20.36. Displaying Per-guest Virtual Machine Information
20.36.1. Displaying the Guest Virtual Machines
To display a list of active guest virtual machines and their current states with
virsh:
# virsh list
Other options available include:
--all- Lists all guest virtual machines. For example:#
virsh list --allId Name State ---------------------------------- 0 Domain-0 running 1 Domain202 paused 2 Domain010 shut off 3 Domain9600 crashedNote
If no results are displayed when runningvirsh list --all, it is possible that you did not create the virtual machine as the root user.Thevirsh list --allcommand recognizes the following states:- running - The
runningstate refers to guest virtual machines that are currently active on a CPU. - idle - The
idlestate indicates that the guest virtual machine is idle, and may not be running or able to run. This can occur when the guest virtual machine is waiting on I/O (a traditional wait state) or has gone to sleep because there was nothing else for it to do. - paused - When a guest virtual machine is paused, it consumes memory and other resources, but it is not eligible for scheduling CPU resources from the hypervisor. The
pausedstate occurs after using the paused button invirt-manageror thevirsh suspendcommand. - in shutdown - The
in shutdownstate is for guest virtual machines in the process of shutting down. The guest virtual machine is sent a shutdown signal and should be in the process of stopping its operations gracefully. This may not work with all guest virtual machine operating systems; some operating systems do not respond to these signals. - shut off - The
shut offstate indicates that the guest virtual machine is not running. This can be caused when a guest virtual machine completely shuts down or has not been started. - crashed - The
crashedstate indicates that the guest virtual machine has crashed and can only occur if the guest virtual machine has been configured not to restart on crash. - pmsuspended - The guest has been suspended by guest power management.
--inactive- Lists guest virtual machines that have been defined but are not currently active. This includes machines that areshut offandcrashed.--managed-save- Guests that have managed save state enabled will be listed assaved. Note that to filter guests with this option, you also need to use the--allor--inactiveoptions.--name- The command lists the names of the guests instead of the default table format. This option is mutually exclusive with the--uuidoption, which only prints a list of guest UUIDs, and with the--tableoption, which determines that the table style output should be used.--title- Lists also the guesttitlefield, which typically contains a short description of the guest. This option must be used with the default (--table) output format. For example:$
virsh list --titleId Name State Title ---------------------------------------------------------------------------- 0 Domain-0 running Mailserver1 2 rhelvm paused--persistent- Only persistent guests are included in a list. Use the--transientargument to list transient guests.--with-managed-save- Lists guests that have been configured with a managed save. To list the guests without one, use the--without-managed-saveoption.--state-running- Lists only guests that are running. Similarly, use--state-pausedfor paused guests,--state-shutofffor guests that are turned off, and--state-otherlists all states as a fallback.--autostart- Only auto-starting guests are listed. To list guests with this feature disabled, use the argument--no-autostart.--with-snapshot- Lists the guests whose snapshot images can be listed. To filter for guests without a snapshot, use the--without-snapshotoption.
20.36.2. Displaying Virtual CPU Information
To display virtual CPU information from a guest virtual machine with
virsh:
# virsh vcpuinfo {domain-id, domain-name or domain-uuid}
An example of
virsh vcpuinfo output:
# virsh vcpuinfo guest1
VCPU: 0
CPU: 2
State: running
CPU time: 7152.4s
CPU Affinity: yyyy
VCPU: 1
CPU: 2
State: running
CPU time: 10889.1s
CPU Affinity: yyyy
20.36.3. Pinning vCPU to a Host Physical Machine's CPU
The
virsh vcpupin command assigns a virtual CPU to a physical one.
# virsh vcpupin guest1
VCPU: CPU Affinity
----------------------------------
0: 0-3
1: 0-3
The
vcpupin command can take the following arguments:
--vcpurequires the vcpu number[--cpulist] stringlists the host physical machine's CPU number(s) to set, or omit option to query--configaffects next boot--liveaffects the running guest virtual machine--currentaffects the current guest virtual machine state
20.36.4. Displaying Information about the Virtual CPU Counts of a Given Domain
The
virsh vcpucount command requires a domain name or a domain ID
# virsh vcpucount guest1
maximum config 2
maximum live 2
current config 2
current live 2
The
vcpucount can take the following arguments:
--maximumget maximum cap on vcpus--activeget number of currently active vcpus--liveget value from running guest virtual machine--configget value to be used on next boot--currentget value according to current guest virtual machine state--guestcount that is returned is from the perspective of the guest
20.36.5. Configuring Virtual CPU Affinity
To configure the affinity of virtual CPUs with physical CPUs:
# virsh vcpupin domain-id vcpu cpulist
The
domain-id parameter is the guest virtual machine's ID number or name.
The
vcpu parameter denotes the number of virtualized CPUs allocated to the guest virtual machine.The vcpu parameter must be provided.
The
cpulist parameter is a list of physical CPU identifier numbers separated by commas. The cpulist parameter determines which physical CPUs the VCPUs can run on.
