Feature Support Matrix¶

When considering which capabilities should be marked as mandatory the following general guiding principles were applied

Inclusivity - people have shown ability to make effective use of a wide range of virtualization technologies with broadly varying feature sets. Aiming to keep the requirements as inclusive as possible, avoids second-guessing what a user may wish to use the cloud compute service for.
Bootstrapping - a practical use case test is to consider that starting point for the compute deploy is an empty data center with new machines and network connectivity. The look at what are the minimum features required of a compute service, in order to get user instances running and processing work over the network.
Competition - an early leader in the cloud compute service space was Amazon EC2. A sanity check for whether a feature should be mandatory is to consider whether it was available in the first public release of EC2. This had quite a narrow feature set, but none the less found very high usage in many use cases. So it serves to illustrate that many features need not be considered mandatory in order to get useful work done.
Reality - there are many virt drivers currently shipped with Nova, each with their own supported feature set. Any feature which is missing in at least one virt driver that is already in-tree, must by inference be considered optional until all in-tree drivers support it. This does not rule out the possibility of a currently optional feature becoming mandatory at a later date, based on other principles above.

Summary

Feature	Status	Hyper-V	Ironic	Libvirt KVM (aarch64)	Libvirt KVM (ppc64)	Libvirt KVM (s390x)	Libvirt KVM (x86)	Libvirt LXC	Libvirt QEMU (x86)	Libvirt Virtuozzo CT	Libvirt Virtuozzo VM	Libvirt Xen	PowerVM	VMware vCenter	zVM
Attach block volume to instance	optional	`✔`	`✖`	`✔`	`✔`	`✔`	`✔`	`✖`	`✔`	`✖`	`✔`	`✔`	`✔`	`✔`	`✖`
Attach tagged block device to instance	optional	`✖`	`✖`	`✔`	`✔`	`✔`	`✔`	`✖`	`✔`	`✖`	`✔`	`✔`	`✖`	`✖`	`✖`
Detach block volume from instance	optional	`✔`	`✖`	`✔`	`✔`	`✔`	`✔`	`✖`	`✔`	`✖`	`✔`	`✔`	`✔`	`✔`	`✖`
Extend block volume attached to instance	optional	`✖`	`✖`	`✔`	`?`	`?`	`✔`	`✖`	`✔`	`✖`	`?`	`?`	`✔`	`✖`	`✖`
Attach virtual network interface to instance	optional	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✖`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✖`
Attach tagged virtual network interface to instance	optional	`✔`	`✖`	`?`	`✔`	`✔`	`✔`	`✖`	`✔`	`✖`	`✔`	`✔`	`✖`	`✖`	`✖`
Detach virtual network interface from instance	optional	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✖`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✖`
Set the host in a maintenance mode	optional	`✖`	`✖`	`✖`	`✖`	`✖`	`✖`	`✖`	`✖`	`✖`	`✖`	`✖`	`✖`	`✖`	`✖`
Evacuate instances from a host	optional	`?`	`?`	`✔`	`?`	`✔`	`✔`	`?`	`?`	`✖`	`✖`	`?`	`✖`	`?`	`?`
Rebuild instance	optional	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✖`	`✔`	`?`
Guest instance status	mandatory	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`
Guest host uptime	optional	`✔`	`✖`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✖`	`✔`
Guest host ip	optional	`✔`	`✖`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`
Live migrate instance across hosts	optional	`✔`	`✖`	`✖`	`✔`	`✔`	`✔`	`✖`	`✔`	`✔`	`✔`	`✔`	`✖`	`✔`	`✖`
