranularityofdetailandperformance.
Adevice’sname,contactdetails,description,location,andsuchlike,willrarelychangeoncethedevicehasbeendeployed,soitwouldbeawastetopollforthosevalueseveryhour(3,600seconds).Bychangingtheintervalto6hoursorevenaday,you’llautomaticallyreduceyournetworktrafficrelatedtoessentiallyfixedinformationbyafactorof6,upto24.
Raisingthepollingintervalforsomeoftheinterfacecounterscanhaveanevenmoredramaticimpactonyoursystemandnetworkload.Whileyou’llprobablywanttochecktheadminandoperationalstatusofaninterfaceasoftenaspossible—otherwiseyouruntheriskofnotgettingnotifiedaboutpossibleproblemsinatimelymanner—ontheotherhand,you’llprobablybeabletolivewithpollingincomingandoutgoingtrafficanderrorseveryfiveminutes(300seconds)insteadofeveryminute.Yourgraphswillstillbeverydetailed,butyournetworkwillbemuchlessfloodedwithSNMPrequests.Keepinmindthatchangeslikethesemightnotseemmuchwhenreferredtoasinglehost,butasthenumberofyourmonitoredobjectsgrow,youcanveryquicklyrunuptohundredsoreventhousandsofnewmonitoringvaluespersecondcomingintoyourZabbixserver.
Thesamecanbesaidwhenitcomestoretentionperiodsandstoragespace.Inthiscase,keepinmindthattrendsstoreaboutthreevaluesperhour(min,maxandaverage)overthetimerangespecified,whilehistorystoresallvaluescollectedinthespecifiedtimerange.Thismeansthatbasedonyourpollinginterval,it’susuallycheapertoextendatrendretentionvaluethanahistoryone.Thisis,ofcourse,validonlyfornumericalvaluesasstringonescan’treallyhavetrends,justhistory.
OnelastthingtonoticeintheaboveimagesisthatthemonitoringprotocolforallitemsissettoSNMPv2.JustlikeSNMPv1,SNMPv2doesn’tofferrealsecurityforthemonitoringdatathatcrossesthenetworkbetweenanapplianceandthemonitoringserver:alltrafficissentandreceivedintheclear,andtheSNMPcommunityisjustastring,easilyparsablefrominterceptedtraffic.Whileit’scertainlytruethatafewnetworkappliancesdon’tsupportSNMPv3becauseeithertheyaretoooldortheyaretoosimple,It’salsotruethat
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thenewversionoftheprotocolhasbeenaroundforquiteawhilenowandanumberofappliancesdosupportit.ThemainadvantagesofSNMPv3areitsauthenticationandencryptioncapabilities.Thesecanhelpmakesurethatallmonitoringtrafficisnotbogusorcorrupted,andthatit’skeptconfidentialfrompryingeyes.Thisisparticularlyimportantifyouneedtomonitorsomehostsoveranetworklinkyouhavenorealcontrolover,suchasaWANconnectionthroughathird-partyprovider.ItwouldalwaysbenicetouseSNMPv3acrossyournetwork,butincaseslikethese,youarestronglyencouragedtodosoasthere’sarealpossibilitythatyourtrafficcanbeindeedinterceptedandtappedinto.
Let’staketheexampleofaCiscorouter,andlet’sseehowtoconfigureSNMPv3onitbeforemovingontotheZabbixside.
Firstofall,let’screateamonitoringgroup.Thisisusedtodefineaccesstothedevice’sMIBs.OntheCiscorouter,openaconsolesessionandgointoconfigurationmode.Thenissuethefollowingcommand:
R1(config)#snmp-servergroupMonitoringGroupv3priv
Thev3keywordspecifiesthatwewanttouseSNMPv3,whiletheprivkeywordspecifiesthatwewanttousebothauthenticationandencryption.It’spossibletopassmoreoptionstotheprecedingcommandinordertodefineanaccesslistifyouwanttolimitaccesstospecificMiBs,butwe’llkeepthingssimplehereandletourZabbixprobeaccessallMIBs.
Nowthatwehaveagroup,wecancreateauser,asfollows:
R1(config)#snmp-serveruserzabbixMonitoringGroupv3authshazbxpasspriv
aes128zbxpriv
Asyoucansee,weassignedtheZabbixusertothepreviouslycreatedgroupanddefinedtheauthenticationandencryptionpassphrases.Takenoteofalltheseelementsasyou’llneedtospecifyallofthemonZabbix’ssideandtheywillneedtomatchwhatyouusedhere.Tosummarize,hereiswhatyou’llinputlaterwhenconfiguringanSNMPv3Zabbixitem:
Field Value
User zabbix
Authenticationprotocol sha
Authenticationpassphrase zbxpass
Privacyprotocol aes
Privacypassphrase zbxpriv
NotePleasedon’tusethepassphrasesshownhere.Theseareintentionallyweak,andweusedthemforillustrationpurposesonly.
Thisisallthereistoit.Later,we’lladdsomeinformationabouttellingtheappliance
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wheretosendSNMPtraps,butfornowyou’rereadytogetSNMPvaluesfromyourappliance,solet’sfocusonthatforawhile.
FindingtherightOIDstomonitorWhileZabbix’sdefaultSNMPtemplateswillhelpyougetstartedwithbasicmonitoring,you’llsoonfindtheneedtopollyourdevicesformoreinformation.Todothat,you’llneedtoknowtheOIDofthemetricyouwanttomonitoraswellasthedatatypeitwillyield.Afirstoptionistoconsultyourvendor’sdocumentationonthedeviceandfindoutwhichMIBsandOIDsareexposedbytheSNMPagent.Another,moreinteractive,optionistofindthemusingthesnmpwalkutilityanddirectlyaskingyourdeviceforthem.
NoteIfyoudon’talreadyhavesnmpwalk(andtheotherSNMPutilitiesforLinux)installed,youcanquicklydosowithasimplecommand:
#yuminstallnet-snmp-utils
OIDsaresentandreceivedbySNMPagentsandserversasdottedsequencesofnumbers.JustlikeIPaddresses,thisisconvenientformachine-to-machinecommunication,buthardtoreadforhumans.Inordertomakethemostfromtheexplorationofyourdeviceusingsnmpwalk,makesureyouhavealltheMIBsyouneedinstalled.MIBsessentiallymapOIDstoreadableandunderstandabledescriptionsofthemselves.Inotherwords,theytakeoutputlikethisone:
.1.3.6.1.2.1.2.2.1.1.1=INTEGER:1
.1.3.6.1.2.1.2.2.1.1.2=INTEGER:2
.1.3.6.1.2.1.2.2.1.1.3=INTEGER:3
.1.3.6.1.2.1.2.2.1.1.5=INTEGER:5
.1.3.6.1.2.1.2.2.1.2.1=STRING:lo
.1.3.6.1.2.1.2.2.1.2.2=STRING:eth1
.1.3.6.1.2.1.2.2.1.2.3=STRING:tap0
.1.3.6.1.2.1.2.2.1.2.5=STRING:br0
.1.3.6.1.2.1.2.2.1.3.1=INTEGER:softwareLoopback(24)
.1.3.6.1.2.1.2.2.1.3.2=INTEGER:ethernetCsmacd(6)
.1.3.6.1.2.1.2.2.1.3.3=INTEGER:ethernetCsmacd(6)
.1.3.6.1.2.1.2.2.1.3.5=INTEGER:ethernetCsmacd(6)
.1.3.6.1.2.1.2.2.1.4.1=INTEGER:16436
.1.3.6.1.2.1.2.2.1.4.2=INTEGER:1500
.1.3.6.1.2.1.2.2.1.4.3=INTEGER:1500
.1.3.6.1.2.1.2.2.1.4.5=INTEGER:1500
.1.3.6.1.2.1.2.2.1.5.1=Gauge32:10000000
.1.3.6.1.2.1.2.2.1.5.2=Gauge32:1000000000
.1.3.6.1.2.1.2.2.1.5.3=Gauge32:10000000
.1.3.6.1.2.1.2.2.1.5.5=Gauge32:0
.1.3.6.1.2.1.2.2.1.6.1=STRING:
.1.3.6.1.2.1.2.2.1.6.2=STRING:0:c:29:24:15:50
.1.3.6.1.2.1.2.2.1.6.3=STRING:2:10:f7:72:77:50
.1.3.6.1.2.1.2.2.1.6.5=STRING:0:c:29:24:15:50
.1.3.6.1.2.1.2.2.1.7.1=INTEGER:up(1)
.1.3.6.1.2.1.2.2.1.7.2=INTEGER:up(1)
.1.3.6.1.2.1.2.2.1.7.3=INTEGER:up(1)
.1.3.6.1.2.1.2.2.1.7.5=INTEGER:up(1)
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.1.3.6.1.2.1.2.2.1.8.1=INTEGER:up(1)
.1.3.6.1.2.1.2.2.1.8.2=INTEGER:up(1)
.1.3.6.1.2.1.2.2.1.8.3=INTEGER:up(1)
.1.3.6.1.2.1.2.2.1.8.5=INTEGER:up(1)
Then,theyturnitintoamuchmorereadableform:
IF-MIB::ifIndex.1=INTEGER:1
IF-MIB::ifIndex.2=INTEGER:2
IF-MIB::ifIndex.3=INTEGER:3
IF-MIB::ifIndex.5=INTEGER:5
IF-MIB::ifDescr.1=STRING:lo
IF-MIB::ifDescr.2=STRING:eth1
IF-MIB::ifDescr.3=STRING:tap0
IF-MIB::ifDescr.5=STRING:br0
IF-MIB::ifType.1=INTEGER:softwareLoopback(24)
IF-MIB::ifType.2=INTEGER:ethernetCsmacd(6)
IF-MIB::ifType.3=INTEGER:ethernetCsmacd(6)
IF-MIB::ifType.5=INTEGER:ethernetCsmacd(6)
IF-MIB::ifMtu.1=INTEGER:16436
IF-MIB::ifMtu.2=INTEGER:1500
IF-MIB::ifMtu.3=INTEGER:1500
IF-MIB::ifMtu.5=INTEGER:1500
IF-MIB::ifSpeed.1=Gauge32:10000000
IF-MIB::ifSpeed.2=Gauge32:1000000000
IF-MIB::ifSpeed.3=Gauge32:10000000
IF-MIB::ifSpeed.5=Gauge32:0
IF-MIB::ifPhysAddress.1=STRING:
IF-MIB::ifPhysAddress.2=STRING:0:c:29:24:15:50
IF-MIB::ifPhysAddress.3=STRING:2:10:f7:72:77:50
IF-MIB::ifPhysAddress.5=STRING:0:c:29:24:15:50
IF-MIB::ifAdminStatus.1=INTEGER:up(1)
IF-MIB::ifAdminStatus.2=INTEGER:up(1)
IF-MIB::ifAdminStatus.3=INTEGER:up(1)
IF-MIB::ifAdminStatus.5=INTEGER:up(1)
IF-MIB::ifOperStatus.1=INTEGER:up(1)
IF-MIB::ifOperStatus.2=INTEGER:up(1)
IF-MIB::ifOperStatus.3=INTEGER:up(1)
IF-MIB::ifOperStatus.5=INTEGER:up(1)
IfyouhavetherightMIBs,youwon’thavetoguessthemeaningofeachOIDfromitsvalueasmostofthetime,itwillbeclearenoughfromitsname.ToaddanewMIBtoyourSNMPtools,youhavetoobtainitfromthevendorofyourdeviceandtheninstallitonyoursystem.VendorsusuallymaketheirMIBsfreelyavailable,soyoushouldn’thaveanyproblemsfindingthem.
HerearesomeofthemajorvendorsofMIBsources,compiledatthetimeofwriting:
Vendor MIBs
Cisco http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml
Juniper http://www.juniper.net/techpubs/software/index_mibs.html
Barracudanetworks https://techlib.barracuda.com/search/go/global?q=MIB
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NoteAveryusefulresourceisOIDView’sfreeMIBdatabasethatyoucanfindhere:
http://www.oidview.com/mibs/detail.html
Atthetimeofwritingthis,thedatabasehadmorethan7,000MIBs,sochancesareyou’llbeabletofindaMIBforthemostobscurenetworkdeviceyoumighthavetomonitor.
MIBsareplaintextfiles,soifyouhaveacompressedarchive,youwillneedtounpackitbeforeyoucaninstallitscontents.OnceyouhavetheplaintextMIBS,it’sasimplematterofcopyingtheminto/usr/share/snmp/mibsandthenusingthe-moptiontotheSNMPcommandstospecifywhichMIByouwanttoloadinadditiontothedefaultones.
ShouldyourMIBscollectionbecometoobigandyouwantedtoorganizethemindifferentdirectories,thenyou’llneedtotellyourtoolswheretofindthem.Youhavetwooptions:eitherspecifyfromthecommandlinethedirectoriesyouwantyourcommandtosearchforMIBs,orputthisinformationinaconfigurationfilesothatyourcommandsalwaysknowtheMIBs’location.Theoptionsarediscussedasfollows:
Thefirstoptionisusefulifyou’rejusttryingoutanewMIBandseeingwhetherthat’stheoneyouneed.EveryNet-SNMP-basedcommandwilltakea-moptionthatyoucanusetospecifyaspecificMIBtoloadfromthemibsdirectory.Here’sacommandforexample:
$snmpwalk-m+CISCO-STUN-MIB-v3-uzabbix-aSHA-Azbxpassword-l
AuthPriv-xAES-Xprivpassword10.10.1.9
ThiscommandwilluseSNMPv3tocontacttheSNMPagentat10.10.1.9withthespecifiedcredentialsandwillloadtheCISCO-STUN-MIBthatitwillfindinthe/usr/share/snmp/mibsdirectory,inadditiontothosealreadyloadedasdefault.
Thesecondoptionismorepermanentandinvolvesediting(orcreating,ifit’snotalreadythere)the/etc/snmp/snmp.conffile.JustaddalinewiththelistofdirectoriestosearchformibsandanotherlinethatspecifieswhichMIBsthecommandsshouldactuallyload(inthiscase,we’llloadallofthem),asfollows:
mibdirs
/usr/share/snmp/mibs:/usr/share/snmp/mibs/cisco:/usr/share/snmp/mibs/ju
niper:/mnt/remote/shared_mibs/
mibs+ALL
Asyoucansee,evenifyoukeepyoursubdirectoriesin/usr/share/snmp/mibs,you’llhavetospecifyeachoneyouwantautomaticallyincluded.OnceyouhaveyourMIBsinstalledandloaded,you’llbereadytofullyexploreyourdevices’SNMPagents.ToperformacompletesnmpwalkonadevicecantakequitealotoftimeandproducealotofoutputdependingonhowmanyOIDsitexposes.Aroutercanhavethousandsofthem,soit’sadvisabletoredirectthecommand’soutputtoafilesothatyouareabletoreferenceitandexploreitatanytimeyouwantwithouthavingtoperformacompletewalkonthedeviceitself,asfollows:
$snmpwalk-v3-uzabbix-aSHA-Azbxpassword-lAuthPriv-xAES-X
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privpassword10.10.1.9>router-R1-snmp_baseline.txt
AnotheradvantageofhavingtheMIBsyouneedisthatit’llbeeasiertocreatenewSNMPitemsinZabbixasyou’llbeabletospecifythestringversionofanOIDandnotonlyitsnumericalvalue.ZabbixreliesontheNet-SNMPlibrary,soitwillalsoreferenceanyMIBsinstalledinyoursystem’sdefaultdirectories.
Solet’sseehowyoucanusetheoutputofsnmpwalktocreatenewZabbixitems.
MappingSNMPOIDstoZabbixitemsAnSNMPvalueiscomposedofthreedifferentparts:theOID,thedatatype,andthevalueitself.WhenyouusesnmpwalkorsnmpgettogetvaluesfromanSNMPagent,theoutputlookslikethis:
SNMPv2-MIB::sysObjectID.0=OID:CISCO-PRODUCTS-MIB::cisco3640
DISMAN-EVENT-MIB::sysUpTimeInstance=Timeticks:(83414)0:13:54.14
SNMPv2-MIB::sysContact.0=STRING:
SNMPv2-MIB::sysName.0=STRING:R1
SNMPv2-MIB::sysLocation.0=STRING:Upperfloorroom13
SNMPv2-MIB::sysServices.0=INTEGER:78
SNMPv2-MIB::sysORLastChange.0=Timeticks:(0)0:00:00.00
...
IF-MIB::ifPhysAddress.24=STRING:c4:1:22:4:f2:f
IF-MIB::ifPhysAddress.26=STRING:
IF-MIB::ifPhysAddress.27=STRING:c4:1:1e:c8:0:0
IF-MIB::ifAdminStatus.1=INTEGER:up(1)
IF-MIB::ifAdminStatus.2=INTEGER:down(2)
…
Andsoon.
Thefirstpart,theonebeforethe=signis,naturally,theOID.ThiswillgointotheSNMPOIDfieldintheZabbixitemcreationpageandistheuniqueidentifierforthemetricyouareinterestedin.SomeOIDsrepresentasingleanduniquemetricforthedevice,sotheyareeasytoidentifyandaddress.Intheaboveexcerpt,onesuchOIDisDISMAN-EVENT-MIB::sysUpTimeInstance.IfyouareinterestedinmonitoringthatOID,you’donlyhavetofillouttheitemcreationformwiththeOIDitselfandthendefineanitemname,adatatype,andaretentionpolicy,andyouarereadytostartmonitoringit.Inthecaseofanuptimevalue,time-ticksareexpressedinseconds,soyou’llchooseanumericdecimaldatatype.We’llseeinthenextsectionhowtochooseZabbixitemdatatypesandhowtostorevaluesbasedonSNMPdatatypes.You’llalsowanttostorethevalueasisandoptionallyspecifyaunitofmeasure.Thisisbecauseanuptimeisalreadyarelativevalueasitexpressesthetimeelapsedsinceadevice’slatestboot.Therewouldbenopointincalculatingafurtherdeltawhengettingthismeasurement.Finally,you’lldefineapollingintervalandchoosearetentionpolicy.Inthefollowingexample,thepollingintervalisshowntobe5minutes(300seconds),thehistoryretentionpolicyas3days,andthetrendstorageperiodasoneyear.Theseshouldbesensiblevaluesasyoudon’tnormallyneedtostorethedetailedhistoryofavaluethateitherresetstozero,or,bydefinition,growslinearlybyonetickeverysecond.
Thefollowingscreenshotencapsulateswhathasbeendiscussedinthisparagraph:
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Rememberthattheitem’skeyvaluestillhastobeuniqueatthehost/templatelevelasitwillbereferencedtobyallotherZabbixcomponents,fromcalculateditemstotriggers,maps,screens,andsoon.Don’tforgettoputtherightcredentialsforSNMPv3ifyouareusingthisversionoftheprotocol.
ManyofthemoreinterestingOIDs,though,areabitmorecomplex:multipleOIDscanberelatedtooneanotherbymeansofthesameindex.Let’slookatanothersnmpwalkoutputexcerpt:
IF-MIB::ifNumber.0=INTEGER:26
IF-MIB::ifIndex.1=INTEGER:1
IF-MIB::ifIndex.2=INTEGER:2
IF-MIB::ifIndex.3=INTEGER:3
…
IF-MIB::ifDescr.1=STRING:FastEthernet0/0
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IF-MIB::ifDescr.2=STRING:Serial0/0
IF-MIB::ifDescr.3=STRING:FastEthernet0/1
…
IF-MIB::ifType.1=INTEGER:ethernetCsmacd(6)
IF-MIB::ifType.2=INTEGER:propPointToPointSerial(22)
IF-MIB::ifType.3=INTEGER:ethernetCsmacd(6)
…
IF-MIB::ifMtu.1=INTEGER:1500
IF-MIB::ifMtu.2=INTEGER:1500
IF-MIB::ifMtu.3=INTEGER:1500
…
IF-MIB::ifSpeed.1=Gauge32:10000000
IF-MIB::ifSpeed.2=Gauge32:1544000
IF-MIB::ifSpeed.3=Gauge32:10000000
…
IF-MIB::ifPhysAddress.1=STRING:c4:1:1e:c8:0:0
IF-MIB::ifPhysAddress.2=STRING:
IF-MIB::ifPhysAddress.3=STRING:c4:1:1e:c8:0:1
…
IF-MIB::ifAdminStatus.1=INTEGER:up(1)
IF-MIB::ifAdminStatus.2=INTEGER:down(2)
IF-MIB::ifAdminStatus.3=INTEGER:down(2)
…
IF-MIB::ifOperStatus.1=INTEGER:up(1)
IF-MIB::ifOperStatus.2=INTEGER:down(2)
IF-MIB::ifOperStatus.3=INTEGER:down(2)
…
IF-MIB::ifLastChange.1=Timeticks:(1738)0:00:17.38
IF-MIB::ifLastChange.2=Timeticks:(1696)0:00:16.96
IF-MIB::ifLastChange.3=Timeticks:(1559)0:00:15.59
…
IF-MIB::ifInOctets.1=Counter32:305255
IF-MIB::ifInOctets.2=Counter32:0
IF-MIB::ifInOctets.3=Counter32:0
…
IF-MIB::ifInDiscards.1=Counter32:0
IF-MIB::ifInDiscards.2=Counter32:0
IF-MIB::ifInDiscards.3=Counter32:0
…
IF-MIB::ifInErrors.1=Counter32:0
IF-MIB::ifInErrors.2=Counter32:0
IF-MIB::ifInErrors.3=Counter32:0
…
IF-MIB::ifOutOctets.1=Counter32:347968
IF-MIB::ifOutOctets.2=Counter32:0
IF-MIB::ifOutOctets.3=Counter32:0
Asyoucansee,foreverynetworkinterface,thereareseveralOIDs,eachonedetailingaspecificaspectoftheinterface:itsname,itstype,whetherit’supordown,theamountoftrafficcominginorgoingout,andsoon.ThedifferentOIDsarerelatedthroughtheirlastnumber,theactualindexoftheOID.Lookingattheprecedingexcerpt,weknowthatthedevicehas26interfaces,ofwhichweareshowingsomevaluesforjustthefirstthree.Bycorrelatingtheindexnumbers,wealsoknowthatinterface1iscalledFastEthernet0/0,itsMACaddressisc4:1:1e:c8:0:0,theinterfaceisupandhasbeenupforjust17
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seconds,andsometrafficalreadywentthroughit.
Now,onewaytomonitorseveralofthesemetricsforthesameinterfaceistomanuallycorrelatethesevalueswhencreatingtheitems,puttingthecompleteOIDintheSNMPOIDfield,andmakingsurethatboththeitemkeyanditsnamereflecttherightinterface.Thisprocessisnotonlypronetoerrorsduringthesetupphase,butitcouldalsointroducesomeinconsistenciesdowntheroad.Thereisnoguarantee,infact,thattheindexwillremainconsistentacrosshardwareorsoftwareupgradesorevenacrossconfigurationswhenitcomestomorevolatilestateslikethenumberofVLANsorroutingtablesinsteadofnetworkinterfaces.FortunatelyZabbixprovidesafeature,calleddynamicindexes,thatallowsyoutoactuallycorrelatedifferentOIDsinthesameSNMPOIDfieldsothatyoucandefineanindexbasedontheindexexposedbyanotherOID.
ThismeansthatifyouwanttoknowtheadminstatusofFastEthernet0/0,youdon’tneedtofindtheindexassociatedwithFastEthernet0/0(inthiscaseitwouldbe1)andthenaddthatindextoIF-MIB::ifAdminStatusofthebaseOID,hopingthatitwon’teverchangeinthefuture.Youcaninsteadusethefollowingcode:
IF-MIB::ifAdminStatus["index","IF-MIB::ifDescr","FastEthernet0/0"]
UponusingtheprecedingcodeintheSNMPOIDfieldofyouritem,theitemwilldynamicallyfindtheindexoftheIF-MIB::ifDescrOIDwherethevalueisFastEthernet0/0andappendittoIF-MIB::ifAdminStatusinordertogettherightstatusfortherightinterface.
Ifyouorganizeyouritemsthisway,you’llalwaysbesurethatrelateditemsactuallyshowtherightrelatedvaluesforthecomponentyouareinterestedinandnotthoseofanotheronebecausethingschangedonthedevice’ssidewithoutyourknowledge.Moreover,we’llbuildonthistechniquetodeveloplow-leveldiscoveryofadeviceaswe’llseeinChapter4,DiscoveringYourNetwork.
Youcanusethesametechniquetogetotherinterestinginformationoutofadevice.Consider,forexample,thefollowingexcerpt:
ENTITY-MIB::entPhysicalVendorType.1=OID:CISCO-ENTITY-VENDORTYPE-OID-
MIB::cevChassis3640
ENTITY-MIB::entPhysicalVendorType.2=OID:CISCO-ENTITY-VENDORTYPE-OID-
MIB::cevContainerSlot
ENTITY-MIB::entPhysicalVendorType.3=OID:CISCO-ENTITY-VENDORTYPE-OID-
MIB::cevCpu37452fe
ENTITY-MIB::entPhysicalClass.1=INTEGER:chassis(3)
ENTITY-MIB::entPhysicalClass.2=INTEGER:container(5)
ENTITY-MIB::entPhysicalClass.3=INTEGER:module(9)
ENTITY-MIB::entPhysicalName.1=STRING:3745chassis
ENTITY-MIB::entPhysicalName.2=STRING:3640ChassisSlot0
ENTITY-MIB::entPhysicalName.3=STRING:c3745MotherboardwithFast
EthernetonSlot0
ENTITY-MIB::entPhysicalHardwareRev.1=STRING:2.0
ENTITY-MIB::entPhysicalHardwareRev.2=STRING:
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ENTITY-MIB::entPhysicalHardwareRev.3=STRING:2.0
ENTITY-MIB::entPhysicalSerialNum.1=STRING:FTX0945W0MY
ENTITY-MIB::entPhysicalSerialNum.2=STRING:
ENTITY-MIB::entPhysicalSerialNum.3=STRING:XXXXXXXXXXX
Itshouldbeimmediatelycleartoyouthatyoucanfindthechassis’sserialnumberbycreatinganitemwith:
ENTITY-MIB::entPhysicalSerialNum["index","ENTITY-MIB::entPhysicalName",
"3745chassis"]
Thenyoucanspecify,inthesameitem,thatitshouldpopulatetheSerialNumberfieldofthehost’sinventory.Thisishowyoucanhaveamoreautomatic,dynamicpopulationofinventoryfields.
