Domain commands
The following commands manipulate domains directly, as stated previously most commands take domain as the first parameter. The domain can be specified as a short integer, a name or a full UUID.
autostart
Syntax:
autostart [--disable] [--once] domain
Configure a domain to be automatically started at each boot of the host. The --once option configures the domain to be started on the next boot of the host.
The option --disable disables the corresponding autostarting.
Note that autostart configured via the --once option is independent from the autostart configured without it. Enabling either of them will cause the VM to be started on the next boot of the host.
blkdeviotune
Syntax:
blkdeviotune domain device [[--config] [--live] | [--current]]
[[total-bytes-sec] | [read-bytes-sec] [write-bytes-sec]]
[[total-iops-sec] | [read-iops-sec] [write-iops-sec]]
[[total-bytes-sec-max] | [read-bytes-sec-max] [write-bytes-sec-max]]
[[total-iops-sec-max] | [read-iops-sec-max] [write-iops-sec-max]]
[[total-bytes-sec-max-length] |
[read-bytes-sec-max-length] [write-bytes-sec-max-length]]
[[total-iops-sec-max-length] |
[read-iops-sec-max-length] [write-iops-sec-max-length]]
[size-iops-sec] [group-name]
Set or query the block disk io parameters for a block device of domain. device specifies a unique target name (<target dev='name'/>) or source file (<source file='name'/>) for one of the disk devices attached to domain (see also domblklist for listing these names).
If no limit is specified, it will query current I/O limits setting. Otherwise, alter the limits with these flags: --total-bytes-sec specifies total throughput limit as a scaled integer, the default being bytes per second if no suffix is specified. --read-bytes-sec specifies read throughput limit as a scaled integer, the default being bytes per second if no suffix is specified. --write-bytes-sec specifies write throughput limit as a scaled integer, the default being bytes per second if no suffix is specified. --total-iops-sec specifies total I/O operations limit per second. --read-iops-sec specifies read I/O operations limit per second. --write-iops-sec specifies write I/O operations limit per second. --total-bytes-sec-max specifies maximum total throughput limit as a scaled integer, the default being bytes per second if no suffix is specified --read-bytes-sec-max specifies maximum read throughput limit as a scaled integer, the default being bytes per second if no suffix is specified. --write-bytes-sec-max specifies maximum write throughput limit as a scaled integer, the default being bytes per second if no suffix is specified. --total-iops-sec-max specifies maximum total I/O operations limit per second. --read-iops-sec-max specifies maximum read I/O operations limit per second. --write-iops-sec-max specifies maximum write I/O operations limit per second. --total-bytes-sec-max-length specifies duration in seconds to allow maximum total throughput limit. --read-bytes-sec-max-length specifies duration in seconds to allow maximum read throughput limit. --write-bytes-sec-max-length specifies duration in seconds to allow maximum write throughput limit. --total-iops-sec-max-length specifies duration in seconds to allow maximum total I/O operations limit. --read-iops-sec-max-length specifies duration in seconds to allow maximum read I/O operations limit. --write-iops-sec-max-length specifies duration in seconds to allow maximum write I/O operations limit. --size-iops-sec specifies size I/O operations limit per second. --group-name specifies group name to share I/O quota between multiple drives. For a QEMU domain, if no name is provided, then the default is to have a single group for each device.
Older versions of virsh only accepted these options with underscore instead of dash, as in --total_bytes_sec.
Bytes and iops values are independent, but setting only one value (such as --read-bytes-sec) resets the other two in that category to unlimited. An explicit 0 also clears any limit. A non-zero value for a given total cannot be mixed with non-zero values for read or write.
It is up to the hypervisor to determine how to handle the length values. For the QEMU hypervisor, if an I/O limit value or maximum value is set, then the default value of 1 second will be displayed. Supplying a 0 will reset the value back to the default.
If --live is specified, affect a running guest. If --config is specified, affect the next start of a persistent guest. If --current is specified, it is equivalent to either --live or --config, depending on the current state of the guest. When setting the disk io parameters both --live and --config flags may be given, but --current is exclusive. For querying only one of --live, --config or --current can be specified. If no flag is specified, behavior is different depending on hypervisor.
domthrottlegroupset
Syntax:
domthrottlegroupset domain group-name [[--config] [--live] | [--current]]
[[total-bytes-sec] | [read-bytes-sec] [write-bytes-sec]]
[[total-iops-sec] | [read-iops-sec] [write-iops-sec]]
[[total-bytes-sec-max] | [read-bytes-sec-max] [write-bytes-sec-max]]
[[total-iops-sec-max] | [read-iops-sec-max] [write-iops-sec-max]]
[[total-bytes-sec-max-length] |
[read-bytes-sec-max-length] [write-bytes-sec-max-length]]
[[total-iops-sec-max-length] |
[read-iops-sec-max-length] [write-iops-sec-max-length]]
[size-iops-sec]
Add or update a throttle group against specific domain. group-name specifies a unique throttle group name, which defines limit, and will be referenced by drives.
If no limit is specified, default them as all zeros, which will fail, Otherwise, set limits with these flags: --total-bytes-sec specifies total throughput limit as a scaled integer, the default being bytes per second if no suffix is specified. --read-bytes-sec specifies read throughput limit as a scaled integer, the default being bytes per second if no suffix is specified. --write-bytes-sec specifies write throughput limit as a scaled integer, the default being bytes per second if no suffix is specified. --total-iops-sec specifies total I/O operations limit per second. --read-iops-sec specifies read I/O operations limit per second. --write-iops-sec specifies write I/O operations limit per second. --total-bytes-sec-max specifies maximum total throughput limit as a scaled integer, the default being bytes per second if no suffix is specified --read-bytes-sec-max specifies maximum read throughput limit as a scaled integer, the default being bytes per second if no suffix is specified. --write-bytes-sec-max specifies maximum write throughput limit as a scaled integer, the default being bytes per second if no suffix is specified. --total-iops-sec-max specifies maximum total I/O operations limit per second. --read-iops-sec-max specifies maximum read I/O operations limit per second. --write-iops-sec-max specifies maximum write I/O operations limit per second. --total-bytes-sec-max-length specifies duration in seconds to allow maximum total throughput limit. --read-bytes-sec-max-length specifies duration in seconds to allow maximum read throughput limit. --write-bytes-sec-max-length specifies duration in seconds to allow maximum write throughput limit. --total-iops-sec-max-length specifies duration in seconds to allow maximum total I/O operations limit. --read-iops-sec-max-length specifies duration in seconds to allow maximum read I/O operations limit. --write-iops-sec-max-length specifies duration in seconds to allow maximum write I/O operations limit. --size-iops-sec specifies size I/O operations limit per second.
Bytes and iops values are independent, but setting only one value (such as --read-bytes-sec) resets the other two in that category to unlimited. An explicit 0 also clears any limit. A non-zero value for a given total cannot be mixed with non-zero values for read or write.
It is up to the hypervisor to determine how to handle the length values. For the QEMU hypervisor, if an I/O limit value or maximum value is set, then the default value of 1 second will be displayed. Supplying a 0 will reset the value back to the default.
If --live is specified, affect a running guest. If --config is specified, affect the next start of a persistent guest. If --current is specified, it is equivalent to either --live or --config, depending on the current state of the guest. When setting the disk io parameters both --live and --config are specified, both live configuration and config are updated while setting the description, but --current is exclusive. If no flag is specified, behavior is different depending on hypervisor.
domthrottlegroupdel
Syntax:
domthrottlegroupdel domain group-name [[--config] [--live] | [--current]]
Delete a Throttlegroup from the domain using the specified group-name. If an Throttlegroup is currently referenced by a disk resource, then the attempt to remove the Throttlegroup will fail. If the group-name does not exist an error will occur.
If --live is specified, affect a running guest. If the guest is not running an error is returned. If --config is specified, affect the next start of a persistent guest. If --current is specified, it is equivalent to either --live or --config, depending on the current state of the guest.
domthrottlegroupinfo
Syntax:
domthrottlegroupinfo domain group-name [[--config] [--live] | [--current]]
Display domain Throttlegroup information including I/O limits setting.
If --live is specified, get the Throttlegroup data from the running guest. If the guest is not running, an error is returned. If --config is specified, get the Throttlegroup data from the next start of a persistent guest. If --current is specified or --live and --config are not specified, then get the Throttlegroup data based on the current guest state, which can either be live or offline. If both --live and --config are specified, the --config option takes precedence on getting the current description.
domthrottlegrouplist
Syntax:
domthrottlegrouplist domain [--inactive]
Print a table showing names of all throttle groups associated with domain. If --inactive is specified, query the Throttlegroup data that will be used on the next boot, rather than those currently in use by a running domain.
blkiotune
Syntax:
blkiotune domain [--weight weight] [--device-weights device-weights]
[--device-read-iops-sec device-read-iops-sec]
[--device-write-iops-sec device-write-iops-sec]
[--device-read-bytes-sec device-read-bytes-sec]
[--device-write-bytes-sec device-write-bytes-sec]
[[--config] [--live] | [--current]]
Display or set the blkio parameters. QEMU/KVM supports --weight. --weight is in range [100, 1000]. After kernel 2.6.39, the value could be in the range [10, 1000].
device-weights is a single string listing one or more device/weight pairs, in the format of /path/to/device,weight,/path/to/device,weight. Each weight is in the range [100, 1000], [10, 1000] after kernel 2.6.39, or the value 0 to remove that device from per-device listings. Only the devices listed in the string are modified; any existing per-device weights for other devices remain unchanged.
device-read-iops-sec is a single string listing one or more device/read_iops_sec pairs, int the format of /path/to/device,read_iops_sec,/path/to/device,read_iops_sec. Each read_iops_sec is a number which type is unsigned int, value 0 to remove that device from per-device listing. Only the devices listed in the string are modified; any existing per-device read_iops_sec for other devices remain unchanged.
device-write-iops-sec is a single string listing one or more device/write_iops_sec pairs, int the format of /path/to/device,write_iops_sec,/path/to/device,write_iops_sec. Each write_iops_sec is a number which type is unsigned int, value 0 to remove that device from per-device listing. Only the devices listed in the string are modified; any existing per-device write_iops_sec for other devices remain unchanged.
device-read-bytes-sec is a single string listing one or more device/read_bytes_sec pairs, int the format of /path/to/device,read_bytes_sec,/path/to/device,read_bytes_sec. Each read_bytes_sec is a number which type is unsigned long long, value 0 to remove that device from per-device listing. Only the devices listed in the string are modified; any existing per-device read_bytes_sec for other devices remain unchanged.
device-write-bytes-sec is a single string listing one or more device/write_bytes_sec pairs, int the format of /path/to/device,write_bytes_sec,/path/to/device,write_bytes_sec. Each write_bytes_sec is a number which type is unsigned long long, value 0 to remove that device from per-device listing. Only the devices listed in the string are modified; any existing per-device write_bytes_sec for other devices remain unchanged.
If --live is specified, affect a running guest. If --config is specified, affect the next start of a persistent guest. If --current is specified, it is equivalent to either --live or --config, depending on the current state of the guest. Both --live and --config flags may be given, but --current is exclusive. If no flag is specified, behavior is different depending on hypervisor.
blockcommit
Syntax:
blockcommit domain path [bandwidth] [--bytes] [base]
[--shallow] [top] [--delete] [--keep-relative]
[--wait [--async] [--verbose]] [--timeout seconds]
[--active] [{--pivot | --keep-overlay}]
Reduce the length of a backing image chain, by committing changes at the top of the chain (snapshot or delta files) into backing images. By default, this command attempts to flatten the entire chain. If base and/or top are specified as files within the backing chain, then the operation is constrained to committing just that portion of the chain; --shallow can be used instead of base to specify the immediate backing file of the resulting top image to be committed. The files being committed are rendered invalid, possibly as soon as the operation starts; using the --delete flag will attempt to remove these invalidated files at the successful completion of the commit operation. When the --keep-relative flag is used, the backing file paths will be kept relative.
When top is omitted or specified as the active image, it is also possible to specify --active to trigger a two-phase active commit. In the first phase, top is copied into base and the job can only be canceled, with top still containing data not yet in base. In the second phase, top and base remain identical until a call to blockjob with the --abort flag (keeping top as the active image that tracks changes from that point in time) or the --pivot flag (making base the new active image and invalidating top).
By default, this command returns as soon as possible, and data for the entire disk is committed in the background; the progress of the operation can be checked with blockjob. However, if --wait is specified, then this command will block until the operation completes (or for --active, enters the second phase), or until the operation is canceled because the optional timeout in seconds elapses or SIGINT is sent (usually with Ctrl-C). Using --verbose along with --wait will produce periodic status updates. If job cancellation is triggered, --async will return control to the user as fast as possible, otherwise the command may continue to block a little while longer until the job is done cleaning up. Using --pivot is shorthand for combining --active --wait with an automatic blockjob --pivot; and using --keep-overlay is shorthand for combining --active --wait with an automatic blockjob --abort.
path specifies fully-qualified path of the disk; it corresponds to a unique target name (<target dev='name'/>) or source file (<source file='name'/>) for one of the disk devices attached to domain (see also domblklist for listing these names). bandwidth specifies copying bandwidth limit in MiB/s, although for QEMU, it may be non-zero only for an online domain. For further information on the bandwidth argument see the corresponding section for the blockjob command.
blockcopy
Syntax:
blockcopy domain path { dest [format] [--blockdev] | --xml file }
[--shallow] [--reuse-external] [bandwidth]
[--wait [--async] [--verbose]] [{--pivot | --finish}]
[--timeout seconds] [granularity] [buf-size] [--bytes]
[--transient-job] [--synchronous-writes] [--dest-is-zero] [--print-xml]
Copy a disk backing image chain to a destination. Either dest as the destination file name, or --xml with the name of an XML file containing a top-level <disk> element describing the destination, must be present. Additionally, if dest is given, format should be specified to declare the format of the destination (if format is omitted, then libvirt will reuse the format of the source, or with --reuse-external will be forced to probe the destination format, which could be a potential security hole). The command supports --raw as a boolean flag synonym for --format=raw. When using dest, the destination is treated as a regular file unless --blockdev is used to signal that it is a block device. By default, this command flattens the entire chain; but if --shallow is specified, the copy shares the backing chain.
If --reuse-external is specified, then the destination must exist and have sufficient space to hold the copy. If --shallow is used in conjunction with --reuse-external then the pre-created image must have guest visible contents identical to guest visible contents of the backing file of the original image. This may be used to modify the backing file names on the destination.
By default, the copy job runs in the background, and consists of two phases. Initially, the job must copy all data from the source, and during this phase, the job can only be canceled to revert back to the source disk, with no guarantees about the destination. After this phase completes, both the source and the destination remain mirrored until a call to blockjob with the --abort and --pivot flags pivots over to the copy, or a call without --pivot leaves the destination as a faithful copy of that point in time. However, if --wait is specified, then this command will block until the mirroring phase begins, or cancel the operation if the optional timeout in seconds elapses or SIGINT is sent (usually with Ctrl-C). Using --verbose along with --wait will produce periodic status updates. Using --pivot (similar to blockjob --pivot) or --finish (similar to blockjob --abort) implies --wait, and will additionally end the job cleanly rather than leaving things in the mirroring phase. If job cancellation is triggered by timeout or by --finish, --async will return control to the user as fast as possible, otherwise the command may continue to block a little while longer until the job has actually cancelled.
path specifies fully-qualified path of the disk. bandwidth specifies copying bandwidth limit in MiB/s. Specifying a negative value is interpreted as an unsigned long long value that might be essentially unlimited, but more likely would overflow; it is safer to use 0 for that purpose. For further information on the bandwidth argument see the corresponding section for the blockjob command. Specifying granularity allows fine-tuning of the granularity that will be copied when a dirty region is detected; larger values trigger less I/O overhead but may end up copying more data overall (the default value is usually correct); hypervisors may restrict this to be a power of two or fall within a certain range. Specifying buf-size will control how much data can be simultaneously in-flight during the copy; larger values use more memory but may allow faster completion (the default value is usually correct).