Force live migration to complete	optional	`✖`	`✖`	`✖`	`✔`	`✔`	`✔`	`✖`	`✔`	`✖`	`✖`	`✖`	`✖`	`✖`	`✖`
Abort an in-progress or queued live migration	optional	`✖`	`✖`	`✖`	`✔`	`✔`	`✔`	`✖`	`✔`	`?`	`?`	`✔`	`✖`	`✖`	`✖`
Launch instance	mandatory	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`
Stop instance CPUs (pause)	optional	`✔`	`✖`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✖`	`✔`	`✔`	`✖`	`✖`	`✔`
Reboot instance	optional	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`
Rescue instance	optional	`✔`	`✔`	`?`	`✔`	`✔`	`✔`	`✖`	`✔`	`✔`	`✔`	`✔`	`✖`	`✔`	`✖`
Resize instance	optional	`✔`	`✖`	`✔`	`✔`	`✔`	`✔`	`✖`	`✔`	`✔`	`✔`	`✔`	`✖`	`✔`	`✖`
Restore instance	optional	`✔`	`✖`	`✔`	`✔`	`✔`	`✔`	`✖`	`✔`	`✔`	`✔`	`✔`	`✖`	`✔`	`✖`
Set instance admin password	optional	`✖`	`✖`	`?`	`✖`	`✖`	`✔`	`✖`	`✔`	`✔`	`✔`	`✖`	`✖`	`✖`	`✖`
Save snapshot of instance disk	optional	`✔`	`✖`	`✔`	`✔`	`✔`	`✔`	`✖`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`
Suspend instance	optional	`✔`	`✖`	`✔`	`✔`	`✔`	`✔`	`✖`	`✔`	`✔`	`✔`	`✔`	`✖`	`✔`	`✖`
Swap block volumes	optional	`✖`	`✖`	`?`	`✔`	`✔`	`✔`	`✖`	`✔`	`✖`	`✔`	`✔`	`✖`	`✖`	`✖`
Shutdown instance	mandatory	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`
Trigger crash dump	optional	`✖`	`✔`	`?`	`✔`	`✔`	`✔`	`✖`	`✔`	`✖`	`✖`	`✖`	`✖`	`✖`	`✖`
Resume instance CPUs (unpause)	optional	`✔`	`✖`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✖`	`✖`	`✔`
uefi boot	optional	`✔`	`✔`	`✔`	`✖`	`✖`	`✔`	`✖`	`✔`	`✖`	`✖`	`✖`	`✖`	`✔`	`✖`
Device tags	optional	`✔`	`✖`	`✔`	`✔`	`✔`	`✔`	`?`	`✔`	`?`	`✔`	`✔`	`✖`	`✖`	`✖`
quiesce	optional	`✖`	`✖`	`?`	`✔`	`✔`	`✔`	`✖`	`✔`	`✖`	`✖`	`✖`	`✖`	`✖`	`✖`
unquiesce	optional	`✖`	`✖`	`?`	`✔`	`✔`	`✔`	`✖`	`✔`	`✖`	`✖`	`✖`	`✖`	`✖`	`✖`
Attach block volume to multiple instances	optional	`✖`	`✖`	`?`	`✔`	`✔`	`✔`	`✖`	`✔`	`✖`	`✔`	`✔`	`✖`	`✖`	`✖`
Attach encrypted block volume to server	optional	`✖`	`✖`	`?`	`?`	`?`	`✔`	`✖`	`✔`	`✖`	`?`	`?`	`✖`	`✖`	`✖`
Validate image with trusted certificates	optional	`✖`	`✖`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✖`	`✖`	`✖`
File backed memory	optional	`✖`	`✖`	`?`	`?`	`?`	`✔`	`✖`	`✔`	`✖`	`✖`	`✖`	`✖`	`✖`	`✖`
Report CPU traits	optional	`✖`	`✖`	`?`	`✔`	`✖`	`✔`	`✖`	`✔`	`✖`	`✖`	`✖`	`✖`	`✖`	`✖`
SR-IOV ports with resource request	optional	`✖`	`✖`	`✖`	`✖`	`✖`	`✔`	`✖`	`✔`	`✖`	`✖`	`✖`	`✖`	`✖`	`✖`
Boot instance with secure encrypted memory	optional	`✖`	`✖`	`✖`	`✖`	`✖`	`✔`	`✖`	`✖`	`✖`	`✖`	`✖`	`✖`	`✖`	`✖`
Cache base images for faster instance boot	optional	`✔`	`✖`	`✔`	`✔`	`✔`	`✔`	`?`	`✔`	`✔`	`✔`	`✔`	`✔`	`✔`	`✖`
Boot instance with an emulated trusted platform module (TPM)	optional	`✖`	`✖`	`✖`	`✖`	`✖`	`✔`	`✖`	`✔`	`✖`	`✖`	`✖`	`✖`	`✖`	`✖`

Details

Attach block volume to instance
Status: optional.

CLI commands:
- nova volume-attach <server> <volume>
Notes: The attach volume operation provides a means to hotplug additional block storage to a running instance. This allows storage capabilities to be expanded without interruption of service. In a cloud model it would be more typical to just spin up a new instance with large storage, so the ability to hotplug extra storage is for those cases where the instance is considered to be more of a pet than cattle. Therefore this operation is not considered to be mandatory to support.