Thepossibilitiesareendlessaswe’veonlyjustscratchedthesurfaceofwhatanygivendevicecanexposeasSNMPmetrics.BeforeyougoandfindyourfavoriteOIDstomonitorthough,let’shaveacloserlookattheprecedingexamples,andlet’sdiscussdatatypes.
GettingdatatypesrightWehavealreadyseenhowanOID’svaluehasaspecificdatatypethatisusuallyclearlystatedwiththedefaultsnmpwalkcommand.Intheprecedingexamples,youcanclearlyseethedatatypejustafterthe=sign,beforetheactualvalue.ThereareanumberofSNMPdatatypes—somestillcurrentandsomedeprecated.YoucanfindtheofficiallistanddocumentationinRFC2578(http://tools.ietf.org/html/rfc2578),butlet’shavealookatthemostimportantonesfromtheperspectiveofaZabbixuser:
SNMPtype Description SuggestedZabbixitemtypeandoptions
INTEGERThiscanhavenegativevaluesandisusuallyusedforenumerations
Numericunsigned,decimalStorevalueasisShowwithvaluemappings
STRING Thisisaregularcharacterstringandcancontainnewlines TextStorevalueasis
OID ThisisanSNMPobjectidentifier CharacterStorevalueasis
IpAddress IPv4onlyCharacterStorevalueasis
Counter32 Thisincludesonlynon-negativeandnondecreasingvaluesNumericunsigned,decimalStorevalueasdelta(speedpersecond)
Gauge32 Thisincludesonlynon-negativevalues,whichcandecrease Numericunsigned,decimalStorevalueasis
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Counter64 Thisincludesnon-negativeandnondecreasing64-bitvalues Numericunsigned,decimalStorevalueasdelta(speedpersecond)
TimeTicks Thisincludesnon-negative,nondecreasingvalues Numericunsigned,decimalStorevalueasis
Firstofall,rememberthattheabovesuggestionsarejustthat—suggestions.Youshouldalwaysevaluatehowtostoreyourdataonacase-by-casebasis,butyou’llprobablyfindthatinmanycasesthoseareindeedthemostusefulsettings.
Movingontotheactualdatatypes,rememberthatthecommandlineSNMPtoolsbydefaultparsethevaluesandshowsomealreadyinterpretedinformation.ThisisespeciallytrueforTimeticksvaluesandforINTEGERvalueswhentheseareusedasenumerations.Inotherwords,youseethefollowingfromthecommandline:
VRRP-MIB::vrrpNotificationCntl.0=INTEGER:disabled(2)
However,whatisactuallypassedasarequestisthebareOID:
1.3.6.1.2.1.68.1.2.0
TheSNMPagentwillrespondwithjustthevalue,which,inthiscase,isthevalue2.
Thismeansthatinthecaseofenumerations,Zabbixwilljustreceiveandstoreanumberandnotthestringdisabled(2)asseenfromthecommandline.Ifyouwanttodisplaymonitoringvaluesthatareabitclearer,youcanapplyvaluemappingstoyournumericitems.Valuemapscontainthemappingbetweennumericvaluesandarbitrarystringrepresentationsforahuman-friendlyrepresentation.Youcanspecifywhichoneyouneedintheitemconfigurationform,asfollows:
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Zabbixcomeswithafewpredefinedvaluemappings.Youcancreateyourownmappingsbyfollowingtheshowvaluemappingslinkand,providedyouhaveadminrolesonZabbix,you’llbetakentoapagewhereyoucanconfigureallvaluemappingsthatwillbeusedbyZabbix.Fromthere,clickonCreatevaluemapintheupper-rightcornerofthepage,andyou’llbeabletocreateanewmapping.NotallINTEGERvaluesareenumerations,butthosethatareusedassuchwillbeclearlyrecognizablefromyourcommand-linetoolsastheywillbedefinedasINTEGERvaluesbutwillshowastringlabelalongwiththeactualvalue,justasintheprecedingexample.
Ontheotherhand,whentheyarenotusedasenumerations,theycanrepresentdifferentthingsdependingonthecontext.Asseeninthepreviousparagraph,theycanrepresentthenumberofindexesavailableforagivenOID.Theycanalsorepresentapplicationorprotocol-specificvalues,suchasdefaultMTU,defaultTTL,routemetrics,andsoon.
Themaindifferencebetweengauges,counters,andintegersisthatintegerscanassumenegativevalues,whilegaugesandcounterscannot.Inadditiontothat,counterscanonlyincreaseorwraparoundandstartagainfromthebottomoftheirvaluerangeoncetheyreachtheupperlimitsofit.FromtheperspectiveofZabbix,thismarksthedifferenceinhowyou’llwanttostoretheirvalues.
Gaugesareusuallyemployedwhenavaluecanvarywithinagivenrange,suchasthespeedofaninterface,theamountoffreememory,oranylimitsandtimeoutsyoumightfindfornotifications,thenumberofinstances,andsoon.Inallofthesecases,thevaluecanincreaseordecreaseintime,soyou’llwanttostorethemastheyarebecauseonceputonagraph,they’lldrawameaningfulcurve.
Counters,ontheotherhand,canonlyincreasebydefinition.Theyaretypicallyusedtoshowhowmanypacketswereprocessedbyaninterface,howmanyweredropped,howmanyerrorswereencountered,andsoon.Ifyoustorecountervaluesastheyare,you’llfindinyourgraphssomeever-ascendingcurvesthatwon’ttellyouverymuchforyourmonitoringorcapacityplanningpurposes.Thisiswhyyou’llusuallywanttotrackacounter’samountofchangeintime,morethanitsactualvalue.Todothat,Zabbixofferstwodifferentwaystostoredeltasordifferencesbetweensuccessivevalues.
Thedelta(simplechange)storagemethoddoesexactlywhatitsays:itsimplycomputesthedifferencebetweenthecurrentlyreceivedvalueandthepreviouslyreceivedone,andstorestheresult.Itdoesn’ttakeintoconsiderationtheelapsedtimebetweenthetwomeasurements,northefactthattheresultcanevenhaveanegativevalueifthecounteroverflows.Thefactisthatmostofthetime,you’llbeveryinterestedinevaluatinghowmuchtimehaspassedbetweentwodifferentmeasurementsandintreatingcorrectlyanynegativevaluesthatcanappearasaresult.
Thedelta(speedpersecond)willdividethedifferencebetweenthecurrentlyreceivedvalueandthepreviouslyreceivedonebythedifferencebetweenthecurrenttimestampandthepreviousone,asfollows:
(value–prev_value)/(time-prev_time)
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Thiswillensurethatthescaleofthechangewillalwaysbeconstant,asopposedtothescaleofthesimplechangedelta,whichwillvaryeverytimeyoumodifytheupdateintervaloftheitem,givingyouinconsistentresults.Moreover,thespeed-per-seconddeltawillignoreanynegativevaluesandjustwaitforthenextmeasurement,soyouwon’tfindanyfalsedipsinyourgraphduetooverflowing.
Finally,whileSNMPusesspecificdatatypesforIPaddressesandSNMPOIDs,therearenosuchtypesinZabbix,soyou’llneedtomapthemtosomekindofstringitem.Thesuggestedtypehereischaracterasbothvalueswon’tbebiggerthan255charactersandwon’tcontainanynewlines.
Stringvalues,ontheotherhand,canbequitelongastheSNMPspecificationallowsfor65,535-character-longtexts;however,textthatlongwouldbeoflittlepracticalvalue.Eveniftheyareusuallymuchshorter,stringvaluescanoftencontainnewlinesandbelongerthan255characters.
Consider,forexample,thefollowingSysDescrOIDforthisdevice:
NMPv2-MIB::sysDescr.0=STRING:CiscoIOSSoftware,3700Software(C3745-
ADVENTERPRISEK9_SNA-M),Version12.4(15)T14,RELEASESOFTWARE(fc2)^M
TechnicalSupport:http://www.cisco.com/techsupport^M
Copyright(c)1986-2010byCiscoSystems,Inc.^M
CompiledTue17-Aug-1012:56byprod_rel_tea
Asyoucansee,thestringspansmultiplelines,andit’sdefinitelylongerthan255characters.Thisiswhythesuggestedtypeforstringvaluesistextasitallowstextofarbitrarylengthandstructure.Ontheotherhand,ifyou’resurethataspecificOIDvaluewillalwaysbemuchshorterandsimpler,youcancertainlyusethecharacterdatatypeforyourcorrespondingZabbixitem.
Now,youaretrulyreadytogetthemostoutofyourdevices’SNMPagentsasyouarenowabletofindtheOIDyouwanttomonitorandmapthemperfectlytoZabbixitems,downtohowtostorethevalues,theirdatatypes,withwhatfrequency,andwithanyvaluemappingthatmightbenecessary.
It’snowtimetoexploretheotheraspectofSNMP:traps.
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SNMPtrapsSNMPtrapsareabitofanoddballwhencomparedtoalltheotherZabbixitemtypes.Unlikeotheritems,SNMPtrapsdonotreportasimplemeasurement,butaneventofsometype.Inotherwords,theyaretheresultofsomekindofcheckorcomputationmadebytheSNMPagentandsentovertothemonitoringserverasastatusreport.AnSNMPtrapcanbeissuedeverytimeahostisrebooted,aninterfaceisdown,adiskisdamaged,oraUPShaslostpowerandiskeepingserversupusingitsbattery.
ThiskindofinformationcontrastswithZabbix’sbasicassumptionthatanitemisasimplemetricnotdirectlyrelatedtoaspecificevent.Ontheotherhand,there’snootherwaytobeawareofcertainsituationsifnotthroughanSNMPtrapeitherbecausetherearenorelatedmetrics(consider,forexample,theeventtheserverisbeingshutdown)orbecausetheappliance’sonlywaytoconveyitsstatusisthroughabunchofSNMPobjectsandtraps.
SotrapsareofrelativelylimitedusetoZabbixasyoucan’tdomuchmorethanbuildasimpletriggeroutofeverytrapandthennotifyabouttheevent(notmuchpointingraphingatraporbuildingcalculateditemsonit).Nevertheless,theymightproveessentialforacompletemonitoringsolution.
TomanageSNMPtrapseffectively,Zabbixneedsacoupleofhelpertools:thesnmptrapddaemontoactuallyhandleconnectionsfromtheSNMPagentsandsomekindofscripttocorrectlyformateverytrapandpassittotheZabbixserverforfurtherprocessing.
SnmptrapdIfyouhavecompiledSNMPsupportintotheZabbixserver,youshouldalreadyhavethecompleteSNMPsuiteinstalled,whichcontainstheSNMPdaemonandtheSNMPtrapdaemonalongwiththeutilitieswehaveusedintheprevioussection.
JustastheZabbixserverhasabunchofdaemonprocessesthatlistenonTCPport10051forincomingconnections(fromagents,proxies,andnodes),snmptrapdisthedaemonprocessthatlistensonUDPport162forincomingtrapscomingfromremoteSNMPagents.
Onceinstalled,snmptrapdreadsitsconfigurationoptionsfromansnmptrapd.conffilethatcanbeusuallyfoundinthe/etc/snmp/directory.ThebareminimumconfigurationforsnmptrapdrequiresthedefinitionofauserandaprivacylevelforSNMPv3,asfollows:
createUserzbxuserSHAauthAESpriv
authUserlog,execute,netzbxuser
TipTheaboveconfigurationwillenablesnmptrapdtoreceiveSNMPv3INFORMpackets.ThesearejustlikeregularSNMPtraps,withtwodifferences:thefirstoneisthatwhileanagentwon’texpectaresponseaftersendingatrap,INFORMpacketsareacknowledged,sosnmptrapdwillsendaresponseforeverytrapreceived.Butthemostimportantdifference
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isthatwithINFORMpackets,theauthoritativeEngineIDwillbethatofthereceivingpartyandnotthesendingpartyaswithregulartraps.Thismeansthatyou’llhavetospecifyyourserver’sEngineIDtoeverydevicethatwillsendSNMPv3INFORMpackets.Sinceyou’llhavetoconfigurethemtosendpacketstotheserveranyway,thiswon’tmeantoomuchwork.Manyagentsautomaticallydiscoverapeer’sEngineIDbeforesendinganINFORM,butifyouneedtosetityourself,youcandiscoveryourserver’sEngineIDusingsnmpgetandaskingforthesnmpEngineID.0OID.
IfyouwanttouseregularSNMPtraps,you’llhavetoinsertanewcreateUserlineforeveryagentthatwillsendtrapstotheserver,witheachonespecifyingthecorrectEngineIDoftheagentsendingtraps.
Withthisminimalconfiguration,snmptrapdwilllimititselftologthetraptosyslog.WhileitcouldbepossibletoextractthisinformationandsendittoZabbix,it’seasiertotellsnmptrapdhowitshouldhandletraps.Whilethedaemonhasnoprocessingcapabilitiesofitsown,itcanexecuteanycommandorapplicationeitherusingthetrapHandledirective,orleveragingitsembeddedPerlfunctionality.Thelatterismoreefficientasthedaemonwon’thavetoforkanewprocessandwaitforitsexecutiontofinish,soit’stherecommendedoneifyouplantoreceiveasignificantnumberoftraps.Justaddthefollowinglinetosnmptrapd.conf:
perldo"/usr/local/bin/zabbix_trap_receiver.pl";
TipYoucangetthezabbix_trap_receiverscriptfromtheZabbixsources.It’slocatedinmisc/snmptrap/zabbix_trap_receiver.pl.
BesuretocheckthatyoualsohavetheNet-SNMPPerlmoduleinstalled.Ifyouneedit,asimpleyuminstallnet-snmp-perlcommandshouldtakecareofeverything.
Oncerestarted,thesnmptrapddaemonwillexecutethePerlscriptyouspecifiedtoprocesseverytrapreceived,translatingitintoaformatthatcanbeeasilyparsedbytheZabbixserver.Inthefollowingsection,we’llseehowanSNMPtrapistranslatedandusedbyZabbix.
TransformingatrapintoaZabbixitemThePerlscriptincludedintheZabbixdistributionworksasatranslatorfromanSNMPtrapformattoaZabbixitemmeasurement.Foreverytrapreceived,itwillformatitaccordingtotherulesdefinedinthescriptandwilloutputtheresultinalogfile.Bydefault,thelogfileiscalled/tmp/zabbix_traps.tmp.YouneedtomakesurethatthesamefileisreadbyZabbixbysettingthefollowingparametersin/etc/zabbix/zabbix_server.conf:
###Option:StartSNMPTrapper
#If1,SNMPtrapperprocessisstarted.
#
#Mandatory:no
#Range:0-1
#Default:
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StartSNMPTrapper=1
###Option:SNMPTrapperFile
#TemporaryfileusedforpassingdatafromSNMPtrapdaemontothe
server.
#Mustbethesameasinzabbix_trap_receiver.plorSNMPTT
configurationfile.
SNMPTrapperFile=/tmp/zabbix_traps.tmp
Thelogfilewillhaveaformatsimilartothefollowingexample:
03:47:102014/12/09ZBXTRAP127.0.0.1
PDUINFO:
notificationtypeTRAP
version0
receivedfromUDP:[127.0.0.1]:34373->[127.0.0.1]
errorstatus0
messageid0
communitypublic
transactionid3
errorindex0
requestid0
VARBINDS:
DISMAN-EVENT-MIB::sysUpTimeInstancetype=67value=Timeticks:(55)
0:00:00.55
SNMPv2-MIB::snmpTrapOID.0type=6value=OID:IF-MIB::linkDown.0.33
IF-MIB::linkDowntype=4value=Hex-STRING:E2809C5445
53544D454E4F57E2809D
SNMP-COMMUNITY-MIB::snmpTrapCommunity.0type=4value=STRING:"public"
SNMPv2-MIB::snmpTrapEnterprise.0type=6value=OID:IF-MIB::linkDown
TheZBXTRAPfollowedbytheIPaddresswillmarkthestartofanewlogstanza.Therestofthelogwillcontainalldetailsaboutthetrap,soyou’llbeabletoactonanyofthose.
TheZabbixserverwillinturnmonitortheaforesaidlogfileandprocesseverynewlineasanSNMPtrapitem,basicallymatchingthecontentofthelogtoanytrapitemdefinedfortherelevanthost.
Asyou’vealreadyseen,thefirstpartoftheloglineisusedbytheZabbixtrapreceivertomatchatrapwithitscorrespondinghost.Therestismatchedtotheaforesaidhost’sSNMPtrapitem’sregexpdefinitionsanditscontentaddedtoeverymatchingitem’shistoryofvalues.ThismeansthatifyouwishtohavealinkDowntrapitemforagivenhost,you’llneedtoconfigureanSNMPtrapitemwithansnmptrap["linkDown"]key,asfollows:
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Youmightneedtomakesurethatthelogtimeformatyouspecifyintheitem’sconfigurationwillmatchtheoneusedbythePerlscript.You’llalsohavetocheckthatthehost’sinterfacewillmatchtheoneloggedbysnmptrapdbecauseit’stheonepieceofdataZabbixwillusetomatchtrapstohosts.
Fromnowon,you’llbeabletoseethecontentsofthetrapintheitem’sdatahistory.
MovingonfromSNMP,therearestillotherdatasourcesthatyoucanrelyontogetmonitoringdataintoZabbix;forthepurposesofthisbook,themostinterestingonesarelogfiles.ComparedtoSNMP,theycanbetrickytoworkwith,buttheydohavetheiruses,solet’sexplorethemforawhile.
GettingnetflowfromthedevicestothemonitoringserverNetflowisaprotocoloriginallydevelopedbyCiscotocollectandmonitorstatisticsofnetworktrafficonadevice.Aftertheinitialrelease,manyvendorsstartedprovidingtheirownimplementationoftheprotocol.In2008IETFstandardizednetflowandpublishedInternetProtocolFlowInformationeXport(IPFIX)basedonnetflowv9withsomeextensions.However,netflowsomehowremainstheexistingnameoftheprotocolinfactbutnotnecessarilybylegalright,sothat’stheonewe’llusehere.
Anetflowrecordcontainsinformationaboutasinglenetworkflow.Aflowisasequenceofpacketsthatsharesomecommonproperties:
IPprotocolSourceIPaddressSourceport(forTCPandUDP)DestinationIPaddressDestinationport(forTCPandUDP)InputinterfaceTypeofservice
Foreachflow,arecordexposesmanydifferentvalues,whichchangewithnetflow
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versionsandimplementations.Herearethemostcommonones:
InputinterfaceofthedeviceOutputinterfaceofthedeviceFlowstarttimeFlowendtimeNumberofbytesintheflowNumberofpacketsintheflowSourceIPaddressSourceIPportSourceIPmaskDestinationIPaddressDestinationIPportDestinationIPmaskICMPtypeandcodeTCPflagsIPaddressoftheimmediatenext-hop
Itshouldbeimmediatelycleartoyouthatthistypeofinformationcanbeextremelyusefultoanetworkadministratorasitallowsyoutobuildapictureofallthetraffictraversingyournetwork.ItcanalsobeusedtoidentifyanomaloustrafficandtraffictoandfromIPaddressesorportsthatshouldnotbethere,orasforensicevidenceafteranincident.Moreover,itcanbeusedasasourceforcapacity-planninganalysistoidentifybottlenecksinyournetwork,periodsofpeakuse,andtoptalkersamongyourserversanddevices.
Finally,aswewereexplainingpreviously,it’sagoodcandidateforaZabbixlogitemasflowdataisusefulevenifitisnotdirectlyrelatedtothehostthatgeneratedit(evenifit’sstillusefultotrackthatpieceofinformationwheneverpossible).
So,let’sseehowtogetnetflowdataintoZabbix.
Firstofall,you’llhavetoconfigureyourdevicetosendflowdatatoaserver.InthecaseofaCiscodevice,herearetheconfigurationcommandsthatyouneedtoissue(remembertosubstituteallreferencestotheexampleZabbixserverwiththerealonesthatapplytoyourenvironment):
R1(config)#ipflow-exportdestination192.168.234.1319995
R1(config)#ipflow-exportversion9
R1(config)#interfacef0/0
R1(config-if)#ipflowingress
R1(config-if)#ipflowegress
R1(config-if)#exit
Inthefirstline,wespecifytheIPaddressofourZabbixserverandtheUDPportthedeviceshouldsendnetflowinformationto.
Thesecondlinesetsthenetflowversion.
Inthethirdline,wegointointerfacef0/0mode.Pleasenotethatyou’llhavetoexplicitlyenablenetflowforeveryinterfaceyouareinterestedin.Thisisusuallynotaproblem
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becauseifyouconfigurenetflowontherightinterfacesofyourrouters,you’llseemost,ifnotallofyourtrafficanyway;youwon’tneedtoenablenetflowoneveryinterfaceofeverynetworkdeviceyouhave.
Thefourthlineenablesnetflowmonitoringforincomingtrafficoninterfacef0/0,whilethefifthlineenablesnetflowmonitoringforoutgoingtrafficonthesameinterface.Ifyouwanttoenablenetflowonotherinterfaces,you’llneedtorepeatlines3to5foreveryinterfaceyouareinterestedin.
Repeatthewholeprocessforalltheroutersyouwanttogetflowinformationfrom,andonceyouaredone,youarereadytoturntoyourZabbixserver.
ReceivingnetflowdataonyourserverToactuallyreceiveandprocessnetflowpacketsonaserver,youneedadaemonthatwilllistenonaspecifiedUDPport,andthatwillunderstandthenetflowprotocol.OnLinux,suchdaemonsandassociatedtoolsarecontainedinthenfdumppackage.
Nfdumpisacollectionoftoolsthatwillenableyoutocapturenetflowdata,storeitondisk,filterit,andanalyzeit.Themostimportantcomponentsare:
nfcapd:Thisisthedaemoncomponentthatlistensforincomingnetflowdataandstoresitondiskinbinaryformatnfdump:Thisissimilartotcpdump;itreadsandfiltersnfcapdfiles,andoutputsreadabledata
Sothebasicdataflowwillbesimilartothisone:
1. Aroutersendsnetflowdatatotheserver.2. Ontheserver,nfcapdcapturesthedataandstoresitinbinaryfiles.3. Aschedulednfdumpprocesswillreadthebinaryfilesandpopulateahumanreadable
logwithnetflowinformation.4. AZabbixagentwillreadthelogandsenddatatotheZabbixserveraccordingtothe
item’sconfiguration.
Wehavealreadytakencareofpoint1,solet’sseehowtoinstallandconfigurethenfdumppackage,beforelookingintotheZabbixside.
Unfortunately,therearenoreadymaderpmpacketsfornfdump,sowe’llneedtofindthesourcecode,compileit,andinstallit.Thisisusuallyastraightforwardprocess.Firstofall,let’sinstallsomerequireddependenciesfornfdump:
#yuminstallrrdtoolrrdtool-develrrdtool-docperl-rrdtool
Then,we’llneedtodownloadthelatestsources.Atthemomentofwritingthis,thelatestavailableversionis1.6.12.Youcandownloadthepackagefromhttp://sourceforge.net/projects/nfdump/andthentransferittoyourserver.Onceyouhavetar.gzready,unpackit:
$tarxvzfnfdump-1.6.12.tar.gz
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Thenmoveintothenfdump-1.6.12directoryandruntheusualconfigure,make,andmakeinstallsequence.Ifyouwanttoinstallnfdumpinthemaindirectoriesinsteadofthe/usr/localtree,justpassthe–prefixoptiontotheconfigurescript.Inthefollowingexample,that’swhatwe’lluse:
$cdnfdump-1.6.12
$./configure–prefix=/usr--sysconfdir=/etc
$make
$suroot
#makeinstall
Onceinstalled,youcanaddadedicateduserfornfcapdsothatitdoesn’thavetorunasrootandsetaworkingdirectoryforit:
#useradd-s/sbin/nologinnetflow
#mkdir-p/var/nfdump/nfcapd
#mkdir-p/var/nfdump/logs
#chown-Rnetflow/var/nfdump
Whenyourunnfcapd,itwillcreateitsbinaryfilesunder/var/nfdump/nfcapd.Nfcapdfilesarerotated,bydefault,onceeveryfiveminutesandcanbeseparatedintoonedumpcollection(currentandrotatedfiles)persendinghostorasinglecollectionforallsendinghosts.Theycanalsobeexpiredafterasetamountoftime.Youarenowreadytowaitfornetflowdataandtransformitintoalogfile.Todothat,you’llneedtopasstherightoptiontonfcapd.Sincetherearequiteafewoptionstopass,let’sbuildthecommandlinelittlebylittle.Pleasedon’truntheintermediatecommands,butonlythefinalone;nfcapdwillcomplainaboutmissingoptionsandrefusetorun.
Firstofall,we’llpasssomeoptionsthatwillinstructnfcapdtogointodaemonmode(-D),tocompressoutput(-z),torunasusernetflow(-u),andtolistenonport9995(-p):
#nfcapd-D-z-unetflow-p9995
Then,we’llneedtoaddsomeoptionsaboutdatasources.Theacceptedcurrentmethodistousethe-nswitch.We’llalsoinstructnfcapdtocreateadditionalsubdirectoriestostorethecapfilestobetterorganizethem(-S):
#nfcapd-D-z-unetflow-p9995-nR1,192.168.11.9,/var/nfdump/nfcapd-n
R2,10.10.1.254,/var/nfdump/nfcapd-S2
Asyoucansee,you’llhavetospecifyadifferent-noptionforeverysourceyouconfigure.Ifyouhavemanynetflowsources,itmightbebettertorundifferentinstancesofnfcapdondifferentUDPportssoastosharetheloadbetweendifferentprocesses.Inthatcase,justremembertoconfigureyourdevicesaccordinglysothattheysendtheirtraffictothecorrectUDPport.The-S2optionwillcreateadditionalyear/month/day/hourdirectoriesunder/var/nfdump/nfcapdtostorecurrentandrotatedfiles.
