virsh (1) Linux Manual Page
virsh – management user interface
Synopsis
virsh [OPTION]… [COMMAND_STRING] virsh [OPTION]… COMMAND [ARG]…
Description
The virsh program is the main interface for managing virsh guest domains. The program can be used to create, pause, and shutdown domains. It can also be used to list current domains. Libvirt is a C toolkit to interact with the virtualization capabilities of recent versions of Linux (and other OSes). It is free software available under the GNU Lesser General Public License. Virtualization of the Linux Operating System means the ability to run multiple instances of Operating Systems concurrently on a single hardware system where the basic resources are driven by a Linux instance. The library aims at providing a long term stable C API. It currently supports Xen, QEMU, KVM, LXC, OpenVZ, VirtualBox and VMware ESX.The basic structure of most virsh usage is:
virsh [OPTION]… <command> <domain> [ARG]…Where command is one of the commands listed below; domain is the numeric domain id, or the domain name, or the domain UUID; and ARGS are command specific options. There are a few exceptions to this rule in the cases where the command in question acts on all domains, the entire machine, or directly on the xen hypervisor. Those exceptions will be clear for each of those commands. Note: it is permissible to give numeric names to domains, however, doing so will result in a domain that can only be identified by domain id. In other words, if a numeric value is supplied it will be interpreted as a domain id, not as a name.
The virsh program can be used either to run one COMMAND by giving the command and its arguments on the shell command line, or a COMMAND_STRING which is a single shell argument consisting of multiple COMMAND actions and their arguments joined with whitespace, and separated by semicolons between commands. Within COMMAND_STRING, virsh understands the same single, double, and backslash escapes as the shell, although you must add another layer of shell escaping in creating the single shell argument. If no command is given in the command line, virsh will then start a minimal interpreter waiting for your commands, and the quit command will then exit the program.
The virsh program understands the following OPTIONS.
- -c, –connect URI
- Connect to the specified URI, as if by the connect command, instead of the default connection.
- -d, –debug LEVEL
- Enable debug messages at integer LEVEL and above. LEVEL can range from 0 to 4 (default). See the documentation of VIRSH_DEBUG environment variable below for the description of each LEVEL.
- -e, –escape string
- Set alternative escape sequence for console command. By default, telnet’s ^] is used. Allowed characters when using hat notation are: alphabetic character, @, [, ], \, ^, _.
- -h, –help
- Ignore all other arguments, and behave as if the help command were given instead.
- -k, –keepalive-interval INTERVAL
- Set an INTERVAL (in seconds) for sending keepalive messages to check whether connection to the server is still alive. Setting the interval to 0 disables client keepalive mechanism.
- -K, –keepalive-count COUNT
- Set a number of times keepalive message can be sent without getting an answer from the server without marking the connection dead. There is no effect to this setting in case the INTERVAL is set to 0.
- -l, –log FILE
- Output logging details to FILE.
- -q, –quiet
- Avoid extra informational messages.
- -r, –readonly
- Make the initial connection read-only, as if by the –readonly option of the connect command.
- -t, –timing
- Output elapsed time information for each command.
- -v, –version[=short]
- Ignore all other arguments, and prints the version of the libvirt library virsh is coming from
- -V, –version=long
- Ignore all other arguments, and prints the version of the libvirt library virsh is coming from and which options and driver are compiled in.
Notes
Most virsh operations rely upon the libvirt library being able to connect to an already running libvirtd service. This can usually be done using the command service libvirtd start.Most virsh commands require root privileges to run due to the communications channels used to talk to the hypervisor. Running as non root will return an error.
Most virsh commands act synchronously, except maybe shutdown, setvcpus and setmem. In those cases the fact that the virsh program returned, may not mean the action is complete and you must poll periodically to detect that the guest completed the operation.
virsh strives for backward compatibility. Although the help command only lists the preferred usage of a command, if an older version of virsh supported an alternate spelling of a command or option (such as –tunnelled instead of –tunneled), then scripts using that older spelling will continue to work.
Several virsh commands take an optionally scaled integer; if no scale is provided, then the default is listed in the command (for historical reasons, some commands default to bytes, while other commands default to kibibytes). The following case-insensitive suffixes can be used to select a specific scale:
Generic Commands
The following commands are generic i.e. not specific to a domain.