Driver Support:
- Hyper-V: complete
- Ironic: missing
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: missing
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: complete
  Notes: This is not tested for every CI run. Add a “powervm:volume-check” comment to trigger a CI job running volume tests.
- VMware vCenter: complete
- zVM: missing
Attach tagged block device to instance
Status: optional.

CLI commands:
- nova volume-attach <server> <volume> [--tag <tag>]
Notes: Attach a block device with a tag to an existing server instance. See “Device tags” for more information.

Driver Support:
- Hyper-V: missing
- Ironic: missing
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: missing
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: missing
- VMware vCenter: missing
- zVM: missing
Detach block volume from instance
Status: optional.

CLI commands:
- nova volume-detach <server> <volume>
Notes: See notes for attach volume operation.

Driver Support:
- Hyper-V: complete
- Ironic: missing
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: missing
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: complete
  Notes: This is not tested for every CI run. Add a “powervm:volume-check” comment to trigger a CI job running volume tests.
- VMware vCenter: complete
- zVM: missing
Extend block volume attached to instance
Status: optional.

CLI commands:
- cinder extend <volume> <new_size>
Notes: The extend volume operation provides a means to extend the size of an attached volume. This allows volume size to be expanded without interruption of service. In a cloud model it would be more typical to just spin up a new instance with large storage, so the ability to extend the size of an attached volume is for those cases where the instance is considered to be more of a pet than cattle. Therefore this operation is not considered to be mandatory to support.

Driver Support:
- Hyper-V: missing
- Ironic: missing
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): unknown
- Libvirt KVM (s390x): unknown
- Libvirt KVM (x86): complete
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: missing
- Libvirt Virtuozzo VM: unknown
- Libvirt Xen: unknown
- PowerVM: complete
  Notes: This is not tested for every CI run. Add a “powervm:volume-check” comment to trigger a CI job running volume tests.
- VMware vCenter: missing
- zVM: missing
Attach virtual network interface to instance
Status: optional.

CLI commands:
- nova interface-attach <server>
Notes: The attach interface operation provides a means to hotplug additional interfaces to a running instance. Hotplug support varies between guest OSes and some guests require a reboot for new interfaces to be detected. This operation allows interface capabilities to be expanded without interruption of service. In a cloud model it would be more typical to just spin up a new instance with more interfaces.

Driver Support:
- Hyper-V: partial
  Notes: Works without issue if instance is off. When hotplugging, only works if using Windows/Hyper-V Server 2016 and the instance is a Generation 2 VM.
- Ironic: complete
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: complete
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: complete
- VMware vCenter: complete
- zVM: missing
Attach tagged virtual network interface to instance
Status: optional.

CLI commands:
- nova interface-attach <server> [--tag <tag>]
Notes: Attach a virtual network interface with a tag to an existing server instance. See “Device tags” for more information.

Driver Support:
- Hyper-V: complete
- Ironic: missing
- Libvirt KVM (aarch64): unknown
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: missing
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: missing
- VMware vCenter: missing
- zVM: missing
Detach virtual network interface from instance
Status: optional.

CLI commands:
- nova interface-detach <server> <port_id>
Notes: See notes for attach-interface operation.

Driver Support:
- Hyper-V: complete
  Notes: Works without issue if instance is off. When hotplugging, only works if using Windows/Hyper-V Server 2016 and the instance is a Generation 2 VM.
- Ironic: complete
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: complete
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: complete
- VMware vCenter: complete
- zVM: missing
Set the host in a maintenance mode
Status: optional.

CLI commands:
- nova host-update <host>
Notes: This operation allows a host to be placed into maintenance mode, automatically triggering migration of any running instances to an alternative host and preventing new instances from being launched. This is not considered to be a mandatory operation to support. The driver methods to implement are “host_maintenance_mode” and “set_host_enabled”.

Driver Support:
- Hyper-V: missing
- Ironic: missing
- Libvirt KVM (aarch64): missing
- Libvirt KVM (ppc64): missing
- Libvirt KVM (s390x): missing
- Libvirt KVM (x86): missing
- Libvirt LXC: missing
- Libvirt QEMU (x86): missing
- Libvirt Virtuozzo CT: missing
- Libvirt Virtuozzo VM: missing
- Libvirt Xen: missing
- PowerVM: missing
- VMware vCenter: missing
- zVM: missing
Evacuate instances from a host
Status: optional.

CLI commands:
- nova evacuate <server>
- nova host-evacuate <host>
Notes: A possible failure scenario in a cloud environment is the outage of one of the compute nodes. In such a case the instances of the down host can be evacuated to another host. It is assumed that the old host is unlikely ever to be powered back on, otherwise the evacuation attempt will be rejected. When the instances get moved to the new host, their volumes get re-attached and the locally stored data is dropped. That happens in the same way as a rebuild. This is not considered to be a mandatory operation to support.

