Managed DNS 102: Advanced DNS Features With Mozilla’s Mark Mayo

Dyn.com | @dyninc

DNS 102: Managing Traffic with DynECT Managed DNS Advanced Services

Tom Daly Chief Scien5st, Dyn Labs [email protected] | @tomdyninc

DNS 102: DNS Advanced Services Tom Daly @tomdyninc Dyn.com | @dyninc

Agenda •  Welcome and Introduc5on

•  Quick Review: DNS Basics

•  DNS and HTTP Interac5on

•  DynECT Managed DNS Advanced Services

•  Traffic Op5miza5on

•  Q&A


Webinar Panel •  Tom Daly, @DynInc

–  Chief Scien5st –  Previously CTO at Dyn –  Working with DNS, Email, and BGP rou5ng for over 10 years.

•  Mark Mayo, @Mozilla –  Principal Engineer –  Previously CTO at Joyent –  Dyn customer, twice.

Quick Review: DNS Basics

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The Domain Name System (DNS) •  Fundamentally, the DNS is a mul5-‐level database distributed throughout the world.

•  DNS maps domain names to network resources, such as the IP address of a web server, FTP server, or e-‐mail server.

•  This is accomplished through a variety of DNS record types. Record types give you the hint about the type of remote server you’re contac5ng.

Working Together: The Lifecycle of a DNS Request

<root>

server1.www.dyn.com.

204.13.248.106

.com

dyn.com

Root DNS Servers

.com Servers

dyn.com Servers

Recursive DNS

DNS and HTTP InteracTon

hWp://www.flickr.com/photos/maW_gibson/2559703930/sizes/o/in/photostream/


DNS and HTTP Working Together •  Client computers make DNS requests to find the IP addresses of HTTP web servers.

•  DNS requests are sent to the ISP Recursive DNS server.

•  DNS requests are resolved via the site’s authorita5ve DNS servers.

•  Client receives the web server IP address and ini5ates and HTTP connect.


DNS and HTTP InteracTon

Primary Web Server (192.168.54.87)

ISP DNS

Home User DynECT DNS Server

HTTP Connec5on to 192.168.54.87

DNS Query for www.catblog.com returns with 192.168.54.87


Traffic Management with DNS •  Fundamentally, managing traffic with DNS means changing DNS responses on the fly.

•  This means we need lower TTLs.

•  We need intelligence in the Authorita5ve DNS to hand out the right IP address.

•  Add in Health and Performance Monitoring for more advanced intelligence services.


DNS-‐Based Traffic Management


ISP DNS

Home User DynECT DNS Server


DNS Query for www.catblog.com returns with 192.168.54.87

Hrm? Can I do something smart with this client?

Secondary Web Server (192.168.55.42)

DynECT Advanced Services and Mozilla Usage

hWp://www.flickr.com/photos/nhuisman/3168683736/sizes/l/in/photostream/


Scenarios for Mozilla •  Ac5ve Failover: Used to enact server to server or site to site disaster recovery.

•  Traffic Management: DNS-‐based cloud load balancing for applica5ons and highly available system.

•  Real-‐Time Traffic Management: Performance monitored and triggered traffic distribu5on.

•  Geo Traffic Management: Advanced targe5ng per state (US), province (CA), or country (world).


DynECT AcTve Failover •  Goal: In case of a failure of Mozilla’s primary server, ac5vate disaster recovery to a backup server.

•  Steps: –  #1: Customer provides IP / FQDN of primary and backup Servers.

–  #2: Health Checks are performed against the primary server. –  #3: If the primary server is unavailable, we return the IP / CNAME’d FQDN of the backup server.


AcTve Failover: Normal State


Backup Web Server (192.168.89.45)

ISP DNS

Home User DynECT DNS w/ Ac5ve Failover


DNS Query for mozilla.org returns with 192.168.54.87


AcTve Failover: Monitoring



ISP DNS


HTTP Health Check to HTTP Server


AcTve Failover: Failover State



ISP DNS



DNS Query for mozilla.org returns with 192.168.89.45


DynECT Traffic Management •  Goal: Distribute web traffic to mul5ple web servers

•  Steps: –  #1: Customer provides IP / FQDN of all servers. –  #2: Declare per region mappings to des5na5on servers –  #2: Health Checks are performed against the servers. –  #3: Configure rules for global or regional traffic distribu5on. –  #4: Use health checks to determine servers available to take traffic.



! !

!"#$%"&'$(!)%"*+,-.#(/#"$"*(

#"0)1(

2)(/3#2'%,(


! !

!"##$%!&'&()**+&*+&",'$-&*.%")/0$(

!"#$%&#'(!#%)

(12-$3&4"5

!"#$%&&(12-$3&4"5


! !