Nfcapdfilesarerotatedeveryfiveminutes,andifyournetworkhasalotoftraffic,yournfcapddirectorycanbecomehuge.Youcouldscheduleaseparatejobtocleanthemup,butwiththe-eoption,nfcapdwillbeabletoalsotakecareofthat.Justsettheexpirationparameterwithnfexpireandnfcapdwillpickthemup:
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#nfexpire-u/var/nfdump/nfcapd-s15G-t90d
#nfcapd-D-z-unetflow-p9995-nR1,192.168.11.9,/var/nfdump/nfcapd-n
R2,10.10.1.254,/var/nfdump/nfcapd-S2-e
Intheaboveexample,wesetthesizelimitofthedirectoryto15gigabytes,andthecap(maximum)fileageto90days.Fileswillbedeletedbynfcapdwheneveroneoftheselimitsisreached.Thelastlineintheprecedingcommandnowcontainsalltheparametersweneedforbasicnetflowdumping.Ifyourunit(don’tforgetthenfexpirecommandtoo)orputitintoastartupscript,nfcapdwilllistenonthespecifiednetworkportforincomingnetflowdataandwriteittothedirectoriesyouspecified.
Onceyouhavesomedatain,youcanreaditwithnfdumpandoutputahuman-readablesetofrecords:
$nfdump-r/var/nfdump/nfcapd/2014/10/29/02/nfcapd.201410290250-o
extended
DateflowstartDurationProtoSrcIPAddr:PortDstIP
Addr:PortFlagsTosPacketsBytesppsbpsBppFlows
2014-10-2902:51:53.16063.545TCP10.13.27.151:80->
123.43.98.124:6523.AP.SF01288412055056
1
2014-10-2902:53:13.37023.135TCP64.76.73.121:25->
10.138.41.151:7643.AP.SF0512450055156
1
...
Timewindow:Oct29201402:50:00-Oct29201402:54:56
Thisisgettingclosertoourobjective.Ifyourunnfdumpandredirectitsoutputtoafileinsteadofthescreen,thereyouhavethelogfilewe’vebeentalkingaboutinthelastseveralpages.Todothat,youareprobablythinkingofsettingupacronjobthatwillfindthelatestnfcapdfilesthatweren’talreadyparsedbynfdump,makenfdumpreadthemwhilespecifyingatimewindowsothatyourlogfilewon’tcontainduplicateddata,andaddtheaforesaidoutputtoalogfilethatwillbemonitoredbyZabbix.Thiscanbeanontrivialexercisewhenyouconsiderthatnfcapdwillcontinuallyproducenewfilesandwillputtheminnewdirectoriesallthetime.Moreover,you’llneedtokeepsomekindofexecutionstatewiththetimestampofthelasttimenfdumpwasruninordertoavoidtheaforesaidduplicates.
Itturnsoutthatyou’llbeabletoavoidallthiswork,thankstoaniceoptionfornfcapd,the-xoption.Solet’srewritethenfcapdcommandonelasttime:
#nfcapd-D-z-unetflow-p9995-nR1,192.168.11.9,/var/nfdump/nfcapd-n
R2,10.10.1.254,/var/nfdump/nfcapd-S2-e-x'nfdump-q-oextended-r%d/%f
>>/var/nfdump/logs/zabbix_netflow.log'
The-xcommandexecutesanarbitrarycommandeverytimeadumpfileisrotated.Youcanreferencethedumpfileandthebasedirectorywiththe%d/%fmacros.Thismeansthatnfdumpwillalwaysbeexecutedonnewdataandonlyonceperdumpfile.Suddenly,youwon’tneedtoscheduleanycomplicatedcronjobtogeneratethefinal,human-readablenetflowlogfile.Wealsoaddeda-qoptiontosuppresstheheaderandstatisticsprintingtokeepthelogfileclean.
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NoteYoumightstillwanttoconfiguresomelogrotationforthe/var/nfdump/logs/zabbix_netflow.logfile.Ifyouletitgrowunchecked,itwillfillupyourdiskspaceinduetime!
It’sfinallytimetomakeZabbixawareofthenetflowlogfile.
MonitoringalogfilewithZabbixAsalreadyexplained,logfilemonitoringneedsaZabbixagent.Forillustrationpurposes,wewillassumethatyouhaveinstallednfdumponthesameboxastheZabbixserver,andthatthelogfileisthuslocallyavailable.Itgoeswithoutsayingthatyoucouldalsoinstallnfdump,alongwithaZabbixagent,onaseparated,possiblydedicatedmachine.Itwon’tmakeanydifferencefromZabbix’sperspective.
Basicitemcreationisfairlystraightforward,justpointtheitemkeytothecorrectfilepathandyou’regoodtogo.Pleasenote,inthefollowingexample,thetimestampparsingfield:
Thisisallyouneedforbasiclogfilemonitoring.Forfurtherexplorations,thelogkeyacceptsdifferentoptions,amongwhichthemostinterestingarethoserelatedtoregularexpressionfilteringandoutputsothatyoucanalsocreateadditionalitemsthatwillonlyextracttheexactinformationyouneed(forinstance,bytespersecondofaflow)anduseitasrawdata,justasyouwoulduseanyotherZabbixitem.Zabbix’sownofficialdocumentationisexcellentinthisrespect,soyouareencouragedtofindoutmoreathttps://www.zabbix.com/documentation/2.4/manual/config/items/itemtypes/log_items.
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Onthenfdumpside,therearemanymoreoptionsandfeaturesavailabletonfdump,we’vereallyonlyscratchedthesurfacetokeepthingssimple.Wedon’thavethespacetofullyexploreithere,butifyou’rewillingtospendsometimeexploringthetool,you’llfindthatnfdumpisnotonlycapableofpowerfultrafficfiltering,justastcpdumpis,butitcanalsocreatestatisticsandaggregateddataonvirtuallyeveryaspectofaflow,fromnetworkportstopacketsizes,andsoon.CombinethiswithZabbix’spowerfulexternalscriptitems,andyoucaneasilyseethatyoucansliceanddiceyourdata;however,ifyouwant,bringitintoZabbixforfurtherprocessing,graphing,andalarming.Really,theskyisthelimitwhenyoulearntocombinethesetoolstogether.
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SummaryInthischapter,youhavelearnedthedifferentpossibilitiesZabbixofferstotheenterprisingnetworkadministrator.
Youshouldnowbeabletochoose,design,andimplementallthemonitoringitemsyouneed,basedonthemethodsillustratedintheprecedingparagraphs:simplechecksthataremoreusefulandpowerfulthanthenameimplies;theall-powerfulSNMPprotocol,bothasgetvaluesandastraps;logfilesingeneral;andtheinfinitelyusefulnetflowprotocol
ThenextchapterwillbuildontheinformationexposedinthischapterandwillfocusmoreonservermonitoringandhowtoextractinformationfromDNSservers,webservers,proxies,andotherappliances.Theseareimportant,ifoftenoverlooked,componentsofanetworkevenfromtheperspectiveofanetworkadministrator,andyou’llfindmanyusefultipsonhowtomonitorthem.
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Chapter3.MonitoringYourNetworkServicesIneveryenvironment,especiallyinalargeone,therearemanynetworkcriticalservicesthataredirectlytiedonthenetworkinfrastructure.Manyofthemcanbemonitoredbythesystemadministrators,butthecorecriticalservicesforthewholenetworkarebetteriftheyaremonitoreddirectlybythenetworkadministrator.
Betweenthosecriticalservices,wecanfindthefollowing:
DNSDHCPNTPApacheproxy/reverseproxiesProxycacheSquid
Asitiseasytounderstand,evenifthoseservicesareprovidedfromsomededicatedserverandnotnetworkdevices,themetricsthatyouareacquiringfromthemarefundamental.Thosemetrics,indeed,playacriticalrolewhenyouwouldliketosetupaproactivealarm.
AnexampleofaservicethatcancausealotofconfusioninyournetworkcanbetheDNS,theDHCP,oreventheNTP.Inanidealenvironment,allthoseservicesneedtoberesponsive,andeventheresponsetimeiscrucial;ifeachoneofthosecomponentsbecomesunresponsive,theywillactastheweakestlinkofyourinfrastructure,causingalotofproblemsthatwillbequicklypropagatedtothewholenetwork.AsimpleNTPservercanintroduceconfusioninthelogsofyoursystemsorevencauseanissueinyourconnections.Workingonapracticalexample,trytoimaginethatyouhaveallyouraccountsstoredinanLDAP.Well,iftheLDAPtakestoomuchtimetoresolvetheUID/GIDofyouraccount,youcanhaveissuespropagatedtoallyoursystems.AnunresponsiveLDAPcancausefilesystemissuesandevenNASissues,andifallyouraccountsarestoredthere,evenanlscanliterallytakeages,withabigimpactonthewholeinfrastructure.Here,wearenotconsideringtheDNS,whereadysfunctioncanbeevenworse.
Also,thoseservicesneedtobetakenundersurveillanceas,iftheybecomeunresponsive,quitesoontheywillaccumulaterequeststoserve,andiftheenvironmentisnotready,theywillbefloodedbytheirownqueriesinaqueue,withaglobalimpactonourinfrastructure.
Inthischapter,wewillgothroughallthemainservicesthatanetworkadminshouldmonitortoavoidthesekindsofissues.Then,thereaderwilllearnandunderstandtheimportanceofaneffectiveproactivealarmtoavoidaquickescalationofissuesacrossthenetwork.
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MonitoringtheDNSThefirstnetworkcomponentwewillanalyzeandseehowtomonitoristheDNS.
ThemostpopularDNSserverisBIND,whichisalsooneoftheoldestpackagesproduced.Here,inthenextexample,weassumeyouhaveBIND9.6orlater.
Startingwithversion9.6,thereisabrandnewfeaturethatisnotevenmentionedinthemainpage(ofRedHatLinuxatleast).Thisfeatureisabuilt-inwebserverthatprovidesstatisticsaboutBINDinaverysimplewaythoughtHTTP.Toenablethisfeature,itisenoughtoaddthoselinestoyourBIND9configurationfile,/etc/named.conf:
statistics-channels{
inet127.0.0.1port8053allow{127.0.0.1;};
};
Thelinewehavejustaddedisagoodexampleasthestatistics’accessiscontrolledandrestrictedtothelocalhost.
TipBIND,bydefault,willusethestandard80HTTPportifyoudon’tspecifytheport.Alsopleasetakecaretolimittheaccesstothestatisticchannel;todoso,youcanusethisclause:
allow{address_match_list}
Ifyoudon’tspecifytheallowclause,BINDwillacceptconnectionsfromanyaddress.Thisneedstobeavoided.
Oncethisisdone,allyouhavetodoisrestartyourservicewith:
$servicenamedrestart
Stoppingnamed:[OK]
Startingnamed:[OK]
Now,youcanevenusecurltocallyourwebserverandhavedeliveredtoyouallthestatistics:
#curlhttp://127.0.0.1:8053
<?xmlversion="1.0"encoding="UTF-8"?>
<?xml-stylesheettype="text/xsl"href="/bind9.xsl"?>
<iscversion="1.0">
<bind>
<statisticsversion="2.2">
<views>
<view>
<name>_default</name>
<zones>
….
<summary>
<TotalUse>5965501</TotalUse>
<InUse>1502936</InUse>
<BlockSize>4718592</BlockSize>
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<ContextSize>3595936</ContextSize>
<Lost>0</Lost>
</summary>
</memory>
</statistics>
</bind>
</isc>
Now,wehavetwowaystoretrievethestatistics:
ConfigureBINDtowritethestatisticsinthestatfile(oldmethod)ConfigureBINDtousethebuilt-inHTTPwebservice
Thefirstandoldmethodcanbeusedforserversthatarenotunderaheavyload;thenewmethodusingthestatistics-channelsisontheotherhandlightweightandveryeasytomanage.Nowadaysthisoneisthepreferredmethodtouse.
NoteStartingfromBIND9.10,thestatisticscanbedeliveredineithertheXMLortheJSONformat.ThepreviousversionofBINDofferedonlystatisticsonXMLv2orV3.StartingwithBIND9.10,theXMLstatisticsareavailableonlyinV3format.Anyway,theJSONformatissignificantlyfasterthanXMLandevenlightweighttoprovide.
Now,tofiltertheoutputobtainedbycurl,thereisaninterestingutilitythatunfortunatelyisnotastandardRPMdistributedbyRedHat.Thetoolwearegoingtouseonthoseexamplesisxml2.
Thisxml2isanXMLprocessingtoolthatcanbeusedtoparseandreadtheXMLenvelopesandrewritethemasaflatformat.Theflatformatisreallyusefultobemanipulatedwithshellscripts.Then,firstofall,youneedtodownloadthisutility(thesourcecodeisavailableathttp://download.ofb.net/gale/xml2-0.5.tar.gz).Here’stheoutputsummary:
#wgethttp://download.ofb.net/gale/xml2-0.5.tar.gz
--2014-11-0110:43:44--http://download.ofb.net/gale/xml2-0.5.tar.gz
Resolvingdownload.ofb.net…64.13.131.34
Connectingtodownload.ofb.net|64.13.131.34|:80…connected.
HTTPrequestsent,awaitingresponse…200OK
Length:86318(84K)[application/x-gzip]
Savingto:"xml2-0.5.tar.gz"
100%[===================================>]86,318155K/sin0.5s
2014-11-0110:43:45(155KB/s)-"xml2-0.5.tar.gz"saved[86318/86318]
Performthefollowingstepstoobtaintheresultssetoutintheprecedingparagraph:
1. Explodethepackage,asfollows:
#tar-zxvfxml2-0.5.tar.gz
xml2-0.5/
xml2-0.5/configure.ac
xml2-0.5/aclocal.m4
…
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xml2-0.5/csv2.c
xml2-0.5/xml2.c
2. Stepintothedirectory,asfollows:
#cdxml2-0.5
3. Runtheusual./configurefollowedbymakeandmakeinstall,asfollows:
#./configure&&make
Then,asroot,youcannowrunthefollowingcommand:
#makeinstall
Onceallthishasbeencompleted,youarereadytoruntheutility.
Tomakeyoubetterunderstandwhatthistoolexactlydoes,youcanrunthefollowingcommand:
#curlhttp://localhost:8053/2>/dev/null|xml2|grep-A1queries
/isc/bind/statistics/server/queries-in/rdtype/name=A
/isc/bind/statistics/server/queries-in/rdtype/counter=11230
/isc/bind/statistics/server/queries-in/rdtype
/isc/bind/statistics/server/queries-in/rdtype/name=AAAA
/isc/bind/statistics/server/queries-in/rdtype/counter=1112
Now,theoutputisfinallyveryeasytomanipulatewithastandardutilitylikesedorawk.
4. Then,thenextsteptoenquirefromthelocallyinstalledagentistoaddthesetwolines:
UserParameter=bind.queries.in[*],curlhttp://localhost:8053/
2>/dev/null|/usr/local/bin/xml2|grep-A1
"/isc/bind/statistics/server/queries-in/rdtype/name=$1$"|tail-1|
cut-d=-f2
UserParameter=bind.queries.out[*],curlhttp://localhost:8053/
2>/dev/null|/usr/local/bin/xml2|grep-A1
"/isc/bind/statistics/views/view/rdtype/name=$1$"|tail-1|cut-d=-
f2
Usingtheprecedingcommandasanexample,youcanrunthestandardqueries,suchasA,AAAA,CNAME,ANY,MX,NS,PTR,SOA,andTXTrecordsin/out.
Now,ontheZabbixserverside,youneedtoconfigureallyouritemsjustastheoneshowninthescreenshotfollowingtheupcominglist,takingcaretocreatethesamekindofitemforAaswell:
AAAA
CNAME
ANY
MX
NS
PTR
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SOA
TXT
Onceyou’veaddedallyouritemsinagraph,thefinalresultwillbejustliketheoneshowninthenextscreenshot.Now,you’reacquiringallthequeriesdoneforthemostimportantDNSfields.
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DNS–responsetimeNow,wearemonitoringallqueriesdoneagainstallthemainDNSrecords,butactuallyweneedtocheckhowourDNSisworkingandthenhowmuchtimeisrequiredtohavetheresponseback.
OntheZabbixhow-to,thereisanexampletodowhat’savailablehere:https://www.zabbix.com/wiki/doku.php?id=howto/monitor/services/monitor_dns_and_ntp_services_on_your_network.
Theproblemwiththisexampleisthatthescriptandcodeproposedsimplyreturnsa0or1dependingontheDNSresponseorDNStimeout.
Well,thatexampleisnotgoodenoughforus;wearelookingfornumberslikeresponsetime,andoverthosenumberswecanimplementatrigger.ThetriggerneedstogoonfirewhenthetimeneededbyDNStogiveusbackaresponseishigherthanavaluethatwecanconsideracceptable.Inacomplexnetwork,youcanhaveaDNSquerywhereyoucantolerateaslowresponse(theentiredevelopmentnetworksegment,forinstance,isnotascriticalastheproductionsegment).Then,thesolutionsweproposeheregiveustheresponsetime.Wecanbuildourtriggerovertheresponsetimeunliketheotherway,whichisalotlessflexible.
Wecanseethescriptstepbystep;firstofall,weneedtoacquiretheresponsetime.Thiscanbedoneusingdig,asfollows:
#digmydomain.com
NoteNOTE
digispartofthebind-utilspackage.Ifyoudon’thaveitinstalledinyoursystem,youneedtorunasrootthefollowingcommand:
yuminstallbind-utils
Anyway,digusesthelocalresolver,andthenifyourunthesamequeryagain,you’llseethatthetimespenttoacquiretheDNSrecordis0minutes.Thisisclearlyafalsevalue!Toavoidanycachedresponseandtomeasuretherealtime,weneedtousethe+traceoption.Whentracingisenabled,digmakesiterativequeriestoresolvethename;practically,digwillfollowreferralsfromtherootservers,showingtheanswerfromeachserverthatwasusedtoresolvethelookup.
Here,weneedtohavethetotaltimespentforthequeryandnotthetimeconsumedbyeveryserver.Todothat,wecanusethefollowingsyntax:
$([email protected]+trace)
real0m1.376s
user0m0.010s
sys0m0.012s
Nowthatwehaveunderstoodthelogic,hereisthefullscriptwewilluse:
www.it-ebooks.info
#cattest_dns.sh
#!/bin/sh
iftest-z"$1";then
echo"YouneedtosupplyaDNSentrytocheck.Quitting"
exit01;
fi
DOMAIN=$1
MYTIME=$((timedig$DOMAIN+trace)2>&1|grepreal|awk-F'[m,s]''{print
$2}')
if[$?-eq0];then
echo$MYTIME
else
echo0
fi
Thisscriptrequiresa$1parameter,whichisthedomaintocheck.Now,weneedtoenablethisscriptontheagent’ssidewithUserParameterontheagentconfigurationfile,thusadding:
UserParameter=dns.responsetime[*],test_dns.sh$1
Thescriptwejustcreatedneedstoplacedinavalidruntimeagent’spath,orweneedtousethefullyqualifiedpathinUserParameter,asfollows:
UserParameter=dns.responsetime[*],/full/path/of/test_dns.sh$1
NoteThismethodisreallyusefulasyoucandeploythescriptondifferentnetworksegments,likeforinstance,theapplicationserverzone,andhavearealvalueofthetimeneededtoresolveaDNShostfromthatnetworksegment.
Asthelaststep,createtherelativeitemontheZabbixserverside,whereyouwillpasstheDNSnametocheck,asshowninthefollowingscreenshot:
Pleasebearinmindthatthisscript,ifexecutedcontinuously,canhammeryourDNSexactlybecauseitavoidsusingthecacheofthelocalresolverandevenoneoftheintermediatesegments.
Then,aswehaveexplained,weneedtoscheduleourscriptwithareasonableperiodthatcanbeforaninstanceof1minute.Pleaseconsideryournetworksegmentsfromwhichyou’rerunningthischeck,forboththequantityofscriptsthatarerunningandfrequency.
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NoteHere,youcancreateatriggerbasedonthezone,bearinginmindthatyou’remonitoringtheDNSresponsetimedirectlyfromthehoststhatrequirethoseDNSentriesresolved.Here,itisimportanttotuneyourtriggerbasedontheresponsetimeyouconsideracceptablefromthepointofviewofthezone.
Whenyou’recreatingyourtrigger,itisimportanttoconsiderthatthispluginprovidesyouwiththerealDNSresponsetime,whichistheworst-casescenario.Here,weavoidusinganycachingsystems,whichisnottherealcasebutapessimisticone.Thatsaid,ifyounoticesomespikesofhighresponsetime,thosecanbeignoredasthosespikescan’timpactyoursystem.Consideringthat,thetriggerneedstobetunedtospottheresponsetimethatisstilltherefortwoorthreeitemcycles(orevenmore—thisdependsonthefrequencyatwhichyourunthecheck)andavoidconsideringsinglespikes.
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DNSSEC–monitoringthezonerolloverHere,wedon’thaveenoughpagestoexplainallthefeaturesaddedbyDNSSECoracompletesetupguideofit.Anyway,itisimportanttoknowthatthebestwaytoavoidissueslikeaDNScachepoisoningattackistouseDNSSEC.DNSSECdoesadeepusageofcryptographickeysanddigitalsignaturestoensurethatlookupdataiscorrectandconnectionsarelegitimate.Then,inasecureenvironment,you’resupposedtousemainlyDNSSEC,andthenitisimportanttomonitorthecriticalDNSSECparameters;thoseitemscanberesumed,asfollows:
Thezonefile’svalidityThezones’rolloverstatusTheDNSresponsetime
Currently,therearetwopluginsavailabletoimplementchecksagainsttheDNSSECzonerollover:
RollstateZonestate
Thefirstonechecksthezonemanagedbythedaemonrollerd;thesecondonechecksthevalidityofDNSzones.
NoteThefullcodeisavailableathttps://github.com/hardaker/dnssec-tools/tree/master/dnssec-tools/apps/zabbix,andthepackageisavailableathttp://www.dnssec-tools.org/download/dnssec-tools-2.1.tar.gz.
OneoftherequirementstoproperlysetupthispluginisthatyouneedtobeawareofthefrequencyofyourrolloveractionstotunetheZabbixitem;pleasebeawarethatalittlelatencyisnormalhere.Anyway,aslongasyoudon’trolloverzoneseveryfewminutes(TTLissettoafewminutes),thislagwillnotbeanissue.
Now,beforeyoucanruntheplugin,youneedtohaveinstalledafewrequiredPerlmodules:
#perl-MCPAN-eshell
cpan>installNet::DNS
cpan>installNet::DNS::SEC
Wearesupposingthatyoualreadyhavecpaninstalled;ifyoudon’thaveitinstalledinyoursystem,pleaseinstallitwiththefollowinglineofcode:
#yuminstallcpan
Now,onceyouhaveinstalledtherequiredmodule,youneedtoinstalltheopenssl-develpackagewiththefollowingcommand:
#yuminstallopenssl-devel.x86_64
Now,youcanfinallyuncompressthesoftwarewiththefollowingcode:
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#tar-zxvf./dnssec-tools-2.1.tar.gz
#cd./dnssec-tools-2.1
#./configure&&make&&makeinstall
Nowin/dnssec-tools-2.1/apps/zabbix/,wehavealltheneededsoftware.Herearethepiecesofsoftwareavailablein/dnssec-tools-2.1/apps/zabbix/:
#ls-l
total40
-rwxrwxr-x.112741274768Jan22013backup-zabbix
-rw-rw-r--.1127412741706Jan22013item.fields
-rw-rw-r--.1127412742878Jan22013README
-rwxrwxr-x.1127412746763Feb152013rollstate
-rwxrwxr-x.1127412747720Feb152013uemstats
-rw-rw-r--.1127412741329Oct192011zabbix_agentd.conf
-rwxrwxr-x.1127412746314Feb152013zonestate
Finally,wecantryournewplugins,asfollows:
#./rollstatemydomain.com
ZSKphase3
#./zonestatemydomain.com
zonefilevalid
Now,it’stimetoenableournewplugins;todothis,weneedtodefineacoupleofnewentriesofUserParameterontheagentside’s/etc/zabbix/zabbix_agentd.conf:
UserParameter=dnssec-tools.rollover.status[*],rollstate$1
UserParameter=dnssec-tools.rollover.statusnum[*],rollstate–numeric$1
Evenhere,youneedtoplacetherollstateplugininadirectorycontainedinthepathorusethefullyqualifiedpathforourplugin.Also,onceyouhaveaddedUserParameter,youneedtorestarttheagentwith:
#servicezabbix-agentrestart
ShuttingdownZabbixagent:[OK]
StartingZabbixagent:[OK]
Therollstatepluginprovidestwodifferentoutputswiththe–numericoptionspecified.ItprovidespositivenumbersfortheZSKphasesandnegativenumbersfortheKSKphases.ThisenablesustoproduceagraphthatrepresentsallthephasesofDNSSEC.
OnceyouhavecreatedtheZabbixagentitemonyourtemplateandyourscriptisrunning,theoutputwillbelikethenextscreenshot.
Intheexampleandtherelativegraph,wehaveahighlyfrequentrollover.Inareal-lifescenario,thetimerequiredtogothroughallthedifferentstatuseswillbelonger.
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ThedetailsoftheDNSSECrolloverintextmode,usefultokeeptrackofallthestatuschanges,willbecontainedinatextitem.Anexampleofthelatestdataisshowninthenextscreenshot:
Asyoucansee,youwillhaveahistoricalstatusofallthestepscrossedduringtherollover,andyouwillhaveacleartrackofthestepsperformed.
NoteThisitemwillbepreciousifyourprocessgetsstuckonastep,especiallyifthishappensperiodically.
Inthenextscreenshot,youcanseethezonestatuspluginatwork:
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Now,theonlythingyoustillhavetodoiscreateatriggerbasedontheinformationwe’reacquiring.Here,itisimportanttobearinmindthatalittlelagisnormalduringthezonetransferprocess;thislagneedstobeconsideredwhenyousetupthetrigger.