Driver Support:
- Hyper-V: unknown
- Ironic: unknown
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): unknown
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: unknown
- Libvirt QEMU (x86): unknown
- Libvirt Virtuozzo CT: missing
- Libvirt Virtuozzo VM: missing
- Libvirt Xen: unknown
- PowerVM: missing
- VMware vCenter: unknown
- zVM: unknown
Rebuild instance
Status: optional.

CLI commands:
- nova rebuild <server> <image>
Notes: A possible use case is additional attributes need to be set to the instance, nova will purge all existing data from the system and remakes the VM with given information such as ‘metadata’ and ‘personalities’. Though this is not considered to be a mandatory operation to support.

Driver Support:
- Hyper-V: complete
- Ironic: complete
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: complete
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: complete
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: missing
- VMware vCenter: complete
- zVM: unknown
Guest instance status
Status: mandatory.

Notes: Provides realtime information about the power state of the guest instance. Since the power state is used by the compute manager for tracking changes in guests, this operation is considered mandatory to support.

Driver Support:
- Hyper-V: complete
- Ironic: complete
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: complete
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: complete
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: complete
- VMware vCenter: complete
- zVM: complete
Guest host uptime
Status: optional.

Notes: Returns the result of host uptime since power on, it’s used to report hypervisor status.

Driver Support:
- Hyper-V: complete
- Ironic: missing
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: complete
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: complete
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: complete
- VMware vCenter: missing
- zVM: complete
Guest host ip
Status: optional.

Notes: Returns the ip of this host, it’s used when doing resize and migration.

Driver Support:
- Hyper-V: complete
- Ironic: missing
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: complete
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: complete
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: complete
- VMware vCenter: complete
- zVM: complete
Live migrate instance across hosts
Status: optional.

CLI commands:
- nova live-migration <server>
- nova host-evacuate-live <host>
Notes: Live migration provides a way to move an instance off one compute host, to another compute host. Administrators may use this to evacuate instances from a host that needs to undergo maintenance tasks, though of course this may not help if the host is already suffering a failure. In general instances are considered cattle rather than pets, so it is expected that an instance is liable to be killed if host maintenance is required. It is technically challenging for some hypervisors to provide support for the live migration operation, particularly those built on the container based virtualization. Therefore this operation is not considered mandatory to support.

Driver Support:
- Hyper-V: complete
- Ironic: missing
- Libvirt KVM (aarch64): missing
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: complete
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: missing
- VMware vCenter: complete
- zVM: missing
Force live migration to complete
Status: optional.

CLI commands:
- nova live-migration-force-complete <server> <migration>
Notes: Live migration provides a way to move a running instance to another compute host. But it can sometimes fail to complete if an instance has a high rate of memory or disk page access. This operation provides the user with an option to assist the progress of the live migration. The mechanism used to complete the live migration depends on the underlying virtualization subsystem capabilities. If libvirt/qemu is used and the post-copy feature is available and enabled then the force complete operation will cause a switch to post-copy mode. Otherwise the instance will be suspended until the migration is completed or aborted.

Driver Support:
- Hyper-V: missing
- Ironic: missing
- Libvirt KVM (aarch64): missing
- Libvirt KVM (ppc64): complete
  Notes: Requires libvirt>=1.3.3, qemu>=2.5.0
- Libvirt KVM (s390x): complete
  Notes: Requires libvirt>=1.3.3, qemu>=2.5.0
- Libvirt KVM (x86): complete
  Notes: Requires libvirt>=1.3.3, qemu>=2.5.0
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
  Notes: Requires libvirt>=1.3.3, qemu>=2.5.0
- Libvirt Virtuozzo CT: missing
- Libvirt Virtuozzo VM: missing
- Libvirt Xen: missing
- PowerVM: missing
- VMware vCenter: missing
- zVM: missing
Abort an in-progress or queued live migration
Status: optional.

CLI commands:
- nova live-migration-abort <server> <migration>
Notes: Live migration provides a way to move a running instance to another compute host. But it can sometimes need a large amount of time to complete if an instance has a high rate of memory or disk page access or is stuck in queued status if there are too many in-progress live migration jobs in the queue. This operation provides the user with an option to abort in-progress live migrations. When the live migration job is still in “queued” or “preparing” status, it can be aborted regardless of the type of underneath hypervisor, but once the job status changes to “running”, only some of the hypervisors support this feature.