!"#$%&'($&$!"#$%&'!()(%*%$($)*"+$!"#*

,*"'-.(*$/%&/$!"#$+,$$!"#*$(+&-0$&..*(11



! !

<head><script src=”https://login.persona.org/include.js”></script></head>


*.login.persona.org =

Fallback IDP

It’s how to bootstrap BID into the web

(so it can’t go down!)


Persona: Globally Distributed


Persona Traffic Management •  Mozilla datacenters in Santa Clara, Phoenix, Amsterdam.

•  Soon: Brazil, APAC •  N+1 redundancy; all sites carry live traffic (“failover” is for suckers).

•  Rolling upgrades (compat with v-‐1) within a DC

•  Stop the world (schema) changes via TM one DC at a 5me

•  Feature releases + TM == happy


Actually, pre`y easy!


Health Checks


Health Checks •  Smaller endpoint-‐specific checks within the DC

•  == LBs doing the majority of the checks frequently

•  “Expensive” single large health check rollup for each site

•  TM makes DC level decisions

•  Currently use external services to monitor content checksums, latency (not RTTM).


Traffic Management: Normal State

Web Server #1 (192.168.54.87)

Web Server #2 (192.168.89.45)

ISP DNS

Home User DynECT DNS w/ Traffic Management


DNS Query for *.login.persona.org returns with 192.168.54.87 and 192.168.89.45


Traffic Management: Next ConnecTon

Web Server #1 (192.168.54.87)

Web Server #2 (192.168.89.45)

ISP DNS

Home User DynECT DNS w/ Traffic Management


DNS Query for *.login.persona.org returns with 192.168.54.87 and 192.168.89.45


Traffic Management: GeolocaTon


Traffic Management: WeighTng


Traffic Management: Serve Count

Web Server #1 (192.168.54.87)

Web Server #2 (192.168.89.45)

Home User

Web Server #3 (192.168.89.46)

Web Server #4 (192.168.89.47)

ISP DNS

DynECT returns 1, 2, 3, or 4 A records at a 5me.


DynECT Real Time Traffic Management •  Goal: Distribute web traffic to mul5ple web servers, based upon network and applica5on latency.

•  Steps: –  #1: Customer provides IP / FQDN of all servers. –  #2: Declare PREFERRED region mappings to servers –  #3: Health Checks are performed against the servers. –  #4: Performance probes are launched from EVERY Dyn monitoring site.

–  #5: Send traffic to the fastest responding servers in the region.


verifier.login.persona.org

Real Time TM

Compute Bound; Scale into AWS/GCE

Using the RTTM APIs to bring up compute on the fly


RTTM: Measurement


RTTM: ComputaTon


RTTM: RouTng


DynECT Geo Traffic Management •  Goal: Distribute web traffic to mul5ple web servers, based upon state (US), province (CA), or country (world) proximity.

•  Steps: –  #1: Customer provides IP / FQDN of all servers. –  #2: Declare state, province, or country mappings to servers –  #3: Health Checks are performed against the servers. –  #4: Send traffic to servers based upon loca5on of the user’s ISP recursive DNS server.


addons.mozilla.org


addons.mozilla.org •  Single datacenter •  Peak ~10,000 req/sec; Low ~5000 req/sec •  > 10GBit/sec •  Mul5ple HA LB clusters

•  Traffic Management for balancing across LB clusters

•  Allows for cluster-‐by-‐cluster maintenance

•  Leans heavily on caching, CDNs •  Geo!


Geo Traffic Management: Targefng

OpTmizaTon

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Minimize DNS Round Trips •  Most DNS-‐based load balancing systems rely on mul5ple DNS round trips: –  Delegate a subdomain to the GSLB system. –  Set up a CNAME to an external system.

•  More round trips means more lookup latency, more entries to cache, more configura5on to manage.

•  DynECT uniquely combines Managed DNS and Traffic Management in a single plazorm, a single query response every 5me.


Minimize DNS Latency •  IP Anycast: A globally distributed IP Anycast network of 17 worldwide Points of Presence (POPs).

•  Customers are given 4 nameservers to delegate to: –  4 discrete anycast IP prefixes –  6 worldwide backbone providers

–  Nearly 70 independent network paths.

•  Queries are answered by geographically local sites

A Proven Track Record

Dedicated Team of DNS Experts

Dyn.com | @dyninc

Stay Tuned! Learn More!

DNS 103: Performance OpTmizaTon and Security

November 14th @ 02:00pm Eastern Time

Thanks for listening!

Dyn.com | @dyninc

Thank You!

Hit us on TwiWer:

@tomdyninc

@mmayo

Thanks for listening!

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Managed DNS 102: Advanced DNS Features With Mozilla’s Mark Mayo