--transient-job allows specifying that the user does not require the job to be recovered if the VM crashes or is turned off before the job completes. This flag removes the restriction of copy jobs to transient domains if that restriction is applied by the hypervisor.
If --synchronous-writes is specified the block job will wait for guest writes to be propagated both to the original image and to the destination of the copy so that it's guaranteed that the job converges if the destination storage is slower. This may impact performance of writes while the blockjob is running.
If --dest-is-zero is specified the hypervisor may assume that the target image was already cleared (any offset reads 0x00 bytes) and thus may skip clearing it.
If --print-xml is specified, then the XML used to start the block copy job is printed instead of starting the job.
blockjob
Syntax:
blockjob domain path { [--abort] [--async] [--pivot] |
[--info] [--raw] [--bytes] | [bandwidth] }
Manage active block operations. There are three mutually-exclusive modes: --info, bandwidth, and --abort. --async and --pivot imply abort mode; --raw implies info mode; and if no mode was given, --info mode is assumed.
path specifies fully-qualified path of the disk; it corresponds to a unique target name (<target dev='name'/>) or source file (<source file='name'/>) for one of the disk devices attached to domain (see also domblklist for listing these names).
In --abort mode, the active job on the specified disk will be aborted. If --async is also specified, this command will return immediately, rather than waiting for the cancellation to complete. If --pivot is specified, this requests that an active copy or active commit job be pivoted over to the new image.
In --info mode, the active job information on the specified disk will be printed. By default, the output is a single human-readable summary line; this format may change in future versions. Adding --raw lists each field of the struct, in a stable format. If the --bytes flag is set, then the command errors out if the server could not supply bytes/s resolution; when omitting the flag, raw output is listed in MiB/s and human-readable output automatically selects the best resolution supported by the server.
bandwidth can be used to set bandwidth limit for the active job in MiB/s. If --bytes is specified then the bandwidth value is interpreted in bytes/s. Specifying a negative value is interpreted as an unsigned long value or essentially unlimited. The hypervisor can choose whether to reject the value or convert it to the maximum value allowed. Optionally a scaled positive number may be used as bandwidth (see NOTES above). Using --bytes with a scaled value permits a finer granularity to be selected. A scaled value used without --bytes will be rounded down to MiB/s. Note that the --bytes may be unsupported by the hypervisor.
Note that the progress reported for blockjobs corresponding to a pull-mode backup don't report progress of the backup but rather usage of temporary space required for the backup.
blockpull
Syntax:
blockpull domain path [bandwidth] [--bytes] [base]
[--wait [--verbose] [--timeout seconds] [--async]]
[--keep-relative]
Populate a disk from its backing image chain. By default, this command flattens the entire chain; but if base is specified, containing the name of one of the backing files in the chain, then that file becomes the new backing file and only the intermediate portion of the chain is pulled. Once all requested data from the backing image chain has been pulled, the disk no longer depends on that portion of the backing chain.
By default, this command returns as soon as possible, and data for the entire disk is pulled in the background; the progress of the operation can be checked with blockjob. However, if --wait is specified, then this command will block until the operation completes, or cancel the operation if the optional timeout in seconds elapses or SIGINT is sent (usually with Ctrl-C). Using --verbose along with --wait will produce periodic status updates. If job cancellation is triggered, --async will return control to the user as fast as possible, otherwise the command may continue to block a little while longer until the job is done cleaning up.
Using the --keep-relative flag will keep the backing chain names relative.
path specifies fully-qualified path of the disk; it corresponds to a unique target name (<target dev='name'/>) or source file (<source file='name'/>) for one of the disk devices attached to domain (see also domblklist for listing these names). bandwidth specifies copying bandwidth limit in MiB/s. For further information on the bandwidth argument see the corresponding section for the blockjob command.
blockresize
Syntax:
blockresize domain path ([size] | [--capacity]) [--extend]
Resize a block device of domain while the domain is running, path specifies the absolute path of the block device; it corresponds to a unique target name (<target dev='name'/>) or source file (<source file='name'/>) for one of the disk devices attached to domain (see also domblklist for listing these names).
The --extend flag instructs the hypervisor to ensure that the new size isn't smaller than the old size, thus prevents (accidental) shrinking of the block device which may lead to data loss. Users are encouraged to always use this flag unless communicating with an older hypervisor.
For image formats without metadata (raw) stored inside fixed-size storage (e.g. block devices) the --capacity flag can be used to resize the device to the full size of the backing device.
size is a scaled integer (see NOTES above) which defaults to KiB (blocks of 1024 bytes) if there is no suffix. You must use a suffix of "B" to get bytes (note that for historical reasons, this differs from vol-resize which defaults to bytes without a suffix).
console
Syntax:
console domain [devname] [--safe] [--force] [--resume]
Connect the virtual serial console for the guest. The optional devname parameter refers to the device alias of an alternate console, serial or parallel device configured for the guest. If omitted, the primary console will be opened.
If the flag --safe is specified, the connection is only attempted if the driver supports safe console handling. This flag specifies that the server has to ensure exclusive access to console devices. Optionally the --force flag may be specified, requesting to disconnect any existing sessions, such as in a case of a broken connection.
If the flag --resume is specified then the guest is resumed after connecting to the console.
cpu-stats
Syntax:
cpu-stats domain [--total] [start] [count]
Provide cpu statistics information of a domain. The domain should be running. Default it shows stats for all CPUs, and a total. Use --total for only the total stats, start for only the per-cpu stats of the CPUs from start, count for only count CPUs' stats.
create
Syntax:
create FILE [--console] [--paused] [--autodestroy]
[--pass-fds N,M,...] [--validate] [--reset-nvram]
Create a domain from an XML <file>. Optionally, --validate option can be passed to validate the format of the input XML file against an internal RNG schema (identical to using virt-xml-validate(1) tool). Domains created using this command are going to be either transient (temporary ones that will vanish once destroyed) or existing persistent guests that will run with one-time use configuration, leaving the persistent XML untouched (this can come handy during an automated testing of various configurations all based on the original XML). See the example below for usage demonstration.
The domain will be paused if the --paused option is used and supported by the driver; otherwise it will be running. If --console is requested, attach to the console after creation. If --autodestroy is requested, then the guest will be automatically destroyed when virsh closes its connection to libvirt, or otherwise exits.
If --pass-fds is specified, the argument is a comma separated list of open file descriptors which should be pass on into the guest. The file descriptors will be re-numbered in the guest, starting from 3. This is only supported with container based virtualization.
If --reset-nvram is specified, any existing NVRAM/varstore file will be deleted and re-initialized from its pristine template.
Example:
- 1.
-
prepare a template from an existing domain (skip directly to 3a if writing one from scratch)
# virsh dumpxml <domain> > domain.xml
- 2.
-
edit the template using an editor of your choice and:
- a.
-
DO CHANGE! <name> and <uuid> (<uuid> can also be removed), or
- b.
-
DON'T CHANGE! either <name> or <uuid>
- 3.
-
create a domain from domain.xml, depending on whether following 2a or 2b respectively:
- a.
-
the domain is going to be transient
- b.
-
an existing persistent guest will run with a modified one-time configuration
# virsh create domain.xml
define
Syntax:
Define a domain from an XML <file>. Optionally, the format of the input XML file can be validated against an internal RNG schema with --validate (identical to using virt-xml-validate(1) tool). The domain definition is registered but not started. If domain is already running, the changes will take effect on the next boot.
desc
Syntax:
desc domain [[--live] [--config] |
[--current]] [--title] [--edit] [--new-desc
New description or title message]
Show or modify description and title of a domain. These values are user fields that allow storing arbitrary textual data to allow easy identification of domains. Title should be short, although it's not enforced. (See also metadata that works with XML based domain metadata.)
Flags --live or --config select whether this command works on live or persistent definitions of the domain. If both --live and --config are specified, the --config option takes precedence on getting the current description and both live configuration and config are updated while setting the description. --current is exclusive and implied if none of these was specified.
Flag --edit specifies that an editor with the contents of current description or title should be opened and the contents saved back afterwards.
Flag --title selects operation on the title field instead of description.
If neither of --edit and --new-desc are specified the note or description is displayed instead of being modified.
destroy
Syntax:
destroy domain [--graceful] [--remove-logs]
Immediately terminate the domain domain. This doesn't give the domain OS any chance to react, and it's the equivalent of ripping the power cord out on a physical machine. In most cases you will want to use the shutdown command instead. However, this does not delete any storage volumes used by the guest, and if the domain is persistent, it can be restarted later.
If domain is transient, then the metadata of any snapshots will be lost once the guest stops running, but the snapshot contents still exist, and a new domain with the same name and UUID can restore the snapshot metadata with snapshot-create. Similarly, the metadata of any checkpoints will be lost, but can be restored with checkpoint-create.
If --graceful is specified, don't resort to extreme measures (e.g. SIGKILL) when the guest doesn't stop after a reasonable timeout; return an error instead.
If --remove-logs is specified, remove per domain log files. Not all deployment configuration can be supported.
In case of QEMU the flag is only supported if virlogd is used to handle QEMU process output. Otherwise the flag is ignored.
domblkerror
Syntax:
Show errors on block devices. This command usually comes handy when domstate command says that a domain was paused due to I/O error. The domblkerror command lists all block devices in error state and the error seen on each of them.
domblkinfo
Syntax:
domblkinfo domain [block-device --all] [--human]
Get block device size info for a domain. A block-device corresponds to a unique target name (<target dev='name'/>) or source file (<source file='name'/>) for one of the disk devices attached to domain (see also domblklist for listing these names). If --human is set, the output will have a human readable output. If --all is set, the output will be a table showing all block devices size info associated with domain. The --all option takes precedence of the others.
domblklist
Syntax:
domblklist domain [--inactive] [--details]
Print a table showing the brief information of all block devices associated with domain. If --inactive is specified, query the block devices that will be used on the next boot, rather than those currently in use by a running domain. If --details is specified, disk type and device value will also be printed. Other contexts that require a block device name (such as domblkinfo or snapshot-create for disk snapshots) will accept either target or unique source names printed by this command.
domblkstat
Syntax:
domblkstat domain [block-device] [--human]
Get device block stats for a running domain. A block-device corresponds to a unique target name (<target dev='name'/>) or source file (<source file='name'/>) for one of the disk devices attached to domain (see also domblklist for listing these names). On a LXC or QEMU domain, omitting the block-device yields device block stats summarily for the entire domain.
Use --human for a more human readable output.
Availability of these fields depends on hypervisor. Unsupported fields are missing from the output. Other fields may appear if communicating with a newer version of libvirtd.
Explanation of fields (fields appear in the following order):
•
|
rd_req - count of read operations
|
•
|
rd_bytes - count of read bytes
|
•
|
wr_req - count of write operations
|
•
|
wr_bytes - count of written bytes
|
•
|
errs - error count
|
•
|
flush_operations - count of flush operations
|
•
|
rd_total_times - total time read operations took (ns)
|
•
|
wr_total_times - total time write operations took (ns)
|
•
|
flush_total_times - total time flush operations took (ns)
|
•
|
<-- other fields provided by hypervisor -->
|
domblkthreshold
Syntax:
domblkthreshold domain dev threshold
Set the threshold value for delivering the block-threshold event. dev specifies the disk device target or backing chain element of given device using the 'target[1]' syntax. threshold is a scaled value of the offset. If the block device should write beyond that offset the event will be delivered.
domcontrol
Syntax:
Returns state of an interface to VMM used to control a domain. For states other than "ok" or "error" the command also prints number of seconds elapsed since the control interface entered its current state.
domdirtyrate-calc
Syntax:
domdirtyrate-calc <domain> [--seconds <sec>]
--mode=[page-sampling | dirty-bitmap | dirty-ring]
Calculate an active domain's memory dirty rate which may be expected by user in order to decide whether it's proper to be migrated out or not. The seconds parameter can be used to calculate dirty rate in a specific time which allows 60s at most now and would be default to 1s if missing. These three page-sampling, dirty-bitmap, dirty-ring modes are mutually exclusive and alternative when specify calculation mode, page-sampling is the default mode if missing. The calculated dirty rate information is available by calling 'domstats --dirtyrate'.
domdisplay
Syntax:
domdisplay domain [--include-password] [[--type] type] [--all]
Output a URI which can be used to connect to the graphical display of the domain via VNC, SPICE or RDP. The particular graphical display type can be selected using the type parameter (e.g. "vnc", "spice", "rdp"). If --include-password is specified, the SPICE channel password will be included in the URI. If --all is specified, then all show all possible graphical displays, for a VM could have more than one graphical displays.
domdisplay-reload
Syntax:
domdisplay-reload <domain> [--type <type>]
Reload the domain's graphical display. This reloads its TLS certificates without restarting the domain. type can be any constant from the virDomainGraphicsReloadType enum. By default any supported type is reloaded (so far only VNC).
domfsfreeze
Syntax:
domfsfreeze domain [[--mountpoint] mountpoint...]
Freeze mounted filesystems within a running domain to prepare for consistent snapshots.
The --mountpoint option takes a parameter mountpoint, which is a mount point path of the filesystem to be frozen. This option can occur multiple times. If this is not specified, every mounted filesystem is frozen.
Note: snapshot-create command has a --quiesce option to freeze and thaw the filesystems automatically to keep snapshots consistent. domfsfreeze command is only needed when a user wants to utilize the native snapshot features of storage devices not supported by libvirt.
domfsinfo
Syntax:
Show a list of mounted filesystems within the running domain. The list contains mountpoints, names of a mounted device in the guest, filesystem types, and unique target names used in the domain XML (<target dev='name'/>).
Note that this command requires a guest agent configured and running in the domain's guest OS.
domfsthaw
Syntax:
domfsthaw domain [[--mountpoint] mountpoint...]
Thaw mounted filesystems within a running domain, which have been frozen by domfsfreeze command.
The --mountpoint option takes a parameter mountpoint, which is a mount point path of the filesystem to be thawed. This option can occur multiple times. If this is not specified, every mounted filesystem is thawed.
domfstrim
Syntax:
domfstrim domain [--minimum bytes] [--mountpoint mountPoint]
Issue a fstrim command on all mounted filesystems within a running domain. It discards blocks which are not in use by the filesystem. If --minimum bytes is specified, it tells guest kernel length of contiguous free range. Smaller than this may be ignored (this is a hint and the guest may not respect it). By increasing this value, the fstrim operation will complete more quickly for filesystems with badly fragmented free space, although not all blocks will be discarded. The default value is zero, meaning "discard every free block". Moreover, if a user wants to trim only one mount point, it can be specified via optional --mountpoint parameter.
domhostname
Syntax:
domhostname domain [--source lease|agent]
Returns the hostname of a domain, if the hypervisor makes it available.
