Comment 9 for bug 1408527

Reviewed: https://review.openstack.org/256059
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=b7f83337658181f0e7117c7f3b07f69856ffe405
Submitter: Jenkins
Branch: master

commit b7f83337658181f0e7117c7f3b07f69856ffe405
Author: ankitagrawal <email address hidden>
Date: Wed Sep 23 03:58:19 2015 -0700

    Detach volume after deleting instance with no host

    If an instance is booted from a volume, shelved, and goes into an error
    state due to some reason, the volume from which instance is booted
    remains even the instance is deleted because instance has no host
    associated with it.

    Called _local_delete() to detach volume and destroy bdm if instance is
    in shelved_offloaded state or has no host associated with it. This will
    cleanup both volumes and the networks.

    Note:
    Ankit had submitted same patch [1] earlier which was reverted [2] due
    to a race condition on jenkins if an instance is deleted when it is in
    building state. The patch was then rebumitted [3] fixing the
    the failure of race condition by reverting the ObjectActionError
    exception handling in _delete. This patch was later re-reverted [4]
    due to continued jenkins race conditions.

    The current patch avoids the jenkins race condition by leaving the flow
    for instances in the BUILDING state unchanged and only calling
    _local_delete() on instances in the shelved_offloaded or error states
    when the instance has no host associated with it. This addresses the
    concerns of the referenced bugs.

    [1] Ic630ae7d026a9697afec46ac9ea40aea0f5b5ffb
    [2] Id4e405e7579530ed1c1f22ccc972d45b6d185f41
    [3] Ic107d8edc7ee7a4ebb04eac58ef0cdbf506d6173
    [4] Ibcbe35b5d329b183c4d0e8233e8ada26ebc512c2

    Co-Authored-By: Ankit Agrawal <email address hidden>

    Closes-Bug: 1404867
    Closes-Bug: 1408527

    Change-Id: I928a397c75b857e94bf5c002e50ec43a2bed9848