Welcome to nova-powervm’s documentation!¶

PowerVM Nova Driver¶

The IBM PowerVM hypervisor provides virtualization on POWER hardware. PowerVM admins can see benefits in their environments by making use of OpenStack. This driver (along with a Neutron ML2 compatible agent and Ceilometer agent) provides the capability for operators of PowerVM to use OpenStack natively.

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 featuresets. 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 featureset, 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

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:

  • PowerVM: complete

• 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:

  • PowerVM: missing

• Detach block volume from instance

  Status: optional.

  CLI commands:

  • nova volume-detach <server> <volume>

  Notes: See notes for attach volume operation.

  Driver Support:

  • PowerVM: complete

• 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:

  • PowerVM: partial

    Notes: Not supported for rbd volumes.

• 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:

  • PowerVM: complete

• 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:

  • PowerVM: 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:

  • PowerVM: complete

• 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:

  • PowerVM: complete

• 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:

  • PowerVM: complete

• 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:

  • PowerVM: complete

• 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:

  • PowerVM: 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:

  • PowerVM: complete

• Guest host ip

  Status: optional.

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

  Driver Support:

  • PowerVM: 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:

  • PowerVM: complete

• 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:

  • PowerVM: 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:

  • PowerVM: 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:

  • PowerVM: missing

• 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:

  • PowerVM: 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:

  • PowerVM: complete

• 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:

  • PowerVM: complete

• Restore instance

  Status: optional.

  CLI commands:

  • nova resume <server>

  Notes: See notes for the suspend operation

  Driver Support:

  • PowerVM: 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:

  • PowerVM: 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:

  • PowerVM: 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:

  • PowerVM: 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:

  • PowerVM: 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:

  • PowerVM: 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:

  • PowerVM: missing

• Resume instance CPUs (unpause)

  Status: optional.

  CLI commands:

  • nova unpause <server>

  Notes: See notes for the “Stop instance CPUs” operation

  Driver Support:

  • PowerVM: missing

• uefi boot

  Status: optional.

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

  Driver Support:

  • PowerVM: 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:

  • PowerVM: 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:

  • PowerVM: missing

• unquiesce

  Status: optional.

  Notes: See notes for the quiesce operation

  Driver Support:

  • PowerVM: 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:

  • PowerVM: missing

Notes:

• This document is a continuous work in progress

Nova-PowerVM Policies¶

In the Policies Guide, you will find documented policies for developing with Nova-PowerVM. This includes the processes we use for blueprints and specs, bugs, contributor onboarding, and other procedural items.

Developer Guide¶

In the Developer Guide, you will find information on how to develop for Nova-PowerVM and how it interacts with Nova compute. You will also find information on setup and usage of Nova-PowerVM

nova_powervm/
  virt/
    powervm/
      disk/
      tasks/
      volume/
      ...
  tests/
    virt/
      powervm/
        disk/
        tasks/
        volume/
        ...

git clone git://git.openstack.org/openstack/nova-powervm
cd nova-powervm

sudo usermod -a -G pvm_admin stacker

oslo-config-generator --namespace nova_powervm > nova_powervm_sample.conf

tox

tox -e pep8

tox -e pep8 HEAD~1

tox -e py27,py34

Example Spec - The title of your blueprint¶

Include the URL of your launchpad blueprint:

https://blueprints.launchpad.net/nova-powervm/+spec/example

Introduction paragraph – why are we doing anything? A single paragraph of prose that operators can understand. The title and this first paragraph should be used as the subject line and body of the commit message respectively.

Some notes about the nova-powervm spec and blueprint process:

• Not all blueprints need a spec. For more information see https://docs.openstack.org/nova/latest/contributor/blueprints.html#specs
• The aim of this document is first to define the problem we need to solve, and second agree the overall approach to solve that problem.
• This is not intended to be extensive documentation for a new feature. For example, there is no need to specify the exact configuration changes, nor the exact details of any DB model changes. But you should still define that such changes are required, and be clear on how that will affect upgrades.
• You should aim to get your spec approved before writing your code. While you are free to write prototypes and code before getting your spec approved, its possible that the outcome of the spec review process leads you towards a fundamentally different solution than you first envisaged.
• But, API changes are held to a much higher level of scrutiny. As soon as an API change merges, we must assume it could be in production somewhere, and as such, we then need to support that API change forever. To avoid getting that wrong, we do want lots of details about API changes upfront.

Some notes about using this template:

• Your spec should be in ReSTructured text, like this template.

• Please wrap text at 79 columns.

• The filename in the git repository should match the launchpad URL, for example: https://blueprints.launchpad.net/nova-powervm/+spec/awesome-thing should be named awesome-thing.rst

• Please do not delete any of the sections in this template. If you have nothing to say for a whole section, just write: None

• For help with syntax, see http://sphinx-doc.org/rest.html

• To test out your formatting, build the docs using tox and see the generated HTML file in doc/build/html/specs/<path_of_your_file>

• If you would like to provide a diagram with your spec, ascii diagrams are required. http://asciiflow.com/ is a very nice tool to assist with making ascii diagrams. The reason for this is that the tool used to review specs is based purely on plain text. Plain text will allow review to proceed without having to look at additional files which can not be viewed in gerrit. It will also allow inline feedback on the diagram itself.

• If your specification proposes any changes to the Nova REST API such as changing parameters which can be returned or accepted, or even the semantics of what happens when a client calls into the API, then you should add the APIImpact flag to the commit message. Specifications with the APIImpact flag can be found with the following query:

  https://review.openstack.org/#/q/status:open+project:openstack/nova-powervm+message:apiimpact,n,z

Nova-PowerVM Specifications¶

Contents:

total: 1
reserved: 0
min_unit: 1
max_unit: 1
step_size: 1
allocation_ratio: 1.0

resources:VCPU=1
resources:MEMORY_MB=2048
resources:DISK_GB=100
resources1:CUSTOM_GPU=1
traits1:CUSTOM_POWERVM_IOSLOT_VENDOR_ID_G00D=required
traits1:CUSTOM_POWERVM_IOSLOT_PRODUCT_ID_F00D=required
resources2:CUSTOM_GPU=1
traits2:CUSTOM_POWERVM_IOSLOT_DRC_INDEX_1C0FFEE1=required