The --source argument specifies what data source to use for the hostnames, currently 'lease' to read DHCP leases or 'agent' to query the guest OS via an agent. If unspecified, driver returns the default method available (some drivers support only one type of source).
domid
Syntax:
domid domain-name-or-uuid
Convert a domain name (or UUID) to a domain id
domif-getlink
Syntax:
domif-getlink domain interface-device [--config]
Query link state of the domain's virtual interface. If --config is specified, query the persistent configuration, for compatibility purposes, --persistent is alias of --config.
interface-device can be the interface's target name or the MAC address.
domif-setlink
Syntax:
domif-setlink domain interface-device state [--config] [--print-xml]
Modify link state of the domain's virtual interface. Possible values for state are "up" and "down". If --config is specified, only the persistent configuration of the domain is modified, for compatibility purposes, --persistent is alias of --config. interface-device can be the interface's target name or the MAC address.
If --print-xml is specified, then the XML used to update the interface is printed instead.
domifaddr
Syntax:
domifaddr domain [interface] [--full]
[--source lease|agent|arp]
Get a list of interfaces of a running domain along with their IP and MAC addresses, or limited output just for one interface if interface is specified. Note that interface can be driver dependent, it can be the name within guest OS or the name you would see in domain XML. Moreover, the whole command may require a guest agent to be configured for the queried domain under some hypervisors, notably QEMU.
If --full is specified, the interface name and MAC address is always displayed when the interface has multiple IP addresses or aliases; otherwise, only the interface name and MAC address is displayed for the first name and MAC address with "-" for the others using the same name and MAC address.
The --source argument specifies what data source to use for the addresses, currently 'lease' to read DHCP leases, 'agent' to query the guest OS via an agent, or 'arp' to get IP from host's arp tables. If unspecified, 'lease' is the default.
backup-begin
Syntax:
backup-begin domain [backupxml] [checkpointxml] [--reuse-external]
[--preserve-domain-on-shutdown]
Begin a new backup job. If backupxml is omitted, this defaults to a full backup using a push model to filenames generated by libvirt; supplying XML allows fine-tuning such as requesting an incremental backup relative to an earlier checkpoint, controlling which disks participate or which filenames are involved, or requesting the use of a pull model backup. The backup-dumpxml command shows any resulting values assigned by libvirt. For more information on backup XML, see: <https://libvirt.org/formatbackup.html>
If --reuse-external is used it instructs libvirt to reuse temporary and output files provided by the user in backupxml.
When the --preserve-domain-on-shutdown flag is used libvirt will not terminate the VM if the guest OS shuts down while the backup is running. The VM will be instead kept in VIR_DOMAIN_PAUSED state until the backup job finishes. The vm can be also resumed in order to boot again.
If checkpointxml is specified, a second file with a top-level element of domaincheckpoint is used to create a simultaneous checkpoint, for doing a later incremental backup relative to the time the backup was created. See checkpoint-create for more details on checkpoints.
This command returns as soon as possible, and the backup job runs in the background; the progress of a push model backup can be checked with domjobinfo or by waiting for an event with event (the progress of a pull model backup is under the control of whatever third party connects to the NBD export). The job is ended with domjobabort.
backup-dumpxml
Syntax:
backup-dumpxml [--xpath EXPRESSION] [--wrap] domain
Output XML describing the current backup job.
If the --xpath argument provides an XPath expression, it will be evaluated against the output XML and only those matching nodes will be printed. The default behaviour is to print each matching node as a standalone document, however, for ease of additional processing, the --wrap argument will cause the matching node to be wrapped in a common root node.
domiflist
Syntax:
domiflist domain [--inactive]
Print a table showing the brief information of all virtual interfaces associated with domain. If --inactive is specified, query the virtual interfaces that will be used on the next boot, rather than those currently in use by a running domain. Other contexts that require a MAC address of virtual interface (such as detach-interface or domif-setlink) will accept the MAC address printed by this command.
domifstat
Syntax:
domifstat domain interface-device
Get network interface stats for a running domain. The network interface stats are only available for interfaces that have a physical source interface. This does not include, for example, a 'user' interface type since it is a virtual LAN with NAT to the outside world. interface-device can be the interface target by name or MAC address. Please note, for an unmanaged ethernet type returned stats might have RX/TX swapped.
domiftune
Syntax:
domiftune domain interface-device [[--config] [--live] | [--current]]
[*--inbound average,peak,burst,floor*]
[*--outbound average,peak,burst*]
Set or query the domain's network interface's bandwidth parameters. interface-device can be the interface's target name (<target dev='name'/>), or the MAC address.
If no --inbound or --outbound is specified, this command will query and show the bandwidth settings. Otherwise, it will set the inbound or outbound bandwidth. average,peak,burst,floor is the same as in command attach-interface. Values for average, peak and floor are expressed in kiB per second, while burst is expressed in kiB in a single burst at peak speed as described in the Network XML documentation at <https://libvirt.org/formatnetwork.html#quality-of-service>.
To clear inbound or outbound settings, use --inbound or --outbound respectfully with average value of zero.
If --live is specified, affect a running guest. If --config is specified, affect the next start of a persistent guest. If --current is specified, it is equivalent to either --live or --config, depending on the current state of the guest. Both --live and --config flags may be given, but --current is exclusive. If no flag is specified, behavior is different depending on hypervisor.
domifannounce
Syntax
domifannounce domain [interface-device] [parameters]
Request that a domain inject "gratuitous" ARP responses into the outbound data stream of a specific network interface of the domain (or if no interface-device is given, inject ARP responses on the outbound data stream of all interfaces of the domain). This can be helpful to re-sync network switches in the broadcast domain of said interfaces when the network topology has changed. This is usually done automatically when a domain is started, or after it has migrated (for example, that is the behavior of QEMU), but a more complicated setup where the topology changes around an already active domain (or possibly all the plumbing isn't yet connected and passing traffic at the time the automatic announcement takes place) might benefit from a manually triggered announce.
The optional parameters are:
- •
-
--initial n
initial delay before first announcement (milliseconds) default: 50
- •
-
--max n
maximum delay between announcements (milliseconds) default: 550
- •
-
--rounds n
total number of announcements default: 5
- •
-
--step n
increment added to delay (milliseconds) after each announcement default 50
dominfo
Syntax:
Returns basic information about the domain.
domjobabort
Syntax:
domjobabort domain [--postcopy]
Abort the currently running domain job.
When the job to be aborted is a migration which entered post-copy mode, it cannot be aborted as none of the hosts involved in migration has a complete state of the domain. Optional --postcopy can be used to interrupt such migration although doing so may effectively suspend the domain until the migration is resumed (see also --postcopy-resume option of migrate).
domjobinfo
Syntax:
domjobinfo domain [--completed [--keep-completed]] [--anystats] [--rawstats]
Returns information about jobs running on a domain. --completed tells virsh to return information about a recently finished job. Statistics of a completed job are automatically destroyed once read (unless --keep-completed is used) or when libvirtd is restarted.
Normally only statistics for running and successful completed jobs are printed. --anystats can be used to also display statistics for failed jobs.
In case --rawstats is used, all fields are printed as received from the server without any attempts to interpret the data. The "Job type:" field is special, since it's reported by the API and not part of stats.
Note that time information returned for completed migrations may be completely irrelevant unless both source and destination hosts have synchronized time (i.e., NTP daemon is running on both of them).
domlaunchsecinfo
Syntax:
Returns information about the launch security parameters associated with a running domain.
The set of parameters reported will vary depending on which type of launch security protection is active. If none is active, no parameters will be reported.
domsetlaunchsecstate
Syntax:
domsetlaunchsecstate domain --secrethdr hdr-filename
--secret secret-filename [--set-address address]
Set a launch security secret in the guest's memory. The guest must have a launchSecurity type enabled in its configuration and be in a paused state. On success, the guest can be transitioned to a running state. On failure, the guest should be destroyed.
--secrethdr specifies a filename containing the base64-encoded secret header. The header includes artifacts needed by the hypervisor firmware to recover the plain text of the launch secret. --secret specifies the filename containing the base64-encoded encrypted launch secret.
The --set-address option can be used to specify a physical address within the guest's memory to set the secret. If not specified, the address will be determined by the hypervisor.
dommemstat
Syntax:
dommemstat domain [--period seconds] [[--config] [--live] | [--current]]
Get memory stats for a running domain.
Availability of these fields depends on hypervisor. Unsupported fields are missing from the output. Other fields may appear if communicating with a newer version of libvirtd.
Explanation of fields:
- •
-
swap_in - The amount of data read from swap space (in KiB)
- •
-
swap_out - The amount of memory written out to swap space (in KiB)
- •
-
major_fault - The number of page faults where disk IO was required
- •
-
minor_fault - The number of other page faults
- •
-
unused - The amount of memory left unused by the system (in KiB)
- •
-
available - The amount of usable memory as seen by the domain (in KiB)
- •
-
actual - Current balloon value (in KiB)
- •
-
rss - Resident Set Size of the running domain's process (in KiB)
- •
-
usable - The amount of memory which can be reclaimed by balloon without causing host swapping (in KiB)
- •
-
last-update - Timestamp of the last update of statistics (in seconds)
- •
-
disk_caches - The amount of memory that can be reclaimed without additional I/O, typically disk caches (in KiB)
- •
-
hugetlb_pgalloc - The number of successful huge page allocations initiated from within the domain
- •
-
hugetlb_pgfail - The number of failed huge page allocations initiated from within the domain
For QEMU/KVM with a memory balloon, setting the optional --period to a value larger than 0 in seconds will allow the balloon driver to return additional statistics which will be displayed by subsequent dommemstat commands. Setting the --period to 0 will stop the balloon driver collection, but does not clear the statistics in the balloon driver. Requires at least QEMU/KVM 1.5 to be running on the host.
The --live, --config, and --current flags are only valid when using the --period option in order to set the collection period for the balloon driver. If --live is specified, only the running guest collection period is affected. If --config is specified, affect the next start of a persistent guest. If --current is specified, it is equivalent to either --live or --config, depending on the current state of the guest.
Both --live and --config flags may be given, but --current is exclusive. If no flag is specified, behavior is different depending on the guest state.
domname
Syntax:
domname domain-id-or-uuid
Convert a domain Id (or UUID) to domain name
dompmsuspend
Syntax:
dompmsuspend domain target [--duration]
Suspend a running domain into one of these states (possible target values):
•
|
mem - equivalent of S3 ACPI state
|
•
|
disk - equivalent of S4 ACPI state
|
•
|
hybrid - RAM is saved to disk but not powered off
|
The --duration argument specifies number of seconds before the domain is woken up after it was suspended (see also dompmwakeup). Default is 0 for unlimited suspend time. (This feature isn't currently supported by any hypervisor driver and 0 should be used.).
Note that this command requires a guest agent configured and running in the domain's guest OS.
Beware that at least for QEMU, the domain's process will be terminated when target disk is used and a new process will be launched when libvirt is asked to wake up the domain. As a result of this, any runtime changes, such as device hotplug or memory settings, are lost unless such changes were made with --config flag.
dompmwakeup
Syntax:
Wakeup a domain from pmsuspended state (either suspended by dompmsuspend or from the guest itself). Injects a wakeup into the guest that is in pmsuspended state, rather than waiting for the previously requested duration (if any) to elapse. This operation does not necessarily fail if the domain is running.
domrename
Syntax:
domrename domain new-name
Rename a domain. This command changes current domain name to the new name specified in the second argument.
Note: Domain must be inactive.
domstate
Syntax:
domstate domain [--reason]
Returns state about a domain. --reason tells virsh to also print reason for the state.
domstats
Syntax:
domstats [--raw] [--enforce] [--backing] [--nowait] [--state]
[--cpu-total] [--balloon] [--vcpu] [--interface]
[--block] [--perf] [--iothread] [--memory] [--dirtyrate] [--vm]
[[--list-active] [--list-inactive]
[--list-persistent] [--list-transient] [--list-running]y
[--list-paused] [--list-shutoff] [--list-other]] | [domain ...]
Get statistics for multiple or all domains. Without any argument this command prints all available statistics for all domains.
The list of domains to gather stats for can be either limited by listing the domains as a space separated list, or by specifying one of the filtering flags --list-NNN. (The approaches can't be combined.)
By default some of the returned fields may be converted to more human friendly values by a set of pretty-printers. To suppress this behavior use the --raw flag.
The individual statistics groups are selectable via specific flags. By default all supported statistics groups are returned. Supported statistics groups flags are: --state, --cpu-total, --balloon, --vcpu, --interface, --block, --perf, --iothread, --memory, --dirtyrate, --vm.
Note that - depending on the hypervisor type and version or the domain state - not all of the following statistics may be returned.
When selecting the --state group the following fields are returned:
- •
-
state.state - state of the VM, returned as number from virDomainState enum
- •
-
state.reason - reason for entering given state, returned as int from virDomain*Reason enum corresponding to given state
--cpu-total returns:
- •
-
cpu.time - total cpu time spent for this domain in nanoseconds
- •
-
cpu.user - user cpu time spent in nanoseconds
- •
-
cpu.system - system cpu time spent in nanoseconds
- •
-
cpu.haltpoll.success.time - cpu halt polling success time spent in nanoseconds
- •
-
cpu.haltpoll.fail.time - cpu halt polling fail time spent in nanoseconds
- •
-
cpu.cache.monitor.count - the number of cache monitors for this domain
- •
-
cpu.cache.monitor.<num>.name - the name of cache monitor <num>
- •
-
cpu.cache.monitor.<num>.vcpus - vcpu list of cache monitor <num>
- •
-
cpu.cache.monitor.<num>.bank.count - the number of cache banks in cache monitor <num>
- •
-
cpu.cache.monitor.<num>.bank.<index>.id - host allocated cache id for bank <index> in cache monitor <num>
- •
-
cpu.cache.monitor.<num>.bank.<index>.bytes - the number of bytes of last level cache that the domain is using on cache bank <index>
--balloon returns:
- •
-
balloon.current - the memory in KiB currently used
- •
-
balloon.maximum - the maximum memory in KiB allowed
- •
-
balloon.swap_in - the amount of data read from swap space (in KiB)
- •
-
balloon.swap_out - the amount of memory written out to swap space (in KiB)
- •
-
balloon.major_fault - the number of page faults when disk IO was required
- •
-
balloon.minor_fault - the number of other page faults
- •
-
balloon.unused - the amount of memory left unused by the system (in KiB)
- •
-
balloon.available - the amount of usable memory as seen by the domain (in KiB)
- •
-
balloon.rss - Resident Set Size of running domain's process (in KiB)
- •
-
balloon.usable - the amount of memory which can be reclaimed by balloon without causing host swapping (in KiB)
- •
-
balloon.last-update - timestamp of the last update of statistics (in seconds)
- •
-
balloon.disk_caches - the amount of memory that can be reclaimed without additional I/O, typically disk (in KiB)
- •
-
balloon.hugetlb_pgalloc - the number of successful huge page allocations from inside the domain via virtio balloon
- •
-
balloon.hugetlb_pgfail - the number of failed huge page allocations from inside the domain via virtio balloon
--vcpu returns:
- •
-
vcpu.current - current number of online virtual CPUs
- •
-
vcpu.maximum - maximum number of online virtual CPUs
- •
-
vcpu.<num>.state - state of the virtual CPU <num>, as number from virVcpuState enum
- •
-
vcpu.<num>.time - virtual cpu time spent by virtual CPU <num> (in nanoseconds)
- •
-
vcpu.<num>.wait - time the vCPU <num> thread was waiting in the runqueue as the scheduler has something else running ahead of it (in nanoseconds), requires CONFIG_SCHED_INFO on Linux
- •
-
vcpu.<num>.halted - virtual CPU <num> is halted: yes or no (may indicate the processor is idle or even disabled, depending on the architecture)
- •
-
vcpu.<num>.delay - time the vCPU <num> thread was waiting in the runqueue as the scheduler has something else running ahead of it (in nanoseconds). Exposed to the VM as a steal time.