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ApachemonitoringMostofthereverseproxiesarenowadaysimplementedusingApache.Apache,otherthanbeingawebserver,isquiteusefulasareverseproxyasitincludessomepowerfulmodules:
mod_proxy
mod_proxy_http
mod_proxy_ftp
Otherthanasareverseproxy,itcanbeusedasaloadbalancerthanksto:
mod_proxy_balancer
Now,unfortunately,thereisn’tavalidmethodtoacquirethemetricsstrictlyrelatedtothemoduleused,butanyway,wecanacquirequiteafewmetricsfromApacheitself.
Thefirstthingyouhavetodobeforeyoucanacquirethestatisticsisenablethem.Todothis,youneedtoputthefollowinglinesinyourApacheconfigurationfile:
<Location/server-status>
SetHandlerserver-status
Allowfrom127.0.0.1
Orderdeny,allow
Denyfromall
</Location>
Also,youcanoptionallyaddthefollowinglinetoyourglobalApacheconfigurationfile:
ExtendedStatusOn
Here,weareconfiguringthemodulewiththeExtendedStatusOnoption.Withthissetting,Apachekeepstrackofextendedstatusinformationforeachrequest.Thiscollectioncanslowdowntheserver,andifyounoticeperformanceissues,itcanbedisabledwiththeExtendedStatusOffkeyword.
TipPleasekeeprestricted,asmuchasyoucan,theaccesstothe/server-statuslocation.Inourcase,itisallowedonlyfrom127.0.0.1.ThismeansthatyouneedtocollectthestatisticsfromtheagentinstalledlocallyonyourApachehost.Itisimportanttoknowthatifmod_statusiscompiledintotheserver,thenitshandlerisavailableinallconfigurationfiles,includingper-directoryfiles,likehtaccess.Thiscanhavesecurity-relatedramificationsforyoursite.
Now,allyouhavetodoisrestartyourApacheandcheckwhetheryoucanretrievethestatisticsrunningthefollowingcommand:
[root@localhost~]#curlhttp://127.0.0.1/server-status
<!DOCTYPEHTMLPUBLIC"-//W3C//DTDHTML3.2Final//EN">
<html><head>
<title>ApacheStatus</title>
</head><body>
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<h1>ApacheServerStatusfor127.0.0.1</h1>
<dl><dt>ServerVersion:Apache/2.2.15(Unix)DAV/2PHP/5.3.3</dt>
<dt>ServerBuilt:Jul23201414:17:29
</dt></dl><hr/><dl>
<dt>CurrentTime:Monday,03-Nov-201419:48:11PST</dt>
<dt>RestartTime:Monday,03-Nov-201419:48:00PST</dt>
<dt>ParentServerGeneration:0</dt>
<dt>Serveruptime:11seconds</dt>
<dt>Totalaccesses:9-TotalTraffic:0kB</dt>
ThisApachemodule’soutputisreallyfullofusefulinformation;lookingattheoutputindetail,youcanseethatitprovidestheinformationshowninthefollowingscreenshot:
Here,youhaveaviewthatissplitintofourmainsections,whichareasfollows:
TheApacheversiondata,modulestarted,andserverbuilddetailsTheApacheserverstatusthatprovidesyoutheuptime,CPU,numberofaccess,numberofrequest/sec,andsomemoreinformationaboutitsstatusTheApachescoreboardAsectionwithallthedetailsoftheconnectionserved
Here,retrievingthestatisticsisnotaseasyasyouwouldimagine.Thefirstandsecondsectionsarequiteverbose,anditiseasytoextracttherequiredinformationfromthemonceyou’veobtainedthewebpage.ThethirdsectionisalittlemorecomplexasitistheApachescoreboard.ThescoreboardisarepresentationofApache’sworkersandtheirrelativestatus.TheworkersareApache’srequest-handlerstatus.Thekeysusedonthescoreboardarethefollowing:
www.it-ebooks.info
ScoreboardKey:"_"WaitingforConnection,"S"Startingup,"R"Reading
Request,"W"SendingReply,"K"Keepalive(read),"D"DNSLookup,"C"Closing
connection,"L"Logging,"G"Gracefullyfinishing,"I"Idlecleanupof
worker,"."Openslotwithnocurrentprocess
Then,toretrieveandanalyzethestatus,weneedtouseaslightlydifferentURL:http://localhost/server-status?auto.
WecantrytheoutputproducedbythisURLusingcurl,asfollows:
#curlhttp://127.0.0.1/server-status?auto
TotalAccesses:1334
TotalkBytes:2163
CPULoad:5.20713
Uptime:2776
ReqPerSec:.480548
BytesPerSec:797.879
BytesPerReq:1660.35
BusyWorkers:1
IdleWorkers:10
Scoreboard:
_______W___…...............................................................
...........................................................................
...........................................................................
.............................
Now,it’seasytoretrievetheCPULoadvalue,forinstance:
#curl-shttp://127.0.0.1/server-status?auto|awk'/^CPULoad:/{print
$2}'
5.15882
Withthesamemethod,wecanacquireallthemetrics,forexample,thenumberofIdleWorkerswillbe:
#curl-shttp://127.0.0.1/server-status?auto|awk'/^IdleWorkers:/
{print$2}'
10
Parsingthescoreboardisalittledifferentasweneedtocountthenumberof_ifwearelookingatalltheworkersthatarewaitingforaconnectioninsteadofcountingalltheoccurrencesofWtocheckalltheworkersthataresendingreplies.Toaddressthisrequirement,youcanusethefollowingcommand:
#curl-shttp://127.0.0.1/server-status?auto|awk'/^Scoreboard:/
{print$2}'|awk'BEGIN{FS="_"};{printNF-1}'
10
ThefirstawkcommandidentifiestheScoreboard:section,thesecondawkcommandcountsalltheoccurrencesof_intheline,definingafieldseparator,andthencountingallthematchedfields.
Currently,therearethreeprebuiltpluginstodothis:
zapache:ThisisashellscriptcalledviaUserParameterZabbixApacheUpdater:ThisisaPythonsoftwarethatneedstobescheduledon
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crontabquery_apachestats.py:ThisisaPythonsoftwaretriggeredbyUserParameter
Inthissection,wewillanalyzezapacheasitusesthesamemethoddescribedtoacquiremetricsfrommod_statusofApache.Thescriptisavailablefordownloadathttps://github.com/lorf/zapache.
Allyouhavetodoisdownloadzapachefromthatlocation,copyzapacheunder/home/zabbix/bin/withtherelativetemplate,andthenconfigureUserParameterintheagentconfigurationfile/etc/zabbix/zabbix_agentd.conf,asshownhere:
UserParameter=zapache[*],/home/zabbix/bin/zapache$1
Now,ontheGUI,youhavetocreateyourtemplateorimporttheonedistributedwithzapache.Then,navigatetoConfiguration|Template|Importandselectthezapache-template.xmltemplateifyouwanttheitemasZabbixagentorthezapache-template-active.xmltemplateifyouprefertheitemsmanagedasZabbixagent(active).
Ifyoutakealookatthezapachesourcecode,youwillnoticethatitcanrunasZabbixagent’smodeorasanexternalscript,whichmeansthatyoucanuseittoacquiretheApachestatisticslocallyonthesameserverorremotely.
Hereisthecodesectionthatmanagesthiskindofbehavior:
if[[$#==1]];then
#AgentMode
STATUS_URL="http://127.0.0.1/server-status?auto"
CASE_VALUE="$1"
elif[[$#==2]];then
#ExternalScriptMode
STATUS_URL="$1"
case"$STATUS_URL"in
http://*|https://*);;
*)STATUS_URL="http://$STATUS_URL/server-status?auto";;
esac
CASE_VALUE="$2"
Asyoucansee,youcanrunthescriptwithonlyoneparameter,whichrepresentsthemetricyouwouldliketoacquire,ortwoparameters,specifyingeventheremoteIPaddressofyourApachereverseproxyorwebserver.Here,inordertokeepthingseasy,weavoidmod_statusfrombeingaccessedexternallyusingaUserParameter.Anyway,itisbettertobeawarethatyoucanevencentralizestatisticacquisitionthankstothiscodesection.
ThefinalresultofoursetupandApache’smetricacquisitionisshowninthenextscreenshot:
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Now,itistimetodiscusstriggersrelatedtothisApachemonitoring.Firstofall,youneedtocreateatriggerbasedonthelastvalueofzapacheping,asfollows:
{TemplateAppApacheWebServerzapache:zapache[ping].last(0)}=0
Ofcourse,ifthezapachepingfails,returning0,youhaveanissue.Someotherparametersthatarecriticalforserverstatusandonwhichyoucancreatetriggersare:
WaitingForConnection:ThisindicatesthatthenumberofprocessesarewaitingforaconnectionReqPerSec:ThisindicatesthenumberofrequestspersecondCPULoad:ThisindicatestheamountofCPUconsumedbyApache
Thosevaluesarestrictlydependentontheserveryou’reusing,thenumberofclientsyouareserving,andmostimportantly,whatexactlyandhowyouareservingtherequest.Aboutwhatandhowyouareservingtherequest,youcanhavesomeverycomplexrewritingandreverserulesthatcanmakeagroupofURLsmorecomplextomanage.Here,thebestthingtodoistrytofindoutyourApache’slimitusingsometoolsthatareabletoproducealotofconcurrentconnectionsandthenworkload,forinstance,youcantrySiege.
NoteMoreinformationaboutSiegeisavailablehere:http://www.joedog.org/siege-home/.
Onceyou’vetestedandfoundthemaximumnumberofclientsyoucanserveperURLandyou’veseenthewebserverlimits,youcancreateandtuneyourcustomtriggers.
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NTPmonitoringThesystemclockissomethingyoushouldkeepmonitoringbecauseif,forsomereason,yoursystemsuffersasystemclockdrift,thiscanbecomeabigissue.
Performingapracticalexampleofheavydriftonthesystemclockwillcauseissues.TheDNSSECzonereplication,yourFTPservice,theIMAPservice,andmanyotherserviceswillbeaffected,makingyourserverunstableandunusable.
TokeepyoursystemclockinsyncwiththeremoteNTP,youcanuseandinstalltheNTPdaemonthatwilltakecareofthesystemclock.
ToinstallNTP,youcanuseyumasusual:
#yuminstallntp
...outputremovedhere…
Installed:
ntp.x86_640:4.2.6p5-1.el6
Complete!
Onceyou’veinstalledtheNTP,youneedtofindtheserverthatisclosertoyouusingthewebsitehttp://www.pool.ntp.org/en/.
Fromthiswebsite,youneedtochoosetheserverthatisbetterforyouandthenchangethe/etc/ntp.confconfigurationfile.
Also,itisagoodpracticetoaddthelogfiledirectiveattheendofthentp.confconfigurationfile,asfollows:
#echo"logfile/var/log/ntp.log">>/etc/ntp.conf
Thenstartorrestarttheservice,asfollows:
#servicentpdstop
Shuttingdownntpd:[OK]
#servicentpdstart
Startingntpd:[OK]
Now,youneedtoconsiderthatyoucanhaveonecentralserverusedasaprimaryntpdserverforyournetworkandpropagatethesystemtimefromthere;inthiscase,youneedtochangethe/etc/ntp.confconfigurationfileabit:
#Hostsonlocalnetworkarelessrestricted.
restrict192.168.1.0mask255.255.255.0nomodifynotrap
Nowfinally,youcanattachallthehostsofyournetworktothisntpdserverandthenmonitorthisNTPandtheclient’stime.
TipIfyouareprotectingaserverwithafirewall,youneedtoenabletheUDPonport123onbothdirections.Ifyou’reusingiptablestoenabletheclientandtheservercommunication,youneedtoaddthefollowingrulestotheOUTPUTandINPUTchains:
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iptables-AINPUT-pudp--dport123-jACCEPT
iptables-AOUTPUT-pudp--sport123-jACCEPT
Now,toretrievemetrics,weneedtoqueryntpd.Forthisoperation,wecanusentpq,whichwillshowallthestatistics.Fromamonitoringperspective,we’relookingfortheoffset,jitter,anddelay.
Inthenextexample,weseethecompleteoutputofntpq,asfollows:
#ntpq-pn127.0.0.1
Remoterefidsttwhenpollreachdelayoffsetjitter
==================================================================
+91.247.253.152191.241.139.1373u964135.27629.4929.791
+217.147.208.1194.242.34.1492u864119.61730.91211.497
*192.33.214.47129.194.21.1952u764125.58132.15711.007
+195.141.190.190212.161.179.1382u664120.73931.14310.983
Pleasenotethatthisserverissufferingabigdriftandthetriggerisalreadyonfire.
Toacquirethemetricthen,wecanuseacommandlikethisone:
#ntpq-pn127.0.0.1|/usr/bin/awk'BEGIN{offset=0}$1~/\*/{
offset=$9}END{printoffset}'
32.157
ThiscommandretrievestheoffsetbetweenthesystemclockandtheNTPserver.
NoteWeareusingthe–pand–noptionstogether;withthe–noption,weareavoidingthenameresolution,andthentheDNSquery.Thisisdoneinordertokeeptheitemaslightweightaswecan.
Now,wecanquicklysetupNTPmonitoringusingUserParameterontheagentsidewith:
UserParameter=ntp.jitter,ntpq-pn127.0.0.1|/usr/bin/awk'BEGIN{
offset=0}$1~/\*/{offset=$9}END{printoffset}'
ThiswillsetUserParametertoretrievethejittervalue;anyway,wecanevendosomethingalittlemorecomplexandthenproduceascriptlikethefollowing:
#!/bin/bash
VERSION="1.0"
functionusage()
{
echo"ntpcheckversion:$VERSION"
echo"usage:"
echo"$0jitter-Checkntpjitterdelay"
echo"$0offset-Checkntpoffset"
echo"$0delay-Checkntpdelay"
}
########
#Main#
########
if[[$#!=1]];then
#NoParameter
usage
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exit0
fi
case"$1"in
'jitter')
value="'ntpq-pn127.0.0.1|/usr/bin/awk'BEGIN{jitter=0}$1
~/\*/{jitter=$10}END{printjitter}''"
rval=$?;;
'offset')
value="'ntpq-pn127.0.0.1|/usr/bin/awk'BEGIN{offset=0}$1
~/\*/{offset=$9}END{printoffset}''"
rval=$?;;
'delay')
value="'ntpq-pn127.0.0.1|/usr/bin/awk'BEGIN{delay=0}$1
~/\*/{delay=$8}END{printdelay}''"
rval=$?;;
*)
usage
exit1;;
esac
if["$rval"-eq0-a-z"$value"];then
rval=1
fi
if["$rval"-ne0];then
echo"ZBX_NOTSUPPORTED"
fi
echo$value
Then,ontheagentside,wecandeploythisscriptcalledntpcheck.shinthe/home/zabbix/bindirectory:
#ls-la/home/zabbix/bin/ntpcheck.sh
-rwxr-xr-x1zabbixzabbix781Nov903:23/home/zabbix/bin/ntpcheck.sh
Oncethisisdone,allwehavetodoiscreateUserParameter,asfollows:
UserParameter=ntp[*],/home/zabbix/bin/ntpcheck.sh$1
Then,restarttheagent:
#servicezabbix-agentrestart
ShuttingdownZabbixagent:[OK]
StartingZabbixagent:[OK]
Testournewitems:
#zabbix_get-s127.0.0.1-kntp[jitter]
2.273
#zabbix_get-s127.0.0.1-kntp[offset]
-6.696
#zabbix_get-s127.0.0.1-kntp[delay]
18.956
Andintheend,createourthreenewitemsontheZabbixGUI,asshowninthefollowingscreenshot:
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NTP–whatarewemonitoring?Now,evenifthoseitemnamesappearassomethingeasytounderstand,itisbettertoknowwhatwearemonitoring.Firstofall,weneedtoclarifythatwe’reacquiringvaluesforthecurrenttimesource,hencewearetakingthevaluesinthelinethatbeginswitha*fromthentpqoutput.Forconvenience,thentpqoutputisreportedhere:
#ntpq-pn127.0.0.1
Remoterefidsttwhenpollreachdelayoffsetjitter
==================================================================
+91.247.253.152191.241.139.1373u964135.27629.4929.791
+217.147.208.1194.242.34.1492u864119.61730.91211.497
*192.33.214.47129.194.21.1952u764125.58132.15711.007
+195.141.190.190212.161.179.1382u664120.73931.14310.983
Asyoucansee,thelinesofthisoutputarenotordered,andtheybeginwith+and*(inthisexample).Weareinterestedintheonethatbeginswith*.Thereasonisthatthelinethatbeginswith*representsthepreferredandcurrenttimesource.
Wecanevenhaveaprefixlikethefollowing:
+:Thissignindicatesthatthepeerisagood,preferredremotepeerorserver(space),x,-,#,and.:Theseindicatethatthispeerisnotbeingusedforsynchronization
Now,wehaveclarifiedthereasonwhywearerunningthisawkcommand:
#ntpq-pn127.0.0.1|/usr/bin/awk'BEGIN{delay=0}$1~/\*/{delay=$8
}END{printdelay}'
Now,tohavesomemoredetailsaboutwhatwe’reacquiring,wecandefinethemas:
Delay:Thisisthecurrentestimateddelay.Itisthetransittimebetweenremotepeersorserversinmilliseconds.Offset:Thisisthecurrentestimatedoffset.Itisthetimedifferencebetweenremotepeersinmilliseconds.Jitter:Thisisthecurrentestimateddispersion,orbetter,thevariationindelaybetweenthesepeersinmilliseconds.
NoteIfyou’remonitoringaserverthatisrunninginavirtualenvironment,youneedtobeawarethatpracticallyallthevirtualizationsoftwaresuffersfromsystemclockdrift.Thencheckthevendor-specificbestpracticetoreducetheNTPdrift.
Nowit’stimetochangethescriptalittleaswecanchecktheNTPhealthstatusbyaddingthefollowingcasestatement:
case"$1"in
…
'health')
primary="'ntpq-pn127.0.01|grep^\*|grep-vgrep|wc-l'"
rval=$?
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if["${primary}"-eq"1"];then
value="1"
else
value="0"
fi
;;
…
esac
Now,wecancheckwhetherwehaveatleastoneprimarypreferredsourcedefinedtogettheNTPsyncinagoodshape.Weneedtothenaddanewitemandarelatedtriggerthatwillgoonfireifthevaluereturnedis0.Otherthanthistrigger,wecanevenhaveatriggerthatwillgoonfireiftheclockdriftisbiggerthan50millisecondsforinstance,orevenless.
Inthenextscreenshot,youseetheinteractionbetweentheJitter,Offset,andDelayonaLinuxvirtualserver(thatsufferfrombigsystemclockdrifts):
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SquidmonitoringSquidisthemostdiffusedcachingproxyfortheWeb.SquidsupportsHTTP,HTTPS,FTP,andmanymoreprotocols.Thisproxysoftwarereducesalotofthebandwidthrequiredtoserveitsclientsandimprovestheresponsetime,implementingaverygoodcachingsystem.Forallthosereasons,itisquiteevidentwhyyoushouldhaveSquidtomonitorinsideyournetwork.
TherearetwoprimarywaystoacquiredataandmetricsfromSquid:
UsingSNMPUsingsquidclient
Ifyou’recuriousabouttheSNMPsetupontheSquidserver,youcanhavealookattheofficialdocumentation,inparticularthesectionavailableathttp://wiki.squid-cache.org/Features/Snmp.
WeshouldavoidenablingSNMPonourSquidasithasbeenaffectedinthepastbymanyoverflowsandissues.Thelastsecurityissue,atthetimeofwritingthis,causedbySNMPenabledonSquid,isavailableathttp://www.squid-cache.org/Advisories/SQUID-2014_3.txt,andasyoucansee,itisareallyrecentissue.
Fortunately,theclientisreallypowerfulandthispermitsustoimplementagoodmonitoringsolutionwithoutenablingSNMP.
Typethefollowingcommand:
#squidclientmgr:info
Inresponsetotheprecedingcommand,Squidwillprintouttheentirestatisticdomainacquireduntilnow:
HTTP/1.0200OK
Server:squid/3.1.10
Mime-Version:1.0
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Then,asyoucanunderstand,itwillbequiteeasytoretrievesomeimportantitemsfromthiskindofoutput.Tryingoutanexample,ifyouwouldliketoacquiretheCPUUsage,youcansimplyrun:
#squidclientmgr:info|grep'CPUUsage:'
CPUUsage:0.01%
Ofcourse,thiskindofoutputneedstobealittleshapedtobeusableforourwork,thenext
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commandwillbeaUserParameterreadycommand:
#squidclientmgr:info|grep'CPUUsage:'|cut-d':'-f2|tr-d'%'|tr-d'
\t'
0.01
Now,wehavetwowaysofdoingthis:
WecreatealonglistofUserParameterontheagentsideWecreatejustaone-userUserParameterandcallitusingaparameter
Thesecondwayisthepreferredapproachasifyouneedtoaddanitemtoacquire,youdon’tneedtorestarttheagent.Hereduetospaceconstraints,wewillnotcommentallthescript;forthecompletescript,pleaserefertoAppendixB,CollectingSquidMetrics.
YouneedtocreateUserParameter:
UserParameter=squid[*],/home/zabbix/bin/squidcheck.sh$1
Now,youneedtorestarttheagent,andyoucancheckwhetheryou’reabletoacquirethemetricswiththefollowingcommand:
#zabbix_get-s127.0.0.1-ksquid[icp_sent]
12
Ifyoucanretrievethemetrics,theconfigurationisfine.
Now,ontheserverside,youneedtocreateyouritems,asshowninthefollowingscreenshot:
Nowthatwearefinallyacquiringallthemetrics,itisimportanttodefineatleasttwo
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triggers:
OnetiedtothenumberofSquidprocessesrunningthatshouldneverbe0Onetiedtothenumberofavailablefiledescriptors;ifthisnumberislessthan100,weneedtohaveatriggeronfire
Thisisshowninthefollowingscreenshotandistheminimumnumberoftriggersyoushouldhave:
ToclosetheSquidmonitoring,wecantellthatyouarenowabletoacquireatleast22itemsusingthescriptavailableonGitHubathttps://github.com/smartmarmot/zabbix_network_monitoring/tree/master/Chapter3;youcannowsetmanyothertriggersdependingonyoursetup,servercapacity,numberofclientstoserve,andthemeanofthenumberofpagesrequiredbyyourclientnetwork.
Amongthemostimportantparameterstomonitor,wehave:
Thebytehitratioover5and60minutesTherequestdiskhitratioover5and60minutesRequestfailureratio
Allthehitratiosneedtobeascloseto100percentaspossible.Everyvalueofcachingunder70percentshouldmakeatriggergoonfire,andeventherequestfailureratio,ifitishigherthan30,shouldtriggeranalarmasitistellingusthatoursystemisnotrespondingproperly.
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SummaryInthischapter,wecoveredalargenumberofcomponents.Westartedourdiscussionfromthemostusedandevenverycriticalnetworkservice:DNS.Goingaheadonthesameway,wediscussedDNSSEC;then,wemovedontoApache,themostusedandeffectivereverseproxy;walkedthroughNTP;andclosedthechapterwithSquid,themostinstalledandusedproxyservice.Forallthesystemsandservicesanalyzed,you’renowabletoacquirethemostcriticalmetrics,andyouknowhowtocreateeffectivetriggers.
Triggersherearecoveringthemostcriticalroleandhenceyourexperiencewithinyournetworkisthetrulyaddedvalue.You,withtheknowledgeacquiredfromthischapterandyourenvironmentexperience,willbethekeytocreatingeffectiveandproactivetriggers.Thischapterhascoveredallthecriticalservicesyoucanfindinanetwork,andnowyoucaneasilyprovideaheavyaddedvalue,creatingproactivechecksandinstallinganeffective,tailor-mademonitoringsolution.Inthenextchapter,youwilllearnhowtoautomatethediscoveringofyournetwork’selementsandhowtoapplyatemplatetothediscovereditem.Also,youhavetoadaptyourmonitoringsystemwithinyourenvironments,andthiskindoftaskisthetypicalboringandtime-consumingtaskthatanetworkadmindoesn’tliketodo.Thechapterwillprovideyouwithallthenecessaryinformationtousethehostdiscoveryandthelow-leveldiscoveryinaneffectiveway.Youwillbeguidedthroughthedifficultwaytoautomatetheitemdiscovery:thiswillheavilyreducethetimeneededtostartupyourmonitoringsolutionbutwillimpactandreducethetimeneededtomaintainyourgrowinganddynamicallymovingsetup.
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Chapter4.DiscoveringYourNetworkInthepreviouschapters,we’veseenhowtogetdifferentmetricsfromquiteafewdifferentsources,usingdifferentmethods.Whatwehaven’tcoveredyet,ishowtoeasilygetallthisdataintoZabbixwhenyouhaveagreatnumberofmonitoredobjects.
Manuallycreatinghosts,items,andtriggersisanexcellentexercisetogetthehangofhowthingsworkinZabbix,butitcanquicklybecomearepetitive,boring,error-proneactivity.Inotherwords,theyarethekindsoftaskscomputersweremadeforinthefirstplace.
Whatifyourmonitoringsolutioncouldjustfindthehostsanddevicesyouwanttomonitor,addthemasZabbixhosts,applyatemplate,andstartmonitoringthem?Andwhatifitdidn’tjustlimititselftofindinghoststomonitor,butitalsofoundoutwhetheryourswitchhas24or48ports,howmanydisksyourwebserverhasattached,andwhatportsareopenonacertainhost?Aftersomeinitialconfiguration,youwouldnothavetobotherwithaddingorremovingthingstomonitor.Itwouldcertainlybegreat,buttheproblemwithautomateddiscoveryisthatitoftenhastocometotermswiththerealityofareal-worldnetwork,whichisoftenfullofexceptionsandspecialrules.Insuchcases,youcouldfindyourselfspendingalotoftimetryingtoadaptyourmonitoringsystemtoyourenvironmentinordertocatchupwithanautomateddiscoverythatmightbejustalittletooautomatic.