Driver Support:
- Hyper-V: missing
- Ironic: missing
- Libvirt KVM (aarch64): missing
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: unknown
- Libvirt Virtuozzo VM: unknown
- Libvirt Xen: complete
- PowerVM: missing
- VMware vCenter: missing
- zVM: missing
Launch instance
Status: mandatory.

Notes: Importing pre-existing running virtual machines on a host is considered out of scope of the cloud paradigm. Therefore this operation is mandatory to support in drivers.

Driver Support:
- Hyper-V: complete
- Ironic: complete
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: complete
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: complete
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: complete
- VMware vCenter: complete
- zVM: complete
Stop instance CPUs (pause)
Status: optional.

CLI commands:
- nova pause <server>
Notes: Stopping an instances CPUs can be thought of as roughly equivalent to suspend-to-RAM. The instance is still present in memory, but execution has stopped. The problem, however, is that there is no mechanism to inform the guest OS that this takes place, so upon unpausing, its clocks will no longer report correct time. For this reason hypervisor vendors generally discourage use of this feature and some do not even implement it. Therefore this operation is considered optional to support in drivers.

Driver Support:
- Hyper-V: complete
- Ironic: missing
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: complete
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: missing
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: missing
- VMware vCenter: missing
- zVM: complete
Reboot instance
Status: optional.

CLI commands:
- nova reboot <server>
Notes: It is reasonable for a guest OS administrator to trigger a graceful reboot from inside the instance. A host initiated graceful reboot requires guest co-operation and a non-graceful reboot can be achieved by a combination of stop+start. Therefore this operation is considered optional.

Driver Support:
- Hyper-V: complete
- Ironic: complete
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: complete
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: complete
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: complete
- VMware vCenter: complete
- zVM: complete
Rescue instance
Status: optional.

CLI commands:
- nova rescue <server>
Notes: The rescue operation starts an instance in a special configuration whereby it is booted from an special root disk image. The goal is to allow an administrator to recover the state of a broken virtual machine. In general the cloud model considers instances to be cattle, so if an instance breaks the general expectation is that it be thrown away and a new instance created. Therefore this operation is considered optional to support in drivers.

Driver Support:
- Hyper-V: complete
- Ironic: complete
- Libvirt KVM (aarch64): unknown
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: complete
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: missing
- VMware vCenter: complete
- zVM: missing
Resize instance
Status: optional.

CLI commands:
- nova resize <server> <flavor>
Notes: The resize operation allows the user to change a running instance to match the size of a different flavor from the one it was initially launched with. There are many different flavor attributes that potentially need to be updated. In general it is technically challenging for a hypervisor to support the alteration of all relevant config settings for a running instance. Therefore this operation is considered optional to support in drivers.

Driver Support:
- Hyper-V: complete
- Ironic: missing
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: complete
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: missing
- VMware vCenter: complete
- zVM: missing
Restore instance
Status: optional.

CLI commands:
- nova resume <server>
Notes: See notes for the suspend operation

Driver Support:
- Hyper-V: complete
- Ironic: missing
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: complete
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: missing
- VMware vCenter: complete
- zVM: missing
Set instance admin password
Status: optional.

CLI commands:
- nova set-password <server>
Notes: Provides a mechanism to (re)set the password of the administrator account inside the instance operating system. This requires that the hypervisor has a way to communicate with the running guest operating system. Given the wide range of operating systems in existence it is unreasonable to expect this to be practical in the general case. The configdrive and metadata service both provide a mechanism for setting the administrator password at initial boot time. In the case where this operation were not available, the administrator would simply have to login to the guest and change the password in the normal manner, so this is just a convenient optimization. Therefore this operation is not considered mandatory for drivers to support.

Driver Support:
- Hyper-V: missing
- Ironic: missing
- Libvirt KVM (aarch64): unknown
- Libvirt KVM (ppc64): missing
- Libvirt KVM (s390x): missing
- Libvirt KVM (x86): complete
  Notes: Requires libvirt>=1.2.16 and hw_qemu_guest_agent.
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
  Notes: Requires libvirt>=1.2.16 and hw_qemu_guest_agent.
- Libvirt Virtuozzo CT: complete
  Notes: Requires libvirt>=2.0.0
- Libvirt Virtuozzo VM: complete
  Notes: Requires libvirt>=2.0.0
- Libvirt Xen: missing
- PowerVM: missing
- VMware vCenter: missing
- zVM: missing
Save snapshot of instance disk
Status: optional.