This group of statistics also reports additional hypervisor-originating per-vCPU stats. The hypervisor-specific statistics in this group have the following naming scheme:
vcpu.<num>.$NAME.$TYPE
- $NAME
-
name of the statistics field provided by the hypervisor
- $TYPE
-
Type of the value. The following types are returned:
cur-
current instant value
The returned value may be either an unsigned long long or a boolean. Meaning is hypervisor specific. Please see the disclaimer for the --vm group which also consists of hypervisor-specific stats.
--interface returns:
•
|
net.count - number of network interfaces on this domain
|
•
|
net.<num>.name - name of the interface <num>
|
•
|
net.<num>.rx.bytes - number of bytes received
|
•
|
net.<num>.rx.pkts - number of packets received
|
•
|
net.<num>.rx.errs - number of receive errors
|
•
|
net.<num>.rx.drop - number of receive packets dropped
|
•
|
net.<num>.tx.bytes - number of bytes transmitted
|
•
|
net.<num>.tx.pkts - number of packets transmitted
|
•
|
net.<num>.tx.errs - number of transmission errors
|
•
|
net.<num>.tx.drop - number of transmit packets dropped
|
--perf returns the statistics of all enabled perf events:
•
|
perf.cmt - the cache usage in Byte currently used
|
•
|
perf.mbmt - total system bandwidth from one level of cache
|
•
|
perf.mbml - bandwidth of memory traffic for a memory controller
|
•
|
perf.cpu_cycles - the count of cpu cycles (total/elapsed)
|
•
|
perf.instructions - the count of instructions
|
•
|
perf.cache_references - the count of cache hits
|
•
|
perf.cache_misses - the count of caches misses
|
•
|
perf.branch_instructions - the count of branch instructions
|
•
|
perf.branch_misses - the count of branch misses
|
•
|
perf.bus_cycles - the count of bus cycles
|
•
|
perf.stalled_cycles_frontend - the count of stalled frontend cpu cycles
|
•
|
perf.stalled_cycles_backend - the count of stalled backend cpu cycles
|
•
|
perf.ref_cpu_cycles - the count of ref cpu cycles
|
•
|
perf.cpu_clock - the count of cpu clock time
|
•
|
perf.task_clock - the count of task clock time
|
•
|
perf.page_faults - the count of page faults
|
•
|
perf.context_switches - the count of context switches
|
•
|
perf.cpu_migrations - the count of cpu migrations
|
•
|
perf.page_faults_min - the count of minor page faults
|
•
|
perf.page_faults_maj - the count of major page faults
|
•
|
perf.alignment_faults - the count of alignment faults
|
•
|
perf.emulation_faults - the count of emulation faults
|
See the perf command for more details about each event.
--block returns information about disks associated with each domain. Using the --backing flag extends this information to cover all resources in the backing chain, rather than the default of limiting information to the active layer for each guest disk. Information listed includes:
- •
-
block.count - number of block devices being listed
- •
-
block.<num>.name - name of the target of the block device <num> (the same name for multiple entries if --backing is present)
- •
-
block.<num>.backingIndex - when --backing is present, matches up with the <backingStore> index listed in domain XML for backing files
- •
-
block.<num>.path - file source of block device <num>, if it is a local file or block device
- •
-
block.<num>.rd.reqs - number of read requests
- •
-
block.<num>.rd.bytes - number of read bytes
- •
-
block.<num>.rd.times - total time (ns) spent on reads
- •
-
block.<num>.wr.reqs - number of write requests
- •
-
block.<num>.wr.bytes - number of written bytes
- •
-
block.<num>.wr.times - total time (ns) spent on writes
- •
-
block.<num>.fl.reqs - total flush requests
- •
-
block.<num>.fl.times - total time (ns) spent on cache flushing
- •
-
block.<num>.errors - Xen only: the 'oo_req' value
- •
-
block.<num>.allocation - offset of highest written sector in bytes
- •
-
block.<num>.capacity - logical size of source file in bytes
- •
-
block.<num>.physical - physical size of source file in bytes
- •
-
block.<num>.threshold - threshold (in bytes) for delivering the VIR_DOMAIN_EVENT_ID_BLOCK_THRESHOLD event. See domblkthreshold.
- •
-
block.<num>.limits.request_alignment - Alignment requirement for requests in bytes
- •
-
block.<num>.limits.discard_max - Maximum number of bytes that can be discarded at once
- •
-
block.<num>.limits.discard_alignment - Optimal alignment for discard requests in bytes
- •
-
block.<num>.limits.write_zeroes_max - Maximum number of bytes that can be zeroed out at once
- •
-
block.<num>.limits.write_zeroes_alignment - Optimal alignment for write_zeroes requests in bytes
- •
-
block.<num>.limits.transfer_optimal - Optimal transfer length in bytes
- •
-
block.<num>.limits.transfer_max - Maximal transfer length in bytes
- •
-
block.<num>.limits.transfer_hw_max - Maximal hardware transfer length of requests bypassing kernel IO scheduler in bytes
- •
-
block.<num>.limits.iov_max - Maximum number of scatter/gather elements
- •
-
block.<num>.limits.iov_hw_max - Maximal number of scatter/gather elements of requests bypassing kernel IO scheduler
- •
-
block.<num>.limits.memory_alignment_minimal - memory alignment in bytes so that no bounce buffer is needed
- •
-
block.<num>.limits.memory_alignment_optimal - memory alignment in bytes that is used for bounce buffers
- •
-
block.<num>.timed_group.count - number of blocks of timed group statistics
- •
-
block.<num>.timed_group.<num>.interval_length - The time interval in seconds for which the statistics in this group were collected.
- •
-
block.<num>.timed_group.<num>.rd_latency_min - minimum latency of read operations in the defined interval in nanoseconds
- •
-
block.<num>.timed_group.<num>.rd_latency_max - maximum latency of read operations in the defined interval in nanoseconds
- •
-
block.<num>.timed_group.<num>.rd_latency_avg - average latency of read operations in the defined interval in nanoseconds
- •
-
block.<num>.timed_group.<num>.wr_latency_min - minimum latency of write operations in the defined interval in nanoseconds
- •
-
block.<num>.timed_group.<num>.wr_latency_max - maximum latency of write operations in the defined interval in nanoseconds
- •
-
block.<num>.timed_group.<num>.wr_latency_avg - average latency of write operations in the defined interval in nanoseconds
- •
-
block.<num>.timed_group.<num>.zone_append_latency_min - minimum latency of zone append operations in the defined interval in nanoseconds
- •
-
block.<num>.timed_group.<num>.zone_append_latency_max - maximum latency of zone append operations in the defined interval in nanoseconds
- •
-
block.<num>.timed_group.<num>.zone_append_latency_avg - average latency of zone append operations in the defined interval in nanoseconds
- •
-
block.<num>.timed_group.<num>.flush_latency_min - minimum latency of flush operations in the defined interval in nanoseconds
- •
-
block.<num>.timed_group.<num>.flush_latency_max - maximum latency of flush operations in the defined interval in nanoseconds
- •
-
block.<num>.timed_group.<num>.flush_latency_avg - average latency of flush operations in the defined interval in nanoseconds
- •
-
block.<num>.timed_group.<num>.rd_queue_depth_avg - average number of pending read operations in the defined interval
- •
-
block.<num>.timed_group.<num>.wr_queue_depth_avg - average number of pending write operations in the defined interval
- •
-
block.<num>.timed_group.<num>.zone_append_queue_depth_avg - average number of pending zone append operations in the defined interval
- •
-
block.<num>.latency_histogram.<type>.bin.count - number of bins in latency histogram. <type> is one of read, write, zone_append, or flush
- •
-
block.<num>.latency_histogram.<type>.bin.<num>.start start boundary of a latency histogram bin in nanoseconds of given operation duration
- •
-
block.<num>.latency_histogram.<type>.bin.<num>.value current number of events corresponding to the given bin and type
--iothread returns information about IOThreads on the running guest if supported by the hypervisor.
The "poll-max-ns" for each thread is the maximum nanoseconds to allow each polling interval to occur. A polling interval is a period of time allowed for a thread to process data before being the guest gives up its CPU quantum back to the host. A value set too small will not allow the IOThread to run long enough on a CPU to process data. A value set too high will consume too much CPU time per IOThread failing to allow other threads running on the CPU to get time. The polling interval is not available for statistical purposes.
- •
-
- iothread.count - maximum number of IOThreads in the subsequent list
-
as unsigned int. Each IOThread in the list will will use it's iothread_id value as the <id>. There may be fewer <id> entries than the iothread.count value if the polling values are not supported.
- •
-
iothread.<id>.poll-max-ns - maximum polling time in nanoseconds used by the <id> IOThread. A value of 0 (zero) indicates polling is disabled.
- •
-
iothread.<id>.poll-grow - polling time grow value. A value of 0 (zero) growth is managed by the hypervisor.
- •
-
iothread.<id>.poll-shrink - polling time shrink value. A value of (zero) indicates shrink is managed by hypervisor.
- •
-
iothread.<id>.poll-weight - polling weight shift value. A value of 0 (zero) indicates the hypervisor's default weight is used.
--memory returns:
- •
-
memory.bandwidth.monitor.count - the number of memory bandwidth monitors for this domain
- •
-
memory.bandwidth.monitor.<num>.name - the name of monitor <num>
- •
-
memory.bandwidth.monitor.<num>.vcpus - the vcpu list of monitor <num>
- •
-
- memory.bandwidth.monitor.<num>.node.count - the number of memory
-
controller in monitor <num>
- •
-
memory.bandwidth.monitor.<num>.node.<index>.id - host allocated memory controller id for controller <index> of monitor <num>
- •
-
memory.bandwidth.monitor.<num>.node.<index>.bytes.local - the accumulative bytes consumed by @vcpus that passing through the memory controller in the same processor that the scheduled host CPU belongs to.
- •
-
memory.bandwidth.monitor.<num>.node.<index>.bytes.total - the total bytes consumed by @vcpus that passing through all memory controllers, either local or remote controller.
--dirtyrate returns:
- •
-
dirtyrate.calc_status - the status of last memory dirty rate calculation, returned as number from virDomainDirtyRateStatus enum.
- •
-
dirtyrate.calc_start_time - the start time of last memory dirty rate calculation.
- •
-
dirtyrate.calc_period - the period of last memory dirty rate calculation.
- •
-
dirtyrate.megabytes_per_second - the calculated memory dirty rate in MiB/s.
- •
-
dirtyrate.calc_mode - the calculation mode used last measurement (page-sampling/dirty-bitmap/dirty-ring)
- •
-
dirtyrate.vcpu.<num>.megabytes_per_second - the calculated memory dirty rate for a virtual cpu in MiB/s
--vm returns:
The --vm option enables reporting of hypervisor-specific statistics. Naming and meaning of the fields is entirely hypervisor dependent.
The statistics in this group have the following naming scheme:
vm.$NAME.$TYPE
- $NAME
-
name of the statistics field provided by the hypervisor
- $TYPE
-
Type of the value. The following types are returned:
cur-
current instant value
The returned value may be either an unsigned long long or a boolean.
WARNING: The stats reported in this group are runtime-collected and hypervisor originated, thus fall outside of the usual stable API policies of libvirt.
Libvirt can't guarantee that the statistics reported from the outside source will be present in further versions of the hypervisor, or that naming or meaning will stay consistent. Changes to existing fields, however, are expected to be rare.
Selecting a specific statistics groups doesn't guarantee that the daemon supports the selected group of stats. Flag --enforce forces the command to fail if the daemon doesn't support the selected group.
When collecting stats libvirtd may wait for some time if there's already another job running on given domain for it to finish. This may cause unnecessary delay in delivering stats. Using --nowait suppresses this behaviour. On the other hand some statistics might be missing for such domain.
domtime
Syntax:
domtime domain { [--now] [--pretty] [--sync] [--time time] }
Gets or sets the domain's system time. When run without any arguments (but domain), the current domain's system time is printed out. The --pretty modifier can be used to print the time in more human readable form.
When --time time is specified, the domain's time is not gotten but set instead. The --now modifier acts like if it was an alias for --time $now, which means it sets the time that is currently on the host virsh is running at. In both cases (setting and getting), time is in seconds relative to Epoch of 1970-01-01 in UTC. The --sync modifies the set behavior a bit: The time passed is ignored, but the time to set is read from domain's RTC instead. Please note, that some hypervisors may require a guest agent to be configured in order to get or set the guest time.
domuuid
Syntax:
domuuid domain-name-or-id
Convert a domain name or id to domain UUID
domxml-from-native
Syntax:
domxml-from-native format config
Convert the file config in the native guest configuration format named by format to a domain XML format. For QEMU/KVM hypervisor, the format argument must be qemu-argv. For Xen hypervisor, the format argument may be xen-xm, xen-xl, or xen-sxpr. For LXC hypervisor, the format argument must be lxc-tools. For VMware/ESX hypervisor, the format argument must be vmware-vmx. For the Bhyve hypervisor, the format argument must be bhyve-argv.
domxml-to-native
Syntax:
domxml-to-native format { [--xml] xml | --domain domain-name-or-id-or-uuid }
Convert the file xml into domain XML format or convert an existing --domain to the native guest configuration format named by format. The xml and --domain arguments are mutually exclusive. For the types of format argument, refer to domxml-from-native.
dump
Syntax:
dump domain corefilepath [--bypass-cache]
{ [--live] | [--crash] | [--reset] }
[--verbose] [--memory-only] [--format string]
Dumps the core of a domain to a file for analysis. If --live is specified, the domain continues to run until the core dump is complete, rather than pausing up front. If --crash is specified, the domain is halted with a crashed status, rather than merely left in a paused state. If --reset is specified, the domain is reset after successful dump. Note, these three switches are mutually exclusive. If --bypass-cache is specified, the save will avoid the file system cache, although this may slow down the operation. If --memory-only is specified, the file is elf file, and will only include domain's memory and cpu common register value. It is very useful if the domain uses host devices directly. --format string is used to specify the format of 'memory-only' dump, and string can be one of: elf, kdump-zlib(kdump-compressed format with zlib-compressed), kdump-lzo(kdump-compressed format with lzo-compressed), kdump-snappy(kdump-compressed format with snappy-compressed), win-dmp(Windows full crashdump format).
The progress may be monitored using domjobinfo virsh command and canceled with domjobabort command (sent by another virsh instance). Another option is to send SIGINT (usually with Ctrl-C) to the virsh process running dump command. --verbose displays the progress of dump.
NOTE: Some hypervisors may require the user to manually ensure proper permissions on file and path specified by argument corefilepath.
NOTE: Crash dump in a old kvmdump format is being obsolete and cannot be loaded and processed by crash utility since its version 6.1.0. A --memory-only option is required in order to produce valid ELF file which can be later processed by the crash utility.
dumpxml
Syntax:
dumpxml [--inactive] [--security-info] [--update-cpu] [--migratable]
[--xpath EXPRESSION] [--wrap] domain
Output the domain information as an XML dump to stdout, this format can be used by the create command. Additional options affecting the XML dump may be used. --inactive tells virsh to dump domain configuration that will be used on next start of the domain as opposed to the current domain configuration. Using --security-info will also include security sensitive information in the XML dump. --update-cpu updates domain CPU requirements according to host CPU. With --migratable one can request an XML that is suitable for migrations, i.e., compatible with older libvirt releases and possibly amended with internal run-time options. This option may automatically enable other options (--update-cpu, --security-info, ...) as necessary.
