Sys::Virt::Domain - Represent & manage a libvirt guest domain

The Sys::Virt::Domain module represents a guest domain managed by the virtual machine monitor.

my $id = $dom->get_id()

Returns an integer with a locally unique identifier for the domain.

my $uuid = $dom->get_uuid()

Returns a 16 byte long string containing the raw globally unique identifier (UUID) for the domain.

my $uuid = $dom->get_uuid_string()

Returns a printable string representation of the raw UUID, in the format 'XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX'.

my $name = $dom->get_name()

Returns a string with a locally unique name of the domain

$dom->is_active()

Returns a true value if the domain is currently running

$dom->is_persistent()

Returns a true value if the domain has a persistent configuration file defined

$dom->is_updated()

Returns a true value if the domain is running and has a persistent configuration file defined that is out of date compared to the current live config.

my $xml = $dom->get_xml_description()

Returns an XML document containing a complete description of the domain's configuration

my $type = $dom->get_os_type()

Returns a string containing the name of the OS type running within the domain.

$dom->create($flags)

Start a domain whose configuration was previously defined using the define_domain method in Sys::Virt. The $flags parameter accepts one of the DOMAIN CREATION constants documented later, and defaults to 0 if omitted.

$dom->undefine()

Remove the configuration associated with a domain previously defined with the define_domain method in Sys::Virt. If the domain is running, you probably want to use the shutdown or destroy methods instead.

$dom->suspend()

Temporarily stop execution of the domain, allowing later continuation by calling the resume method.

$dom->resume()

Resume execution of a domain previously halted with the suspend method.

$dom->save($filename)

Take a snapshot of the domain's state and save the information to the file named in the $filename parameter. The domain can later be restored from this file with the restore_domain method on the Sys::Virt object.

$dom->managed_save($flags=0)

Take a snapshot of the domain's state and save the information to a managed save location. The domain will be automatically restored with this state when it is next started. The $flags parameter is unused and defaults to zero.

$bool = $dom->has_managed_save_image($flags=0)

Return a non-zero value if the domain has a managed save image that will be used at next start. The $flags parameter is unused and defaults to zero.

$dom->managed_save_remove($flags=0)

Remove the current managed save image, causing the guest to perform a full boot next time it is started. The $flags parameter is unused and defaults to zero.

$dom->core_dump($filename[, $flags])

Trigger a core dump of the guest virtual machine, saving its memory image to $filename so it can be analysed by tools such as crash. The optional $flags flags parameter is currently unused and if omitted will default to 0.

$dom->destroy()

Immediately terminate the machine, and remove it from the virtual machine monitor. The $dom handle is invalid after this call completes and should not be used again.

my $info = $dom->get_info()

Returns a hash reference summarising the execution state of the domain. The elements of the hash are as follows:

maxMem

The maximum memory allowed for this domain, in kilobytes

memory

The current memory allocated to the domain in kilobytes

cpuTime

The amount of CPU time used by the domain

nrVirtCpu

The current number of virtual CPUs enabled in the domain

state

The execution state of the machine, which will be one of the constants &Sys::Virt::Domain::STATE_*.

my $info = $dom->get_block_info($dev, $flags=0)

Returns a hash reference summarising the disk usage of the host backing store for a guest block device. The $dev parameter should be the path to the backing store on the host. $flags is currently unused and defaults to 0 if omitted. The returned hash contains the following elements

capacity

Logical size in bytes of the block device backing image *

allocation

Highest allocated extent in bytes of the block device backing image

physical

Physical size in bytes of the container of the backing image

$dom->set_max_memory($mem)

Set the maximum memory for the domain to the value $mem. The value of the $mem parameter is specified in kilobytes.

$mem = $dom->get_max_memory()

Returns the current maximum memory allowed for this domain in kilobytes.

