Add swap volume notifications

https://blueprints.launchpad.net/nova/+spec/add-swap-volume-notifications

Add versioned notifications when updating volume attachment (swapping volumes).

This blueprint was proposed and approved for Mitaka and Newton. It was a specless blueprint. But according to [1], if the change “needs more then one commit”, it needs a spec. So this spec is submitted.

[2][3] are patches implementing this function.

Problem description

Currently no notifications are emitted when updating volume attachment (swapping volumes). Updating volume attachment is an asynchronous operation, so it cannot be known via the API response whether it succeeds or not, when it completes.

Use Cases

Users or operators get whether the updating volume attachment operation succeeds or not and when it completes.

Proposed change

Add the following notifications.

  • instance.volume_swap.start

  • instance.volume_swap.end

  • instance.volume_swap.error

Alternatives

It is possible to know whether the operation completes or not by calling the API that lists volume attachments (nova) or get the volume status (cinder). But it is inefficient.

Data model impact

No database schema change is required.

The following new objects will be added:

@nova_base.NovaObjectRegistry.register_notification
class InstanceActionVolumeSwapPayload(InstanceActionPayload):
    VERSION = '1.0'

    fields = {
        'old_volume_id': fields.UUIDField(),
        'new_volume_id': fields.UUIDField(),
    }

@nova_base.NovaObjectRegistry.register_notification
class InstanceActionVolumeSwapNotification(base.NotificationBase):
    # Version 1.0: Initial version
    VERSION = '1.0'

    fields = {
        'payload': fields.ObjectField('InstanceActionVolumeSwapPayload')
    }

REST API impact

None

Security impact

None

Notifications impact

Add the following notifications.

  • instance.volume_swap.start

  • instance.volume_swap.end

  • instance.volume_swap.error

Notification samples are included in [2] and [3] .

Other end user impact

None

Performance Impact

None

Other deployer impact

None

Developer impact

None

Implementation

Assignee(s)

Primary assignee:

natsume-takashi

Work Items

  • Add ‘instance.volume_swap.start’ notification. [2]

  • Add ‘instance.volume_swap.end’ notification. [2]

  • Add ‘instance.volume_swap.error’ notification. [3]

Dependencies

None

Testing

Add the following tests.

  • Notification sample functional tests

Documentation Impact

Versioned notification samples will be added to the Nova developer documentation.

References

History

Note: For Mitaka and Newton, this blueprint was a specless blueprint.

Revisions

Release Name

Description

Mitaka

Approved

Newton

Reapproved

Ocata

Reproposed