Additional parameters such as
--config effect the next boot, whereas --live effects the running guest virtual machine and --current affects the current guest virtual machine state.
20.36.6. Configuring Virtual CPU Count
Use this command to change the number of virtual CPUs active in a guest virtual machine. By default, this command works on active guest virtual machines. To change the inactive settings that will be used the next time a guest virtual machine is started, use the
--config flag.To modify the number of CPUs assigned to a guest virtual machine with virsh:
# virsh setvcpus {domain-name, domain-id or domain-uuid} count [[--config] [--live] | [--current]] [--maximum] [--guest]
For example:
# virsh setvcpus guestVM1 2 --live
will set the number of vCPUs to guestVM1 to two and this action will be performed while the guestVM1 is running.
Important
Hot unplugging vCPUs is not supported on Red Hat Enterprise Linux 7.
The count value may be limited by host, hypervisor, or a limit coming from the original description of the guest virtual machine.
If the
--config flag is specified, the change is made to the stored XML configuration for the guest virtual machine, and will only take effect when the guest is started.
If
--live is specified, the guest virtual machine must be active, and the change takes place immediately. This option will allow hot plugging of a vCPU. Both the --config and --live flags may be specified together if supported by the hypervisor.
If
--current is specified, the flag affects the current guest virtual machine state.
When no flags are specified, the
--live flag is assumed. The command will fail if the guest virtual machine is not active. In addition, if no flags are specified, it is up to the hypervisor whether the --config flag is also assumed. This determines whether the XML configuration is adjusted to make the change persistent.
The
--maximum flag controls the maximum number of virtual CPUs that can be hot-plugged the next time the guest virtual machine is booted. Therefore, it can only be used with the --config flag, not with the --live flag.
Note that
count cannot exceed the number of CPUs assigned to the guest virtual machine.
If
--guest is specified, the flag modifies the CPU state in the current guest virtual machine.
20.36.7. Configuring Memory Allocation
To modify a guest virtual machine's memory allocation with
virsh:
# virsh setmem {domain-id or domain-name} count
For example:
# virsh setmem vr-rhel6u1-x86_64-kvm --kilobytes 1025000
You must specify the
count in kilobytes. The new count value cannot exceed the amount you specified for the guest virtual machine. Values lower than 64 MB are unlikely to work with most guest virtual machine operating systems. A higher maximum memory value does not affect active guest virtual machines. If the new value is lower than the available memory, it will shrink possibly causing the guest virtual machine to crash.
This command has the following options
- domain - specified by a domain name, id, or uuid
- size - Determines the new memory size, as a scaled integer. The default unit is KiB, but a different one can be specified:Valid memory units include:
borbytesfor bytesKBfor kilobytes (103 or blocks of 1,000 bytes)korKiBfor kibibytes (210 or blocks of 1024 bytes)MBfor megabytes (106 or blocks of 1,000,000 bytes)MorMiBfor mebibytes (220 or blocks of 1,048,576 bytes)GBfor gigabytes (109 or blocks of 1,000,000,000 bytes)GorGiBfor gibibytes (230 or blocks of 1,073,741,824 bytes)TBfor terabytes (1012 or blocks of 1,000,000,000,000 bytes)TorTiBfor tebibytes (240 or blocks of 1,099,511,627,776 bytes)
Note that all values will be rounded up to the nearest kibibyte by libvirt, and may be further rounded to the granularity supported by the hypervisor. Some hypervisors also enforce a minimum, such as 4000KiB (or 4000 x 210 or 4,096,000 bytes). The units for this value are determined by the optional attributememory unit, which defaults to the kibibytes (KiB) as a unit of measure where the value given is multiplied by 210 or blocks of 1024 bytes. --config- the command takes effect on the next boot--live- the command controls the memory of a running guest virtual machine--current- the command controls the memory on the current guest virtual machine
20.36.8. Changing the Memory Allocation for the Domain
The
virsh setmaxmem domain size --config --live --current command allows the setting of the maximum memory allocation for a guest virtual machine as shown:
# virsh setmaxmem guest1 1024 --current
The size that can be given for the maximum memory is a scaled integer that by default is expressed in kibibytes, unless a supported suffix is provided. The following arguments can be used with this command:
--config- takes affect next boot--live- controls the memory of the running guest virtual machine, providing the hypervisor supports this action as not all hypervisors allow live changes of the maximum memory limit.--current- controls the memory on the current guest virtual machine
20.36.9. Displaying Guest Virtual Machine Block Device Information
Use the
virsh domblkstat command to display block device statistics for a running guest virtual machine. Use the --human to display the statistics in a more user friendly way.
# virsh domblkstat GuestName block-device20.36.10. Displaying Guest Virtual Machine Network Device Information
Use the
virsh domifstat command to display network interface statistics for a running guest virtual machine.
# virsh domifstat GuestName interface-device 