$dom->set_memory($mem, $flags)

Set the current memory for the domain to the value $mem. The value of the $mem parameter is specified in kilobytes. This must be less than, or equal to the domain's max memory limit. The $flags parameter can control whether the update affects the live guest, or inactive config, defaulting to modifying the current state.

$dom->shutdown()

Request that the guest OS perform a graceful shutdown and poweroff.

$dom->reboot([$flags])

Request that the guest OS perform a graceful shutdown and optionally restart. The optional $flags parameter is currently unused and if omitted defaults to zero.

$dom->get_max_vcpus()

Return the maximum number of vcpus that are configured for the domain

$dom->attach_device($xml[, $flags])

Hotplug a new device whose configuration is given by $xml, to the running guest. The optional <$flags> parameter defaults to 0, but can accept one of the device hotplug flags described later.

$dom->detach_device($xml[, $flags])

Hotunplug a existing device whose configuration is given by $xml, from the running guest. The optional <$flags> parameter defaults to 0, but can accept one of the device hotplug flags described later.

$dom->update_device($xml[, $flags])

Update the configuration of an existing device. The new configuration is given by $xml. The optional <$flags> parameter defaults to 0 but can accept one of the device hotplug flags described later.

$data = $dom->block_peek($path, $offset, $size[, $flags)

Peek into the guest disk $path, at byte $offset capturing $size bytes of data. The returned scalar may contain embedded NULLs. The optional $flags parameter is currently unused and if omitted defaults to zero.

$data = $dom->memory_peek($offset, $size[, $flags])

Peek into the guest memory at byte $offset virtual address, capturing $size bytes of memory. The return scalar may contain embedded NULLs. The optional $flags parameter is currently unused and if omitted defaults to zero.

$flag = $dom->get_autostart();

Return a true value if the guest domain is configured to automatically start upon boot. Return false, otherwise

$dom->set_autostart($flag)

Set the state of the autostart flag, which determines whether the guest will automatically start upon boot of the host OS

$dom->set_vcpus($count, [$flags])

Set the number of virtual CPUs in the guest VM to $count. The optional $flags parameter can be used to control whether the setting changes the live config or inactive config.

$count = $dom->get_vcpus([$flags])

Get the number of virtual CPUs in the guest VM. The optional $flags parameter can be used to control whether to query the setting of the live config or inactive config.

$type = $dom->get_scheduler_type()

Return the scheduler type for the guest domain

%stats = $dom->block_stats($path)

Fetch the current I/O statistics for the block device given by $path. The returned hash containins keys for

my %params = $dom->get_scheduler_parameters()

Return the set of scheduler tunable parameters for the guest.

$dom->set_scheduler_parameters($params)

Update the set of scheduler tunable parameters. The value names for tunables vary, and can be discovered using the get_scheduler_params call

my $params = $dom->get_memory_parameters()

Return a hash reference containing the set of memory tunable parameters for the guest. The keys in the hash are one of the constants MEMORY PARAMETERS described later.

$dom->set_memory_parameters($params)

Update the memory tunable parameters for the guest. The $params should be a hash reference whose keys are one of the MEMORY PARAMETERS constants.

rd_req

Number of read requests

rd_bytes

Number of bytes read

wr_req

Number of write requests

wr_bytes

Number of bytes written

errs

Some kind of error count

my $params = $dom->get_blkio_parameters()

Return a hash reference containing the set of blkio tunable parameters for the guest. The keys in the hash are one of the constants BLKIO PARAMETERS described later.

$dom->set_blkio_parameters($params)

Update the blkio tunable parameters for the guest. The $params should be a hash reference whose keys are one of the BLKIO PARAMETERS constants.

weight

Relative I/O weighting

$dom->interface_stats($path)

Fetch the current I/O statistics for the block device given by $path. The returned hash containins keys for

rx_bytes

Total bytes received

rx_packets

Total packets received

rx_errs

Total packets received with errors

rx_drop

Total packets drop at reception

tx_bytes

Total bytes transmitted

tx_packets

Total packets transmitted

tx_errs

Total packets transmitted with errors

tx_drop

Total packets dropped at transmission.