If the --xpath argument provides an XPath expression, it will be evaluated against the output XML and only those matching nodes will be printed. The default behaviour is to print each matching node as a standalone document, however, for ease of additional processing, the --wrap argument will cause the matching node to be wrapped in a common root node.
edit
Syntax:
Edit the XML configuration file for a domain, which will affect the next boot of the guest.
This is equivalent to:
virsh dumpxml --inactive --security-info domain > domain.xml
vi domain.xml (or make changes with your other text editor)
virsh define domain.xml
except that it does some error checking.
The editor used can be supplied by the $VISUAL or $EDITOR environment variables, and defaults to vi.
emulatorpin
Syntax:
emulatorpin domain [cpulist] [[--live] [--config] | [--current]]
Query or change the pinning of domain's emulator threads to host physical CPUs.
See vcpupin for cpulist.
If --live is specified, affect a running guest. If --config is specified, affect the next start of a persistent guest. If --current is specified, it is equivalent to either --live or --config, depending on the current state of the guest. Both --live and --config flags may be given if cpulist is present, but --current is exclusive. If no flag is specified, behavior is different depending on hypervisor.
event
Syntax:
event {[domain] { event | --all } [--loop] [--timeout seconds] [--timestamp] | --list}
Wait for a class of domain events to occur, and print appropriate details of events as they happen. The events can optionally be filtered by domain. Using --list as the only argument will provide a list of possible event values known by this client, although the connection might not allow registering for all these events. It is also possible to use --all instead of event to register for all possible event types at once.
By default, this command is one-shot, and returns success once an event occurs; you can send SIGINT (usually via Ctrl-C) to quit immediately. If --timeout is specified, the command gives up waiting for events after seconds have elapsed. With --loop, the command prints all events until a timeout or interrupt key.
When --timestamp is used, a human-readable timestamp will be printed before the event.
await
Syntax:
await <domain> --condition <string> [--timeout seconds]
Wait until the --condition for <domain> is satisfied. Uses events for efficient state updates.
Supported conditions:
domain-inactive
domain is or becomes inactive
guest-agent-available
the guest agent inside the guest connects and becomes available for commands (usually means that the guest has booted)
If --timeout is specified, the command gives up waiting for the condition to satisfy after seconds have elapsed. If SIGINT is delivered to virsh (usually via Ctrl-C) the wait is given up immediately. In non-interactive mode virsh will return '2' if either of those cases instead of '1' which means an error happened.
get-user-sshkeys
Syntax:
get-user-sshkeys domain user
Print SSH authorized keys for given user in the guest domain. Please note, that an entry in the file has internal structure as defined by sshd(8) and virsh/libvirt does handle keys as opaque strings, i.e. does not interpret them.
guest-agent-timeout
Syntax:
guest-agent-timeout domain [--timeout value]
Set how long to wait for a response from guest agent commands. By default, agent commands block forever waiting for a response. value must be a positive value (wait for given amount of seconds) or one of the following values:
- •
-
-2 - block forever waiting for a result (used when --timeout is omitted),
- •
-
-1 - reset timeout to the default value (currently defined as 5 seconds in libvirt daemon),
- •
-
0 - do not wait at all,
In all guest-agent based APIs when a timeout happens if an actual command was send to the guest agent the returned error code will be VIR_ERR_AGENT_COMMAND_TIMEOUT.
guestinfo
Syntax:
guestinfo domain [--user] [--os] [--timezone] [--hostname] [--filesystem]
[--disk] [--interface] [--devices]
Print information about the guest from the point of view of the guest agent. Note that this command requires a guest agent to be configured and running in the domain's guest OS.
When run without any arguments, this command prints all information types that are supported by the guest agent at that point, omitting unavailable ones. Success is always reported in this case.
You can limit the types of information that are returned by specifying one or more flags. Available information types flags are --user, --os, --timezone, --hostname, --filesystem, --disk, --interface, --load and --devices. If an explicitly requested information type is not supported by the guest agent at that point, the processes will provide an exit code of 1.
Note that depending on the hypervisor type and the version of the guest agent running within the domain, not all of the following information may be returned.
When selecting the --user information type, the following fields may be returned:
- •
-
user.count - the number of active users on this domain
- •
-
user.<num>.name - username of user <num>
- •
-
user.<num>.domain - domain of the user <num> (may only be present on certain guets types)
- •
-
user.<num>.login-time - the login time of user <num> in milliseconds since the epoch
--os returns:
•
|
os.id - a string identifying the operating system
|
•
|
os.name - the name of the operating system
|
•
|
os.pretty-name - a pretty name for the operating system
|
•
|
os.version - the version of the operating system
|
•
|
os.version-id - the version id of the operating system
|
•
|
os.kernel-release - the release of the operating system kernel
|
•
|
os.kernel-version - the version of the operating system kernel
|
•
|
os.machine - the machine hardware name
|
•
|
os.variant - a specific variant or edition of the operating system
|
•
|
os.variant-id - the id for a specific variant or edition of the operating system
|
--timezone returns:
•
|
timezone.name - the name of the timezone
|
•
|
timezone.offset - the offset to UTC in seconds
|
--hostname returns:
- •
-
hostname - the hostname of the domain
--filesystem returns:
•
|
fs.count - the number of filesystems defined on this domain
|
•
|
fs.<num>.mountpoint - the path to the mount point for filesystem <num>
|
•
|
fs.<num>.name - device name in the guest (e.g. sda1) for filesystem <num>
|
•
|
fs.<num>.fstype - the type of filesystem <num>
|
•
|
fs.<num>.total-bytes - the total size of filesystem <num>
|
•
|
fs.<num>.used-bytes - the number of bytes used in filesystem <num>
|
•
|
fs.<num>.disk.count - the number of disks targeted by filesystem <num>
|
•
|
fs.<num>.disk.<num>.alias - the device alias of disk <num> (e.g. sda)
|
•
|
fs.<num>.disk.<num>.serial - the serial number of disk <num>
|
•
|
fs.<num>.disk.<num>.device - the device node of disk <num>
|
--disk returns:
•
|
disk.count - the number of disks defined on this domain
|
•
|
disk.<num>.name - device node (Linux) or device UNC (Windows)
|
•
|
disk.<num>.partition - whether this is a partition or disk
|
•
|
disk.<num>.dependency.count - the number of device dependencies
|
•
|
disk.<num>.dependency.<num>.name - a dependency name
|
•
|
disk.<num>.serial - optional disk serial number
|
•
|
disk.<num>.alias - the device alias of the disk (e.g. sda)
|
•
|
disk.<num>.guest_alias - optional alias assigned to the disk
|
•
|
disk.<num>.guest_bus - bus type as reported by the guest
|
--interface returns: * if.count - the number of interfaces defined on this domain * if.<num>.name - name in the guest (e.g. eth0) for interface <num> * if.<num>.hwaddr - hardware address in the guest for interface <num> * if.<num>.addr.count - the number of IP addresses of interface <num> * if.<num>.addr.<num1>.type - the IP address type of addr <num1> (e.g. ipv4) * if.<num>.addr.<num1>.addr - the IP address of addr <num1> * if.<num>.addr.<num1>.prefix - the prefix of IP address of addr <num1>
--load returns: * load.1m - average load in guest for last 1 minute * load.5m - average load in guest for last 5 minutes * load.15m - average load in guest for last 15 minutes
--devices returns: * device.count - the number of devices that info is returned for * device.<num>.driverName - name of the driver associated with device * device.<num>.driverDate - driver release date in seconds since the epoch * device.<num>.driverVersion - version of the driver associated with the device * device.<num>.idType - device identification type (e.g. pci) * device.<num>.pciVendor - vendor ID for PCI device (in decimal) * device.<num>.pciDevice - device ID for PCI device (in decimal)
guestvcpus
Syntax:
guestvcpus domain [[--enable] | [--disable]] [cpulist]
Query or change state of vCPUs from guest's point of view using the guest agent. When invoked without cpulist the guest is queried for available guest vCPUs, their state and possibility to be offlined.
If cpulist is provided then one of --enable or --disable must be provided too. The desired operation is then executed on the domain.
See vcpupin for information on cpulist.
iothreadadd
Syntax:
iothreadadd domain iothread_id [[--config] [--live] | [--current]]
Add a new IOThread to the domain using the specified iothread_id. If the iothread_id already exists, the command will fail. The iothread_id must be greater than zero.
If --live is specified, affect a running guest. If the guest is not running an error is returned. If --config is specified, affect the next start of a persistent guest. If --current is specified, it is equivalent to either --live or --config, depending on the current state of the guest.
iothreaddel
Syntax:
iothreaddel domain iothread_id [[--config] [--live] | [--current]]
Delete an IOThread from the domain using the specified iothread_id. If an IOThread is currently assigned to a disk resource such as via the attach-disk command, then the attempt to remove the IOThread will fail. If the iothread_id does not exist an error will occur.
If --live is specified, affect a running guest. If the guest is not running an error is returned. If --config is specified, affect the next start of a persistent guest. If --current is specified, it is equivalent to either --live or --config, depending on the current state of the guest.
iothreadinfo
Syntax:
iothreadinfo domain [[--live] [--config] | [--current]]
Display basic domain IOThreads information including the IOThread ID and the CPU Affinity for each IOThread.
If --live is specified, get the IOThreads data from the running guest. If the guest is not running, an error is returned. If --config is specified, get the IOThreads data from the next start of a persistent guest. If --current is specified or --live and --config are not specified, then get the IOThread data based on the current guest state, which can either be live or offline.
iothreadpin
Syntax:
iothreadpin domain iothread cpulist [[--live] [--config] | [--current]]
Change the pinning of a domain IOThread to host physical CPUs. In order to retrieve a list of all IOThreads, use iothreadinfo. To pin an iothread specify the cpulist desired for the IOThread ID as listed in the iothreadinfo output.
cpulist is a list of physical CPU numbers. Its syntax is a comma separated list and a special markup using '-' and '^' (ex. '0-4', '0-3,^2') can also be allowed. The '-' denotes the range and the '^' denotes exclusive. If you want to reset iothreadpin setting, that is, to pin an iothread to all physical cpus, simply specify 'r' as a cpulist.
If --live is specified, affect a running guest. If the guest is not running, an error is returned. If --config is specified, affect the next start of a persistent guest. If --current is specified, it is equivalent to either --live or --config, depending on the current state of the guest. Both --live and --config flags may be given if cpulist is present, but --current is exclusive. If no flag is specified, behavior is different depending on hypervisor.
Note: The expression is sequentially evaluated, so "0-15,^8" is identical to "9-14,0-7,15" but not identical to "^8,0-15".
iothreadset
Syntax:
iothreadset domain iothread_id [[--poll-max-ns ns] [--poll-grow factor]
[--poll-shrink divisor] [--poll-weight factor]
[--thread-pool-min value] [--thread-pool-max value]]
[[--config] [--live] | [--current]]
Modifies an existing iothread of the domain using the specified iothread_id. The --poll-max-ns provides the maximum polling interval to be allowed for an IOThread in ns. If a 0 (zero) is provided, then polling for the IOThread is disabled. The --poll-grow is the factor by which the current polling time will be adjusted in order to reach the maximum polling time. If a 0 (zero) is provided, then the default factor will be used. The --poll-shrink is the quotient by which the current polling time will be reduced in order to get below the maximum polling interval. If a 0 (zero) is provided, then the default quotient will be used. The --poll-weight sets the weight shift value for adaptive polling, determining how much the most recent event interval affects the next polling duration calculation. Larger values reduce the weight of recent events. Valid range is [0, 63]. If omitted, the value is not changed. The polling values are purely dynamic for a running guest. Saving, destroying, stopping, etc. the guest will result in the polling values returning to hypervisor defaults at the next start, restore, etc.
The --thread-pool-min and --thread-pool-max options then set lower and upper bound, respectively of number of threads in worker pool of given iothread. For changes to an inactive configuration -1 can be specified to remove corresponding boundary from the domain configuration. For changes to a running guest it's recommended to set the upper boundary first (--thread-pool-max) and only after that set the lower boundary (--thread-pool-min). It is allowed for the lower boundary to be the same as the upper boundary, however it's not allowed for the upper boundary to be value of zero.
If --live is specified, affect a running guest. If the guest is not running an error is returned. If --current is specified or --live is not specified, then handle as if --live was specified. (Where "current" here means whatever the present guest state is: live or offline.)
managedsave
Syntax:
managedsave domain [--bypass-cache] [{--running | --paused}] [--verbose]
Save and destroy (stop) a running domain, so it can be restarted from the same state at a later time. When the virsh start command is next run for the domain, it will automatically be started from this saved state. If --bypass-cache is specified, the save will avoid the file system cache, although this may slow down the operation.
The progress may be monitored using domjobinfo virsh command and canceled with domjobabort command (sent by another virsh instance). Another option is to send SIGINT (usually with Ctrl-C) to the virsh process running managedsave command. --verbose displays the progress of save.
Normally, starting a managed save will decide between running or paused based on the state the domain was in when the save was done; passing either the --running or --paused flag will allow overriding which state the start should use.
The dominfo command can be used to query whether a domain currently has any managed save image.
managedsave-define
Syntax:
managedsave-define domain xml [{--running | --paused}]
Update the domain XML that will be used when domain is later started. The xml argument must be a file name containing the alternative XML, with changes only in the host-specific portions of the domain XML. For example, it can be used to change disk file paths.
The managed save image records whether the domain should be started to a running or paused state. Normally, this command does not alter the recorded state; passing either the --running or --paused flag will allow overriding which state the start should use.
managedsave-dumpxml
Syntax:
managedsave-dumpxml [--security-info] [--xpath EXPRESSION] [--wrap] domain
Extract the domain XML that was in effect at the time the saved state file file was created with the managedsave command. Using --security-info will also include security sensitive information.
If the --xpath argument provides an XPath expression, it will be evaluated against the output XML and only those matching nodes will be printed. The default behaviour is to print each matching node as a standalone document, however, for ease of additional processing, the --wrap argument will cause the matching node to be wrapped in a common root node.
managedsave-edit
Syntax:
managedsave-edit domain [{--running | --paused}]
Edit the XML configuration associated with a saved state file of a domain was created by the managedsave command.
The managed save image records whether the domain should be started to a running or paused state. Normally, this command does not alter the recorded state; passing either the --running or --paused flag will allow overriding which state the restore should use.
This is equivalent to:
virsh managedsave-dumpxml domain-name > state-file.xml
vi state-file.xml (or make changes with your other text editor)
virsh managedsave-define domain-name state-file-xml
except that it does some error checking.