Luckily,Zabbixcansupportmanydifferentdiscoverystrategies,mixthemupwithregularhostanditemcreation,andgenerallyprovideagoodbalancebetweentheneedtohaveafullyautomatedsystemandtheneeddohaveamonitoringsolutionthatmatchesascloselyaspossibletheenvironmentithastomonitor,withallitsexceptionsandspecialcasesthatareimpossibletocapturewithjustadiscoverystrategy.
ThischapterwillbedividedintotwomainpartsthatmirrorthetwomainlevelsofdiscoverythatZabbixsupports:networkdiscoveryandlow-leveldiscovery.Theformerisusedtofindoutwhichhostsareinyournetwork,andthelatterisusedtofindoutwhatfacilitiesandcomponentsarefeaturedinagivenhost.
Let’sstartwithfindingouthownetworkdiscoveryworksandhowtomakethemostoutofit.
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FindinghoststheZabbixwayZabbix’sdiscoveryfacilitiesconsistofasetofrulesthatperiodicallyscanthenetwork,lookingfornewhosts,ordisappearingones,accordingtopredeterminedconditions.
ThethreemethodsZabbixcanusetocheckfornewordisappearedhosts,givenanIPrange,are:
TheavailabilityofaZabbixagentTheavailabilityofanSNMPagentTheresponsetosimpleexternalchecks(FTP,SSH,andsoon)
Thesecheckscanalsobecombined,asillustratedinthefollowingexample:
Asyoucansee,whenenabled,thisrulewillcheckeveryhour,intheIPrange192.168.1.1-254,foranyserverthat:
ReturnsanSNMPv3valuefortheSNMPv2-MIB::sysDescr.0OIDIslisteningtoandacceptingconnectionsviaSSHHasanHTTPSserverlisteningonport8000
Beawarethatadiscoveryeventwillbegeneratedifanyoneoftheseconditionsismet.
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So,ifadiscoveryrulehasthreechecksdefinedandahostinthenetworkrespondstoallthreechecks,threeeventswillbegenerated,oneperservice.
AsusualwithallthingsZabbix,adiscoveryrulewillnotdoanythingbyitself,exceptgenerateadiscoveryevent.ItwillthenbethejobofZabbix’sactionsfacilitytodetecttheaforesaideventanddecidewhetherandhowtoactonit.
Discoveryeventactionsareverysimilartoregulartriggereventactions,soyou’llprobablybealreadyabletomakethemostoutofthem.ThemainthingtorememberisthatwithZabbix,youcannotactdirectlyonaneventtocreateordisableahost:youneedtoeithercopytheeventdatabyhandsomewhereandthenproceedwithallthemanualoperationsneededbasedonthatdata,oryouneedtoproperlyconfiguresomeactionstodothatworkforyou.Inotherwords,withoutaproperlyconfiguredaction,adiscoveryrulewillnotaddbyitselfanydiscoveredhosttothelistofmonitoredones.
Everyactionhasaglobalscope:it’snottiedtoanyparticulartrigger,host,orhostgroupbydefault.Thismeansthatwhenyoucreateanaction,you’llneedtoprovidesomeactionconditionsinordertomakeitvalidonlyforcertaineventsandnotothers.ToaccessthediscoveryactionssectioninthewebUI,headtoConfiguration|ActionsandthenselectDiscoveryfromtheEventsourcedrop-downmenu,justundertheCreateactionbutton.
Whenyoucreateanaction,you’llstartwithgivingitanameanddefiningadefaultmessageintheactiondefinitionsection.You’llthenmovetotheactionconditionssectiontoprovidefilteringintelligence,beforefinishingwiththeactionoperationssectiontoprovidetheaction’scorefunctionality.Actiondefinitionsareprettysimpleasyou’lljustneedtoprovideauniquenamefortheactionandadefaultmessage,ifyouneedone.So,let’smovestraighttotheinterestingsectionsofactionconfiguration:conditionsandoperations.
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DefiningactionconditionsTheactionconditionssectionletsyoudefineconditionsbasedontheevent’sreportedhostIPaddress,servicestatusandreportedvalue,discoveryrules,andafewothers:
TheReceivedvalueconditionisofparticularinterest,asitallowsyoutodothingslikedifferentiatingbetweenoperatingsystems,applicationversions,andanyotherinformationyoucouldgetfromaZabbixorSNMPagentquery.Thiswillbeinvaluablewhendefiningactionoperations,asyou’llseeinthenextparagraph.Areceivedvaluedependsonthediscoveryruleandontheoutputofthediscoveryeventthattriggerstheaction.Forexample,ifadiscoveryruleissettolookforhostsrespondingtoanSNMPGetfortheSNMPv2-MIB::sysDescr.0OID,andthatrulefindsarouterthathasC3745asthevalueofthatOID,thenthediscoveryeventwillpassC3745totheactionasthereceivedvalue.
Singleconditionscanbecombinedtogetherwithlogicaloperators.There’snotmuchflexibilityinhowyoucancombinethemthough.
YoucaneitherhaveallAND,allOR,oracombinationofthetwowhereconditionsofdifferenttypesarecombinedwithAND,whileconditionsofthesametypearecombinedwithOR.
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ChoosingactionoperationsDiscoveryactionsaresomewhatsimplerthantriggeractionsastherearenostepsorescalationsinvolved.Thisdoesn’tmeanthatyoudon’thavequiteafewoptionstochoosefrom:
Pleasenotethatevenifyoudefinedadefaultmessage,itwon’tbesentuntilyouspecifytherecipientsinthissectionusingtheSendmessageoperation.Ontheotherhand,ifadding(orremoving)ahostisaquiteself-explanatoryaction,whenitcomestoaddingtoahostgrouporlinkingtoatemplate,itbecomesclearthatagoodsetofactionswithspecificreceivedvalueconditionsandtemplate-linkingoperationscangiveahighlevelofautomationtoyourZabbixinstallation.
NoteThishighlevelofautomationisprobablymoreusefulinrapidlychangingenvironmentsthatstilldisplayagoodlevelofpredictability,forexample,thekindofhostsyoucanfind,suchasfast-growinggridsorclusters.Inthesekindsofenvironments,youcanhavenewhostsappearingonadailybasis,andmaybeoldhostsdisappearatalmostthesamerate,butthekindofhostismoreorlessalwaysthesame.Thisistheidealpremiseforasmallsetofwell-configureddiscoveryrulesandactions,soyoudon’thavetoconstantlyandmanuallyaddorremovethesametypesofhosts.Ontheotherhand,ifyourenvironmentisquitestableoryouhaveaveryhighhosttypevariability,youmightwanttolookmorecloselyatwhich,andhowmanyhosts,youaremonitoringasanyerrorcanbemuchmorecriticalinsuchenvironments.
Also,limitingdiscoveryactionstosendingmessagesaboutdiscoveredhostscanprove
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quiteusefulinsuchchaoticenvironmentsorwhereyoudon’tcontroldirectlyyoursystems’inventoryanddeployment.Insuchcases,gettingsimplealertsaboutnewhosts,ordisappearingones,canhelpthemonitoringteamkeepZabbixupdateddespiteanycommunicationfailurebetweenITdepartments,accidentalorotherwise.
Moreover,youarenotstuckwithe-mailsandSMSesfornotificationsorlogging.InanActionoperationform,youcanonlychooserecipientsasZabbixusersandgroups.Iftheusersdon’thaveanymediadefined,ortheydon’thavetherightmediafortheactionoperation,theywon’treceiveanymessage.AddingmediatousersisdonethroughtheAdministrationtaboftheZabbixfrontend,whereyoucanalsospecifyatimewindowforaspecificmediatobeused(sothatyouwon’tgetdiscoverymessagesasanSMSinthemiddleofthenightforexample).Speakingofusersandmediatypes,youcanalsodefinecustomones,throughtheMediatypessectionoftheAdministrationtabinZabbix’sfrontend.NewmediatypeswillbeavailablebothintheMediasectionoftheuserconfigurationandastargetsformessagesendingintheActionoperationsform.
AninterestingusefornewmediatypesistodefinecustomscriptsthatcangobeyondsimpleemailorSMSsending.
AcustommediascripthastoresideontheZabbixserver,inthedirectoryindicatedbytheAlertScriptsPathvariable,inthezabbix_server.confconfigurationfile.Whencalledupon,itwillbeexecutedwiththreeparameterspassedbytheserverandtakenfromtheactionconfigurationinthecontextoftheeventthatwasgenerated:
$1:Thisistherecipientofthemessage$2:Thisisthesubjectofthemessage$3:Thisisthemainmessagebody
Therecipient’saddresswillbetheonedefinedforthenewmediatypeinthecorrespondingmediapropertyfortheuserspecifiedintheactionoperationstep.Thesubjectandthemessagebodywillalsobepassedaccordingtotheactionoperationstep,asshownintheprecedinglist.ThisisallthatZabbixneedstoknowaboutthescript.
Thefactis,acustomscriptcanactuallydomanydifferentthingswiththemessage:loggingtoalocalorremotedirectory,creatinganXMLdocumentandinteractingwithalogmanagerwebservicesAPI,printingonacustomdisplay—justaswitheverycustomsolution,thesky’sthelimitwithcustommediatypes.
Hereisasimple,practicalexampleofsuchacustommediatype.Let’ssaythatyourITdepartmenthasimplementedaself-provisioningserviceforvirtualmachinessothatdevelopersandsystemadminscancreatetheirownVMsandusethemforalimitedamountoftimebeforetheyaredestroyedandtheresourcesrecycled.Thislaboratoryofsortshasbeenputinaseparatenetwork,butusersstillhavetogainaccesstoit,andtheyarealsoadministratorsofthoseVMs,sothere’sverylittlecontroloverwhatgetsinstalled,configured,oruninstalledonthosemachines.Inotherwords,whileyoucouldprovisiontheVMswithapreinstalledZabbixagent,youcan’treallyrelyonthefactthatyourusers,whetherinadvertentlyorforspecificreasons,wouldnotdisableit,orwouldnotinstallservicesthatshouldreallynotbethere,likeaDHCPserverforexample.So,youdecideto
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keepaneyeonthosemachinesdirectlyfromtheZabbixserver(orasuitableproxy)andimplementasimplediscoveryrulethatwillgenerateadiscoveryeventforeveryhostthatrespondstoanICMPechorequestandnothingmore,asfollows:
Basedonthatrule,you’llwanttoconfigureanactionthat,foreveryhostinthatsubnet,willperformaportscanandreporttheresultsviamailtoyou.
Todothat,you’llfirstneedtohaveacustommediatypeandthecorrespondingscript.So,youheadtoAdministration|MediatypesandclickonCreatemediatype.Oncethere,youassignasuitablename,selectScriptasatypeandprovideZabbixwiththenameofthescripttoexecute.Here,youjustneedtodefinethescriptname,asshowninthefollowingscreenshot.You’llfindoutlaterinthechapterinwhatdirectorytheactualscriptshouldbeplaced:
Justaddingamediatypeisnotenoughthough,you’llhavetoenableitfortheuseryouintendtosendthosereportsto.JustheadtoAdministration|Usersandselecttheuseryouwanttoaddthenewmediatypeto.Quitepredictably,thetabyouwantiscalledMedia.Addthemediayoujustcreatedandremembertoalsoaddawaytotellthescript
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whereitshouldsendtheresults.Sinceyouareinterestedinreceivingane-mailaddressafterall,that’swhatwe’lltellZabbix,asfollows:
TheSendtoparameterwillbethefirstargumentpassedtoport_scan.sh,followedbythesubjectandthebodyofthemessagetosend.So,beforeactuallydeployingthescript,let’sdefinethesubjectandthebodyofthemessage.Todothat,you’llneedtocreateanactionforthediscoveryevent,asfollows:
Forthepurposesofthescript,allyoureallyneedistheIPaddressofthehostyouaregoingtoscan,butitcertainlywouldn’thurttoaddsomemoreinformationinthefinalmessage.
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Thenextstepistodefinesomeconditionsfortheaction.Rememberthatactionsareglobal,sothefirstconditionyouwanttosetistheIPrangeonwhichthisactionwillbeperformed,otherwiseyou’druntheriskofperformingaportscanoneverydiscoveredhostinyournetwork.
Youmightalsowanttolimittheactionasaconsequenceforthediscoveryruleyoucreated,independentofanyotherrulesyoumighthaveonthesamenetwork.
Finally,youshouldmakeadecisionaboutthediscoverystatus.Ifyouwantaperiodicupdateofwhatportsareopenonadiscoveredhost,you’llalsoneedtodefineaconditionforthehosttobeUp:inotherwords,forthehosttobereportedasliveforatleasttwoconsecutivechecks.
Foraslongasthehoststaysup,aportscanwillbeexecutedandreportedaccordingtothediscoveryintervaloftheruleyoudefinedearlier.Ifyoujustwantaportscanforanewhostorforahostthathasbeenreportedasdownforawhile,you’lljustneedtofiretheactionontheconditionthatthehostisDiscovered;thatis,itisnowbeingreportedup,whileitwasdownbefore.Whatiscertainisthatyou’llwanttoavoidanyactionifthehostisdownorunavailable.
Thefollowingscreenshotencapsulatesthediscussioninthisparagraph:
Thelaststepistodefinetheactionoperationthatissendingthemessageviatheport_scancustommediatypetotheuseryouwant,asfollows:
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Oncedonewiththis,youarefinallyreadytocreatetheport_scan.shscript.So,headtotheAlertScriptsPathdirectoryasconfiguredinyourzabbix_server.conf(it’susuallydefinedas/usr/lib/zabbix/alertscripts)andcreatethefollowingscriptthere:
#!/bin/bash
RECIPIENT=$1
IPADDRESS=$2
MESSAGE=$3
SCAN="nmap-AT5-sT"
RESULT=$($SCAN$IPADDRESS)
(echo"ScanresultsforIP$IPADDRESS";
echo"$RESULT";
echo"";
echo"$MESSAGE")|mailx-s"Scanresultsfor$IPADDRESS"$RECIPIENT
NoteDon’tforgettosetthecorrectownershipandpermissionsforthescriptonceyouaredone:
#chownzabbixport_scan.sh
#chmod755port_scan.sh
Asyoucansee,theprogramthatwillperformtheactualportscanisNmap,somakesureyouhaveitinstalled.Incaseyoudon’thaveitinstalled,asimpleyuminstallnmapwilltakecareofthat.TheoptionspassedtoNmaparejustthebasics:-sTperformsasimpleconnect()scan.It’snotthefanciestone,butit’stheonlyoneavailabletonon-rootusers,
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andthescriptwillbeexecutedbyZabbixasthezabbixuser.–Aturnsontraceroute,OS,andservicedetectionsothattheoutputisascompleteaspossible.Finally,-T5forcesNmaptoexecutetheportscaninaslittletimeaspossible.Oncethescripthastheresultsoftheportscan,itwilljustconstructthemessageandsendittotherecipientdefinedintheaction.
Thisis,ofcourse,averybasicscript,butitwillgetthejobdone,andyou’llsoonreceiveaportscanreportforeverynewVMcreatedinyourself-provisioninglab.Tokeepthingssimpleandclear,wedidnotincludeanyconsistencycheckingorerrorreportingincaseofproblems,sothat’scertainlyawayyoucanimproveonthisexample.Youcouldalsotrytosendtheresultstoalogfile(oralogdirectory)insteadofamailaddress,oreventoadatabase,sothatotherautomationcomponentscanpickupthereportsandmakethemavailableviaothermediasuchaswebpages.Whatyou’llprobablywanttoavoidistodirectlychangethehost’sconfiguration,orZabbix’sownone,throughthisscript.
Evenifnoonewillpreventyoufromdoingso,it’sprobablybestifyouavoidusingallthispowertoexecutecomplexscriptsthatmightchangeyournetworkconfiguration,suchasenablinginterfaces,addingrulestoafirewall,andsuchlike.Whilethisisperfectlypossibleusingacustommediascript,thisshouldbethedomainofremotecommands.Thesewilltakecenterstageinthenextparagraph.
RemotecommandsTherearequiteafewoptionsavailabletoyouwhenitcomestoexecutingremotecommandsasanactionoperation.
YoucandefinealistofIPMIcommandstoberunonthetargethostoraseriesofSSHcommandsthatconnecttoaboxandperformvariousoperationsthere.AremotecommandcouldevenbeasimplewrapperforaremotescriptdeployedonaZabbixagent,oracustomscriptthatwillberuneitheronanagentorontheZabbixserveritself.
Thetruthis,sometimes,remotecommandscanbejustalittletoopowerful.Youcanstartandstopservices,deployorprovisionsoftware,makeconfigurationchanges,openorclosefirewallports,andeverythingelseyoucanpossiblyimagine,aslongasyoucanwriteascriptforit.Whilethiscansoundfascinatingandpromising,wehavefoundovertheyearsthatthesesolutionstendtobefragileandunpredictable.OneofthereasonsisthatZabbixdoesn’twarnyouifaremotecommandfails.Moreimportantly,environmentstendtochangefasterthantheseautomationtoolssothatyoucanquicklyfindyourselfdealingwiththeunintendedconsequencesofaremotecommandrunningwhereitshouldnotrun,ornotrunningwhenitshouldrun.
Themoreoftheseyouadd,themoreitwillbehardtokeeptrackofthem,andthemoreonecanbeluredintoafalsesenseofsecurity,countingonthefactthatremotecommandsaretakingcareofthings,while,infact,theymaybecontributingtothechaosinsteadoftamingit.
Thatsaid,it’scertainlyundeniablethatremotecommandscanbeuseful.Let’sseeanexamplethatisbothhelpfulforyourZabbixconfigurationandalsofairlysafe.
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InChapter2,ActiveMonitoringofYourDevices,we’veseenhowit’spossibletousesomeofthemeasurements,asreportedbyahost’sitems,topopulatethesamehost’sinventoryfields.Thisisagreatsolutionforthefieldsthatcanbefilledthisway,butwhatabouttheotherones?ThingslikePOCdetails,maintenancedates,installername,installedsoftware,andsuchlikecan’talwaysbeextrapolatedfrommonitoringmetricsastheymaysimplynotbeavailableonthemonitoredhostitself.
Theyusuallyareavailable,though,onassetinventorysystemsthatITdepartmentsusetokeeptrackofavailableresources.
Inthefollowingexample,you’llcreateanactionoperationthatwillexecutearemotecommandontheZabbixserver,fetchsomeinventoryinformationfromanassetdatabase,andfilluporupdatethehost’sinventorydetails.
Beforeproceedingwiththecommand,let’smakeanassumptionandsomepreparations.
Therearemanyassetinventorysystemsavailable,someproprietaryandsomeopensource.Allofthemhavedifferentdatabaseschemasanddifferentwaystoexposetheirdata.Moreover,aninventorydatabasestructuredependsasmuchontheactualenvironmentit’sputinto,andtheprocessesthatgoverntheaforesaidenvironment,asitisonitsinternalspecifications.So,wedecidedtouseadummyassetmanagementtoolthatwillreturn,givenanIPaddress,asimpleJSONobjectcontainingalltheinventorydatayouneedforthetaskathand.Theassumptionisthatyou’llbeabletoputtheexampleintoyourcontextandfigureouthowtoextractthesameinformationfromyourowninventorymanagementsystem,andthatyouwillalsoknowwhatauthenticationschemeyouwillrelyonifyouneedtomakejustonerequestormultiplerelatedrequests,andsoon.
Secondly,forpracticalreasonswearegoingtousePythonasthelanguageofthecommandscript,soyou’llwanttomakesurethatit’sinstalledandavailableonyourZabbixserver.Ifit’snotthere,youcaninstallit,andtherelatedutilities,quiteeasilyusingyum:
#yuminstallpython
#yuminstallpython-setuptools
#easy_installpip
Finally,wearegoingtointeractwithZabbix’sconfigurationnotthroughdirectqueriestoitsdatabase,butthroughitsAPI.Inordertodothat,we’lluseaveryusefulPythonlibrary,calledpyzabbix.Youcanfinditathttps://github.com/lukecyca/pyzabbix,butsinceyouinstalledpip,itwillbeextremelyeasytomakeitavailabletoyourPythoninstallation.Justrunthefollowingcommand:
#pipinstallpyzabbix
ThePythonpackagemanagerwilldownloadandinstallitforyou.
Nowwearereadytoconfigurethediscoveryactionandwritetheactualcommandscript.
Youcanchoosetoreuseanexistingdiscoveryrule,suchasthesimpleICMPruleyouusedinthepreviousparagraph,youcancreateanewonespecifictoasinglenetworktoscan,asingleTCPportthathastobeavailable,orthepresenceofaZabbixagent.Wewon’tgo
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intoanymoredetailshere,asyou’vealreadylearnedhowtoconfigureoneearlierinthechapter.Similarly,wecansafelyskipanydetailabouttheactionconditionsastheymightalsobeentirelysimilartothoseshownearlier.Whatchangesis,ofcourse,theactionoperation.Thefollowingscreenshotwillgiveyouabetterideaofwhatwehavebeentalkingaboutinthisparagraph:
TheimportantelementsherearethefactthatthescriptshouldbeexecutedontheZabbixserver,thefactthatwespecifiedthefullpathforthescript,andthefactthatweareusingthe{DISCOVERY.IPADDRESS}macroastheargument.
Oncetheactionisconfigured,youarereadytopreparetheactualscript.Let’sseehowitwouldlook:
#!/usr/bin/python
importsys
importjson
frompyzabbiximportZabbixAPI
importdummy_inventory_api
ipaddr=sys.argv[1]
hostinfo_json=dummy_inventory_api.getinfo(ipaddr)
#hostinfo_jsonwillcontainaJSONstringsimilartothisone:
#{"hostip":"172.16.11.11",
#"hostname":"HostA",
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#"inventory":{
#"asset_tag":"12345678",
#"install_date":"31-11-2014",
#"installer_name":"SKL"
#}
#}
hostinv=json.loads(hostinfo_json)['inventory']
zbx=ZabbixAPI(http://127.0.0.1/zabbix/)
zbx.login("admin","zabbix")
hostinfo=zbx.host.get(output=['hostid'],filter={'ip':ipaddr})
hid=hostinfo[0]['hostid]
zbx_inventory={
'date_hw_install':hostinv['install_date'],
'installer_name':hostinv['installer_name'],
'asset_tag':'12345678'
#addotherfieldsyoumaybeinterestedin…
}
zbx.host.update(hostid=hid,inventory=zbx_inventory)
sys.exit()
Asyoucansee,thescriptisfairlystraightforwardandsimplistic,butitcanbeusedasastartingpointforyourowninventory-updatingscripts.Themainthingthatyouneedtotakecareofistofigureouthowtogetyourinventorydatafromyourassetdatabase.YoumightneedtoconnecttoaRESTAPI,orgetanXMLdocumentviaawebservice,orevenperformsomequeriesviaODBC.WhatmattersisthatyouendupwithaPythondictionaryorlistcontainingallthatyouneedtoupdatetherelevanthostinZabbix.
ThesecondpartofthescriptfirstofallshowsyouhowtoconnecttotheZabbixAPIusingtheZabbixAPIconstructor.Itthenproceedswiththeloginmethod,whereyou’llneedtoprovidethecredentialsyouconfiguredearlier.
Allgetmethodsacceptafilterparameterthatyoucanusetoretrieveasingleobjectoralistofobjectsthatsatisfycertainconditions.Inthiscase,weusedittogetthehostidofthehostthatisassociatedwithaspecificIPaddress.
Payattentiontothenextlineasthevaluereturnedbyallgetmethodsisalwaysalist,evenifitcontainsonlyoneelement.That’swhyweneedtoreferencethefirstelementofhostinfo,element0,beforereferencingtheinventorydictionarykey.
Weonlyshowedthreeinventoryfieldshere,buttherearemanymoreavailableinZabbix,soitmaybeagoodideatobuildadictionarywithallZabbixinventoryfieldsaskeysandtheretrievedvaluesasvalues.
Nowthatwehavethehostidandtheinventoryinformationatourdisposal,wecanproceedwiththeactualinventoryupdate.Theupdatemethodisfairlystraightforward:youspecifythehostidofthehostyouwanttoupdateandthenewvaluesforthefieldsthatyouneedtoupdate.
Andthat’sit,withascriptlikethisconfiguredasaremotecommandforadiscoveryaction,youcankeepyourZabbixinventorydatainsyncwithwhateverassetmanagementsystemyoumayhave.
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Asyoumighthaverealized,hostdiscoverycanbequiteacomplexmatterbecauseofthesheernumberofvariablesyouneedtotakecareof,andbecauseit’snotalwayseasy,inareal-worldnetwork,toidentifyaclearlogicforhostcreation,templateassignment,andothermonitoringparameters,basedondiscoverydata.
Low-leveldiscovery,bycontrast,ismuchmoresimple,givenitspowertodynamicallycreatespecificitemsasahost’savailableresourcesarediscovered.So,let’susetheremainingpagesofthischaptertoexploreafewaspectsofthisextremelyusefulfeature.
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Low-leveldiscoveryAnextremelyusefulandimportantfeatureofZabbixtemplatesistheirabilitytosupportspecialkindsofitemscalledlow-leveldiscoveryrules.Onceappliedtoactualhosts,theseruleswillquerythehostforwhateverkindofresourcestheyareconfiguredtolookfor:filesystems,networkinterfaces,SNMPOIDs,andmore.Foreveryresourcefound,theserverwilldynamicallycreateitems,triggers,andgraphsaccordingtospecialentityprototypesconnectedtothediscoveryrules.
Thegreatadvantageoflow-leveldiscoveryrulesisthattheytakecareofthemorevariablepartsofamonitoredhost,suchasthetypeandnumberofnetworkinterfaces,inadynamicandgeneralway.Thismeansthat,insteadofmanuallycreatingspecificitemsandtriggersofeveryhost’snetworkinterfacesorfilesystems,orcreatinghugetemplateswithanypossiblekindofitemforaparticularoperatingsystemandkeepingmostoftheseitemsdisabled,youcanhaveareasonablenumberofgeneraltemplatesthatwilladaptthemselvestothespecificsofanygivenhostbycreatingontheflyanyentityrequired,basedondiscoveredresourcesandpreviouslyconfiguredprototypes.
