Linux: PowerKVM tool and feature reference

Linux

PowerKVM tool and feature reference

IBM

Linux


IBM

NoteBefore using this information and the product it supports, read the information in “Notices” onpage 9.

Second Edition (October 2014)

© Copyright IBM Corporation 2014.US Government Users Restricted Rights – Use, duplication or disclosure restricted by GSA ADP Schedule Contractwith IBM Corp.

Contents

PowerKVM tool and feature reference . . 1PowerKVM tools and features . . . . . . . . 1

CPU options for the libvirt API on PowerKVM . . 7

Notices . . . . . . . . . . . . . . . 9Privacy policy considerations . . . . . . . . 10Trademarks . . . . . . . . . . . . . . 10

© Copyright IBM Corp. 2014 iii

iv Linux: PowerKVM tool and feature reference


In many ways, IBM PowerKVM™ is identical to KVM on x86. There are, however, some differences inhow certain features and tools work. This topic lists the most important commands, features, and toolssupported on PowerKVM, gives details about using the commands on host and guest systems, andprovides links to detailed information.

PowerKVM tools and featuresThe following table lists the commands and tools that you can use to manage your PowerKVMenvironment. The table lists important limitations and additional function for a PowerKVM environmentversus a traditional x86 environment. There may be additional commands and tools that operate onPowerKVM equivalently as they do in an x86 KVM environment.

Table 1. PowerKVM tools and features in host systems and guests

Command or Tool DescriptionLimitations on PowerKVMhosts and guests Additional information

Dynamicallycreate and deleteguests.

You can use Kimchi to easily createand remove guests, which are alsoreferred to as virtual machines.

Creating a guest withKimchi

Extended errorhandling (EEH)

EEH isolates PCI errors within IOdomains without affecting the restof the system, providing enhancedsystem reliability and availability.

EEH overview from theLinux Foundation

Ganglia agent Ganglia is a scalable, distributedmonitoring system that monitorshigh performance computingsystems. Ganglia agents monitorand retrieve system usage data.Ganglia monitoring agents arepre-installed on PowerKVM.

Ganglia project onSourceForge

Hot plug Hot plug allows you to add andremove components while thesystem is active.

v Network hot plug issupported.

v Memory hot plug is notsupported. Memoryballooning (inflation anddeflation of memory) issupported is guests.

v CPU hot plug is notsupported. You can, however,take CPUs on- and off-line.

IBM® PowerKVMstorage

© Copyright IBM Corp. 2014 1

http://events.linuxfoundation.org/images/stories/pdf/lcjp2012_shan.pdf

http://events.linuxfoundation.org/images/stories/pdf/lcjp2012_shan.pdf

http://ganglia.sourceforge.net/

http://ganglia.sourceforge.net/

Table 1. PowerKVM tools and features in host systems and guests (continued)


Huge pages andtransparent hugepages

Huge pages and transparent hugepages allow memory page tableentries to cover large ranges, up tomultiple megabytes, of contiguousphysical memory

When using huge pages:

v You can only use huge (16M)pages in the guest if it isbacked by huge (16M) pagesin the host.

v Memory settings should be inmultiples of 16MB.

v Using huge pages withmemory ballooning is notsupported.

Transparent huge pages are notsupported in the followingsituations:

v In the host kernel

v For backing guests

v In guests

Configuring hugepages

ibm-configure-system

This utility, which is preloaded onPowerLinux™ systems, allows youto easily set up system informationsuch as your network configuration,DNS configuration, root password,and date and time settings.

Not applicable on guests. Theibm-configure-systemutility

ibm-update-system This tool updates or upgrades thePowerKVM system using an ISOimage that has been downloaded orordered from IBM FixCentral.

You can use this tool to update yoursystem if you cannot directly accessthe Internet.

Updating IBMPowerKVM

IPMItool IPMItool is a utility to monitor,configure, and manage devices thatsupport the Intelligent PlatformManagement Interface (IPMI).

You can install the IPMItool fromyour Linux distribution's packagerepository.