To display only commands for a specific group, give the keyword for that group as an option. For example:
virsh # help hostTo display detailed information for a specific command, give its name as the option instead. For example:
Host and Hypervisor (help keyword ‘host’):
capabilities capabilities
cpu-models show the CPU models for an architecture
connect (re)connect to hypervisor
freecell NUMA free memory
hostname print the hypervisor hostname
qemu-attach Attach to existing QEMU process
qemu-monitor-command QEMU Monitor Command
qemu-agent-command QEMU Guest Agent Command
sysinfo print the hypervisor sysinfo
uri print the hypervisor canonical URI
virsh # help list
NAME
list – list domains
SYNOPSIS
list [–inactive] [–all]
DESCRIPTION
Returns list of domains.
OPTIONS
–inactive list inactive domains
–all list inactive & active domains
- Example
$ virsh version
Compiled against library: libvirt 1.2.3
Using library: libvirt 1.2.3
Using API: QEMU 1.2.3
Running hypervisor: QEMU 2.0.50
$ virsh version –daemon
Compiled against library: libvirt 1.2.3
Using library: libvirt 1.2.3
Using API: QEMU 1.2.3
Running hypervisor: QEMU 2.0.50
Running against daemon: 1.2.6
- Example
This command is only available in interactive mode.
- xen:///
- this is used to connect to the local Xen hypervisor
- qemu:///system
- connect locally as root to the daemon supervising QEMU and KVM domains
- qemu:///session
- connect locally as a normal user to his own set of QEMU and KVM domains
- lxc:///
- connect to a local linux container
- xen:///
- To find the currently used URI, check the uri command documented below.
For remote access see the documentation page at <http://libvirt.org/uri.html> on how to make URIs. The –readonly option allows for read-only connection
With –pretty the online CPUs are printed as a range instead of a list.
Note: Currently the “shared memory service” only means KSM (Kernel Samepage Merging).
Each hypervisor will have different requirements regarding which options are required and which are optional. A hypervisor can support providing a default value for any of the options.
The virttype option specifies the virtualization type used. The value to be used is either from the ‘type’ attribute of the <domain/> top level element from the domain XML or the ‘type’ attribute found within each <guest/> element from the virsh capabilities output. The emulatorbin option specifies the path to the emulator. The value to be used is either the <emulator> element in the domain XML or the virsh capabilities output. The arch option specifies the architecture to be used for the domain. The value to be used is either the “arch” attribute from the domain’s XML <os/> element and <type/> subelement or the “name” attribute of an <arch/> element from the virsh capabililites output. The machine specifies the machine type for the emulator. The value to be used is either the “machine” attribute from the domain’s XML <os/> element and <type/> subelement or one from a list of machines from the virsh capabilities output for a specific architecture and domain type.
For the qemu hypervisor, a virttype of either ‘qemu’ or ‘kvm’ must be supplied along with either the emulatorbin or arch in order to generate output for the default machine. Supplying a machine value will generate output for the specific machine.
An example format for the list is as follows:
virsh list
Name is the name of the domain. ID the domain numeric id. State is the run state (see below).
STATES
The State field lists what state each domain is currently in. A domain can be in one of the following possible states:
- running
- The domain is currently running on a CPU
- idle
- The domain is idle, and not running or runnable. This can be caused because the domain is waiting on IO (a traditional wait state) or has gone to sleep because there was nothing else for it to do.
- paused
- The domain has been paused, usually occurring through the administrator running virsh suspend. When in a paused state the domain will still consume allocated resources like memory, but will not be eligible for scheduling by the hypervisor.
- in shutdown
- The domain is in the process of shutting down, i.e. the guest operating system has been notified and should be in the process of stopping its operations gracefully.
- shut off
- The domain is not running. Usually this indicates the domain has been shut down completely, or has not been started.
- crashed
- The domain has crashed, which is always a violent ending. Usually this state can only occur if the domain has been configured not to restart on crash.
- pmsuspended
- The domain has been suspended by guest power management, e.g. entered into s3 state.
- running
- Normally only active domains are listed. To list inactive domains specify –inactive or –all to list both active and inactive domains.
To further filter the list of domains you may specify one or more of filtering flags supported by the list command. These flags are grouped by function. Specifying one or more flags from a group enables the filter group. Note that some combinations of flags may yield no results. Supported filtering flags and groups:
- Persistence
- Flag –persistent is used to include persistent domains in the returned list. To include transient domains specify –transient.