The editor used can be supplied by the $VISUAL or $EDITOR environment variables, and defaults to vi.
managedsave-remove
Syntax:
managedsave-remove domain
Remove the managedsave state file for a domain, if it exists. This ensures the domain will do a full boot the next time it is started.
maxvcpus
Syntax:
Provide the maximum number of virtual CPUs supported for a guest VM on this connection. If provided, the type parameter must be a valid type attribute for the <domain> element of XML.
memtune
Syntax:
memtune domain [--hard-limit size] [--soft-limit size] [--swap-hard-limit size]
[--min-guarantee size] [[--config] [--live] | [--current]]
Allows you to display or set the domain memory parameters. Without flags, the current settings are displayed; with a flag, the appropriate limit is adjusted if supported by the hypervisor. LXC and QEMU/KVM support --hard-limit, --soft-limit, and --swap-hard-limit. --min-guarantee is supported only by ESX hypervisor. Each of these limits are scaled integers (see NOTES above), with a default of kibibytes (blocks of 1024 bytes) if no suffix is present. Libvirt rounds up to the nearest kibibyte. Some hypervisors require a larger granularity than KiB, and requests that are not an even multiple will be rounded up. For example, vSphere/ESX rounds the parameter up to mebibytes (1024 kibibytes).
If --live is specified, affect a running guest. If --config is specified, affect the next start of a persistent guest. If --current is specified, it is equivalent to either --live or --config, depending on the current state of the guest. Both --live and --config flags may be given, but --current is exclusive. If no flag is specified, behavior is different depending on hypervisor.
For QEMU/KVM, the parameters are applied to the QEMU process as a whole. Thus, when counting them, one needs to add up guest RAM, guest video RAM, and some memory overhead of QEMU itself. The last piece is hard to determine so one needs guess and try.
For LXC, the displayed hard_limit value is the current memory setting from the XML or the results from a virsh setmem command.
- •
-
--hard-limit
The maximum memory the guest can use.
- •
-
--soft-limit
The memory limit to enforce during memory contention.
- •
-
--swap-hard-limit
The maximum memory plus swap the guest can use. This has to be more than hard-limit value provided.
- •
-
--min-guarantee
The guaranteed minimum memory allocation for the guest.
Specifying -1 as a value for these limits is interpreted as unlimited.
metadata
Syntax:
metadata domain [[--live] [--config] | [--current]]
[--edit] [uri] [key] [set] [--remove]
Show or modify custom XML metadata of a domain. The metadata is a user defined XML that allows storing arbitrary XML data in the domain definition. Multiple separate custom metadata pieces can be stored in the domain XML. The pieces are identified by a private XML namespace provided via the uri argument. (See also desc that works with textual metadata of a domain.)
Flags --live or --config select whether this command works on live or persistent definitions of the domain. If both --live and --config are specified, the --config option takes precedence on getting the current description and both live configuration and config are updated while setting the description. --current is exclusive and implied if none of these was specified.
Flag --remove specifies that the metadata element specified by the uri argument should be removed rather than updated.
Flag --edit specifies that an editor with the metadata identified by the uri argument should be opened and the contents saved back afterwards. Otherwise the new contents can be provided via the set argument.
When setting metadata via --edit or set the key argument must be specified and is used to prefix the custom elements to bind them to the private namespace.
If neither of --edit and set are specified the XML metadata corresponding to the uri namespace is displayed instead of being modified.
migrate
Syntax:
migrate [--live] [--offline] [--direct] [--p2p [--tunnelled]]
[--persistent] [--undefinesource] [--suspend] [--copy-storage-all]
[--copy-storage-inc] [--change-protection] [--unsafe] [--verbose]
[--rdma-pin-all] [--abort-on-error] [--postcopy]
[--postcopy-after-precopy] [--postcopy-resume] [--zerocopy]
domain desturi [migrateuri] [graphicsuri] [listen-address] [dname]
[--timeout seconds [--timeout-suspend | --timeout-postcopy]]
[--xml file]
[--migrate-disks disk-list] [--migrate-disks-detect-zeroes disk-list]
[--migrate-disks-target-zero disk-list]
[--disks-port port]
[--compressed] [--comp-methods method-list]
[--comp-mt-level] [--comp-mt-threads] [--comp-mt-dthreads]
[--comp-xbzrle-cache] [--comp-zlib-level] [--comp-zstd-level]
[--auto-converge] [auto-converge-initial]
[auto-converge-increment] [--persistent-xml file] [--tls]
[--postcopy-bandwidth bandwidth]
[--parallel [--parallel-connections connections]]
[--bandwidth bandwidth] [--tls-destination hostname]
[--disks-uri URI] [--copy-storage-synchronous-writes]
[--available-switchover-bandwidth bandwidth]
Migrate domain to another host. Add --live for live migration; <--p2p> for peer-2-peer migration; --direct for direct migration; or --tunnelled for tunnelled migration. --offline migrates domain definition without starting the domain on destination and without stopping it on source host. Offline migration may be used with inactive domains and it must be used with --persistent option.
--persistent leaves the domain persistent on destination host (See below for quirks when used together with --xml), --undefinesource undefines the domain on the source host, and --suspend leaves the domain paused on the destination host.
--copy-storage-all indicates migration with non-shared storage with full disk copy, --copy-storage-inc indicates migration with non-shared storage with incremental copy (same base image shared between source and destination). In both cases the disk images have to exist on destination host, the --copy-storage-... options only tell libvirt to transfer data from the images on source host to the images found at the same place on the destination host. By default only non-shared non-readonly images are transferred. Use --migrate-disks to explicitly specify a list of disk targets to transfer via the comma separated disk-list argument. The --migrate-disks-detect-zeroes option which takes a comma separated list of disk target names enables zeroed block detection for the listed migrated disks. These blocks are not transferred or allocated (requires that 'discard' option on given disk is set to 'unmap') on destination, effectively sparsifying the disk at the cost of CPU overhead. The --migrate-disks-target-zero option which takes a comma separated list of disk target names specifies disk images where the target was zeroed out prior to the migration and thus hypervisor will not attempt to zero them. With --copy-storage-synchronous-writes flag used the disk data migration will synchronously handle guest disk writes to both the original source and the destination to ensure that the disk migration converges at the price of possibly decreased burst performance.
--change-protection enforces that no incompatible configuration changes will be made to the domain while the migration is underway; this flag is implicitly enabled when supported by the hypervisor, but can be explicitly used to reject the migration if the hypervisor lacks change protection support.
--verbose displays the progress of migration.
--abort-on-error cancels the migration if a soft error (for example I/O error) happens during the migration.
--postcopy enables post-copy logic in migration, but does not actually start post-copy, i.e., migration is started in pre-copy mode. Once migration is running, the user may switch to post-copy using the migrate-postcopy command sent from another virsh instance or use --postcopy-after-precopy along with --postcopy to let libvirt automatically switch to post-copy after the first pass of pre-copy is finished. The maximum bandwidth consumed during the post-copy phase may be limited using --postcopy-bandwidth. The maximum bandwidth consumed during the pre-copy phase may be limited using --bandwidth. In case connection between the hosts breaks while migration is in post-copy mode, the domain cannot be resumed on either source or destination host and the migrate command will report an error leaving the domain active on both hosts. To recover from such situation repeat the original migrate command with an additional --postcopy-resume flag.
--auto-converge forces convergence during live migration. The initial guest CPU throttling rate can be set with auto-converge-initial. If the initial throttling rate is not enough to ensure convergence, the rate is periodically increased by auto-converge-increment.
--rdma-pin-all can be used with RDMA migration (i.e., when migrateuri starts with rdma://) to tell the hypervisor to pin all domain's memory at once before migration starts rather than letting it pin memory pages as needed. For QEMU/KVM this requires hard_limit memory tuning element (in the domain XML) to be used and set to the maximum memory configured for the domain plus any memory consumed by the QEMU process itself. Beware of setting the memory limit too high (and thus allowing the domain to lock most of the host's memory). Doing so may be dangerous to both the domain and the host itself since the host's kernel may run out of memory.
--zerocopy requests zero-copy mechanism to be used for migrating memory pages. For QEMU/KVM this means QEMU will be temporarily allowed to lock all guest pages in host's memory, although only those that are queued for transfer will be locked at the same time.
Note: Individual hypervisors usually do not support all possible types of migration. For example, QEMU does not support direct migration.
In some cases libvirt may refuse to migrate the domain because doing so may lead to potential problems such as data corruption, and thus the migration is considered unsafe. For QEMU domain, this may happen if the domain uses disks without explicitly setting cache mode to "none". Migrating such domains is unsafe unless the disk images are stored on coherent clustered filesystem, such as GFS2 or GPFS. If you are sure the migration is safe or you just do not care, use --unsafe to force the migration.
dname is used for renaming the domain to new name during migration, which also usually can be omitted.
--xml file, while usually not required, can be used to supply an alternative XML file for use on the destination to supply a larger set of changes to any host-specific portions of the domain XML, such as accounting for naming differences between source and destination in accessing underlying storage. If --xml is used together with --persistent it's usually required to provide a persistent XML definition via --persistent-xml (see below) which is fixed the same way as the XML passed to --file was.
If --persistent is enabled, --persistent-xml file can be used to supply an alternative XML file which will be used as the persistent guest definition on the destination host.
--timeout seconds tells virsh to run a specified action when live migration exceeds that many seconds. It can only be used with --live. If --timeout-suspend is specified, the domain will be suspended after the timeout and the migration will complete offline; this is the default if no --timeout-\`` option is specified on the command line. When *--timeout-postcopy is used, virsh will switch migration from pre-copy to post-copy upon timeout; migration has to be started with --postcopy option for this to work.
--compressed activates compression, the compression method is chosen with --comp-methods. Supported methods are "mt", "xbzrle", "zlib", and "zstd". The supported set of methods and their combinations depend on a hypervisor and migration options. QEMU only supports "zlib" and "zstd" methods when --parallel is used and they cannot be used at once. When no methods are specified, a hypervisor default methods will be used. QEMU defaults to "xbzrle" as long as --parallel is not used. For --parallel migrations QEMU does not provide any default compression method and thus it has to be specified explicitly using --comp-method. Compression methods can be tuned further. --comp-mt-level sets compression level for "mt" method. Values are in range from 0 to 9, where 1 is maximum speed and 9 is maximum compression. --comp-mt-threads and --comp-mt-dthreads set the number of compress threads on source and the number of decompress threads on target respectively. --comp-xbzrle-cache sets size of page cache in bytes. --comp-zlib-level sets the compression level when using "zlib" method. Values are in range from 0 to 9 and defaults to 1, where 0 is no compression, 1 is maximum speed and 9 is maximum compression. --comp-zstd-level sets the compression level when using "zstd" method. Values are in range from 0 to 20 and defaults to 1, where 0 is no compression, 1 is maximum speed and 20 is maximum compression.
Providing --tls causes the migration to use the host configured TLS setup (see migrate_tls_x509_cert_dir in /etc/libvirt/qemu.conf) in order to perform the migration of the domain. Usage requires proper TLS setup for both source and target. Normally the TLS certificate from the destination host must match the host's name for TLS verification to succeed. When the certificate does not match the destination hostname and the expected certificate's hostname is known, --tls-destination can be used to pass the expected hostname when starting the migration.
--parallel option will cause migration data to be sent over multiple parallel connections. The number of such connections can be set using --parallel-connections. Parallel connections may help with saturating the network link between the source and the target and thus speeding up the migration.
Running migration can be canceled by interrupting virsh (usually using Ctrl-C) or by domjobabort command sent from another virsh instance.
The desturi and migrateuri parameters can be used to control which destination the migration uses. desturi is important for managed migration, but unused for direct migration; migrateuri is required for direct migration, but can usually be automatically determined for managed migration.
Note: The desturi parameter for normal migration and peer2peer migration has different semantics:
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normal migration: the desturi is an address of the target host as seen from the client machine.
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peer2peer migration: the desturi is an address of the target host as seen from the source machine.
In a special circumstance where you require a complete control of the connection and/or libvirt does not have network access to the remote side you can use a UNIX transport in the URI and specify a socket path in the query, for example with the qemu driver you could use this:
qemu+unix:///system?socket=/path/to/socket
When migrateuri is not specified, libvirt will automatically determine the hypervisor specific URI. Some hypervisors, including QEMU, have an optional "migration_host" configuration parameter (useful when the host has multiple network interfaces). If this is unspecified, libvirt determines a name by looking up the target host's configured hostname.
There are a few scenarios where specifying migrateuri may help:
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The configured hostname is incorrect, or DNS is broken. If a host has a hostname which will not resolve to match one of its public IP addresses, then libvirt will generate an incorrect URI. In this case migrateuri should be explicitly specified, using an IP address, or a correct hostname.
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The host has multiple network interfaces. If a host has multiple network interfaces, it might be desirable for the migration data stream to be sent over a specific interface for either security or performance reasons. In this case migrateuri should be explicitly specified, using an IP address associated with the network to be used.
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The firewall restricts what ports are available. When libvirt generates a migration URI, it will pick a port number using hypervisor specific rules. Some hypervisors only require a single port to be open in the firewalls, while others require a whole range of port numbers. In the latter case migrateuri might be specified to choose a specific port number outside the default range in order to comply with local firewall policies.
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The desturi uses UNIX transport method. In this advanced case libvirt should not guess a migrateuri and it should be specified using UNIX socket path URI:
See <https://libvirt.org/migration.html#uris> for more details on migration URIs.
Optional graphicsuri overrides connection parameters used for automatically reconnecting a graphical clients at the end of migration. If omitted, libvirt will compute the parameters based on target host IP address. In case the client does not have a direct access to the network virtualization hosts are connected to and needs to connect through a proxy, graphicsuri may be used to specify the address the client should connect to. The URI is formed as follows:
protocol://hostname[:port]/[?parameters]
where protocol is either "spice" or "vnc" and parameters is a list of protocol specific parameters separated by '&'. Currently recognized parameters are "tlsPort" and "tlsSubject". For example,
spice://target.host.com:1234/?tlsPort=4567
Optional listen-address sets the listen address that hypervisor on the destination side should bind to for incoming migration. Both IPv4 and IPv6 addresses are accepted as well as hostnames (the resolving is done on destination). Some hypervisors do not support specifying the listen address and will return an error if this parameter is used. This parameter cannot be used if desturi uses UNIX transport method.
Optional disks-port sets the port that hypervisor on destination side should bind to for incoming disks traffic. Currently it is supported only by QEMU.
Optional disks-uri can also be specified (mutually exclusive with disks-port) to specify what the remote hypervisor should bind/connect to when migrating disks. This can be tcp://address:port to specify a listen address (which overrides --migrate-uri and --listen-address for the disk migration) and a port or unix:///path/to/socket in case you need the disk migration to happen over a UNIX socket with that specified path. In this case you need to make sure the same socket path is accessible to both source and destination hypervisors and connecting to the socket on the source (after hypervisor creates it on the destination) will actually connect to the destination. If you are using SELinux (at least on the source host) you need to make sure the socket on the source is accessible to libvirtd/QEMU for connection. Libvirt cannot change the context of the existing socket because it is different from the file representation of the socket and the context is chosen by its creator (usually by using setsockcreatecon{,_raw}() functions).