Outofthebox,Zabbixsupportsfourdiscoveryrules:
NetworkinterfacesFilesystems’typesSNMPOIDsCPUsandCPUcores(asofversion2.4)
Asdiscoveryrulesareeffectivelyspecialkindsofitems,youcancreateyourownrules,providedyouunderstandtheirpeculiaritycomparedtoregularitems.
Youneedtocreateandmanagelow-leveldiscoveryrulesintheDiscoveryrulessectionofatemplateconfigurationandnotintheusualItemssection,evenifthediscoveryrulesendupcreatingsomekindofitems.Themaindifferencebetweendiscoveredandregularitemsisthat,whereasaregularitemusuallyreturnsasinglevalue,adiscoveryitemalwaysreturnsalist,expressedinJSON,ofmacrovaluepairs.Thislistrepresentsalltheresourcesfoundbythediscoveryitems,togetherwithameanstoreferencethem.
ThefollowingtableshowsZabbix’ssupporteddiscoveryitemsandtheirreturnvalues,togetherwithageneralizationthatshouldgiveyouanideaofhowtocreateyourownrules:
Discoveryitemkey Itemtype Returnvalues
vfs.fs.discovery Zabbixagent
{"data":[
{"{#FSNAME}":<path>","{#FSTYPE}":"<fstype>"},
{"{#FSNAME}":<path>","{#FSTYPE}":"<fstype>"},
{"{#FSNAME}":<path>","{#FSTYPE}":"<fstype>"},
…
]}
{"data":[
{"{#IFNAME}":"<name>"},
{"{#IFNAME}":"<name>"},
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net.if.discovery Zabbixagent {"{#IFNAME}":"<name>"},
…
]}
snmp.discovery SNMP(v1,v2,orv3)agent
{"data":[
{"{#SNMPINDEX}":"<idx>","{#SNMPVALUE}":"<value>},
{"{#SNMPINDEX}":"<idx>","{#SNMPVALUE}":"<value>},
{"{#SNMPINDEX}":"<idx>","{#SNMPVALUE}":"<value>},
…
]}
system.cpu.discovery Zabbixagent
{"data":[
{""{#CPU.NUMBER}":"<idx>","{#CPU.STATUS}":"<value>},
{"{#CPU.NUMBER}":"<idx>","{#CPU.STATUS}":"<value>},
{"{#CPU.NUMBER}":"<idx>","{#CPU.STATUS}":"<value>},
…
]}
custom.discovery Any
{"data":[
{"{#CUSTOM1}":"<value>","{#CUSTOM2}":"<value>"},
{"{#CUSTOM1}":"<value>","{#CUSTOM2}":"<value>"},
{"{#CUSTOM1}":"<value>","{#CUSTOM2}":"<value>"},
…
]}
TipJustaswithallSNMPitems,theitemkeyisnotreallyimportantaslongasitisunique.It’stheSNMPOIDvaluethatyouaskanagentforthatmakesthedifference:youcancreatedifferentSNMPdiscoveryrulesthatlookfordifferentkindsofresourcesbychangingtheitemkeyandlookingfordifferentOIDvalues.Thecustomdiscoveryexampleisevenmoreabstractasitwilldependontheactualitemtype.
Asyoucansee,adiscoveryitemalwaysreturnsalistofvalues,buttheactualcontentsofthelistchange,dependingonwhatresourcesyouarelookingfor.Inthecaseofafilesystem,thereturnedlistwillcontainvalueslike{#FSNAME}:"/usr",{#FSTYPE}:"btrfs",andsoonforeverydiscoveredfilesystem.Ontheotherhand,anetworkdiscoveryrulewillreturnalistofthenamesofthediscoverednetworkinterfaces.ThisisthecaseforthedefaultSNMPnetworkinterfacestemplate.Let’sseeindetailhowitworks.
Thetemplatehasadiscoveryrulecallednetworkinterfaces.Itlooksjustlikearegularitemasithasaname,atype,anupdateinterval,andakey.It’sanSNMPtype,soitalsohasanSNMPOID,IF-MIB::ifDescr.Thisisadiscoveryrule,soinsteadofasinglevalue,itwillreturnalistofalltheOIDsthatarepartoftheIF-MIB::ifDescrsubtreeforthatparticulardevice.ThismeansthatitwillreturntheOIDanditsvalueforallthenetworkinterfacespresentonthedevice.Everytimethediscoveryruleisexecutedonahost(basedontheupdateinterval,justlikeanyotheritem),itwillreturnalistofallinterfacesthatareavailableatthatparticularmoment.Ifthedevicehadfournetworkinterfaces,itcouldreturnsomethingsimilartothis:
{"data":[
{"{#SNMPINDEX}":"1",
"{#SNMPVALUE}":"FastEthernet0/0"},
{"{#SNMPINDEX}":"2",
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"{#SNMPVALUE}":"FastEthernet0/1"},
{"{#SNMPINDEX}":"3",
"{#SNMPVALUE}":"FastEthernet1/0"},
{"{#SNMPINDEX}":"4",
"{#SNMPVALUE}":"FastEthernet1/1"},
]}
Thediscoveryrulewillthenproceedtoapplythelisttotheitemandtriggerprototypesithasconfigured,asfollows:
TakingtheIncomingtrafficoninterface{#SNMPVALUE}itemprototypeasanexample,youcanseehowitallcomestogether:
The{#SNMPVALUE}macroisusedintheitem’skeyand,therefore,intheitem’snameaswell(lookatthe$1macrothatreferencesthefirstargumentoftheitem’skey).
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Ontheotherhand,the{#SNMPINDEX}macrowillbeusedbyZabbixtoactuallygettheincomingtrafficvalueforthatspecificinterfaceasitshouldbeclearbynowifyouobservethevalueintheSNMPOIDfield.
Whenconfiguringatemplate’sdiscoveryrules,youdon’tneedtocareabouttheactualvaluesreturnedintheirlists,northelists’length.Theonlythingyouhavetoknowisthenameofthemacrosthatyoucanreferenceinyourprototypes.Thesearetobereferencedinthesecondhalfofthelow-leveldiscoverymechanism,objectprototypes.Youcreatethemasregulartemplateentities,makingsureyouusethediscoveryitemmacroswhereneeded,andZabbixwilltakecareoftherestforyou,creatingforeachitemprototypeasmanyitemsasthereareelementsinthelistreturnedbythediscoveryrule,foreachtriggerprototypeasmanytriggersasthereareelementsinthelistreturned,andsoon.
So,whenyouapplythetemplatetoahost,itwillcreateitems,triggers,andgraphsbasedontheresourcesdiscoveredbythediscoveryitemsandconfiguredaccordingtothediscoveryprototypes.
Customdiscoveryrules,fromthispointofview,workexactlyinthesamewayascustomitems,whetheryoudecidetouseagent-sidescripts(therebyusingacustomzabbix.agentitemkey),externalscripts,databasequeries,oranythingelse.Theonlythingsyouhavetomakesureofisthatyourcustomitemsreturnkeys/valuesthatfollowtheJSONsyntax,asshownintheprecedingtable,andthatyoureferenceyourcustommacrosintheentitiesprototypesthatyouwillcreate.
Let’sseeanexampleofacustomdiscoveryruleusingagainNmapanditsoutputtodynamicallycreatesomeitemsforahost,representingtheopenportithas,andthekindofservicesthatarelistening.WhywouldyouwanttouseNmapandaportscan?Thedeviceyouneedtomonitormaybedoesn’tsupporttheZabbixagent,soifyoujustaskfortheoutputofnetstat,youmightnotbeabletoinstalltheagentforadministrativereasons,oryoumighthavetomakesurethattheservicesarealsoavailablefromanothernetwork,socheckingthemfromafar,insteadofdirectlyonthehost,willenableyoutoalsoverifyyourfirewallrules,killingtwobirdswithonestone.
Eitherway,we’llcreateanexternalcheckitemperopenTCPport,configuredasacharacter-typeitem.Eachitemwillcontainthenameoftheservicethatwasfoundlistening,ifany,asreportedbyNmap’sservicediscoveryfacilities.
Startbycreatingthediscoveryruleasanexternalcheckthatwillcallaport-mappingscript,asfollows:
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Asyoucansee,thescriptwillreceivethehost’sIPastheonlyargument,anditwillrunonceanhourforeveryhostthathasthisdiscoveryruleconfiguredandisactive.
ThescriptitselfisverysimpleandisbasedonNMAP’sXMLoutputcoupledwiththeniftyxml2toolyoualreadyusedinChapter3,MonitoringYourNetworkServices,asfollows:
#!/bin/bash
IPADDR=$1
#storeportsasarray
PORTS=($(nmap-sV-oX-${IPADDR}|xml2|grepportid|cut-d'='-f2))
#countelementsofthearrayanduseascounterforlaterprocessing
COUNTER=${#PORTS[@]}
#openJSON
echo'{"data":['
#loopthroughportsandprintkey/value
forPORTin"${PORTS[@]}";do
COUNTER=$((COUNTER-1))
if[$COUNTER-ne0];then
echo"{\"{#PORTID}\":\"${PORT}\"}",
else
#it'sthelastelement.TohavevalidJSONWedon'taddatrailingcomma
echo"{\"{#PORTID}\":\"${PORT}\"}"
fi
done
#closeJSON
echo]}
#exitwithcleanexitcode
exit0
Thelinestartingwithnmapistheheartofthescript.The–oXoptionenablesXMLoutput,whichismorestableandeasytomanagecomparedtothenormalone.Thedashafter–oXspecifiesstdoutastheoutputinsteadofaregularfile,sowecanpipetheresulttoxml2andthentakeonlythelinesthatcontainportid,thatis,theopenportnumbersforthathost.
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Asaresult,thescriptjustoutputsasimpleJSONobject.Here’sanexampleofwhatthediscoveryrulewillget,asshownfromthecommandline:
./port_map.sh'127.0.0.1'
{"data":[
{"{#PORTID}":"22"},
{"{#PORTID}":"25"},
{"{#PORTID}":"80"},
{"{#PORTID}":"631"},
{"{#PORTID}":"3306"}
]}
It’snowtimetodefinetheitemandtriggerprototypes,basedontheopenportthatyoufound.We’llshowhereanexampleofanitemprototypethatwillreturnthenameandversionofthedaemonlisteningontheport,asreturned,onceagain,byNmap:
Theexternalcheckwillcallascriptthatisevensimplerthanthepreviousone,asfollows:
#!/bin/bash
IPADDR=$1
PORT=$2
nmap-sV-oX--p${PORT}${IPADDR}|xml2|grep'port/service/@\
(product\|version\|extrainfo\)'
ComparedtothepreviousNmapcommand,weaddeda–sVoptiontomakeNMAPrunaseriesofprobesinordertofindoutwhatserviceisrunningbehindthatopenportanda–poptiontospecifyasingleporttoscan.
Theoutputwaskeptsimpleonpurposetoshowyouanexampleofxml2’soutput.Youcan,ofcourse,sliceitanddiceittosuityourownneeds:
./port_service.sh127.0.0.180
/nmaprun/host/ports/port/service/@product=Apachehttpd
/nmaprun/host/ports/port/service/@version=2.2.15
/nmaprun/host/ports/port/service/@extrainfo=(CentOS)
NoteTheamountofinformationNmapwillbeabletogetfromanetworkservicedependsvery
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muchonhowmuchandonwhatkindofdatatheserviceisconfiguredtoexpose.Thismightdependonbuilt-inparametersorsecurityconsiderationsonthepartoftheserviceowner.Comparedtothepreviousexample,yourmileagecanvary.
Thisiswhatwillappearasthevalueoftheitemoncethediscoveryruleisactivated.
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SummaryInthischapter,youlearnedhowtouseZabbix’sdiscoveryfacilitiestoautomateitsconfigurationasmuchaspossible.Itshouldalsobecleartoyouwhyit’simportanttominimizethedifferencebetweenwhatisconfiguredinZabbixandwhatisactuallyoutthereonthewire.Keepingtrackofeverythingthatcanappearordisappearonabusynetworkcanbeafulltimejobandonethatisbettersuitedtoautomatedmonitoringfacilitieslikethisone.Younowhavealltheskillsneededtoactuallydoit,andyouarereadytoapplytheminyourreal-worldenvironment.
Inthenextchapter,we’llwrapthingsupbyshowingyouhowtoleverageZabbix’spresentationpowertocreateandmanagegraphs,dynamicmaps,andscreens.
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Chapter5.VisualizingYourTopologywithMapsandGraphsAsyouprobablyalreadyknow,Zabbix’sapproachtomonitoringisbasedonseparatingdatagatheredfromtriggerlogicandeventlogging.Ontheonehand,thismeansthatyouareabletoreferenceanymeasurement,presentandpast,inyourtriggers,makingthemallthemorepowerful.Ontheotherhand,italsomeansthatyouhavedirectaccesstoallyourmeasurementhistoryforallyouritems.
Whilesortingthroughallofyourhistoricaldatatolookforaspecificvaluecancertainlybeuseful,therealadvantagehereistoleverageZabbix’sgraphingandmappingfunctionalitiestoaggregateandvisualizedatainmeaningfulways.
Inthischapter,you’llseehowtocreatecomplexgraphsfromyouritems’numericalvalues,howtoautomaticallydrawmapsthatreflectthecurrentstatusofyournetwork,andhowtobringitalltogetherusingscreensasatooltocustomizemonitoringdatapresentation.
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CreatingcustomgraphsBasicgraphicaldatarepresentationcomesforfreeforanyitemthathasanumericdatatype.YoujustneedtogotoMonitoring|LatestData,selectthehostyouareinterestedin,findtherelevantitem,andclickonGraphinthelastcolumnontheright-handside.You’llgetalinegraphwithatimesliderthatyoucanusetochangethetimeframeofthegraphitself;widenittocoveralongeramountoftime,orshortenittofocusonaspecificpointintime.
SinceZabbix2.4,youcanalsocomparedifferentitemsontheflywithadhocgraphs.Theseareadirectextensionofsimplegraphs:fromMonitoring|LatestData,youjustneedtomarkthecheckboxontheleft-handsideofeveryitemthatyouwanttographandselectDisplaystackedgraphorDisplaygraphfromthedrop-downmenuatthebottomofthepage,asfollows:
Theresultisprettymuchtheoneyouexpect.Youalsodon’thavetoworrytoomuchaboutchoosingbetweenanormalgraphandastackedgraphasyou’llbeabletoswitchbetweenthetwofromthegraphitself,asfollows:
Thesequick,adhocgraphscanreallycovermostofyourvisualizationneeds,especiallyforvaluesthatyoudon’tconsultthatoftenorifyouneedtocompareitemsthatyou
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normallydon’thaveto,aspartofanewanalysisortoinvestigateanewclassofproblems.
Ontheotherhand,ifyouneedtocomparethesametypesofitemsoverandover,andfordifferenthosts,you’llneedawaytosaveyourselectionssothatyouareabletoaccessyouraggregatedgraphswithouthavingtospecifyeverytimewhatitemsneedtobegraphed.Youcanachieveallthiswithcustomgraphs.
NoteIfyouliketovisualizeyourpercentiledatawithpiecharts,you’llalsoneedtocreatecustomgraphsasthey’recurrentlytheonlywaytocreatepiechartsinZabbix.
Customgraphscanbecreatedaspartofahost,orbetteryetaspartofatemplate,oralow-leveldiscoveryrule,sothatanyhostinheritingthetemplateordiscoveryrulewillautomaticallyalsoinheritthecustomgraph.
Tocreateone,youneedtogotoConfiguration|Templates,choosethetemplateyouwanttoputyourgraphinto,selectGraphs,andclickonCreategraph.Thiswillbringyoutothegraphcreationform.Forconvenience,thefollowingexamplewillshowyousomeitemsalreadyaddedtotheitemlistandsomeotheroptionsalreadyselectedinsteadofanemptyform,butyou’lleasilybeabletoaddyourownitemsbyfollowingtheaddlinkatthebottomoftheitemlist,asfollows:
Asyoucansee,thereareafewoptionsworthnoting.Firstofall,youcanselectthegraphtypebetweenNormal,Stacked,Pie,andExploded(thatis,apiechartwithallslicesseparatedinsteadofclosetogether).Next,ifyouselecttheShowtriggerscheckbox,thegraphwillincludeahorizontallineforeverytriggerthathasanyoftheitemspresentin
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thegraph’sitemlistinitsexpression.Youdon’thavetospecifythetriggerorfindthemmanually;Zabbixwilltakecareoffindingallrelevanttriggersandshowthemonthegraph.
Youcanalsospecifytherangeofyaxisvalueseitherasfixedvaluesorcalculatedbasedonthedatayouhave.You’llnormallywanttosetthemascalculatedasthisoptionwillusuallyshowtheclearestandbest-lookinggraphs,butsometimes,youmightwanttosetthemtoafixedvaluetohaveabetterunderstandingofhowthevalueschange,especiallyiftheyfluctuatealotbetweenverybigandverysmallvalues,andtheitemexpressesapercentilerange.
Movingtotheitemlist,youcanordertheitemsbydragginganddroppingthebluearrowsontheleft-handsideoftheitem’snameandchangetheircolorbyeitherspecifyinganRGBvalueorchoosingfromacolorpalette.
Thedrawstylecanbequiteusefulifyouwantaspecificitemtostandoutfromtherest.Therearequiteafewstylesavailableforanormalgraph,whilethisoptionisnotavailableforstackedandpiecharts.
TheFunctiondrop-downmenuenablesyoutochoosehowtheitemshouldbegraphedforeverytickinthexaxis:youcanchoosebetweentheminimumvalue,themaximumone,andtheaverage.Keepinmindthatthex-axistickdensitywillchangedynamicallywiththetimescaleofthegraph(youcanselectdifferenttimeframeswhilelookingatagraph;youdon’thavetospecifytheminadvance):fortimeframesuptoanhour,itwillshoweverysamplecollected,dependingontheitems’samplefrequency;forlargertimeframes,you’llhavex-axisticksproportionaltothetimeframeselected,whichisafewminutesiftheglobaltimeframeisafewhours,todaysorweeksifyouselectmonths’oryears’worthofmonitoringdata.Foreverytick,Zabbixwillusethefunctionyouselectedheretoplottheitemvalueeitherbyselectingthemaximum,theminimum,ortheaveragevalueforthattimetick.
Finally,youcanchoosewhethertheyaxisforanitemwillbeshownontheleft-handsideortheright-handside.Oneofthereasonstoseparatedifferentitemsondifferenty-axissidesisthatmaybeyouareplottingonthesamegraphitemsthathaveabsolutevaluestogetherwithitemsthatexpressapercentilevalue.Inthiscase,itmakessensetoshowtheabsolutescaleononesideandthepercentileoneontheothersideofthegraph.
Anotherreasonmightbethatyouareplottingtogetheritemsthatwillshow,onaverage,verybigorverysmallvalues,andyoucanpredictaheadoftimetheonesthatwillgravitatetowardsthebottomofthescale,andtheonesthatwillmakethescalegoupwithbigvalues.Inthatcase,youmightwanttoseparatethetwo;otherwise,theitemswithbigvalueswillmaketheotherslookveryflatandnotveryinformativeonthechart.Thisisthecaseillustratedintheprecedinggraph:wepredictedthatthetotalnumberofquerieswouldbemuchbigger(bydefinition)comparedtoalltheothers,sowemoveditsyaxistotheright-handside.Here’stheresultofthegraphwecreated:
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Whatwehaven’tshownhere,butyoucaneasilyimagine,isthataswithalmosteverythinginZabbix,youarenotlimitedtographingitemsfromthesamehost:youcanjustaseasilygraphthesameitemfromdifferenthosts,orevendifferentitemsfromdifferenthosts.Youmightbeinterested,forexample,intrackingnetworktrafficfromabunchofdifferentroutersandlookingathowthistrafficchangesintime,whichmachinesarethebusiestandwhen,whichonesarenotasbusyasyouexpectedcomparedtotheoveralltrafficyouhave,andsoon.Todothat,youcaneasilycreateagraphfollowingtheguidelinesabove,onlyselectingtherelevantnetworkinterfacesinboundandoutbounditemsfromthedifferentappliancesandputtingthemallonthesameitemlist.
YoucanuseZabbix’scustomgraphcreationfacilitiestoexploreyourdatainverymeaningfulwaysthatcanbehardtoachieveotherwise:don’tbefooledbythefactthatit’sallmainlytime-based(youcan’tputcustomvaluesonthexaxis).You’llsoonfindthattheabilitytocorrelatedifferentitemsfromdifferentsourcesisaverypowerfultoolforbothtroubleshootingandcapacityplanning.
AnotherpowerfultoolisZabbix’smappingfacility.We’llexploreafewinterestingaspectsofmapcreationandmaintenanceinthefollowingsection.
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Maps–aquicksetupforalargetopologyCreatingcomplexmapsisthekindofjobthatcantakealotoftime.Whiledoingapracticalexample,ifyouwouldliketodesignamapof20-30elements,itiseasytospendupto2hoursevenifyoualreadyknowthejob.
Tomanuallyproduceamap,youneedto:
AddalltheitemsonthemapMovetheitemsarounduntilyouseeanice-lookingdisposition
Everytimeyouneedtoaddinamaponehost,youneedtorepeatmanytimesthesamestepsasaforementioned,whichwillbecomeaboringandcomplextask.Currently,therearemanyopen-featurerequeststhatcanfacilitatethiskindoftask;unfortunately,theyhavebeenopenforalongtime,evenyears.
Theissuesyoucanfaceare:
Youcan’tmovemultipleelementsatthesametime,somethingthatcanbefoundathttps://support.zabbix.com/browse/ZBXNEXT-161Youcan’taddhostsinabulkway,somethingthatcanbefoundathttps://support.zabbix.com/browse/ZBXNEXT-163Youcan’tcloneanyexistingmapelement,somethingthatcanbefoundathttps://support.zabbix.com/browse/ZBXNEXT-51Whenyouareusingicons,youcan’tselectthemautomatically,soyouneedtochecktheirsizeandseewhethertheyfitonyourmap,somethingthatcanbefoundathttps://support.zabbix.com/browse/ZBXNEXT-1608
Forallthoseissues,weneedtofindadifferentwaytoautomatethislongandslowprocess.Clearly,thisisthekindoftaskthatneedstobeautomatedasmuchaspossible.
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Maps–automatingtheDOTcreationWhatismissinghereissomethingthatcanprocessourinformationandproduceasoutputsomethingusablebyZabbix.Toautomatethistask,thereisonelibrarythatcanhelpus—NetworkX—whichisavailableathttp://networkx.github.io/.
NetworkXisaPythonsoftwarelibrarytailor-madeforthecreation,manipulation,andstudyofdynamicnetworkstructures.
Inthisexample,weassumethatyou’reusingCiscoPrime,whichisavendor-specifictooltoexportadiscoveredtopology.
Anyway,thisconceptisstillvalidasherewearegoingtouseanexportfileobtained,whichisinCSV.ThiskindofCSVcanbeobtainedasanexportfrommanyothervendors’softwareandcanbeeasilyproducedfromanythird-partysoftware.
Thefilethatwearegoingtoparseisinthefollowingform:
IPaddress,Systemname,SysObjectID,Foundbymodules,Neighbors,Status
Asyoucansee,itcontainstheIPaddressofthedevicediscovered,thesystemname,theOIDofthesystem,themodulethatfoundthedevice,alistofalltheneighborsthatareconnectedtoit,anditendswiththestatus.
Thefollowingisanexampleofthelinethatweareexpectingtosee:
10.12.50.1,main.example.com,.1.3.6.1.4.1.9.1.896,System,"10.12.2.1,
10.12.2.2,10.12.3.1,10.12.4.1,10.12.5.1",Reachable
Wearemostlyinterestedinthefollowingfields:
IPaddressSystemnameSysObjectIDNeighbors
Then,whatwecandoiswritesomePythonlinesthatcanreadthisfile,identifyalltherequiredinformation,andwriteintheoutputaDOTfile.
Here,IamgoingtospendafewwordsabouttheDOTnotation,performinganexampleinordertoclarifyhowthisnotationisdone.
Firstofall,IwouldliketoexplainwhywearegoingtohaveaGraphvizDOTfile.
TheGraphvizDOTfileisreallyeasytoread,maintain,andupdate,andnevertheless,itcanbestoredinaCVSorSVN.
Somethingthatisreallyimportanttohaveisafilethatcanbequicklyusedtospotallthedifferencesbetweenversionsandiseasytomaintain.Also,weareconsideringusingitasitisastandardlanguageandagoodstartingpoint,onwhichwecantransformallouracquireddatafromallthedifferentversionsofexport.
Indeed,someothervendor-specificsoftwarecanexportthesamedatabutinadifferentform,soitisimportanttonormalizeallourdatainacommonlanguage.
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ThiscommonlanguagefilewillbethefiletousetopopulateourZabbixmap.
Thissection,asyouprobablyalreadyhaveunderstood,willbealargeusageoftheGraphviz’spackages.
TheeasiestwaytoinstallandmaintainGraphvizonRedHatEnterpriseLinuxistousethededicatedyumrepository.Tosetupyum,firstofall,youneedtodownloadthegraphviz-rhel.repofileandsaveit(asroot)in/etc/yum.repos.d/,asfollows:
#cd/etc/yum.repos.d
#wgethttp://www.graphviz.org/graphviz-rhel.repo
--2014-11-2702:52:17--http://www.graphviz.org/graphviz-rhel.repo
Resolvingwww.graphviz.org…204.178.9.49
Connectingtowww.graphviz.org|204.178.9.49|:80…connected.
