Live-migration leaves instance in MIGRATING state if scheduler fails to find a host

[Hans Lindgren]

This can be easily reproduced on a single devstack install:

1. Boot an instance and wait for it to become active
2. Issue live-migration command without setting destination host to trigger scheduler host selection

Since there is just one compute node in this setup (the source node), scheduling will return a NoValidHost exception.

Expected behavior is for the instance task state to be reset to None, while the actual behavior is that it is left as MIGRATING.

The solution is to add this exception to the list of exceptions for which the instance state is reset on a failure.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/26475

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/26475
Committed: http://github.com/openstack/nova/commit/b5732a454a8221bb98cb6a7241b4d4fc17840c6a
Submitter: Jenkins
Branch: master

commit b5732a454a8221bb98cb6a7241b4d4fc17840c6a
Author: Hans Lindgren <email address hidden>
Date: Tue Apr 9 14:55:08 2013 +0200

    Catch NoValidHost exception during live-migration

    To avoid leaving the instance state as MIGRATING if scheduling of
    a target host fails, add this exception to the list of exceptions
    for which the instance task state is reset to None.

    Resolves bug 1166771.

    Change-Id: I23343091725051624c0eb0b82e9f03a7f9d5f4f4

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/grizzly
Review: https://review.openstack.org/26603

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/26603
Committed: http://github.com/openstack/nova/commit/994ed959f250b21926bfdbfe4b0bc064389d668c
Submitter: Jenkins
Branch: stable/grizzly

commit 994ed959f250b21926bfdbfe4b0bc064389d668c
Author: Hans Lindgren <email address hidden>
Date: Tue Apr 9 14:55:08 2013 +0200

    Catch NoValidHost exception during live-migration

    To avoid leaving the instance state as MIGRATING if scheduling of
    a target host fails, add this exception to the list of exceptions
    for which the instance task state is reset to None.

    Resolves bug 1166771.

    Change-Id: I23343091725051624c0eb0b82e9f03a7f9d5f4f4
    (cherry picked from commit b5732a454a8221bb98cb6a7241b4d4fc17840c6a)