Not applicable on guests. Using IPMI on IBMPowerKVM

iostat The iostat command monitorssystem input/output device load byobserving the time that the devicesare active in relation to theiraverage transfer rates.

Can be run on both hosts andguests. Applicable only on guestIO in guests.

iostat man page

kdump A kernel crash dump is the memoryimage of an operating system kernelthat is written to a file. Typically,the system writes a crash dump filewhen the OS experiences a seriousproblem such as a crash.

Kdump in guests is notsupported. You must disablekdump in your guests. Ifkdump is enabled in a guestand the guest crashes, the guestwill attempt a kdump, but willhang during the process.

2 Linux: PowerKVM tool and feature reference

http://linux.die.net/man/1/iostat



Kernel samepagemerging (KSM)

KSM is a kernel feature that sharesmemory pages between variousprocesses, over-committing thememory.

KSM is similar to Active Memory™

deduplication on other Power®

servers.

Kernel SamepageMerging

Kimchi Kimchi is a KVM management tool,based on HTML5. Kimchi providesa web-based interface from which tomanage PowerKVM guests. Kimchirelies on the libvirt API for manyfunctions.

Kimchi is included on KVM-enabledPOWER8® systems.

Kimchi provides the followingguest management capabilities:

v Create VMs with variousresource definitions for CPU,memory, disk, network andinput devices.

v Start, stop, and destroy VMs.

v Define VM CPU and memoryresource limits.

v Create a VM with storage ona local disk, a network filesystem (NFS) share, a FibreChannel (FC) storage volume,or an iSCSI volume.

v Create a VM with networkaddress translation (NAT) orbridge connectivity.

Using Kimchi

kvm_stat The kvm_stat command outputsstatistics for all guests and the host.

KVM performanceevents

libvirt Libvirt is an open-source projectproviding a low-level virtualizationmanagement API. The libvirt API isthe standard way to expose KVMvirtualization managementinterfaces to higher-levelmanagement tools.

See the Kimchi description for moredetails about libvirt functionality onPowerKVM.

v The following universal serialbus (USB) controller modelsare supported:

– pci-ohci

– ehci

– nec-xhci

Other models are notsupported. To change the USBcontroller, edit the XML filegenerated by the libvirt API.

v The on_crash event is notsupported.

v The sanlock feature is notsupported by PowerKVM.

“CPU options for thelibvirt API onPowerKVM” on page 7

lm-sensors Open-source tool that gathers andreports data about the health ofyour hardware.

The following information isavailable for the PowerKVMhost:

v temperature

v fan speed

v voltage

v power use

Not applicable on guests.

LM-sensors project

PowerKVM tool and feature reference 3

http://www.linux-kvm.org/page/KSM

http://www.linux-kvm.org/page/KSM

http://www.linux-kvm.org/page/Perf_events

http://www.linux-kvm.org/page/Perf_events

http://lm-sensors.org/



lshw The hardware lister tool providesinformation about your hardwareconfiguration.

Not applicable on guests. Hardware Lister (lshw)

Memoryovercommitment

Memory overcommitment allowsyou to achieve greater resourcedensity by allocating resources inreaction to changing demand.

Over-committingprocessor and memoryresources

modprobe Check and configure KVM modules. Modprobe

Nagios Nagios is a system and networkmonitoring application. You canspecify the hosts and services to bewatched by Nagios.

Nagios monitoring on PowerKVMis enabled using Nagios remoteplug-in executor (NRPE), which isthe preferred method for remotemonitoring of hosts.

Nagios Core

Nestedvirtualization

In nested virtualization, guestvirtual machines run on a guesthypervisor.

Nested virtualization is notsupported.

Non-maskableinterrupt (NMI)injection

An NMI is used to signal hardwareerrors.

NMI injection to guests is notsupported.

ocount ocount is an OProfile tool that youcan use to count native hardwareevents occurring in either a specificapplication, a set of processes orthreads, a set of active systemprocessors, or the entire system.

