The nova.virt.xenapi.vmops Module

Management class for VM-related functions (spawn, reboot, etc).

class VMOps(session, virtapi)

Bases: object

Management class for VM-related tasks.

change_instance_metadata(instance, diff)

Apply changes to instance metadata to xenstore.

check_can_live_migrate_destination(ctxt, instance_ref, block_migration=False, disk_over_commit=False)

Check if it is possible to execute live migration.

  • ctxt – security context
  • instance_ref – nova.db.sqlalchemy.models.Instance object
  • block_migration – if true, prepare for block migration if None, calculate it from driver
  • disk_over_commit – if true, allow disk over commit
check_can_live_migrate_source(ctxt, instance_ref, dest_check_data)

Check if it’s possible to execute live migration on the source side.

  • ctxt – security context
  • instance_ref – nova.db.sqlalchemy.models.Instance object
  • dest_check_data – data returned by the check on the destination, includes block_migration flag
confirm_migration(migration, instance, network_info)
destroy(instance, network_info, block_device_info=None, destroy_disks=True)

Destroy VM instance.

This is the method exposed by xenapi_conn.destroy(). The rest of the destroy_* methods are internal.

finish_migration(context, migration, instance, disk_info, network_info, image_meta, resize_instance, block_device_info=None, power_on=True)
finish_revert_migration(context, instance, block_device_info=None, power_on=True)

Return running bandwidth counter for each interface on each running VM.


Return last few lines of instance console.


Return data about VM diagnostics.

get_info(instance, vm_ref=None)

Return data about VM instance.


Return data about VM diagnostics using the common API.


Get usage info about each active instance.


Return connection info for a vnc console.

inject_file(instance, path, contents)

Write a file to the VM instance.

inject_network_info(instance, network_info, vm_ref=None)

Generate the network info and make calls to place it into the xenstore and the xenstore param list. vm_ref can be passed in because it will sometimes be different than what vm_utils.lookup(session, instance[‘name’]) will find (ex: rescue)


Get the list of nova instance uuids for VMs found on the hypervisor.


List VM instances.

live_migrate(context, instance, destination_hostname, post_method, recover_method, block_migration, migrate_data=None)
migrate_disk_and_power_off(context, instance, dest, flavor, block_device_info)

Copies a VHD from one host machine to another, possibly resizing filesystem beforehand.

  • instance – the instance that owns the VHD in question.
  • dest – the destination host machine.
  • flavor – flavor to resize to

Pause VM instance.

plug_vifs(instance, network_info)

Set up VIF networking on the host.

poll_rebooting_instances(timeout, instances)

Look for rebooting instances that can be expired.

  • issue a “hard” reboot to any instance that has been stuck in a reboot state for >= the given timeout
post_interrupted_snapshot_cleanup(context, instance)

Cleans up any resources left after a failed snapshot.

post_live_migration(context, instance, migrate_data=None)
post_live_migration_at_destination(context, instance, network_info, block_migration, block_device_info)

Power off the specified instance.


Power on the specified instance.

pre_live_migration(context, instance, block_device_info, network_info, disk_info, migrate_data)
reboot(instance, reboot_type, bad_volumes_callback=None)

Reboot VM instance.


recreates security group rules for specified instance.


recreates security group rules for every instance.

rescue(context, instance, network_info, image_meta, rescue_password)

Rescue the specified instance.

  • shutdown the instance VM.
  • set ‘bootlock’ to prevent the instance from starting in rescue.
  • spawn a rescue VM (the vm name-label will be instance-N-rescue).
reset_network(instance, rescue=False)

Calls resetnetwork method in agent.


Restore the specified instance.


Resume the specified instance.

rollback_live_migration_at_destination(instance, block_device_info)
set_admin_password(instance, new_pass)

Set the root/admin password on the VM instance.

set_bootable(instance, is_bootable)

Set the ability to power on/off an instance.

snapshot(context, instance, image_id, update_task_state)

Create snapshot from a running VM instance.

  • context – request context
  • instance – instance to be snapshotted
  • image_id – id of image to upload to

Steps involved in a XenServer snapshot:

  1. XAPI-Snapshot: Snapshotting the instance using XenAPI. This creates: Snapshot (Template) VM, Snapshot VBD, Snapshot VDI, Snapshot VHD
  2. Wait-for-coalesce: The Snapshot VDI and Instance VDI both point to a ‘base-copy’ VDI. The base_copy is immutable and may be chained with other base_copies. If chained, the base_copies coalesce together, so, we must wait for this coalescing to occur to get a stable representation of the data on disk.
  3. Push-to-data-store: Once coalesced, we call ‘image_upload_handler’ to upload the images.

Soft delete the specified instance.

spawn(context, instance, image_meta, injected_files, admin_password, network_info=None, block_device_info=None, name_label=None, rescue=False)

Suspend the specified instance.

unfilter_instance(instance_ref, network_info)

Removes filters for each VIF of the specified instance.


Unpause VM instance.

unplug_vifs(instance, network_info, vm_ref)

Unrescue the specified instance.

  • unplug the instance VM’s disk from the rescue VM.
  • teardown the rescue VM.
  • release the bootlock to allow the instance VM to start.
make_step_decorator(context, instance, update_instance_progress, total_offset=0)

Factory to create a decorator that records instance progress as a series of discrete steps.

Each time the decorator is invoked we bump the total-step-count, so after:

def step1():

def step2():

we have a total-step-count of 2.

Each time the step-function (not the step-decorator!) is invoked, we bump the current-step-count by 1, so after:


the current-step-count would be 1 giving a progress of 1 / 2 * 100 or 50%.

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