CLI commands:
- nova image-create <server> <name>
Notes: The snapshot operation allows the current state of the instance root disk to be saved and uploaded back into the glance image repository. The instance can later be booted again using this saved image. This is in effect making the ephemeral instance root disk into a semi-persistent storage, in so much as it is preserved even though the guest is no longer running. In general though, the expectation is that the root disks are ephemeral so the ability to take a snapshot cannot be assumed. Therefore this operation is not considered mandatory to support.

Driver Support:
- Hyper-V: complete
- Ironic: missing
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: complete
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: partial
  Notes: Only cold snapshots (pause + snapshot) supported
- PowerVM: complete
  Notes: When using the localdisk disk driver, snapshot is only supported if I/O is being hosted by the management partition. If hosting I/O on traditional VIOS, we are limited by the fact that a VSCSI device can’t be mapped to two partitions (the VIOS and the management) at once.
- VMware vCenter: complete
- zVM: complete
Suspend instance
Status: optional.

CLI commands:
- nova suspend <server>
Notes: Suspending an instance can be thought of as roughly equivalent to suspend-to-disk. The instance no longer consumes any RAM or CPUs, with its live running state having been preserved in a file on disk. It can later be restored, at which point it should continue execution where it left off. As with stopping instance CPUs, it suffers from the fact that the guest OS will typically be left with a clock that is no longer telling correct time. For container based virtualization solutions, this operation is particularly technically challenging to implement and is an area of active research. This operation tends to make more sense when thinking of instances as pets, rather than cattle, since with cattle it would be simpler to just terminate the instance instead of suspending. Therefore this operation is considered optional to support.

Driver Support:
- Hyper-V: complete
- Ironic: missing
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: complete
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: missing
- VMware vCenter: complete
- zVM: missing
Swap block volumes
Status: optional.

CLI commands:
- nova volume-update <server> <attachment> <volume>
Notes: The swap volume operation is a mechanism for changing a running instance so that its attached volume(s) are backed by different storage in the host. An alternative to this would be to simply terminate the existing instance and spawn a new instance with the new storage. In other words this operation is primarily targeted towards the pet use case rather than cattle, however, it is required for volume migration to work in the volume service. This is considered optional to support.

Driver Support:
- Hyper-V: missing
- Ironic: missing
- Libvirt KVM (aarch64): unknown
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: missing
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: missing
- VMware vCenter: missing
- zVM: missing
Shutdown instance
Status: mandatory.

CLI commands:
- nova delete <server>
Notes: The ability to terminate a virtual machine is required in order for a cloud user to stop utilizing resources and thus avoid indefinitely ongoing billing. Therefore this operation is mandatory to support in drivers.

Driver Support:
- Hyper-V: complete
- Ironic: complete
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: complete
  Notes: Fails in latest Ubuntu Trusty kernel from security repository (3.13.0-76-generic), but works in upstream 3.13.x kernels as well as default Ubuntu Trusty latest kernel (3.13.0-58-generic).
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: complete
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: complete
- VMware vCenter: complete
- zVM: complete
Trigger crash dump
Status: optional.

CLI commands:
- nova trigger-crash-dump <server>
Notes: The trigger crash dump operation is a mechanism for triggering a crash dump in an instance. The feature is typically implemented by injecting an NMI (Non-maskable Interrupt) into the instance. It provides a means to dump the production memory image as a dump file which is useful for users. Therefore this operation is considered optional to support.

Driver Support:
- Hyper-V: missing
- Ironic: complete
- Libvirt KVM (aarch64): unknown
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: missing
- Libvirt Virtuozzo VM: missing
- Libvirt Xen: missing
- PowerVM: missing
- VMware vCenter: missing
- zVM: missing
Resume instance CPUs (unpause)
Status: optional.

CLI commands:
- nova unpause <server>
Notes: See notes for the “Stop instance CPUs” operation

Driver Support:
- Hyper-V: complete
- Ironic: missing
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: complete
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: complete
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: missing
- VMware vCenter: missing
- zVM: complete
uefi boot
Status: optional.

Notes: This allows users to boot a guest with uefi firmware.

Driver Support:
- Hyper-V: complete
  Notes: In order to use uefi, a second generation Hyper-V vm must be requested.
- Ironic: partial
  Notes: depends on hardware support
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): missing
- Libvirt KVM (s390x): missing
- Libvirt KVM (x86): complete
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: missing
- Libvirt Virtuozzo VM: missing
- Libvirt Xen: missing
- PowerVM: missing
- VMware vCenter: complete
- zVM: missing
Device tags
Status: optional.