- Existence of managed save image
- To list domains having a managed save image specify flag –with-managed-save. For domains that don’t have a managed save image specify –without-managed-save.
- Domain state
- The following filter flags select a domain by its state: –state-running for running domains, –state-paused for paused domains, –state-shutoff for turned off domains and –state-other for all other states as a fallback.
- Autostarting domains
- To list autostarting domains use the flag –autostart. To list domains with this feature disabled use –no-autostart.
- Snapshot existence
- Domains that have snapshot images can be listed using flag –with-snapshot, domains without a snapshot –without-snapshot.
- Persistence
- When talking to older servers, this command is forced to use a series of API calls with an inherent race, where a domain might not be listed or might appear more than once if it changed state between calls while the list was being collected. Newer servers do not have this problem.
If –managed-save is specified, then domains that have managed save state (only possible if they are in the shut off state, so you need to specify –inactive or –all to actually list them) will instead show as saved in the listing. This flag is usable only with the default –table output. Note that this flag does not filter the list of domains.
If –name is specified, domain names are printed instead of the table formatted one per line. If –uuid is specified domain’s UUID‘s are printed instead of names. Flag –table specifies that the legacy table-formatted output should be used. This is the default.
If both –name and –uuid are specified, domain UUID‘s and names are printed side by side without any header. Flag –table specifies that the legacy table-formatted output should be used. This is the default if neither –name nor –uuid are specified. Option –table is mutually exclusive with options –uuid and –name.
If –title is specified, then the short domain description (title) is printed in an extra column. This flag is usable only with the default –table output.
Example:
virsh list –title
Id Name State Title
————————————————————————–
0 Domain-0 running Mailserver 1
2 fedora paused
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 [–disable] domain
- Configure a domain to be automatically started at boot.
The option –disable disables autostarting.
- console domain [devname] [–safe] [–force]
- 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.
- create FILE [–console] [–paused] [–autodestroy] [–pass-fds N,M,…]
- Create a domain from an XML <file>. An easy way to create the XML <file> is to use the dumpxml command to obtain the definition of a pre-existing guest. 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.
Example
virsh dumpxml <domain> > domain.xml
vi domain.xml (or make changes with your other text editor)
virsh create domain.xml - define FILE
- Define a domain from an XML <file>. The domain definition is registered but not started. If domain is already running, the changes will take effect on the next boot.
- 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 to store 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 domain [–graceful]
- 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.
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.
- 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 –>
- domifaddr domain [interface] [–full] [–source lease|agent]
- 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 drivers, notably qemu. If –full is specified, the interface name is always displayed when the interface has multiple addresses or alias, otherwise it only displays the interface name for the first address, and “-” for the others. The –source argument specifies what data source to use for the addresses, currently one of ‘lease’ to read DHCP leases, or ‘agent’ to query the guest OS via an agent. If unspecified, ‘lease’ is the default.
- domifstat domain interface-device
- Get network interface stats for a running domain.
- domif-setlink domain interface-device state [–config]
- 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.
- 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.
- domifaddr domain [interface] [–full] [–source lease|agent]
- 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 kilobytes per second, while burst is expressed in kilobytes in a single burst at peak speed as described in the Network XML documentation at <http://libvirt.org/formatnetwork.html#elementQoS>.
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 boot of a persistent guest. If –current is specified, affect the current guest state. Both –live and –config flags may be given, but –current is exclusive. If no flag is specified, behavior is different depending on hypervisor.
- 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 kB)
swap_out – The amount of memory written out to swap space (in kB)
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 kB)
available – The amount of usable memory as seen by the domain (in kB)
actual – Current balloon value (in KB)
rss – Resident Set Size of the running domain’s process (in kB)
usable – The amount of memory which can be reclaimed by balloon without causing host swapping (in KB)
last-update – Timestamp of the last update of statistics (in seconds) 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 boot of a persistent guest. If –current is specified, affect the current guest state.
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.
- domblkerror domain
- 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 domain block-device
- 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).
- 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.
- domstats [–raw] [–enforce] [–backing] [–state] [–cpu-total] [–balloon] [–vcpu] [–interface] [–block] [–perf] [[–list-active] [–list-inactive] [–list-persistent] [–list-transient] [–list-running] [–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-*. (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.