$dom->memory_stats($flags=0)

Fetch the current memory statistics for the guest domain. The $flags parameter is currently unused and can be omitted. The returned hash containins keys for

swap_in

Data read from swap space

swap_out

Data written to swap space

major_fault

Page fault involving disk I/O

minor_fault

Page fault not involving disk I/O

unused

Memory not used by the system

available

Total memory seen by guest

%info = $dom->get_security_label()

Fetch information about the security label assigned to the guest domain. The returned hash has two keys, model gives the name of the security model in effect (eg selinux), while label provides the name of the security label applied to the domain.

$ddom = $dom->migrate(destcon, flags, dname, uri, bandwidth)

Migrate a domain to an alternative host. The destcon parameter should be a Sys::Virt connection to the remote target host. If the flags parameter is zero offline migration will be performed. The Sys::Virt::Domain::MIGRATE_LIVE constant can be used to request live migration. The dname parameter allows the guest to be renamed on the target host, if set to undef, the domains' current name will be maintained. In normal circumstances, the source host determines the target hostname from the URI associated with the destcon connection. If the destination host is multi-homed it may be necessary to supply an alternate destination hostame via the uri parameter. The bandwidth parameter allows network usage to be throttled during migration. If set to zero, no throttling will be performed. The flags, dname, uri and bandwidth parameters are all optional, and if omitted default to zero, undef, undef, and zero respectively.

$dom->migrate_to_uri(desturi, flags, dname, bandwidth)

Migrate a domain to an alternative host. The destri parameter should be a valid libvirt connection URI for the remote target host. If the flags parameter is zero offline migration will be performed. The Sys::Virt::Domain::MIGRATE_LIVE constant can be used to request live migration. The dname parameter allows the guest to be renamed on the target host, if set to undef, the domains' current name will be maintained. In normal circumstances, the source host determines the target hostname from the URI associated with the destcon connection. If the destination host is multi-homed it may be necessary to supply an alternate destination hostame via the uri parameter. The bandwidth parameter allows network usage to be throttled during migration. If set to zero, no throttling will be performed. The flags, dname and bandwidth parameters are all optional, and if omitted default to zero, undef, undef, and zero respectively.

$dom->migrate_set_max_downtime($downtime, $flags)

Set the maximum allowed downtime during migration of the guest. A longer downtime makes it more likely that migration will complete, at the cost of longer time blackout for the guest OS at the switch over point. The downtime parameter is measured in milliseconds. The $flags parameter is currently unused and defaults to zero.

$dom->migrate_set_max_speed($bandwidth, $flags)

Set the maximum allowed bandwidth during migration of the guest. The bandwidth parameter is measured in kilobytes/second. The $flags parameter is currently unused and defaults to zero.

@vcpuinfo = $dom->get_vcpu_info()

Obtain information about the state of all virtual CPUs in a running guest domain. The returned list will have one element for each vCPU, where each elements contains a hash reference. The keys in the hash are, number the vCPU number, cpu the physical CPU on which the vCPU is currently scheduled, cpuTime the cummulative execution time of the vCPU, state the running state and affinity giving the allowed shedular placement. The value for affinity is a string representing a bitmask against physical CPUs, 8 cpus per character.

$dom->pin_vcpu($vcpu, $mask)

Ping the virtual CPU given by index $vcpu to physical CPUs given by $mask. The $mask is a string representing a bitmask against physical CPUs, 8 cpus per character.

my $info = $dom->get_job_info()

Returns a hash reference summarising the execution state of the background job. The elements of the hash are as follows:

$dom->abort_job()

Aborts the currently executing job

$count = $dom->num_of_snapshots()

Return the number of saved snapshots of the domain

@names = $dom->list_snapshot_names()

List the names of all saved snapshots. The names can be used with the lookup_snapshot_by_name

@snapshots = $dom->list_snapshots()

Return a list of all snapshots currently known to the domain. The elements in the returned list are instances of the Sys::Virt::DomainSnapshot class.