CLI commands:
- nova boot
Notes: This allows users to set tags on virtual devices when creating a server instance. Device tags are used to identify virtual device metadata, as exposed in the metadata API and on the config drive. For example, a network interface tagged with “nic1” will appear in the metadata along with its bus (ex: PCI), bus address (ex: 0000:00:02.0), MAC address, and tag (nic1). If multiple networks are defined, the order in which they appear in the guest operating system will not necessarily reflect the order in which they are given in the server boot request. Guests should therefore not depend on device order to deduce any information about their network devices. Instead, device role tags should be used. Device tags can be applied to virtual network interfaces and block devices.

Driver Support:
- Hyper-V: complete
- Ironic: missing
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: unknown
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: unknown
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: missing
- VMware vCenter: missing
- zVM: missing
quiesce
Status: optional.

Notes: Quiesce the specified instance to prepare for snapshots. For libvirt, guest filesystems will be frozen through qemu agent.

Driver Support:
- Hyper-V: missing
- Ironic: missing
- Libvirt KVM (aarch64): unknown
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: missing
- Libvirt Virtuozzo VM: missing
- Libvirt Xen: missing
- PowerVM: missing
- VMware vCenter: missing
- zVM: missing
unquiesce
Status: optional.

Notes: See notes for the quiesce operation

Driver Support:
- Hyper-V: missing
- Ironic: missing
- Libvirt KVM (aarch64): unknown
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: missing
- Libvirt Virtuozzo VM: missing
- Libvirt Xen: missing
- PowerVM: missing
- VMware vCenter: missing
- zVM: missing
Attach block volume to multiple instances
Status: optional.

CLI commands:
- nova volume-attach <server> <volume>
Notes: The multiattach volume operation is an extension to the attach volume operation. It allows to attach a single volume to multiple instances. This operation is not considered to be mandatory to support. Note that for the libvirt driver, this is only supported if qemu<2.10 or libvirt>=3.10.

Driver Support:
- Hyper-V: missing
- Ironic: missing
- Libvirt KVM (aarch64): unknown
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: missing
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: missing
- VMware vCenter: missing
- zVM: missing
Attach encrypted block volume to server
Status: optional.

CLI commands:
- nova volume-attach <server> <volume>
Notes: This is the same as the attach volume operation except with an encrypted block device. Encrypted volumes are controlled via admin-configured volume types in the block storage service. Since attach volume is optional this feature is also optional for compute drivers to support.

Driver Support:
- Hyper-V: missing
- Ironic: missing
- Libvirt KVM (aarch64): unknown
- Libvirt KVM (ppc64): unknown
- Libvirt KVM (s390x): unknown
- Libvirt KVM (x86): complete
  Notes: For native QEMU decryption of the encrypted volume (and rbd support), QEMU>=2.6.0 and libvirt>=2.2.0 are required and only the “luks” type provider is supported. Otherwise both “luks” and “cryptsetup” types are supported but not natively, i.e. not all volume types are supported.
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
  Notes: The same restrictions apply as KVM x86.
- Libvirt Virtuozzo CT: missing
- Libvirt Virtuozzo VM: unknown
- Libvirt Xen: unknown
- PowerVM: missing
- VMware vCenter: missing
- zVM: missing
Validate image with trusted certificates
Status: optional.

CLI commands:
- nova boot --trusted-image-certificate-id ...
Notes: Since trusted image certification validation is configurable by the cloud deployer it is considered optional. However, it is a virt-agnostic feature so there is no good reason that all virt drivers cannot support the feature since it is mostly just plumbing user requests through the virt driver when downloading images.

Driver Support:
- Hyper-V: missing
- Ironic: missing
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: complete
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: complete
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: missing
- VMware vCenter: missing
- zVM: missing
File backed memory
Status: optional.

Notes: The file backed memory feature in Openstack allows a Nova node to serve guest memory from a file backing store. This mechanism uses the libvirt file memory source, causing guest instance memory to be allocated as files within the libvirt memory backing directory. This is only supported if qemu>2.6 and libvirt>4.0.0

Driver Support:
- Hyper-V: missing
- Ironic: missing
- Libvirt KVM (aarch64): unknown
- Libvirt KVM (ppc64): unknown
- Libvirt KVM (s390x): unknown
- Libvirt KVM (x86): complete
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: missing
- Libvirt Virtuozzo VM: missing
- Libvirt Xen: missing
- PowerVM: missing
- VMware vCenter: missing
- zVM: missing
Report CPU traits
Status: optional.