Getting started withOProfile using ocount

operf operf is an OProfile profiling toolthat can be used instead ofopcontrol. operf uses the Linuxkernel performance eventssubsystem. With operf you canprofile a single process or the entiresystem. If you are profiling a singleprocess, you can run operf even ifyou do not have root authority.

Introduction to OProfileon PowerLinux

Oprofile OProfile is a system-wide profilerfor Linux systems.

Introduction to OProfileon PowerLinux

PCI pass-through With PCI pass-through, you canassign a PCI device directly to oneguest operating system. You do notneed to emulate a network device.

Enabling PCIpassthrough

perf You can use perf to profile yourproject and analyze its performance.Perf uses information produced bythe Linux kernel perf eventssubsystem to profile a runningapplication. Perf analyzes software,hardware, and tracepoint events.

For details about theLinux distributions thatsupport this feature,see Supported featuresfor PowerLinux servers.


http://ezix.org/project/wiki/HardwareLiSter

http://www.nagios.com/products/nagioscore

http://oprofile.sourceforge.net/doc/getting-started-with-ocount.html

http://oprofile.sourceforge.net/doc/getting-started-with-ocount.html



Petitboot Petitboot is a simplified boot loaderthat is based on kexec. UsingPetitboot, you can load images filesfrom a device or from a network.

Petitboot is comparable to LILO,GRUB, GRUB2, and EFI menus onx86 systems.

Applicable for booting the hostonly, not guests.

Petitboot is pre-loadedon POWER8 systems.See Petitbootbootloader.

ppc64_cpu Display or set the processorsimultaneous multithreading (SMT),cores, data stream control register(DSCR), and frequency settings.

The run mode setting is notsupported on PowerKVM.

Service aids

opal-dump-parse Use the opal-dump-parse utility tofind OPAL logs in the system dumpfiles (SYSDUMP) that are generatedby Power Systems.

See man page foropal-dump-parse.

Open vSwitch Open vSwitch is a open sourcemulti-layer distributed virtualswitch that supports standardmanagement protocols andinterfaces. The key advantage of itthat Open vSwitch can bedistributed across many physicalmachines.

Open vSwitch

Puppet Puppet is an open-source tool thatallows you to automate repetitivetasks.

You can run Puppet manifestson the PowerKVM host.Supported workflows includethe following:

v Monitoring configuration

v Security configuration

v User configuration

v Guest configuration

v NTP configuration

Puppet Master is not currentlysupported.

Puppet Open Source

QEMU QEMU is a machine emulator. Itprovides a link between the hostkernel and the functionality thatallows guests to be run. QEMU alsoprovides peripheral hardwareemulation.

v Emulated E1000 NetworkInterface Card (NIC) is notsupported.

v Emulated chipsets specific toIntel are not supported (forexample, ICH9).

v Cirrus VGA emulation is notsupported.

Qemu project mainpage

QEMU guestagent

Daemon program running insidethe domain to help managementapplications with executingfunctions which need assistance ofthe guest OS.

QEMU guest agent


http://openvswitch.org/

http://puppetlabs.com/puppet/puppet-open-source

http://wiki.qemu.org/Main_Page

http://wiki.qemu.org/Main_Page

http://wiki.libvirt.org/page/Qemu_guest_agent



Simple Protocolfor IndependentComputingEnvironments(SPICE)

SPICE is an open source, adaptive,remote rendering protocol used byRed Hat Enterprise Linux to connectusers to their virtual desktops.

SPICE is not supported.

Simultaneousmulti-threading(SMT)

Simultaneous multi-threading is theability of a single physical processorto simultaneously dispatchinstructions from more than onehardware thread context. Becausethere are two hardware threads perphysical processor, additionalinstructions can run at the sametime.

For details about theLinux distributionversions that supportSMT, see Supportedfeatures forPowerLinux servers.

Simple networkmanagementprotocol (SNMP)for collectingmetrics on thehost system

PowerKVM supports the standardSNMP management informationbases (MIBs) for gathering dataabout the host system.