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
–cpu-total returns:
virDomainState enum
"state.reason" – reason for entering given state, returned
as int from virDomain*Reason enum corresponding
to given state"cpu.time" – total cpu time spent for this domain in nanoseconds
–balloon returns:
"cpu.user" – user cpu time spent in nanoseconds
"cpu.system" – system cpu time spent in nanoseconds"balloon.current" – the memory in kiB currently used
–vcpu returns:
"balloon.maximum" – the maximum memory in kiB allowed
"balloon.swap_in" – the amount of data read from swap space (in kB)
"balloon.swap_out" – the amount of memory written out to swap
space (in kB)
"balloon.major_fault" – the number of page faults then 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 kB)
"balloon.available" – the amount of usable memory as seen by
the domain (in kB)
"balloon.rss" – Resident Set Size of running domain’s process
(in kB)
"balloon.usable" – the amount of memory which can be reclaimed by
balloon without causing host swapping (in KB)
"balloon.last-update" – timestamp of the last update of statistics
(in seconds)"vcpu.current" – current number of online virtual CPUs
–interface returns:
"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 microseconds)
"vcpu.<num>.wait" – virtual cpu time spent by virtual
CPU <num> waiting on I/O (in microseconds)
"vcpu.<num>.halted" – virtual CPU <num> is halted: yes or
no (may indicate the processor is idle
or even disabled, depending on the
architecture)"net.count" – number of network interfaces on this domain
–perf returns the statistics of all enabled perf events:
"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.cmt" – the cache usage in Byte currently used
See the perf command for more details about each event.
"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–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
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.
"block.<num>.name" – name of the target of the block
device <num> (the same name for
multiple entries if I<–backing>
is present)
"block.<num>.backingIndex" – when I<–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.
- 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.
- 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 domain path { dest [format] [–blockdev] | –xml file } [–shallow] [–reuse-external] [bandwidth] [–wait [–async] [–verbose]] [{–pivot | –finish}] [–timeout seconds] [granularity] [buf-size] [–bytes] [–transient-job]
- 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 to specify 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.
- 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.
- 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 boot of a persistent guest. If –current is specified, affect the current guest state. 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.
- 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 allows to use finer granularity. A scaled value used without –bytes will be rounded down to MiB/s. Note that the –bytes may be unsupported by the hypervisor.
- 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.
- blockresize domain path size
- 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).
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).
- 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.
- domfsinfo domain
- 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.
- 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.
- 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 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 domain
- Returns the hostname of a domain, if the hypervisor makes it available.
- dominfo domain
- Returns basic information about the domain.
- domuuid domain-name-or-id
- Convert a domain name or id to domain UUID
- domid domain-name-or-uuid
- Convert a domain name (or UUID) to a domain id
- domjobabort domain
- Abort the currently running domain job.
- domjobinfo domain [–completed]
- 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 or when libvirtd is restarted. 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).
- domname domain-id-or-uuid
- Convert a domain Id (or UUID) to domain name
- 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 and without snapshots.
- domstate domain [–reason]
- Returns state about a domain. –reason tells virsh to also print reason for the state.
- domcontrol domain
- 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.
- 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.
- 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.
- domxml-to-native format xml
- Convert the file xml in domain XML format to the native guest configuration format named by 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.
- 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 them: 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).
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 domain [–inactive] [–security-info] [–update-cpu] [–migratable]
- 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.
- edit domain
- 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
except that it does some error checking.
vi domain.xml (or make changes with your other text editor)
virsh define domain.xmlThe editor used can be supplied by the $VISUAL or $EDITOR environment variables, and defaults to "vi".
- 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.
- 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 boot 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.
- 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 boot of a persistent guest. If –current is specified or –live and –config are not specified, affect the current guest state. 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”.
- 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 boot of a persistent guest. If –current is specified or –live and –config are not specified, affect the current guest state.
- 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 boot of a persistent guest. If –current is specified or –live and –config are not specified, affect the current guest state.
- 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-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 [type]
- 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.
- 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.
- 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 to store 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 [–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] domain desturi [migrateuri] [graphicsuri] [listen-address] [dname] [–timeout seconds [–timeout-suspend | –timeout-postcopy]] [–xml file] [–migrate-disks disk-list] [–disks-port port] [–compressed] [–comp-methods method-list] [–comp-mt-level] [–comp-mt-threads] [–comp-mt-dthreads] [–comp-xbzrle-cache] [–auto-converge] [auto-converge-initial] [auto-converge-increment] [–persistent-xml file] [–tls]
- 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, –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. –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.