$dom->has_current_snapshot()

Returns a true value if the domain has a currently active snapshot

$snapshot = $dom->current_snapshot()

Returns the currently active snapshot for the domain.

type

The type of job, one of the JOB TYPE constants listed later in this document.

timeElapsed

The elapsed time in milliseconds

timeRemaining

The expected remaining time in milliseconds. Only set if the type is JOB_UNBOUNDED.

dataTotal

The total amount of data expected to be processed by the job, in bytes.

dataProcessed

The current amount of data processed by the job, in bytes.

dataRemaining

The expected amount of data remaining to be processed by the job, in bytes.

memTotal

The total amount of mem expected to be processed by the job, in bytes.

memProcessed

The current amount of mem processed by the job, in bytes.

memRemaining

The expected amount of mem remaining to be processed by the job, in bytes.

fileTotal

The total amount of file expected to be processed by the job, in bytes.

fileProcessed

The current amount of file processed by the job, in bytes.

fileRemaining

The expected amount of file remaining to be processed by the job, in bytes.

A number of the APIs take a flags parameter. In most cases passing a value of zero will be satisfactory. Some APIs, however, accept named constants to alter their behaviour. This section documents the current known constants.

The domain state constants are useful in interpreting the state key in the hash returned by the get_info method.

Sys::Virt::Domain::STATE_NOSTATE

The domain is active, but is not running / blocked (eg idle)

Sys::Virt::Domain::STATE_RUNNING

The domain is active and running

Sys::Virt::Domain::STATE_BLOCKED

The domain is active, but execution is blocked

Sys::Virt::Domain::STATE_PAUSED

The domain is active, but execution has been paused

Sys::Virt::Domain::STATE_SHUTDOWN

The domain is active, but in the shutdown phase

Sys::Virt::Domain::STATE_SHUTOFF

The domain is inactive, and shut down.

Sys::Virt::Domain::STATE_CRASHED

The domain is inactive, and crashed.

The following constants can be used to control the behaviour of domain creation

Sys::Virt::Domain::START_PAUSED

Keep the guest vCPUs paused after starting the guest

The following constants can be used with the memory_peek method's flags parameter

Sys::Virt::Domain::MEMORY_VIRTUAL

Indicates that the offset is using virtual memory addressing.

The following constants are useful when interpreting the virtual CPU run state

Sys::Virt::Domain::VCPU_OFFLINE

The virtual CPU is not online

Sys::Virt::Domain::VCPU_RUNNING

The virtual CPU is executing code

Sys::Virt::Domain::VCPU_BLOCKED

The virtual CPU is waiting to be scheduled

The following constants are used to control the information included in the XML configuration dump

Sys::Virt::Domain::XML_INACTIVE

Report the persistent inactive configuration for the guest, even if it is currently running.

Sys::Virt::Domain::XML_SECURE

Include security sensitive information in the XML dump, such as passwords.

The following constants are used to control device hotplug operations

Sys::Virt::Domain::DEVICE_MODIFY_CURRENT

Modify the domain in its current state

Sys::Virt::Domain::DEVICE_MODIFY_LIVE

Modify only the live state of the domain

Sys::Virt::Domain::DEVICE_MODIFY_CONFIG

Modify only the persistent config of the domain

The following constants are used to control memory change operations

Sys::Virt::Domain::MEM_LIVE

Modify only the live state of the domain

Sys::Virt::Domain::MEM_CONFIG

Modify only the persistent config of the domain

The following constants are used to control how migration is performed

Sys::Virt::Domain::MIGRATE_LIVE

Migrate the guest without interrupting its execution on the source host.