For a detaileddescription of the MIBsavailable over SNMP,see RetrievingPerformance Data overSNMP. Thisinformation applies tothe PowerKVM host.

sosreport Generates a compressed .tar filecontaining information about thehardware and software on thesystem. You can then send this fileto your support contact.

In order to identify problems oneach, this tool can be run onboth hosts and guests. It is alsoavailable from Kimchi.

Collecting support data

sysstat tools The sysstat collection providesvarious performance monitoringtools.

Sysstat HOWTO: ADeployment andConfiguration Guide

virsh You can create, delete, run, stop,and manage your KVM hypervisorusing the virsh command. Virsh isthe command line interface tolibvirt, whereas Kimchi provides anequivalent graphical interface.

v The amount of informationdisplayed with the virshsysinfo command is limited.

v virsh nodesuspend is notsupported.

v Password-based migration isnot supported.

v virsh vcpuinfo output maynot accurately display anySMT mode changes that havebeen done by a guest.

Common virshcommand options

virt-clone Command line tool for cloningexisting virtual machine images.

virt-clone man page

virt-install The virt-install command is usedto create new KVM guests.

Using the virt-installcommand to createguests


https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Deployment_Guide/sect-System_Monitoring_Tools-Net-SNMP-Retrieving.html#tabl-System_Monitoring_Tools-Net-SNMP-OIDs



http://www.linux.com/learn/tutorials/33766-sysstat-howto-a-deployment-and-configuration-guide-for-linux-servers



http://linux.die.net/man/1/virt-clone



VirtIO virtual I/Odevices

The VirtIO API allowspara-virtualized devices to gainspeed and efficiency. The VirtIO APIspecifies an interface betweenvirtual machines and the hypervisorthat is independent of thehypervisor. VirtIO para-virtualizeddevices are especially useful forguest operating systems that runI/O heavy tasks and applications.

The following VirtIO devices aresupported:

v blk

v serial/console

v balloon

v SCSI

v mg

v netNote: VirtIO-net may notfunction correctly on Ubuntuguests.

Other devices are not supported.

Adding guestpara-virtualizednetwork devices withlibvirt

virt-manager Virtual Machine Manager(virt-manager) is a desktop userinterface for creating and managingKVM guests.

Virt-manager is not fullysupported on PowerKVM, andits use is not recommended.

virt-viewer The virt-viewer command can useSSH tunnels to display the VNCgraphical console of your remoteguests.

Virt-viewer is not supported onPowerKVM. Use VNC as analternative.

For information about reliability and serviceability tools supported on PowerKVM, see Managing yourserver with service and productivity tools.

CPU options for the libvirt API on PowerKVMIf you have PowerKVM guests that have different CPU capabilities than your host system, you canchange the CPU setting for the libvirt API.

In most cases, you do not need to specify a CPU mode. The libvirt API will automatically choose theappropriate setting. The exception is the case in which you are migrating from a previous version of thePower processor to a POWER8 system running PowerKVM.

The choices for the CPU mode setting on the libvirt API are as follows:

customIn this mode, the cpu element describes the CPU that should be presented to the guest. In thismode, a persistent guest will see the same hardware, regardless of on what host the guest isbooted. On systems running PowerKVM, this mode supports power6 and power7 compatibilityonly. In the following libvirt XML examples, the guests are started explicitly in compatibilitymode:

<cpu mode=’custom’><model>power7</model><vendor>IBM</vendor>

</cpu

<cpu mode=’custom’><model>power6</model><vendor>IBM</vendor>

</cpu


host-modelThis mode provides a shortcut for copying the host CPU definition. If you specify this mode, theguest is provided the host CPU model only, even if the guest does not support the host CPUmodel.

host-passthroughWith this mode, the CPU visible to the guest must be exactly the same as the host CPU. If youspecify this mode, the guest is provided the host CPU model only, even if the guest does notsupport the host CPU model.

The host-passthrough and host-model options behave the same on PowerKVM systems.


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Linux: PowerKVM tool and feature reference