HTTPrequestsent,awaitingresponse…200OK
Length:1138(1.1K)[text/plain]
Savingto:"graphviz-rhel.repo"
100%[======================================>]1,138--.-K/sin0s
2014-11-2702:52:17(134MB/s)-"graphviz-rhel.repo"saved[1138/1138]
#ls-lagraphviz-rhel.repo
-rw-r--r--.1rootroot1138Feb162012graphviz-rhel.repo
Then,youcanfinallylistalltheGraphvizpackagesasroot:
yumlistavailable'graphviz*'
Installthem,asfollows:
yuminstall'graphviz*'
Nowthatwe’veclarifiedthereasonwhywe’redoingthosesteps,itisimportanttowalkthroughtheDOTlanguage.TheDOTlanguageisalanguagemadetorepresentobjectsconnectedbetweeneachother.
Whileperformingapracticalexample,ifwewanttodefinetwoconnectednodeswiththeGraphvizDOTlanguage,wecandoasfollows:
graph{
A—B
}
Thisisaveryeasy-to-understandlanguage;wearenowrepresentingtwonodesconnectedtoeachother.
Toseethegraphicalresult,wecanuseasimplePythonprogramxdot.pyavailablefordownloadhere:
https://github.com/jrfonseca/xdot.py
Allyouhavetodoisdownloadtheprogram,writeafilewiththeGraphvizDOTcontentthatweshowedpreviously,andthenruntheprogram,asfollows:
xdot.pyexample.dot
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TheresultistheDOTexpressedtopologyvisualized,asfollows:
Usingthesamegrammar,wecandefinethreenodesconnected,asfollows:
graph{
A—B—C
}
Usingthesamexdot.pyusedpreviously,theresultisthefollowing:
Writingacoupleoflinesmore,wecanevenavoidusinglongnamesusingthefollowinggrammar:
graph{
//Wecancreatealiasestoavoidtouseverylongnamesonthedependency
definition
Andrea[hostname="andrea.dalle.vacche.example.com"]
Stefano[hostname="stefano.kewan.lee.example.com"]
router[label="Ournetworkrouter"zbximage="router"]
//nowit'stimetodefineconnectionsbetweenthenodes
//Thisnotationallowsformultipleedgesfrom"router"inonego
router—{AndreaStefano}
}
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Andtheresultisshownhere:
Foradetaileddocumentationofthisgrammar,pleaserefertotheofficialdocumentationavailableathttp://www.graphviz.org/content/dot-language.
Untilnow,we’vecoveredallthatisneededtoknowforoursmallapplication.
Now,wecancomebacktoourCSVfileweextractedfromCiscoPrime.
HereistheCSVofaverysimplenetwork,butitcanbeappliedonverycomplexnetworktopologies,aswell:
[root@localhostgraphs]#catmy_export.csv
IPAddress,SystemName,SysObjectID,FoundByModules,Neighbors,Status
10.12.20.1,main.example.com,.1.3.6.1.4.1.9.1.896,System,"10.12.2.1,
10.12.2.2,10.12.3.1,10.12.4.1,10.12.5.1",Reachable
10.12.2.1,cluster1.example.com,.1.3.6.1.4.1.9.1.634,System,"10.12.2.2,
192.168.99.1",Reachable
10.12.1.1,london.example.com,.1.3.6.1.4.1.9.1.503,System,"",Reachable
10.12.2.2,cluster2.example.com,.1.3.6.1.4.1.9.1.634,System,"10.12.2.1,
192.168.99.1",Reachable
10.12.3.1,switch1.example.com,.1.3.6.1.4.1.9.1.503,System,"192.168.99.1",Re
achable
10.12.4.1,4.example.com,.1.3.6.1.4.1.9.1.502,System,"192.168.99.1,
10.12.4.42,10.12.4.47,10.12.4.48,10.12.4.49",Reachable
10.12.4.45,4d.example.com,.1.3.6.1.4.1.9.1.503,System,"10.12.4.1",Reachable
10.12.4.46,4e.example.com,.1.3.6.1.4.1.9.1.502,System,"10.12.4.1",Reachable
10.12.4.47,4f.example.com,.1.3.6.1.4.1.9.1.503,System,"10.12.4.1",Reachable
10.12.4.48,4g.example.com,.1.3.6.1.4.1.9.1.503,System,"10.12.4.1",Reachable
10.12.5.1,5.example.com,.1.3.6.1.4.1.9.1.502,System,"192.168.99.1,
10.12.5.45,10.12.5.43,10.12.5.44,10.12.5.46,10.12.5.47,10.12.5.48,
10.12.6.1",Reachable
10.12.5.44,5c.example.com,.1.3.6.1.4.1.9.1.503,System,"10.12.5.1",Reachable
10.12.5.45,5d.example.com,.1.3.6.1.4.1.9.1.503,System,"10.12.5.1",Reachable
10.12.5.46,5e.example.com,.1.3.6.1.4.1.9.1.502,System,"10.12.5.1",Reachable
10.12.5.47,5f.example.com,.1.3.6.1.4.1.9.1.503,System,"10.12.5.1",Reachable
10.12.5.48,5g.example.com,.1.3.6.1.4.1.9.1.503,System,"10.12.5.1",Reachable
10.12.5.155,5i.example.com,.1.3.6.1.4.1.9.1.634,System,"10.12.5.1",Reachabl
e
10.12.6.1,6.example.com,.1.3.6.1.4.1.9.1.502,System,"10.12.6.45,
10.12.6.46,10.12.6.47,,10.12.5.1",Reachable
10.12.6.45,6d.example.com,.1.3.6.1.4.1.9.1.503,System,"10.12.6.1",Reachable
10.12.6.46,6e.example.com,.1.3.6.1.4.1.9.1.502,System,"10.12.6.1",Reachable
www.it-ebooks.info
10.12.6.47,6f.example.com,.1.3.6.1.4.1.9.1.503,System,"10.12.6.1",Reachable
Fromthisfile,weseethatalltherelationsbetweenneighborsarealreadycontainedintheCSV,andthatweonlyneedtoconvertthemintoDOTnotationusingthenodenotation.
Here,wecanstartcodingafewPythonlinestoproduceourdesiredoutput:
#FirstofallweneedtoimportcsvandNetworkx
importcsv
importnetworkxasnx
#Thenweneedtodefinewhoisourzabbixserverandsomeotherdetailto
properlyproducetheDOTfile
zabbix_service_ipaddr="192.168.1.100"
main_loop_ipaddr="10.12.20.1"
main_vlan_ipaddr="149.148.56.1"
#Nowwecanfinallycreateourgraph
G=nx.Graph()
#wecanopenourCSVfile
csv_reader=csv.DictReader(open('my_export.csv'),\
delimiter=",",\
fieldnames=("ipaddress","hostname","oid","dontcare","neighbors"))
#Skiptheheader
csv_reader.next()
forrowincsv_reader:
neighbor_list=row["neighbors"].split(",")
forneighborinneighbor_list:
#Removespaces
neighbor=neighbor.lstrip()
#Addneighbors,andherewe'vedecidedtoignoreisolatednodes
ifneighbor!="":
G.add_edge(row["ipaddress"],neighbor)
#Addadditionalinformationtonodesoredgeshere
G.node[row["ipaddress"]]["hostname"]=row["hostname"]
#CiscoPrimedoesn'texportallIPaddressesofadevice
#butonlythefirstforeachnetwork,Herewemergehostswith
#multipleIPaddresses
mapping={main_vlan_ipaddr:main_loop_ipaddr}
G=nx.relabel_nodes(G,mapping)
#Removeclusterconnectionnotneededinourmap
G.remove_edge("10.12.2.1","10.12.2.2")
#AddingconnectionbetweenZabbixserverandmainswitch
G.add_edge(zabbix_service_ipaddr,main_loop_ipaddr)
main_neigh_list=G.neighbors(main_loop_ipaddr)
#finallywriteoutourfile
nx.draw_graphviz(G)
nx.write_dot(G,"/tmp/total.dot")
Now,ifyourunthissmallsoftwareagainsttheCSVfilewehaveshownbeforeyouseeourDOTfilegeneratedon/tmp/total.dot.Now,itisinterestingtoseehowourDOTfile
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isrepresentedonXDot.Here,inthenextdiagram,weseetherepresentationofourDOTfile:
Now,allthatwehavetodoisproducethemapstartingfromtheDOTfilewejustgenerated.
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DraftingZabbixmapsfromDOTHavingarrivedatthispoint,wehaveourGraphvizDOTfilethatiswaitingtobeused.Asyoucanseefromthepreviousimage,thankstoGraphviz,wealreadyhaveaready-to-goimagetouse.Then,allweneedtodois:
1. ReadouttheDOTfile.2. GeneratethetopologyusingGraphviz.3. Acquireallthecoordinatesfromourtopologygenerated.4. UsepyzabbixtoconnecttoourZabbixserver.5. Generateourtopologyinafullyautomatedway.
It’snowtimetowritesomelinesofPython;thefollowingexampleissimilartosomethingpresentedbyVolkerFröhlich.Anyway,thecodeherehasbeenchangedandfixed(itdidnotworkwellwithZabbix2.4).
Asthefirstthing,weneedtoimporttheZabbixApiandnetworkXlibraries:
importnetworkxasnx
frompyzabbiximportZabbixAPI
Then,wecandefinetheGraphvizDOTfiletouseasasource;agoodexampleistheonewejustgenerated:
dot_file="/tmp/total.dot"
Inthenextfewlines,wedefineourusername,password,mapdimension,andrelativemapname:
username="Admin"
password="zabbix"
width=800
height=600
mapname="my_network"
Whatfollowsisastaticmaptodefinetheelementtype:
ELEMENT_TYPE_HOST=0
ELEMENT_TYPE_MAP=1
ELEMENT_TYPE_TRIGGER=2
ELEMENT_TYPE_HOSTGROUP=3
ELEMENT_TYPE_IMAGE=4
ADVANCED_LABELS=1
LABEL_TYPE_LABEL=0
Then,wecandefinetheiconstouseandtherelativecolorcode:
icons={
"router":23,
"cloud":26,
"desktop":27,
"laptop":28,
"server":29,
"sat":30,
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"tux":31,
"default":40,
}
colors={
"purple":"FF00FF",
"green":"00FF00",
"default":"00FF00",
}
Now,wedefinesomefunctionsthatwecanreuse.Thefirstoneistomanagethelogin,andthesecondoneistodefineahostlookup,asfollows:
defapi_connect():
zapi=ZabbixAPI("http://127.0.0.1/zabbix/")
zapi.login(username,password)
returnzapi
defhost_lookup(hostname):
hostid=zapi.host.get({"filter":{"host":hostname}})
ifhostid:
returnstr(hostid[0]['hostid'])
Thenextthingtodo,isreadourDOTfileandstartconvertingitintoagraph:
G=nx.read_dot(dot_file)
Then,wecanfinallyopenourgraph,asfollows:
pos=nx.graphviz_layout(G)
NoteHere,youcanselectyourpreferredalgorithm.Graphvizsupportsmanydifferentkindsoflayout,andthenyoucanchangethelookandfeelofyourmapasyouprefer.FormoreinformationaboutGraphviz,pleasechecktheofficialdocumentationavailableathttp://www.graphviz.org/.
Then,asthegraphisalreadygenerated,thenextthingtodoisfindthemaximumcoordinatesofthelayout.Thiswillenableustoscalebetterourpredefinedmapoutputsize.
positionlist=list(pos.values())
maxpos=map(max,zip(*positionlist))
forhost,coordinatesinpos.iteritems():
pos[host]=[int(coordinates[0]*width/maxpos[0]*0.95-
coordinates[0]*0.1),int((height-
coordinates[1]*height/maxpos[1])*0.95+coordinates[1]*0.1)]
nx.set_node_attributes(G,'coordinates',pos)
NoteGraphvizandZabbixusetwodifferentdataorigins:Graphvizstartsfromthebottom-leftcorner,andZabbixworksstartingfromthetop-leftcorner.
Then,weneedtoretrievetheselementidsastheyarerequiredforlinksandevenforthenodedatacoordinates,asfollows:
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selementids=dict(enumerate(G.nodes_iter(),start=1))
selementids=dict((v,k)fork,vinselementids.iteritems())
nx.set_node_attributes(G,'selementid',selementids)
nx.set_node_attributes(G,'selementid',selementids)
Now,wedefinethemaponZabbix,thename,andtherelativemapsize:
map_params={
"name":mapname,
"label_type":0,
"width":width,
"height":height
}
element_params=[]
link_params=[]
Finally,wecanconnecttoourZabbixserver:
zapi=api_connect()
Then,prepareallthenodeinformationandthecoordinatesandthensettheicontouse,asfollows:
fornode,datainG.nodes_iter(data=True):
#Genericpart
map_element={}
map_element.update({
"selementid":data['selementid'],
"x":data['coordinates'][0],
"y":data['coordinates'][1],
"use_iconmap":0,
})
Checkwhetherwehavethehostname,asfollows:
if"hostname"indata:
map_element.update({
"elementtype":ELEMENT_TYPE_HOST,
"elementid":host_lookup(data['hostname'].strip('"')),
"iconid_off":icons['server'],
})
else:
map_element.update({
"elementtype":ELEMENT_TYPE_IMAGE,
"elementid":0,
})
Wesetlabelsforimages,asfollows:
if"label"indata:
map_element.update({
"label":data['label'].strip('"')
})
if"zbximage"indata:
map_element.update({
"iconid_off":icons[data['zbximage'].strip('"')],
})
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elif"hostname"notindataand"zbximage"notindata:
map_element.update({
"iconid_off":icons['default'],
})
element_params.append(map_element)
Now,weneedtoscanalltheedgestocreatetheelementlinksbasedontheelementweidentified,asfollows:
nodenum=nx.get_node_attributes(G,'selementid')
fornodea,nodeb,datainG.edges_iter(data=True):
link={}
link.update({
"selementid1":nodenum[nodea],
"selementid2":nerodenum[nodeb],
})
if"color"indata:
color=colors[data['color'].strip('"')]
link.update({
"color":color
})
else:
link.update({
"color":colors['default']
})
if"label"indata:
label=data['label'].strip('"')
link.update({
"label":label,
})
link_params.append(link)
#Jointhepreparedinformation
map_params["selements"]=element_params
map_params["links"]=link_params
Now,wehavepopulatedallmap_params,andnowweneedtocallZabbix’sAPIwiththisdata:
map=zapi.map.create(map_params)
Theprogramisnowcomplete,andwecanletitrun!Inareal-worldcase,thetimespenttodesignatopologyofmorethan2,500hostsisonly2–3seconds!
Wecantestthesoftwarehere,proposedagainsttheDOTfilewegeneratedbefore:
[root@localhost]#time./Generate_MyMap.py
real0m0.005s
user0m0.002s
sys0m0.003s
Asyoucansee,oursoftwareisreallyquick…butlet’scheckwhathasbeengenerated.In
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thenextscreenshot,youcanseethemapthatisgeneratedautomaticallyin0.005seconds:
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PuttingeverythingtogetherwithscreensUnlikeanyotherZabbixfeaturewedescribedinthischapter,screensdon’tactuallygiveyouneworimprovedinformationaboutyourmonitoreddata.PrettymuchanythingthatyoucandecidetoputonascreencanbefoundsomewhereelseinZabbix.
Frommapsandgraphs,totriggerstatusanditemdata,allofthisandmorecanbeeasilyfoundbyexploringtheMonitoringtabofthewebfrontend.
ButthepointofgatheringexistingdataonaZabbixscreenispreciselythatyoubringtogetherrelateddata,ordifferentviewsofthesamedatasothatyoudon’thavetolookforitaroundthefrontend,andsothatyoucanhaveagoodoverviewofthestatusofyoursystemsandseeataglancewhetherthereareanyproblemswithinyourinfrastructure.
Whenyoucreateascreen(Configuration|Screens|Createscreen),yougiveitanameandastartingnumberofrowsandcolumns.Don’tworrytoomuchabouthowmanyrowsandcolumnsyouassigntoascreenasyouwillbeabletochangethemduringscreenconfiguration.
Onceyouhavethescreencreated,youcangoaheadandconfigureitbyselectingitsnameinConfiguration|Screens.
Ascreenisbasicallyatablewithrowsandcolumnsthatidentifiescells.Everycellcancontaindifferenttypesofdata:
Celltype Description
Actionlog ThisshowsalogofthelatestactionsexecutedbyZabbix.Youcanconfigurehowmanyactionsyouwanttoseeinthecell.
Clock Thisshowsananalogclockwiththecurrenttime.
Dataoverview Thisshowsthelatestitemdataforaspecificgroupofhosts.
Graph Thisshowsanexistingcustomgraph.
Graphprototype Thisshowsacustomgraphcreatedfromalow-leveldiscoveryruleprototype.
Historyofevents
Thisshowsalogofthelatestevents(thesedon’tnecessarilyleadtoactions).Youcanconfigurehowmanyeventsyouwanttoseeinthecell.
Hostgroupissues Thisshowsthecurrentissuesforaspecifichostgroup.
Hostissues Thisshowsthecurrentissuesforaspecifichost.
Host’sinfo Thisshowsasummaryofhostavailabilityforaspecificgroup,suchastheoneyoufindinMonitoring|Overview.
Map Thisshowsanexistingmap.
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PlaintextThisshowstheplaintexthistoryofaspecificitemtogetherwiththetimestampforeachmeasurement.Youcanconfigurehowmanyentriesyouwanttoseeinthecell.
Screen Thisshowsanexistingscreen.Yes,youcanembedascreenintoanotherscreenifyouwant.
Serverinfo ThisshowsasummaryofthemonitoringstatusfortheZabbixserver,suchasDBconnectivity,numberofhosts,itemsandtriggers,newvaluespersecond,andsoon.
Simplegraph Thisshowsthegraphforasingleitem,suchastheonesyoucanseeinLatestdatawithoutcreatingacustomgraph.
Simplegraphprototype
Thisislikeasimplegraph,butisforitemscreatedautomaticallyfromalow-leveldiscoveryruleprototype.
Systemstatus Thisshowsasummaryofthecurrentissues,dividedintohostgroupsandseverity.
Triggerinformation
Thisshowsasummaryoftriggerscurrentlyinaproblemstate,dividedbyseverity.Youhavetospecifyahostgroup.
Triggeroverview Thisshowseverytriggerstatusforeveryhostinaspecifichostgroup(andoptionally,application).
URL Thisshowsthecontentofanarbitrarywebpage,givenitsURL.
Everycellisalsoindependentfromtheothers:youcanbringtogetherdatabelongingtothesamehostaswellasbelongingtodifferenthostsandhosts’groups,dependingonhowyouwanttoorganizeyourscreen.
Finally,foreverycell,youcanspecifyhowmanyrowsandcolumnsitshouldspan,andforgraphiccelltypes(maps,graphs,andsoon),youcanalsodefinehowmuchspacetheyshouldtakebyspecifyingthewidthandheightinpixels.
Allthisflexibilityiscertainlypowerfulbutcanbeabitoverwhelming,soherearesomegeneralguidelinesthatyoucanrefertowhenyoucreateyourownscreens.
Averyusefultypeofscreenbringstogetherdatafromasinglehostsothatyoucanseeataglanceitsoverallperformance.You’lltypicallywanttoseesomegraphsinascreenlikethis,suchasnetworkandCPUperformance,diskusage,andanyapplication-specificgraphoritemsummaryyoumightneed,suchasdatabaseperformancegraphs,applicationserverstatistics,andsoon.
Inthefollowingexample,we’vekeptthingssimpleduetospaceconstraints,butyoucanseehowevenfourgraphscanproveusefulwhenputtogetherthisway:
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Aninterestingfeatureofscreencellsisthatyoucanmakethecontentdynamicbyflaggingtheaptlynamedcheckbox.Dynamiccellswillreferthesametypeofcontenttodifferenthostsdependingonthecontext.
Thismeansthatyoucancreateascreenatthetemplatelevel,flagallcellsasdynamic,andjustlikethat,everyhostinheritingthetemplatewillalsoinheritapersonalizedscreen,withallgraphsandtablesreferencingtheaforesaidhost.Thisway,youwon’thavetomanuallycreateaspecificscreenforeveryhost.
Inanothertypeofscreen,youmightwanttofocusongrouptriggersandissues.Inthiskindofscreen,atypicalcell’scontentswillbesomemaps,withhostsandlinksthatchangecolorbasedontriggerstatus,sometriggerinformationandtriggeroverviewcells,andpossiblyalogofthelatesteventsandactions.
Finally,youmightwanttocreatespecificscreensthatbringtogetherhistoricaldatafromdifferentitems,suchasapplication-specificlogfiles,outputfromexternalcommands,suchasNmap,Windowsupdatestatusforahost,andsoon.Asusual,thesky’sthelimithere.
TipKeepinmindthattheprecedingscreentypesaremerelyexamplesthatbarelyscratchthesurfaceofwhat’spossiblewithZabbix’sscreen.Youarebynomeanslimitedtothesetypes;onthecontrary,youareencouragedtomixandmatchthedifferentcellstosuityourownneeds.Don’tletusstopyoufromcreatingawesomescreens!
Onceyouhavecreatedafewscreens,thenextlogicalstepistofindawaytobringthemtogetherinanorganizedway.Slideshowsservethispurposeinaninterestingandusefulway.YoucancreateaslideshowbygoingtoConfiguration|Slideshowsandclicking
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onCreateslideshow.Thecreationformisprettyself-explanatory:
Muchlikeaddingitemstoacustomgraph,byclickingontheAddlinkatthebottomoftheSlideslist,youcanaddexistingscreenstotheslideshow,andyoucanreorderthembydragginganddroppingthebluearrowsnearthescreennameinthelist.Theresultwillbe,quitepredictably,aslideshowofallthescreensyouhaveputinthelist.Itwillrunoverandovercyclingthroughalltheelements.Eachslidewillhavethefocusforthenumberofsecondsequaltothedefaultdelayifyoudon’tspecifyanythingintheslide’sDelayfield.
Slideshowsareveryusefulwhenshownonabigscreeninadatacenter,butyouneedtobecarefulwhencreatingscreensthatyouknowwillendupinaslideshow.Slidesdon’tscrollvertically,soifascreenisbiggerthanthebrowserwindowusedtoshowtheslides,you’llneverbeabletoseesomeofthedata.Apossibleworkaroundistocreatescreensthatwilltakeupthewholewindowsize,butnothingmore.Thisway,you’llbesurethatallrelevantdatawillalwaysshowupontheslideshowthatyouplayonthatbigscreenyouputonthewallformonitoringpurposes.
Anotherworkaroundistomakesurethatforeachscreenbiggerthanthewindowsize,youputallimportantdataatthetopofthescreen.Thisway,someofthescreen’sdatawillshowupontheslides,whileyou’llstillbeabletoaccessallofitwhenaccessingthescreenonitsownandnotaspartoftheslideshow.
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SummaryInthischapter,youexploredZabbix’svisualizationfeaturesandlearnedhowtousethemtogetthemostoutofyourmonitoringdata.Sometimes,thevalueofameasurementdoesn’tlieintheeventsandactionsthatitcantrigger,butinitscorrelationwithothermeasurements,bothintime(graphs)andinstantly(maps).Thisisespeciallytruewithnetworkmonitoring,wheretheabilitytopredictthefutureneedsofanetwork,andadapttothem,isjustasimportantasactingoncontingentissues.
WehavereachedtheendofourbriefjourneythroughZabbix’sconfigurationanduse.Now,youshouldbeabletocorrectlysizeaZabbixinstallationbasedonyouenvironment;findthebestandmostappropriatetoolsandprotocolstomonitoryourdata;automatedevicediscoveryandmonitoringasmuchaspossible(andwhennottoautomateit);andmovebeyondactionsandtriggersandvisualizeallyourdatainmeaningfulways.
Withalltheseskillsunderyourbelt,weareconfidentthatyou’llbeabletoadaptapowerfulandflexibletoollikeZabbixtoyourownnetworkandnotbeconfinedtodefaulttemplatesthatmay,ormaynot,reflectyouractualmonitoringneeds.
Monitoringacomputernetworkisoftenalsoadiscoveryjourney,whereyoucangainunexpectedwisdomfromapparentlydryanduninspiringdata,suchasSNMPvaluesandserverlogs.Withthisshortbook,wehopewehaveshownyouhowZabbixcanbeanexcellentmeanstogainsuchwisdomifyouarewillingtoplaywithitforawhileandputtogooduseallitspowerfulfeatures.
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MySQLpartitioningHereareallthestoredproceduresyouneedtocreatetoproperlyhandledatabasepartitioningwithMySQL.
YouneedtocreatealloftheminyourZabbixdatabase.
Notethatalltheproceduresdescribedherearealsoavailableathttps://github.com/smartmarmot/zabbix_network_monitoring/tree/master/Chapter1.