Optional --available-switchover-bandwidth overrides the automatically computed bandwidth (in MiB/s) available for the final phase of (pre-copy) migration during which CPUs are stopped and all the remaining memory and device state is transferred. Knowing this bandwidth is important for accurate estimation of the domain downtime and deciding the right moment for switching over. Normally this would be estimated based on the bandwidth used by migration, but this could be lower than the actual available bandwidth. Using this option may help with migration convergence when the migration would keep iterating over and over thinking there's not enough bandwidth to comply with the configured maximum downtime.
migrate-compcache
Syntax:
migrate-compcache domain [--size bytes]
Sets and/or gets size of the cache (in bytes) used for compressing repeatedly transferred memory pages during live migration. When called without size, the command just prints current size of the compression cache. When size is specified, the hypervisor is asked to change compression cache to size bytes and then the current size is printed (the result may differ from the requested size due to rounding done by the hypervisor). The size option is supposed to be used while the domain is being live-migrated as a reaction to migration progress and increasing number of compression cache misses obtained from domjobinfo.
migrate-getmaxdowntime
Syntax:
migrate-getmaxdowntime domain
Get the maximum tolerable downtime for a domain which is being live-migrated to another host. This is the number of milliseconds the guest is allowed to be down at the end of live migration.
migrate-getspeed
Syntax:
migrate-getspeed domain [--postcopy]
Get the maximum migration bandwidth (in MiB/s) for a domain. If the --postcopy option is specified, the command will get the maximum bandwidth allowed during a post-copy migration phase.
migrate-postcopy
Syntax:
Switch the current migration from pre-copy to post-copy. This is only supported for a migration started with --postcopy option.
migrate-setmaxdowntime
Syntax:
migrate-setmaxdowntime domain downtime
Set maximum tolerable downtime for a domain which is being live-migrated to another host. The downtime is a number of milliseconds the guest is allowed to be down at the end of live migration.
migrate-setspeed
Syntax:
migrate-setspeed domain bandwidth [--postcopy]
Set the maximum migration bandwidth (in MiB/s) for a domain which is being migrated to another host. bandwidth is interpreted as an unsigned long long value. Specifying a negative value results in an essentially unlimited value being provided to the hypervisor. The hypervisor can choose whether to reject the value or convert it to the maximum value allowed. If the --postcopy option is specified, the command will set the maximum bandwidth allowed during a post-copy migration phase.
numatune
Syntax:
numatune domain [--mode mode] [--nodeset nodeset]
[[--config] [--live] | [--current]]
Set or get a domain's numa parameters, corresponding to the <numatune> element of domain XML. Without flags, the current settings are displayed.
mode can be one of `strict', `interleave', `preferred' and 'restrictive' or any valid number from the virDomainNumatuneMemMode enum in case the daemon supports it. For a running domain, the mode can't be changed, and the nodeset can be changed only if the domain was started with `restrictive' mode.
nodeset is a list of numa nodes used by the host for running the domain. Its syntax is a comma separated list, with '-' for ranges and '^' for excluding a node.
If --live is specified, set scheduler information of a running guest. If --config is specified, affect the next start of a persistent guest. If --current is specified, it is equivalent to either --live or --config, depending on the current state of the guest.
For running guests in Linux hosts, the changes made in the domain's numa parameters does not imply that the guest memory will be moved to a different nodeset immediately. The memory migration depends on the guest activity, and the memory of an idle guest will remain in its previous nodeset for longer. The presence of VFIO devices will also lock parts of the guest memory in the same nodeset used to start the guest, regardless of nodeset changes.
perf
Syntax:
perf domain [--enable eventSpec] [--disable eventSpec]
[[--config] [--live] | [--current]]
Get the current perf events setting or enable/disable specific perf events for a guest domain.
Perf is a performance analyzing tool in Linux, and it can instrument CPU performance counters, tracepoints, kprobes, and uprobes (dynamic tracing). Perf supports a list of measurable events, and can measure events coming from different sources. For instance, some event are pure kernel counters, in this case they are called software events, including context-switches, minor-faults, etc.. Now dozens of events from different sources can be supported by perf.
Currently only QEMU/KVM supports this command. The --enable and --disable option combined with eventSpec can be used to enable or disable specific performance event. eventSpec is a string list of one or more events separated by commas. Valid event names are as follows:
Valid perf event names
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cmt - A PQos (Platform Qos) feature to monitor the usage of cache by applications running on the platform.
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mbmt - Provides a way to monitor the total system memory bandwidth between one level of cache and another.
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mbml - Provides a way to limit the amount of data (bytes/s) send through the memory controller on the socket.
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cache_misses - Provides the count of cache misses by applications running on the platform.
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cache_references - Provides the count of cache hits by applications running on th e platform.
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instructions - Provides the count of instructions executed by applications running on the platform.
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cpu_cycles - Provides the count of cpu cycles (total/elapsed). May be used with instructions in order to get a cycles per instruction.
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branch_instructions - Provides the count of branch instructions executed by applications running on the platform.
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branch_misses - Provides the count of branch misses executed by applications running on the platform.
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bus_cycles - Provides the count of bus cycles executed by applications running on the platform.
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stalled_cycles_frontend - Provides the count of stalled cpu cycles in the frontend of the instruction processor pipeline by applications running on the platform.
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stalled_cycles_backend - Provides the count of stalled cpu cycles in the backend of the instruction processor pipeline by applications running on the platform.
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ref_cpu_cycles - Provides the count of total cpu cycles not affected by CPU frequency scaling by applications running on the platform.
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cpu_clock - Provides the cpu clock time consumed by applications running on the platform.
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task_clock - Provides the task clock time consumed by applications running on the platform.
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page_faults - Provides the count of page faults by applications running on the platform.
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context_switches - Provides the count of context switches by applications running on the platform.
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cpu_migrations - Provides the count cpu migrations by applications running on the platform.
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page_faults_min - Provides the count minor page faults by applications running on the platform.
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page_faults_maj - Provides the count major page faults by applications running on the platform.
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alignment_faults - Provides the count alignment faults by applications running on the platform.
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emulation_faults - Provides the count emulation faults by applications running on the platform.
Note: The statistics can be retrieved using the domstats command using the --perf flag.
If --live is specified, affect a running guest. If --config is specified, affect the next start of a persistent guest. If --current is specified, it is equivalent to either --live or --config, depending on the current state of the guest. Both --live and --config flags may be given, but --current is exclusive. If no flag is specified, behavior is different depending on hypervisor.
reboot
Syntax:
reboot domain [--mode MODE-LIST]
Reboot a domain. This acts just as if the domain had the reboot command run from the console. The command returns as soon as it has executed the reboot action, which may be significantly before the domain actually reboots.
The exact behavior of a domain when it reboots is set by the on_reboot parameter in the domain's XML definition.
By default the hypervisor will try to pick a suitable shutdown method. To specify an alternative method, the --mode parameter can specify a comma separated list which includes acpi, agent, initctl, signal and paravirt. The order in which drivers will try each mode is undefined, and not related to the order specified to virsh. For strict control over ordering, use a single mode at a time and repeat the command.
reset
Syntax:
Reset a domain immediately without any guest shutdown. reset emulates the power reset button on a machine, where all guest hardware sees the RST line set and reinitializes internal state.
Note: Reset without any guest OS shutdown risks data loss.
restore
Syntax:
restore state-file [--bypass-cache] [--xml file]
[{--running | --paused}] [--reset-nvram] [--parallel-channels]
Restores a domain from a virsh save state file. See save for more info.
If --bypass-cache is specified, the restore will avoid the file system cache. Depending on the specific scenario this may slow down or speed up the operation.
--xml file is usually omitted, but can be used to supply an alternative XML file for use on the restored guest with changes only in the host-specific portions of the domain XML. For example, it can be used to account for file naming differences in underlying storage due to disk snapshots taken after the guest was saved.
Normally, restoring a saved image will use the state recorded in the save image to decide between running or paused; passing either the --running or --paused flag will allow overriding which state the domain should be started in.
If --reset-nvram is specified, any existing NVRAM/varstore file will be deleted and re-initialized from its pristine template.
--parallel-channels option can specify number of parallel IO channels to be used when loading memory from file. Parallel save may significantly reduce the time required to save large memory domains.
Note: To avoid corrupting file system contents within the domain, you should not reuse the saved state file for a second restore unless you have also reverted all storage volumes back to the same contents as when the state file was created.
resume
Syntax:
Moves a domain out of the suspended state. This will allow a previously suspended domain to now be eligible for scheduling by the underlying hypervisor.
save
Syntax:
save domain state-file [--bypass-cache] [--xml file]
[--image-format format]
[--parallel-channels channels]
[{--running | --paused}] [--verbose]
Saves a running domain (RAM, but not disk state) to a state file so that it can be restored later. Once saved, the domain will no longer be running on the system, thus the memory allocated for the domain will be free for other domains to use. virsh restore restores from this state file.
If --bypass-cache is specified, the save will avoid the file system cache. Depending on the specific scenario this may slow down or speed up the operation.
The progress may be monitored using domjobinfo virsh command and canceled with domjobabort command (sent by another virsh instance). Another option is to send SIGINT (usually with Ctrl-C) to the virsh process running save command. --verbose displays the progress of save.
This is roughly equivalent to doing a hibernate on a running computer, with all the same limitations. Open network connections may be severed upon restore, as TCP timeouts may have expired.
--xml file is usually omitted, but can be used to supply an alternative XML file for use on the restored guest with changes only in the host-specific portions of the domain XML. For example, it can be used to account for file naming differences that are planned to be made via disk snapshots of underlying storage after the guest is saved.
Normally, restoring a saved image will decide between running or paused based on the state the domain was in when the save was done; passing either the --running or --paused flag will allow overriding which state the restore should use.
--image-format option can change the default image format used to save data into file. For more details consult the qemu.conf configuration file.
--parallel-channels option can specify number of parallel IO channels to be used when saving memory to file. Using parallel IO channels requires the use of sparse image save format. Parallel save may significantly reduce the time required to save large memory domains.
Domain saved state files assume that disk images will be unchanged between the creation and restore point. For a more complete system restore point, where the disk state is saved alongside the memory state, see the snapshot family of commands.
save-image-define
Syntax:
save-image-define file xml [{--running | --paused}]
Update the domain XML that will be used when file is later used in the restore command. The xml argument must be a file name containing the alternative XML, with changes only in the host-specific portions of the domain XML. For example, it can be used to account for file naming differences resulting from creating disk snapshots of underlying storage after the guest was saved.
The save image records whether the domain should be restored to a running or paused state. Normally, this command does not alter the recorded state; passing either the --running or --paused flag will allow overriding which state the restore should use.
save-image-dumpxml
Syntax:
save-image-dumpxml [--security-info] [--xpath EXPRESSION] [--wrap] file
Extract the domain XML that was in effect at the time the saved state file file was created with the save command. Using --security-info will also include security sensitive information.
If the --xpath argument provides an XPath expression, it will be evaluated against the output XML and only those matching nodes will be printed. The default behaviour is to print each matching node as a standalone document, however, for ease of additional processing, the --wrap argument will cause the matching node to be wrapped in a common root node.
save-image-edit
Syntax:
save-image-edit file [{--running | --paused}]
Edit the XML configuration associated with a saved state file file created by the save command.
The save image records whether the domain should be restored to a running or paused state. Normally, this command does not alter the recorded state; passing either the --running or --paused flag will allow overriding which state the restore should use.
This is equivalent to:
virsh save-image-dumpxml state-file > state-file.xml
vi state-file.xml (or make changes with your other text editor)
virsh save-image-define state-file state-file-xml
except that it does some error checking.
The editor used can be supplied by the $VISUAL or $EDITOR environment variables, and defaults to vi.
schedinfo
Syntax:
schedinfo domain [[--config] [--live] | [--current]] [[--set] parameter=value]...
schedinfo [--weight number] [--cap number] domain
Allows you to show (and set) the domain scheduler parameters. The parameters available for each hypervisor are:
LXC (posix scheduler) : cpu_shares, vcpu_period, vcpu_quota
QEMU/KVM (posix scheduler): cpu_shares, vcpu_period, vcpu_quota, emulator_period, emulator_quota, global_period, global_quota, iothread_period, iothread_quota
Xen (credit scheduler): weight, cap
ESX (allocation scheduler): reservation, limit, shares
If --live is specified, set scheduler information of a running guest. If --config is specified, affect the next start of a persistent guest. If --current is specified, it is equivalent to either --live or --config, depending on the current state of the guest.
Note: The cpu_shares parameter has a valid value range of 2-262144 with cgroups v1, 1-10000 with cgroups v2.
Note: The weight and cap parameters are defined only for the XEN_CREDIT scheduler.
Note: The vcpu_period, emulator_period, and iothread_period parameters have a valid value range of 1000-1000000 or 0, and the vcpu_quota, emulator_quota, and iothread_quota parameters have a valid value range of 1000-17592186044415 or less than 0. The value 0 for either parameter is the same as not specifying that parameter.
screenshot
Syntax:
screenshot domain [imagefilepath] [--screen screenID]
Takes a screenshot of a current domain console and stores it into a file. Optionally, if the hypervisor supports more displays for a domain, screenID allows specifying which screen will be captured. It is the sequential number of screen. In case of multiple graphics cards, heads are enumerated before devices, e.g. having two graphics cards, both with four heads, screen ID 5 addresses the second head on the second card.
send-key
Syntax:
send-key domain [--codeset codeset] [--holdtime holdtime] keycode...
Parse the keycode sequence as keystrokes to send to domain. Each keycode can either be a numeric value or a symbolic name from the corresponding codeset. If --holdtime is given, each keystroke will be held for that many milliseconds. The default codeset is linux, but use of the --codeset option allows other codesets to be chosen.
If multiple keycodes are specified, they are all sent simultaneously to the guest, and they may be received in random order. If you need distinct keypresses, you must use multiple send-key invocations.
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linux
The numeric values are those defined by the Linux generic input event subsystem. The symbolic names match the corresponding Linux key constant macro names.
See virkeycode-linux(7) and virkeyname-linux(7)
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xt
The numeric values are those defined by the original XT keyboard controller. No symbolic names are provided
See virkeycode-xt(7)
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atset1
The numeric values are those defined by the AT keyboard controller, set 1 (aka XT compatible set). Extended keycoes from atset1 may differ from extended keycodes in the xt codeset. No symbolic names are provided
See virkeycode-atset1(7)
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atset2
The numeric values are those defined by the AT keyboard controller, set 2. No symbolic names are provided
See virkeycode-atset2(7)
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atset3
The numeric values are those defined by the AT keyboard controller, set 3 (aka PS/2 compatible set). No symbolic names are provided
See virkeycode-atset3(7)
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os_x
The numeric values are those defined by the macOS keyboard input subsystem. The symbolic names match the corresponding macOS key constant macro names
See virkeycode-osx(7) and virkeyname-osx(7)
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xt_kbd
The numeric values are those defined by the Linux KBD device. These are a variant on the original XT codeset, but often with different encoding for extended keycodes. No symbolic names are provided.
See virkeycode-xtkbd(7)
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win32
The numeric values are those defined by the Win32 keyboard input subsystem. The symbolic names match the corresponding Win32 key constant macro names
See virkeycode-win32(7) and virkeyname-win32(7)
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usb
The numeric values are those defined by the USB HID specification for keyboard input. No symbolic names are provided
See virkeycode-usb(7)
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qnum
The numeric values are those defined by the QNUM extension for sending raw keycodes. These are a variant on the XT codeset, but extended keycodes have the low bit of the second byte set, instead of the high bit of the first byte. No symbolic names are provided.
See virkeycode-qnum(7)
Examples:
# send three strokes 'k', 'e', 'y', using xt codeset. these
# are all pressed simultaneously and may be received by the guest
# in random order
virsh send-key dom --codeset xt 37 18 21
# send one stroke 'right-ctrl+C'
virsh send-key dom KEY_RIGHTCTRL KEY_C
# send a tab, held for 1 second
virsh send-key --holdtime 1000 0xf
send-process-signal
Syntax:
send-process-signal domain-id pid signame
Send a signal signame to the process identified by pid running in the virtual domain domain-id. The pid is a process ID in the virtual domain namespace.