Sys::Virt::Domain::MIGRATE_PEER2PEER

Manage the migration process over a direct peer-2-peer connection between the source and destination host libvirtd daemons.

Sys::Virt::Domain::MIGRATE_TUNNELLED

Tunnel the migration data over the libvirt daemon connection, rather than the native hypervisor data transport. Requires PEER2PEER flag to be set.

Sys::Virt::Domain::MIGRATE_PERSIST_DEST

Make the domain persistent on the destination host, defining its configuration file upon completion of migration.

Sys::Virt::Domain::MIGRATE_UNDEFINE_SOURCE

Remove the domain's persistent configuration after migration completes successfully.

Sys::Virt::Domain::MIGRATE_PAUSED

Do not re-start execution of the guest CPUs on the destination host after migration completes.

The following constants describe the different background job types.

Sys::Virt::Domain::JOB_NONE

No job is active

Sys::Virt::Domain::JOB_BOUNDED

A job with a finite completion time is active

Sys::Virt::Domain::JOB_UNBOUNDED

A job with an unbounded completion time is active

Sys::Virt::Domain::JOB_COMPLETED

The job has finished, but isn't cleaned up

Sys::Virt::Domain::JOB_FAILED

The job has hit an error, but isn't cleaned up

Sys::Virt::Domain::JOB_CANCELLED

The job was aborted at user request, but isn't cleaned up

The following constants are useful when getting/setting memory parameters for guests

Sys::Virt::Domain::MEMORY_HARD_LIMIT

The maximum memory the guest can use.

Sys::Virt::Domain::MEMORY_SOFT_LIMIT

The memory upper limit enforced during memory contention.

Sys::Virt::Domain::MEMORY_MIN_GUARANTEE

The minimum memory guaranteed to be reserved for the guest.

Sys::Virt::Domain::MEMORY_SWAP_HARD_LIMIT

The maximum swap the guest can use.

Sys::Virt::Domain::MEMORY_PARAM_UNLIMITED

The value of an unlimited memory parameter

Sys::Virt::Domain::BLKIO_WEIGHT

The I/O weight parameter

The following constants are useful when getting/setting the VCPU count for a guest

Sys::Virt::Domain::VCPU_LIVE

Flag to request the live value

Sys::Virt::Domain::VCPU_CONFIG

Flag to request the persistent config value

The following constants allow domain state change events to be interpreted. The events contain both a state change, and a reason.

Sys::Virt::Domain::EVENT_DEFINED

Indicates that a persistent configuration has been defined for the domain.

Sys::Virt::Domain::EVENT_DEFINED_ADDED

The defined configuration is newly added

Sys::Virt::Domain::EVENT_DEFINED_UPDATED

The defined configuration is an update to an existing configuration

Sys::Virt::Domain::EVENT_RESUMED

The domain has resumed execution

Sys::Virt::Domain::EVENT_RESUMED_MIGRATED

The domain resumed because migration has completed. This is emitted on the destination host.

Sys::Virt::Domain::EVENT_RESUMED_UNPAUSED

The domain resumed because the admin unpaused it.

Sys::Virt::Domain::EVENT_STARTED

The domain has started running

Sys::Virt::Domain::EVENT_STARTED_BOOTED

The domain was booted from shutoff state

Sys::Virt::Domain::EVENT_STARTED_MIGRATED

The domain started due to an incoming migration

Sys::Virt::Domain::EVENT_STARTED_RESTORED

The domain was restored from saved state file

Sys::Virt::Domain::EVENT_STOPPED

The domain has stopped running

Sys::Virt::Domain::EVENT_STOPPED_CRASHED

The domain stopped because guest operating system has crashed

Sys::Virt::Domain::EVENT_STOPPED_DESTROYED

The domain stopped because administrator issued a destroy command.

Sys::Virt::Domain::EVENT_STOPPED_FAILED

The domain stopped because of a fault in the host virtualization environment.