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Thepartition_maintenanceprocedureThisisthemostimportantprocedure,whichwillmanagealltheotherstoredproceduresinvolvedinthecreation/dropandverificationofpartitions,asfollows:
DELIMITER$$
CREATEPROCEDURE`partition_maintenance`(SCHEMA_NAMEVARCHAR(32),
TABLE_NAMEVARCHAR(32),KEEP_DATA_DAYSINT,HOURLY_INTERVALINT,
CREATE_NEXT_INTERVALSINT)
BEGIN
DECLAREOLDER_THAN_PARTITION_DATEVARCHAR(16);
DECLAREPARTITION_NAMEVARCHAR(16);
DECLARELESS_THAN_TIMESTAMPINT;
DECLARECUR_TIMEINT;
CALLpartition_verify(SCHEMA_NAME,TABLE_NAME,HOURLY_INTERVAL);
SETCUR_TIME=UNIX_TIMESTAMP(DATE_FORMAT(NOW(),'%Y-%m-%d
00:00:00'));
IFDATE(NOW())='2014-04-01'THEN
SETCUR_TIME=UNIX_TIMESTAMP(DATE_FORMAT(DATE_ADD(NOW(),
INTERVAL1DAY),'%Y-%m-%d00:00:00'));
ENDIF;
SET@__interval=1;
create_loop:LOOP
IF@__interval>CREATE_NEXT_INTERVALSTHEN
LEAVEcreate_loop;
ENDIF;
SETLESS_THAN_TIMESTAMP=CUR_TIME+(HOURLY_INTERVAL*
@__interval*3600);
SETPARTITION_NAME=FROM_UNIXTIME(CUR_TIME+
HOURLY_INTERVAL*(@__interval-1)*3600,'p%Y%m%d%H00');
CALLpartition_create(SCHEMA_NAME,TABLE_NAME,
PARTITION_NAME,LESS_THAN_TIMESTAMP);
SET@__interval=@__interval+1;
ENDLOOP;
SETOLDER_THAN_PARTITION_DATE=DATE_FORMAT(DATE_SUB(NOW(),INTERVAL
KEEP_DATA_DAYSDAY),'%Y%m%d0000');
CALLpartition_drop(SCHEMA_NAME,TABLE_NAME,
OLDER_THAN_PARTITION_DATE);
END$$
DELIMITER;
Thisstoredprocedurewillbethecoreofourhousekeeping.Itwillbecalledwiththefollowingsyntax:
CALLpartition_maintenance('<zabbix_db_name>','<table_name>',
<days_to_keep_data>,<hourly_interval>,<num_future_intervals_to_create>)
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Thepartition_createprocedureThisprocedureisresponsibleforcreatingnewpartitionsacrossyourschema.Whatfollowshereistheprocedureitself:
DELIMITER$$
CREATEPROCEDURE`partition_create`(SCHEMANAMEVARCHAR(64),TABLENAME
VARCHAR(64),PARTITIONNAMEVARCHAR(64),CLOCKINT)
BEGIN
/*
SCHEMANAME=TheDBschemainwhichtomakechanges
TABLENAME=Thetablewithpartitionstopotentiallydelete
PARTITIONNAME=Thenameofthepartitiontocreate
*/
/*
Verifythatthepartitiondoesnotalreadyexist
*/
DECLARERETROWSINT;
SELECTCOUNT(1)INTORETROWS
FROMinformation_schema.partitions
WHEREtable_schema=SCHEMANAMEANDTABLE_NAME=TABLENAMEAND
partition_name=PARTITIONNAME;
IFRETROWS=0THEN
/*
1.Printamessageindicatingthatapartitionwas
created.
2.CreatetheSQLtocreatethepartition.
3.ExecutetheSQLfrom#2.
*/
SELECTCONCAT("partition_create(",SCHEMANAME,",",
TABLENAME,",",PARTITIONNAME,",",CLOCK,")")ASmsg;
SET@SQL=CONCAT('ALTERTABLE',SCHEMANAME,'.',
TABLENAME,'ADDPARTITION(PARTITION',PARTITIONNAME,'VALUESLESSTHAN
(',CLOCK,'));');
PREPARESTMTFROM@SQL;
EXECUTESTMT;
DEALLOCATEPREPARESTMT;
ENDIF;
END$$
DELIMITER;
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Thepartition_verifyprocedureThispartitionisresponsibleforverifyingwhetherapartitionisalreadypresent,andifitisn’t,partition_verifywillcreatethem,asfollows:
DELIMITER$$
CREATEPROCEDURE`partition_verify`(SCHEMANAMEVARCHAR(64),TABLENAME
VARCHAR(64),HOURLYINTERVALINT(11))
BEGIN
DECLAREPARTITION_NAMEVARCHAR(16);
DECLARERETROWSINT(11);
DECLAREFUTURE_TIMESTAMPTIMESTAMP;
/*
*Checkifanypartitionsexistforthegiven
SCHEMANAME.TABLENAME.
*/
SELECTCOUNT(1)INTORETROWS
FROMinformation_schema.partitions
WHEREtable_schema=SCHEMANAMEANDTABLE_NAME=TABLENAMEAND
partition_nameISNULL;
/*
*Ifpartitionsdonotexist,goaheadandpartitionthetable
*/
IFRETROWS=1THEN
/*
*Takethecurrentdateat00:00:00andaddHOURLYINTERVAL
toit.Thisisthetimestampbelowwhichwewillstorevalues.
*Webeginpartitioningbasedonthebeginningofaday.
Thisisbecausewedon'twanttogeneratearandompartition
*thatwon'tnecessarilyfallinlinewiththedesired
partitionnaming(ie:ifthehourintervalis24hours,wecould
*endupcreatingapartitionnownamed"p201403270600"
whenallotherpartitionswillbelike"p201403280000").
*/
SETFUTURE_TIMESTAMP=TIMESTAMPADD(HOUR,HOURLYINTERVAL,
CONCAT(CURDATE(),"",'00:00:00'));
SETPARTITION_NAME=DATE_FORMAT(CURDATE(),'p%Y%m%d%H00');
—Createthepartitioningquery
SET@__PARTITION_SQL=CONCAT("ALTERTABLE",SCHEMANAME,
".",TABLENAME,"PARTITIONBYRANGE(`clock`)");
SET@__PARTITION_SQL=CONCAT(@__PARTITION_SQL,"(PARTITION
",PARTITION_NAME,"VALUESLESSTHAN(",UNIX_TIMESTAMP(FUTURE_TIMESTAMP),
"));");
—Runthepartitioningquery
PREPARESTMTFROM@__PARTITION_SQL;
EXECUTESTMT;
DEALLOCATEPREPARESTMT;
ENDIF;
END$$
DELIMITER;
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Thepartition_dropprocedureThisstoredprocedureisresponsiblefordroppingthepartitionsolderthanagivenperiod,asfollows:
DELIMITER$$
CREATEPROCEDURE`partition_drop`(SCHEMANAMEVARCHAR(64),TABLENAME
VARCHAR(64),DELETE_BELOW_PARTITION_DATEBIGINT)
BEGIN
/*
SCHEMANAME=TheDBschemainwhichtomakechanges
TABLENAME=Thetablewithpartitionstopotentiallydelete
DELETE_BELOW_PARTITION_DATE=Deleteanypartitionswithnames
thataredatesolderthanthisone(yyyy-mm-dd)
*/
DECLAREdoneINTDEFAULTFALSE;
DECLAREdrop_part_nameVARCHAR(16);
/*
Getalistofallthepartitionsthatareolderthanthedate
inDELETE_BELOW_PARTITION_DATE.Allpartitionsareprefixed
with
a"p",souseSUBSTRINGTOgetridofthatcharacter.
*/
DECLAREmyCursorCURSORFOR
SELECTpartition_name
FROMinformation_schema.partitions
WHEREtable_schema=SCHEMANAMEANDTABLE_NAME=TABLENAME
ANDCAST(SUBSTRING(partition_nameFROM2)ASUNSIGNED)<
DELETE_BELOW_PARTITION_DATE;
DECLARECONTINUEHANDLERFORNOTFOUNDSETdone=TRUE;
/*
Createthebasicsforwhenweneedtodropthepartition.Also,
create
@drop_partitionstoholdacomma-delimitedlistofall
partitionsthat
shouldbedeleted.
*/
SET@alter_header=CONCAT("ALTERTABLE",SCHEMANAME,".",
TABLENAME,"DROPPARTITION");
SET@drop_partitions="";
/*
Startloopingthroughallthepartitionsthataretooold.
*/
OPENmyCursor;
read_loop:LOOP
FETCHmyCursorINTOdrop_part_name;
IFdoneTHEN
LEAVEread_loop;
ENDIF;
SET@drop_partitions=IF(@drop_partitions="",
drop_part_name,CONCAT(@drop_partitions,",",drop_part_name));
ENDLOOP;
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IF@drop_partitions!=""THEN
/*
1.BuildtheSQLtodropallthenecessarypartitions.
2.RuntheSQLtodropthepartitions.
3.Printoutthetablepartitionsthatweredeleted.
*/
SET@full_sql=CONCAT(@alter_header,@drop_partitions,
";");
PREPARESTMTFROM@full_sql;
EXECUTESTMT;
DEALLOCATEPREPARESTMT;
SELECTCONCAT(SCHEMANAME,".",TABLENAME)AS`table`,
@drop_partitionsAS`partitions_deleted`;
ELSE
/*
Nopartitionsarebeingdeleted,soprintout"N/A"(Not
applicable)toindicate
thatnochangesweremade.
*/
SELECTCONCAT(SCHEMANAME,".",TABLENAME)AS`table`,"N/A"
AS`partitions_deleted`;
ENDIF;
END$$
DELIMITER;
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Thepartition_maintenance_allprocedureThisprocedurecallsthepartition_maintenanceprocedureforeachhistory/trendtable.Pleasenotethatforallthehistorytables,weareapplyingthesameintervals,whichare730daysoftrenddataand28daysofhistorydata.Here’showthisprocedureworks:
DELIMITER$$
CREATEPROCEDURE`partition_maintenance_all`(SCHEMA_NAMEVARCHAR(32))
BEGIN
CALLpartition_maintenance(SCHEMA_NAME,'history',28,24,
14);
CALLpartition_maintenance(SCHEMA_NAME,'history_log',28,
24,14);
CALLpartition_maintenance(SCHEMA_NAME,'history_str',28,
24,14);
CALLpartition_maintenance(SCHEMA_NAME,'history_text',28,
24,14);
CALLpartition_maintenance(SCHEMA_NAME,'history_uint',28,
24,14);
CALLpartition_maintenance(SCHEMA_NAME,'trends',730,24,
14);
CALLpartition_maintenance(SCHEMA_NAME,'trends_uint',730,
24,14);
END$$
DELIMITER;
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HousekeepingconfigurationAsperourexample,thehousekeepingneedstobeconfigured,asshowninthefollowingscreenshot,withahistorydatastorageperiodof730daysandatrenddatastorageperiodof28days.Here,youcanchangethosevaluesbearinginmindthatyoualsoneedtochangetheparameterpassedtothestoredprocedures.
Tochangethehousekeepingsettinginthewebinterface,yousimplyneedtogotoAdministration|General|Housekeeping(fromthedrop-downlist),andhereistheconfiguration:
www.it-ebooks.info
SquidmetricscriptHere,youcanfindthescriptwediscussedinChapter3,MonitoringYourNetworkServices,andcreatethescriptintheusuallocation,thatis,at/home/zabbix/bin/squidcheck.sh.
Createthescriptwiththefollowingcontent:
catsquidcheck.sh
#!/bin/bash
VERSION="1.0"
functionusage()
{
echo"squidcheckversion:$VERSION"
echo"usage:"
echo"$0http_requests-NumberofHTTPrequestsreceived"
echo"$0clients-Numberofclientsaccessing
cache"
echo"$0icp_received-NumberofICPmessagesreceived"
echo"$0icp_sent-NumberofICPmessagessent"
echo"$0icp_queued-NumberofqueuedICPreplies"
echo"$0htcp_received-NumberofHTCPmessagesreceived"
echo"$0htcp_sent-NumberofHTCPmessagessent"
echo"$0req_fail_ratio-Requestfailureratio"
echo"$0avg_http_req_per_min-AverageHTTPrequestsperminute
sincestart"
echo"$0avg_icp_msg_per_min-AverageICPmessagesperminute
sincestart"
echo"$0request_hit_ratio-RequestHitRatios"
echo"$0byte_hit_ratio_5-ByteHitRatio5mins"
echo"$0byte_hit_ratio_60-ByteHitRatio60mins"
echo"$0request_mem_hit_ratio_5-RequestMemoryHitRatios5mins"
echo"$0request_mem_hit_ratio_60-RequestMemoryHitRatios60
mins"
echo"$0request_disk_hit_ratio_5-RequestDiskHitRatios5mins"
echo"$0request_disk_hit_ratio_60-RequestDiskHitRatios60mins"
echo"$0servicetime_httpreq-HTTPRequests(All)"
echo"$0process_mem-ProcessDataSegmentSizevia
sbrk"
echo"$0cpu_usage-CPUUsage"
echo"$0cache_size_disk-StorageSwapsize"
echo"$0cache_size_mem-StorageMemsize"
echo"$0mean_obj_size-MeanObjectSize"
echo"$0filedescr_max-Maximumnumberoffile
descriptors"
echo"$0filedescr_avail-Availablenumberoffile
descriptors"
}
########
#Main#
########
www.it-ebooks.info
if[[$#!=1]];then
#NoParameter
usage
exit0
fi
case$1in
"http_requests")
value="`squidclientmgr:info|grep'NumberofHTTPrequests
received:'|cut-d':'-f2|tr-d'\t'`"
rval=$?;;
"clients")
value="`squidclientmgr:info|grep'Numberofclientsaccessing
cache:'|cut-d':'-f2|tr-d'\t'`"
rval=$?;;
"icp_received")
value="`squidclientmgr:info|grep'NumberofICPmessages
received:'|cut-d':'-f2|tr-d'\t'`"
rval=$?;;
"icp_sent")
value="`squidclientmgr:info|grep'NumberofICPmessages
sent:'|cut-d':'-f2|tr-d'\t'`"
rval=$?;;
"icp_queued")
value="`squidclientmgr:info|grep'NumberofqueuedICP
replies:'|cut-d':'-f2|tr-d'\t'`"
rval=$?;;
"htcp_received")
value="`squidclientmgr:info|grep'NumberofHTCPmessages
received:'|cut-d':'-f2|tr-d'\t'`"
rval=$?;;
"htcp_sent")
value="`squidclientmgr:info|grep'NumberofHTCPmessages
sent:'|cut-d':'-f2|tr-d'\t'`"
rval=$?;;
"req_fail_ratio")
value="`squidclientmgr:info|grep'Requestfailureratio:'|cut-
d':'-f2|tr-d'\t'`"
rval=$?;;
"avg_http_req_per_min")
value="`squidclientmgr:info|grep'AverageHTTPrequestsperminute
sincestart:'|cut-d':'-f2|tr-d'\t'`"
rval=$?;;
"avg_icp_msg_per_min")
value="`squidclientmgr:info|grep'AverageICPmessagesperminute
sincestart:'|cut-d':'-f2|tr-d'\t'`"
rval=$?;;
"request_hit_ratio")
value="`squidclientmgr:info|grep'RequestHitRatios:'|cut-d':'-
f3|cut-d','-f1|tr-d'%'`"
rval=$?;;
"byte_hit_ratio_5")
value="`squidclientmgr:info|grep'Hitsas%ofbytessent:'|awk
-F'[:,%]''{print$10}'|tr-d'\t'`"
rval=$?;;
"byte_hit_ratio_60")
value="`squidclientmgr:info|grep'Hitsas%ofbytessent:'|awk
www.it-ebooks.info
-F'[:,%]''{print$15}'|tr-d'\t'`"
rval=$?;;
"request_mem_hit_ratio_5")
value="`squidclientmgr:info|grep'Hitsas%ofallrequests:'|
awk-F'[:,%]''{print$10}'|tr-d'\t'`"
rval=$?;;
"request_mem_hit_ratio_60")
value="`squidclientmgr:info|grep'Hitsas%ofallrequests:'|
awk-F'[:,%]''{print$15}'|tr-d'\t'`"
rval=$?;;
"request_disk_hit_ratio_5")
value="`squidclientmgr:info|grep'Diskhitsas%ofhit
requests:'|awk-F'[:,%]''{print$11}'|tr-d'\t'`"
rval=$?;;
"request_disk_hit_ratio_60")
value="`squidclientmgr:info|grep'Diskhitsas%ofhit
requests:'|awk-F'[:,%]''{print$16}'|tr-d'\t'`"
rval=$?;;
"servicetime_httpreq")
value="`squidclientmgr:info|grep'HTTPRequests(All):'|cut-d':'
-f2|tr-s''|awk'{print$1}'`"
rval=$?;;
"process_mem")
value="`squidclientmgr:info|grep'ProcessDataSegmentSizevia
sbrk'|cut-d':'-f2|awk'{print$1}'`"
rval=$?;;
"cpu_usage")
value="`squidclientmgr:info|grep'CPUUsage:'|cut-d':'-f2|tr-d
'%'|tr-d'\t'`"
rval=$?;;
"cache_size_disk")
value="`squidclientmgr:info|grep'StorageSwapsize:'|cut-d':'-
f2|awk'{print$1}'`"
rval=$?;;
"cache_size_mem")
value="`squidclientmgr:info|grep'StorageMemsize:'|cut-d':'-
f2|awk'{print$1}'`"
rval=$?;;
"mean_obj_size")
value="`squidclientmgr:info|grep'MeanObjectSize:'|cut-d':'-
f2|awk'{print$1}'`"
rval=$?;;
"filedescr_max")
value="`squidclientmgr:info|grep'Maximumnumberoffile
descriptors:'|cut-d':'-f2|awk'{print$1}'`"
rval=$?;;
"filedescr_avail")
value="`squidclientmgr:info|grep'Availablenumberoffile
descriptors:'|cut-d':'-f2|awk'{print$1}'`"
rval=$?;;
*)
usage
exit1;;
esac
if["$rval"-eq0-a-z"$value"];then
www.it-ebooks.info
rval=1
fi
if["$rval"-ne0];then
echo"ZBX_NOTSUPPORTED"
fi
echo$value
www.it-ebooks.info
IndexA
actionconditionssection/FindinghoststheZabbixwayactiondefinitionsection/Definingactionconditionsactionoperationssection/FindinghoststheZabbixwayApache
modules/ApachemonitoringApachemonitoring
about/Apachemonitoringperforming/Apachemonitoring
architectures,Zabbixabout/Zabbixarchitectures
www.it-ebooks.info
Ccomplexmaps
issues/Maps–aquicksetupforalargetopologyCPULoadparameter/Apachemonitoringcustomgraphs
creating/Creatingcustomgraphs
www.it-ebooks.info
Ddatabase
installing/Installingadatabasesize,considering/Consideringthedatabasesizeitems/Consideringthedatabasesizerefreshrate/Consideringthedatabasesizespace/ConsideringthedatabasesizeMySQLpartitioning/MySQLpartitioning
dataflow,Zabbixabout/UnderstandingZabbixdataflow
datatypes,SNMPabout/GettingdatatypesrightURL/GettingdatatypesrightINTEGER/GettingdatatypesrightSTRING/GettingdatatypesrightOID/GettingdatatypesrightIpAddress/GettingdatatypesrightCounter32/GettingdatatypesrightGauge32/GettingdatatypesrightCounter64/GettingdatatypesrightTimeTicks/Gettingdatatypesright
digabout/DNS–responsetime
discoveryitemsabout/Low-leveldiscovery
discoveryrulesabout/Low-leveldiscovery
DNSmonitoringabout/MonitoringtheDNSperforming/MonitoringtheDNSresponsetime,monitoring/DNS–responsetimeDNSSECzonerollover,monitoring/DNSSEC–monitoringthezonerollover
DNSSECparametersabout/DNSSEC–monitoringthezonerollover
www.it-ebooks.info
Ggraph
putting,onscreen/Puttingeverythingtogetherwithscreens
www.it-ebooks.info
Hhostgroups
about/Hostsandhostgroupsroutersgroup/Hostsandhostgroupsswitchesgroup/Hostsandhostgroupssubnetgroup/Hostsandhostgroups
hostsabout/UnderstandingZabbixhostsinterfaces/Hostinterfacesinventory/Hostinventory
housekeepingconfigurationabout/Housekeepingconfiguration
www.it-ebooks.info
IICMPechochecks
about/Simplechecksinterfaces/HostinterfacesInternetProtocolFlowInformationeXport(IPFIX)/Gettingnetflowfromthedevicestothemonitoringserver
www.it-ebooks.info
Llow-leveldiscovery
about/Low-leveldiscoveryadvantage/Low-leveldiscoveryrules,creating/Low-leveldiscoveryrules,managing/Low-leveldiscovery
www.it-ebooks.info
Mmaps
complexmaps/Maps–aquicksetupforalargetopologyDOTcreation,automating/Maps–automatingtheDOTcreationdrafting,fromDOT/DraftingZabbixmapsfromDOTputting,onscreen/Puttingeverythingtogetherwithscreens
MIBsabout/FindingtherightOIDstomonitor
MySQLpartitioningabout/MySQLpartitioningbenefits/MySQLpartitioningstoredprocedures/MySQLpartitioningpartition_maintenanceprocedure/Thepartition_maintenanceprocedurepartition_createprocedure/Thepartition_createprocedurepartition_verifyprocedure/Thepartition_verifyprocedurepartition_dropprocedure/Thepartition_dropprocedurepartition_maintenance_allprocedure/Thepartition_maintenance_allprocedure
www.it-ebooks.info
Nnetflow
about/Gettingnetflowfromthedevicestothemonitoringserverdata,gettingintoZabbix/Gettingnetflowfromthedevicestothemonitoringserverdata,receivingonserver/Receivingnetflowdataonyourserver
networkdiscoveryhosts,finding/FindinghoststheZabbixwayactionconditions,defining/Definingactionconditionsactionoperations,selecting/Choosingactionoperationsremotecommands,executing/Remotecommands
networkinterfacesabout/Low-leveldiscovery
networkservicesDNS,monitoring/MonitoringtheDNSApache,monitoring/ApachemonitoringNTP,monitoring/NTPmonitoringSquid,monitoring/Squidmonitoring
NetworkXURL/Maps–automatingtheDOTcreationabout/Maps–automatingtheDOTcreation
Nfdumpabout/Receivingnetflowdataonyourservernfcapd/Receivingnetflowdataonyourservernfdump/ReceivingnetflowdataonyourserverURL,fornfdumppackage/Receivingnetflowdataonyourserver
Nmap/ChoosingactionoperationsNTPmonitoring
about/NTPmonitoringperforming/NTPmonitoring,NTP–whatarewemonitoring?Delay/NTP–whatarewemonitoring?Offset/NTP–whatarewemonitoring?Jitter/NTP–whatarewemonitoring?
www.it-ebooks.info
OOIDs
finding,formonitoring/FindingtherightOIDstomonitorabout/FindingtherightOIDstomonitormapping,toZabbixitems/MappingSNMPOIDstoZabbixitems
www.it-ebooks.info
Ppartition_createprocedure
about/Thepartition_createprocedurepartition_dropprocedure
about/Thepartition_dropprocedurepartition_maintenanceprocedure
about/Thepartition_maintenanceprocedurepartition_maintenance_allprocedure
about/Thepartition_maintenance_allprocedurepartition_verifyprocedure
about/Thepartition_verifyprocedurePerlmodules
about/DNSSEC–monitoringthezonerolloverproxiesdataflow,Zabbix
about/UnderstandingtheZabbixproxies’dataflowProxyConfigFrequency=parameter
about/UnderstandingtheZabbixproxies’dataflowProxyDataFrequency=parameter
about/UnderstandingtheZabbixproxies’dataflowpyzabbix
about/RemotecommandsURL/Remotecommands
www.it-ebooks.info
RReadingRequestparameter/ApachemonitoringReqPerSecparameter/Apachemonitoringrollstateplugin
about/DNSSEC–monitoringthezonerollover
www.it-ebooks.info
Sscreen
about/Puttingeverythingtogetherwithscreenscreating/Puttingeverythingtogetherwithscreensmaps,puttingon/Puttingeverythingtogetherwithscreensgraph,puttingon/Puttingeverythingtogetherwithscreens
SiegeURL/Apachemonitoring
simplechecksabout/SimplechecksIcmpping/SimplechecksIcmppingloss/SimplechecksIcmppingsec/SimplechecksNet.tcp.service/SimplechecksNet.tcp.service.perf/Simplechecksconfiguring/Simplechecks
slideshowcreating/Puttingeverythingtogetherwithscreens
SNMPabout/KeepingSNMPsimpledata,gettingintoZabbix/GettingSNMPdataintoZabbixOIDs,findingformonitoring/FindingtherightOIDstomonitorOIDs,mappingtoZabbixitems/MappingSNMPOIDstoZabbixitemsdatatypes/Gettingdatatypesrightnetflowdata,receivingonserver/Receivingnetflowdataonyourserverlogfile,monitoringwithZabbix/MonitoringalogfilewithZabbix
SNMPgetsabout/KeepingSNMPsimple
snmptrapdabout/Snmptrapd
SNMPtrapsabout/KeepingSNMPsimple,SNMPtrapssnmptrapd/Snmptrapdtransforming,intoZabbixitem/TransformingatrapintoaZabbixitemnetflow,gettingfromdevices/Gettingnetflowfromthedevicestothemonitoringserver
Squidabout/SquidmonitoringURL/Squidmonitoring
Squidmetricscriptabout/Squidmetricscript
Squidmonitoringperforming/Squidmonitoring
www.it-ebooks.info
StartProxyPollers=parameterabout/UnderstandingtheZabbixproxies’dataflow
www.it-ebooks.info
TTCP/IPconnectionchecks
about/Simplecheckstriggerinformationcell/Puttingeverythingtogetherwithscreenstriggeroverviewcell/Puttingeverythingtogetherwithscreens
www.it-ebooks.info
WWaitingForConnectionparameter/ApachemonitoringWebGUIinterface
installing/InstallingtheWebGUIinterface
www.it-ebooks.info
Xxdot.py
URL/Maps–automatingtheDOTcreationxml2
about/MonitoringtheDNS
www.it-ebooks.info
ZZabbix
architectures/Zabbixarchitecturesdataflow/UnderstandingZabbixdataflowproxiesdataflow/UnderstandingtheZabbixproxies’dataflowinstalling/InstallingZabbixdatabase,installing/Installingadatabasehosts/UnderstandingZabbixhostshostgroups/Hostsandhostgroups
Zabbixagentpackage,forLinuxOSURL/CreatingaZabbixagentpackagewithCheckInstall
Zabbixagentsabout/GoingbeyondZabbixagentssimplechecks/SimplechecksSNMP/KeepingSNMPsimpleSNMPtraps/SNMPtraps
ZabbixApacheUpdaterplugin/ApachemonitoringZabbixinstallation
about/InstallingZabbixinstalling,frompackages/InstallingfrompackagesZabbixagent,settingup/SettingupaZabbixagentZabbixagentpackage,creatingwithCheckInstall/CreatingaZabbixagentpackagewithCheckInstallserverconfiguration/Serverconfiguration
Zabbixproxyinstalling/InstallingaZabbixproxy
zapacheplugin/ApachemonitoringURL/Apachemonitoring
zonestatepluginabout/DNSSEC–monitoringthezonerollover
www.it-ebooks.info
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