–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.
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. Likewise, –xml file is usually omitted, but 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 –persistent is enabled, –persistent-xml file can be used to supply an alternative XML file which will be used as the persistent domain 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” and “xbzrle” and can be used in any combination. When no methods are specified, a hypervisor default methods will be used. QEMU defaults to “xbzrle”. Compression methods can be tuned further. –comp-mt-level sets compression level. 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.
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.
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:
- •
- normal migration: the desturi is an address of the target host as seen from the client machine.
- •
- peer2peer migration: the desturi is an address of the target host as seen from the source machine.
- •
- 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:
- •
- 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.
- •
- 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.
- •
- 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.
- •
- See <http://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 this feature and will return an error if this parameter is used.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.
- 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-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-setspeed domain bandwidth
- 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.
- migrate-getspeed domain
- Get the maximum migration bandwidth (in MiB/s) for a domain.
- migrate-postcopy domain
- Switch the current migration from pre-copy to post-copy. This is only supported for a migration started with –postcopy option.
- 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’ and `preferred’ 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 a mode of `strict’.
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 boot of a persistent guest. If –current is specified, affect the current guest state.
- 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 domain
- 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 state-file [–bypass-cache] [–xml file] [{–running | –paused}]
- 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, although this may slow down 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.
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.
- save domain state-file [–bypass-cache] [–xml file] [{–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, 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 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.
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 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 file [–security-info]
- 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.
- 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
except that it does some error checking.
vi state-file.xml (or make changes with your other text editor)
virsh save-image-define state-file state-file-xmlThe editor used can be supplied by the $VISUAL or $EDITOR environment variables, and defaults to "vi".
- 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, iothread_quota, iothread_period
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 boot of a persistent guest. If –current is specified, affect the current guest state.
Note: The cpu_shares parameter has a valid value range of 0-262144; Negative values are wrapped to positive, and larger values are capped at the maximum. Therefore, -1 is a useful shorthand for 262144. On the Linux kernel, the values 0 and 1 are automatically converted to a minimal value of 2.
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 1000-18446744073709551 or less than 0. The value 0 for either parameter is the same as not specifying that parameter.
- screenshot domain [imagefilepath] [–screen screenID]
- Takes a screenshot of a current domain console and stores it into a file. Optionally, if hypervisor supports more displays for a domain, screenID allows to specify 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 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.
- 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.
- xt
- The numeric values are those defined by the original XT keyboard controller. No symbolic names are provided
- 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
- atset2
- The numeric values are those defined by the AT keyboard controller, set 2. No symbolic names are provided
- atset3
- The numeric values are those defined by the AT keyboard controller, set 3 (aka PS/2 compatible set). No symbolic names are provided
- os_x
- The numeric values are those defined by the OS-X keyboard input subsystem. The symbolic names match the corresponding OS-X key constant macro names
- 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.
- win32
- The numeric values are those defined by the Win32 keyboard input subsystem. The symbolic names match the corresponding Win32 key constant macro names
- usb
- The numeric values are those defined by the USB HID specification for keyboard input. No symbolic names are provided
- rfb
- The numeric values are those defined by the RFB 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.
- linux
- 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 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",
The symbol name may optionally be prefixed with ‘sig’ or ‘sig_’ and may be in uppercase or lowercase.
"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"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
- 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 boot of a persistent guest. If –current is specified, affect the current guest state. 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.
- setmem domain size [[–config] [–live] | [–current]]
- 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.
- 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 boot of a persistent guest. If –current is specified, affect the current guest state. 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).
- 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 boot of a persistent guest. If –current is specified, affect the current guest state. 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.
- –hard-limit
- Specifying -1 as a value for these limits is interpreted as unlimited.
- 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
cmt – A PQos (Platform Qos) feature to monitor the
usage of cache by applications running on the
platform.
mbmt – Provides a way to monitor the total system
memory bandwidth between one level of cache
and another.
mbml – Provides a way to limit the amount of data
(bytes/s) send through the memory controller
on the socket.
cache_misses – Provides the count of cache misses by
applications running on the platform.
cache_references – Provides the count of cache hits by
applications running on th e platform.
instructions – Provides the count of instructions executed
by applications running on the platform.
cpu_cycles – Provides the count of cpu cycles
(total/elapsed). May be used with