Sys::Virt::Domain::EVENT_STOPPED_MIGRATED

The domain stopped because it was migrated to another machine.

Sys::Virt::Domain::EVENT_STOPPED_SAVED

The domain was saved to a state file

Sys::Virt::Domain::EVENT_STOPPED_SHUTDOWN

The domain stopped due to graceful shutdown of the guest.

Sys::Virt::Domain::EVENT_SUSPENDED

The domain has stopped executing, but still exists

Sys::Virt::Domain::EVENT_SUSPENDED_MIGRATED

The domain has been suspended due to offline migration

Sys::Virt::Domain::EVENT_SUSPENDED_PAUSED

The domain has been suspended due to administrator pause request.

Sys::Virt::Domain::EVENT_UNDEFINED

The persistent configuration has gone away

Sys::Virt::Domain::EVENT_UNDEFINED_REMOVED

The domain configuration has gone away due to it being removed by administrator.

Sys::Virt::Domain::EVENT_ID_LIFECYCLE

Domain lifecycle events

Sys::Virt::Domain::EVENT_ID_REBOOT

Soft / warm reboot events

Sys::Virt::Domain::EVENT_ID_RTC_CHANGE

RTC clock adjustments

Sys::Virt::Domain::EVENT_ID_IO_ERROR

File IO errors, typically from disks

Sys::Virt::Domain::EVENT_ID_WATCHDOG

Watchdog device triggering

Sys::Virt::Domain::EVENT_ID_GRAPHICS

Graphics client connections.

Sys::Virt::Domain::EVENT_ID_IO_ERROR_REASON

File IO errors, typically from disks, with a root cause

These constants describe what action was taken due to the IO error.

Sys::Virt::Domain::EVENT_IO_ERROR_NONE

No action was taken, the error was ignored & reported as success to guest

Sys::Virt::Domain::EVENT_IO_ERROR_PAUSE

The guest is paused since the error occurred

Sys::Virt::Domain::EVENT_IO_ERROR_REPORT

The error has been reported to the guest OS

These constants describe what action was taken due to the watchdog firing

Sys::Virt::Domain::EVENT_WATCHDOG_NONE

No action was taken, the watchdog was ignored

Sys::Virt::Domain::EVENT_WATCHDOG_PAUSE

The guest is paused since the watchdog fired

Sys::Virt::Domain::EVENT_WATCHDOG_POWEROFF

The guest is powered off after the watchdog fired

Sys::Virt::Domain::EVENT_WATCHDOG_RESET

The guest is reset after the watchdog fired

Sys::Virt::Domain::EVENT_WATCHDOG_SHUTDOWN

The guest attempted to gracefully shutdown after the watchdog fired

Sys::Virt::Domain::EVENT_WATCHDOG_DEBUG

No action was taken, the watchdog was logged

These constants describe the phase of the graphics connection

Sys::Virt::Domain::EVENT_GRAPHICS_CONNECT

The initial client connection

Sys::Virt::Domain::EVENT_GRAPHICS_INITIALIZE

The client has been authenticated & the connection is running

Sys::Virt::Domain::EVENT_GRAPHICS_DISCONNECT

The client has disconnected

These constants describe the format of the address

Sys::Virt::Domain::EVENT_GRAPHICS_ADDRESS_IPV4

An IPv4 address

Sys::Virt::Domain::EVENT_GRAPHICS_ADDRESS_IPV6

An IPv6 address

Daniel P. Berrange <berrange@redhat.com>

Copyright (C) 2006 Red Hat Copyright (C) 2006-2007 Daniel P. Berrange

This program is free software; you can redistribute it and/or modify it under the terms of either the GNU General Public License as published by the Free Software Foundation (either version 2 of the License, or at your option any later version), or, the Artistic License, as specified in the Perl README file.

Sys::Virt, Sys::Virt::Error, http://libvirt.org