Notes: The report CPU traits feature in OpenStack allows a Nova node to report its CPU traits according to CPU mode configuration. This gives users the ability to boot instances based on desired CPU traits.

Driver Support:
- Hyper-V: missing
- Ironic: missing
- Libvirt KVM (aarch64): unknown
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): missing
- Libvirt KVM (x86): complete
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: missing
- Libvirt Virtuozzo VM: missing
- Libvirt Xen: missing
- PowerVM: missing
- VMware vCenter: missing
- zVM: missing
SR-IOV ports with resource request
Status: optional.

CLI commands:
- nova boot --nic port-id <neutron port with resource request> ...
Notes: To support neutron SR-IOV ports (vnic_type=direct or vnic_type=macvtap) with resource request the virt driver needs to include the ‘parent_ifname’ key in each subdict which represents a VF under the ‘pci_passthrough_devices’ key in the dict returned from the ComputeDriver.get_available_resource() call.

Driver Support:
- Hyper-V: missing
- Ironic: missing
- Libvirt KVM (aarch64): missing
- Libvirt KVM (ppc64): missing
- Libvirt KVM (s390x): missing
- Libvirt KVM (x86): complete
- Libvirt LXC: missing
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: missing
- Libvirt Virtuozzo VM: missing
- Libvirt Xen: missing
- PowerVM: missing
- VMware vCenter: missing
- zVM: missing
Boot instance with secure encrypted memory
Status: optional.

CLI commands:
- openstack server create <usual server create parameters>
Notes: The feature allows VMs to be booted with their memory hardware-encrypted with a key specific to the VM, to help protect the data residing in the VM against access from anyone other than the user of the VM. The Configuration and Security Guides specify usage of this feature.

Driver Support:
- Hyper-V: missing
- Ironic: missing
- Libvirt KVM (aarch64): missing
- Libvirt KVM (ppc64): missing
- Libvirt KVM (s390x): missing
- Libvirt KVM (x86): partial
  Notes: This feature is currently only available with hosts which support the SEV (Secure Encrypted Virtualization) technology from AMD.
- Libvirt LXC: missing
- Libvirt QEMU (x86): missing
- Libvirt Virtuozzo CT: missing
- Libvirt Virtuozzo VM: missing
- Libvirt Xen: missing
- PowerVM: missing
- VMware vCenter: missing
- zVM: missing
Cache base images for faster instance boot
Status: optional.

CLI commands:
- openstack server create <usual server create parameters>
Notes: Drivers supporting this feature cache base images on the compute host so that subsequent boots need not incur the expense of downloading them. Partial support entails caching an image after the first boot that uses it. Complete support allows priming the cache so that the first boot also benefits. Image caching support is tunable via config options in the [image_cache] group.

Driver Support:
- Hyper-V: partial
- Ironic: missing
- Libvirt KVM (aarch64): complete
- Libvirt KVM (ppc64): complete
- Libvirt KVM (s390x): complete
- Libvirt KVM (x86): complete
- Libvirt LXC: unknown
- Libvirt QEMU (x86): complete
- Libvirt Virtuozzo CT: complete
- Libvirt Virtuozzo VM: complete
- Libvirt Xen: complete
- PowerVM: partial
  Notes: The PowerVM driver does image caching natively when using the SSP disk driver. It does not use the config options in the [image_cache] group.
- VMware vCenter: partial
- zVM: missing
Boot instance with an emulated trusted platform module (TPM)
Status: optional.

CLI commands:
- openstack server create <usual server create parameters>
Notes: Allows VMs to be booted with an emulated trusted platform module (TPM) device. Only lifecycle operations performed by the VM owner are supported, as the user’s credentials are required to unlock the virtual device files on the host.

Driver Support:
- Hyper-V: missing
- Ironic: missing
- Libvirt KVM (aarch64): missing
- Libvirt KVM (ppc64): missing
- Libvirt KVM (s390x): missing
- Libvirt KVM (x86): partial
  Notes: Move operations are not yet supported.
- Libvirt LXC: missing
- Libvirt QEMU (x86): partial
  Notes: Move operations are not yet supported.
- Libvirt Virtuozzo CT: missing
- Libvirt Virtuozzo VM: missing
- Libvirt Xen: missing
- PowerVM: missing
- VMware vCenter: missing
- zVM: missing

Notes:

This document is a continuous work in progress

Feature Support Matrix

Feature Support Matrix¶

nova 22.4.1.dev30