The signame argument may be either an integer signal constant number, or one of the symbolic names:
"nop", "hup", "int", "quit", "ill",
"trap", "abrt", "bus", "fpe", "kill",
"usr1", "segv", "usr2", "pipe", "alrm",
"term", "stkflt", "chld", "cont", "stop",
"tstp", "ttin", "ttou", "urg", "xcpu",
"xfsz", "vtalrm", "prof", "winch", "poll",
"pwr", "sys", "rt0", "rt1", "rt2", "rt3",
"rt4", "rt5", "rt6", "rt7", "rt8", "rt9",
"rt10", "rt11", "rt12", "rt13", "rt14", "rt15",
"rt16", "rt17", "rt18", "rt19", "rt20", "rt21",
"rt22", "rt23", "rt24", "rt25", "rt26", "rt27",
"rt28", "rt29", "rt30", "rt31", "rt32"
The symbol name may optionally be prefixed with sig or sig_ and may be in uppercase or lowercase.
Examples:
virsh send-process-signal myguest 1 15
virsh send-process-signal myguest 1 term
virsh send-process-signal myguest 1 sigterm
virsh send-process-signal myguest 1 SIG_HUP
set-lifecycle-action
Syntax:
set-lifecycle-action domain type action
[[--config] [--live] | [--current]]
Set the lifecycle action for specified lifecycle type. The valid types are "poweroff", "reboot" and "crash", and for each of them valid action is one of "destroy", "restart", "rename-restart", "preserve". For type "crash", additional actions "coredump-destroy" and "coredump-restart" are supported.
set-user-password
Syntax:
set-user-password domain user password [--encrypted]
Set the password for the user account in the guest domain.
If --encrypted is specified, the password is assumed to be already encrypted by the method required by the guest OS.
For QEMU/KVM, this requires the guest agent to be configured and running.
set-user-sshkeys
Syntax:
set-user-sshkeys domain user [--file FILE] [{--reset | --remove}]
Append keys read from FILE into user's SSH authorized keys file in the guest domain. In the FILE keys must be on separate lines and each line must follow authorized keys format as defined by sshd(8).
If --reset is specified, then the guest authorized keys file content is removed before appending new keys. As a special case, if --reset is provided and no FILE was provided then no new keys are added and the authorized keys file is cleared out.
If --remove is specified, then instead of adding any new keys then keys read from FILE are removed from the authorized keys file. It is not considered an error if the key does not exist in the file.
setmaxmem
Syntax:
setmaxmem domain size [[--config] [--live] | [--current]]
Change the maximum memory allocation limit for a guest domain. If --live is specified, affect a running guest. If --config is specified, affect the next start of a persistent guest. If --current is specified, it is equivalent to either --live or --config, depending on the current state of the guest. Both --live and --config flags may be given, but --current is exclusive. If no flag is specified, behavior is different depending on hypervisor.
Some hypervisors such as QEMU/KVM don't support live changes (especially increasing) of the maximum memory limit. Even persistent configuration changes might not be performed with some hypervisors/configuration (e.g. on NUMA enabled domains on QEMU). For complex configuration changes use command edit instead).
size is a scaled integer (see NOTES above); it defaults to kibibytes (blocks of 1024 bytes) unless you provide a suffix (and the older option name --kilobytes is available as a deprecated synonym) . Libvirt rounds up to the nearest kibibyte. Some hypervisors require a larger granularity than KiB, and requests that are not an even multiple will be rounded up. For example, vSphere/ESX rounds the parameter up to mebibytes (1024 kibibytes).
setmem
Syntax:
setmem domain size [[--config] [--live] | [--current]]
Change the memory allocation for a guest domain. If --live is specified, perform a memory balloon of a running guest. If --config is specified, affect the next start of a persistent guest. If --current is specified, it is equivalent to either --live or --config, depending on the current state of the guest. Both --live and --config flags may be given, but --current is exclusive. If no flag is specified, behavior is different depending on hypervisor.
size is a scaled integer (see NOTES above); it defaults to kibibytes (blocks of 1024 bytes) unless you provide a suffix (and the older option name --kilobytes is available as a deprecated synonym) . Libvirt rounds up to the nearest kibibyte. Some hypervisors require a larger granularity than KiB, and requests that are not an even multiple will be rounded up. For example, vSphere/ESX rounds the parameter up to mebibytes (1024 kibibytes).
For Xen, you can only adjust the memory of a running domain if the domain is paravirtualized or running the PV balloon driver.
For LXC, the value being set is the cgroups value for limit_in_bytes or the maximum amount of user memory (including file cache). When viewing memory inside the container, this is the /proc/meminfo "MemTotal" value. When viewing the value from the host, use the virsh memtune command. In order to view the current memory in use and the maximum value allowed to set memory, use the virsh dominfo command.
setvcpus
Syntax:
setvcpus domain count [--maximum] [[--config] [--live] | [--current]] [--guest] [--hotpluggable] [--async]
Change the number of virtual CPUs active in a guest domain. By default, this command works on active guest domains. To change the settings for an inactive guest domain, use the --config flag.
The count value may be limited by host, hypervisor, or a limit coming from the original description of the guest domain. For Xen, you can only adjust the virtual CPUs of a running domain if the domain is paravirtualized.
If the --config flag is specified, the change is made to the stored XML configuration for the guest domain, and will only take effect when the guest domain is next started.
If --live is specified, the guest domain must be active, and the change takes place immediately. Both the --config and --live flags may be specified together if supported by the hypervisor. If this command is run before the guest has finished booting, the guest may fail to process the change.
If --current is specified, it is equivalent to either --live or --config, depending on the current state of the guest.
When no flags are given, the --live flag is assumed and the guest domain must be active. In this situation it is up to the hypervisor whether the --config flag is also assumed, and therefore whether the XML configuration is adjusted to make the change persistent.
If --async is specified, live vCPU unplug requests are fired without waiting for the guest to comply. Final completion is reported by the vcpu-removed domain event, while rejected unplug requests continue to be reported by device-removal-failed. This flag cannot be combined with --guest.
If --guest is specified, then the count of cpus is modified in the guest instead of the hypervisor. This flag is usable only for live domains and may require guest agent to be configured in the guest.
To allow adding vcpus to persistent definitions that can be later hotunplugged after the domain is booted it is necessary to specify the --hotpluggable flag. Vcpus added to live domains supporting vcpu unplug are automatically marked as hotpluggable.
The --maximum flag controls the maximum number of virtual cpus that can be hot-plugged the next time the domain is booted. As such, it must only be used with the --config flag, and not with the --live or the --current flag. Note that it may not be possible to change the maximum vcpu count if the processor topology is specified for the guest.
setvcpu
Syntax:
setvcpu domain vcpulist [--enable] | [--disable] [--async]
[[--live] [--config] | [--current]]
Change state of individual vCPUs using hot(un)plug mechanism.
See vcpupin for information on format of vcpulist. Hypervisor drivers may require that vcpulist contains exactly vCPUs belonging to one hotpluggable entity. This is usually just a single vCPU but certain architectures such as ppc64 require a full core to be specified at once.
Note that hypervisors may refuse to disable certain vcpus such as vcpu 0 or others.
If --live is specified, affect a running domain. If --config is specified, affect the next startup of a persistent guest. If --current is specified, it is equivalent to either --live or --config, depending on the current state of the guest. This is the default. Both --live and --config flags may be given, but --current is exclusive.
If --async is specified with --disable, live vCPU unplug requests are fired without waiting for the guest to comply. Final completion of this operation is reported by the vcpu-removed domain event, while rejected unplug requests continue to be reported by device-removal-failed.
shutdown
Syntax:
shutdown domain [--mode MODE-LIST]
Gracefully shuts down a domain. This coordinates with the domain OS to perform graceful shutdown, so there is no guarantee that it will succeed, and may take a variable length of time depending on what services must be shutdown in the domain.
The exact behavior of a domain when it shuts down is set by the on_poweroff parameter in the domain's XML definition.
If domain is transient, then the metadata of any snapshots and checkpoints will be lost once the guest stops running, but the underlying contents still exist, and a new domain with the same name and UUID can restore the snapshot metadata with snapshot-create, and the checkpoint metadata with checkpoint-create.
By default the hypervisor will try to pick a suitable shutdown method. To specify an alternative method, the --mode parameter can specify a comma separated list which includes acpi, agent, initctl, signal and paravirt. The order in which drivers will try each mode is undefined, and not related to the order specified to virsh. For strict control over ordering, use a single mode at a time and repeat the command.
start
Syntax:
start domain-name-or-uuid [--console] [--paused]
[--autodestroy] [--bypass-cache] [--force-boot]
[--pass-fds N,M,...] [--reset-nvram]
Start a (previously defined) inactive domain, either from the last managedsave state, or via a fresh boot if no managedsave state is present. The domain will be paused if the --paused option is used and supported by the driver; otherwise it will be running. If --console is requested, attach to the console after creation. If --autodestroy is requested, then the guest will be automatically destroyed when virsh closes its connection to libvirt, or otherwise exits. If --bypass-cache is specified, and managedsave state exists, the restore will avoid the file system cache, although this may slow down the operation. If --force-boot is specified, then any managedsave state is discarded and a fresh boot occurs.
If --pass-fds is specified, the argument is a comma separated list of open file descriptors which should be pass on into the guest. The file descriptors will be re-numbered in the guest, starting from 3. This is only supported with container based virtualization.
If --reset-nvram is specified, any existing NVRAM/varstore file will be deleted and re-initialized from its pristine template.
suspend
Syntax:
Suspend a running domain. It is kept in memory but won't be scheduled anymore.
ttyconsole
Syntax:
Output the device used for the TTY console of the domain. If the information is not available the processes will provide an exit code of 1.
undefine
Syntax:
undefine domain [--managed-save] [--snapshots-metadata]
[--checkpoints-metadata] [--nvram] [--keep-nvram]
[ {--storage volumes | --remove-all-storage
[--delete-storage-volume-snapshots]} --wipe-storage]
[--tpm] [--keep-tpm]
Undefine a domain. If the domain is running, this converts it to a transient domain, without stopping it. If the domain is inactive, the domain configuration is removed.
The --managed-save flag guarantees that any managed save image (see the managedsave command) is also cleaned up. Without the flag, attempts to undefine a domain with a managed save image will fail.
The --snapshots-metadata flag guarantees that any snapshots (see the snapshot-list command) are also cleaned up when undefining an inactive domain. Without the flag, attempts to undefine an inactive domain with snapshot metadata will fail. If the domain is active, this flag is ignored.
The --checkpoints-metadata flag guarantees that any checkpoints (see the checkpoint-list command) are also cleaned up when undefining an inactive domain. Without the flag, attempts to undefine an inactive domain with checkpoint metadata will fail. If the domain is active, this flag is ignored.
The --nvram and --keep-nvram flags specify whether to delete or keep the NVRAM (/domain/os/nvram/) or varstore (/domain/os/varstore) file respectively. If the domain has an NVRAM/varstore file and the flags are omitted, the undefine operation will fail.
The --storage flag takes a parameter volumes, which is a comma separated list of volume target names or source paths of storage volumes to be removed along with the undefined domain. Volumes can be undefined and thus removed only on inactive domains. Volume deletion is only attempted after the domain is undefined; if not all of the requested volumes could be deleted, the error message indicates what still remains behind. If a volume path is not found in the domain definition, it's treated as if the volume was successfully deleted. Only volumes managed by libvirt in storage pools can be removed this way. Note that this also removes only the top level image of a backing chain, any backing stores of the image are kept as they may be shared. (See domblklist for list of target names associated to a domain). Example: --storage vda,/path/to/storage.img
The --remove-all-storage flag specifies that all of the domain's storage volumes should be deleted as if they were specified via --storage.
The --delete-storage-volume-snapshots (previously --delete-snapshots) flag specifies that any snapshots associated with the storage volume should be deleted as well. Requires the --remove-all-storage flag to be provided. Not all storage drivers support this option, presently only rbd. Using this when also removing volumes handled by a storage driver which does not support the flag will result in failure.
The flag --wipe-storage specifies that the storage volumes should be wiped before removal.
--tpm and --keep-tpm specify accordingly to delete or keep a TPM's persistent state directory structure and files. If the flags are omitted then the persistent_state attribute in the TPM emulator definition in the domain XML determines whether the TPM state is kept.
NOTE: For an inactive domain, the domain name or UUID must be used as the domain.
vcpucount
Syntax:
vcpucount domain [{--maximum | --active}
{--config | --live | --current}] [--guest]
Print information about the virtual cpu counts of the given domain. If no flags are specified, all possible counts are listed in a table; otherwise, the output is limited to just the numeric value requested. For historical reasons, the table lists the label "current" on the rows that can be queried in isolation via the --active flag, rather than relating to the --current flag.
--maximum requests information on the maximum cap of vcpus that a domain can add via setvcpus, while --active shows the current usage; these two flags cannot both be specified. --config requires a persistent guest and requests information regarding the next time the domain will be booted, --live requires a running domain and lists current values, and --current queries according to the current state of the domain (corresponding to --live if running, or --config if inactive); these three flags are mutually exclusive.
If --guest is specified, then the count of cpus is reported from the perspective of the guest. This flag is usable only for live domains and may require guest agent to be configured in the guest.
vcpuinfo
Syntax:
vcpuinfo domain [--pretty]
Returns basic information about the domain virtual CPUs, like the number of vCPUs, the running time, the affinity to physical processors.
With --pretty, cpu affinities are shown as ranges.
Example:
$ virsh vcpuinfo fedora
VCPU: 0
CPU: 0
State: running
CPU time: 7,0s
CPU Affinity: yyyy
VCPU: 1
CPU: 1
State: running
CPU time: 0,7s
CPU Affinity: yyyy
STATES
The State field displays the current operating state of a virtual CPU
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offline
The virtual CPU is offline and not usable by the domain. This state is not supported by all hypervisors.
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running
The virtual CPU is available to the domain and is operating.
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blocked
The virtual CPU is available to the domain but is waiting for a resource. This state is not supported by all hypervisors, in which case running may be reported instead.
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no state
The virtual CPU state could not be determined. This could happen if the hypervisor is newer than virsh.
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N/A
There's no information about the virtual CPU state available. This can be the case if the domain is not running or the hypervisor does not report the virtual CPU state.
vcpupin
Syntax:
vcpupin domain [vcpu] [cpulist] [[--live] [--config] | [--current]]
Query or change the pinning of domain VCPUs to host physical CPUs. To pin a single vcpu, specify cpulist; otherwise, you can query one vcpu or omit vcpu to list all at once.
cpulist is a list of physical CPU numbers. Its syntax is a comma separated list and a special markup using '-' and '^' (ex. '0-4', '0-3,^2') can also be allowed. The '-' denotes the range and the '^' denotes exclusive. For pinning the vcpu to all physical cpus specify 'r' as a cpulist. If --live is specified, affect a running guest. If --config is specified, affect the next start of a persistent guest. If --current is specified, it is equivalent to either --live or --config, depending on the current state of the guest. Both --live and --config flags may be given if cpulist is present, but --current is exclusive. If no flag is specified, behavior is different depending on hypervisor.
Note: The expression is sequentially evaluated, so "0-15,^8" is identical to "9-14,0-7,15" but not identical to "^8,0-15".
vncdisplay
Syntax:
Output the IP address and port number for the VNC display. If the information is not available the processes will provide an exit code of 1.