Comment 11 for bug 1408527

Reviewed: https://review.openstack.org/335697
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=5ce74fa06c0e7a70fdc927b2c1f364af83f7de1d
Submitter: Jenkins
Branch: master

commit 5ce74fa06c0e7a70fdc927b2c1f364af83f7de1d
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 patch [5] intended to avoid 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. It however also had
    to be reverted [6] because of yet another race condition.

    This version takes a more minimal approach of adding the ERROR state
    to the logic for doing a local delete plus cleanup of resources on
    a compute host. Comments have also been added to the existing code
    to explain more about the different flows.

    [1] Ic630ae7d026a9697afec46ac9ea40aea0f5b5ffb
    [2] Id4e405e7579530ed1c1f22ccc972d45b6d185f41
    [3] Ic107d8edc7ee7a4ebb04eac58ef0cdbf506d6173
    [4] Ibcbe35b5d329b183c4d0e8233e8ada26ebc512c2
    [5] I928a397c75b857e94bf5c002e50ec43a2bed9848
    [6] I6b9b886e0d6f2ec86141c048fb50969bccf5cb30

    Co-Authored-By: Ankit Agrawal <email address hidden>
    Co-Authored-By: Samuel Matzek <email address hidden>
    Co-Authored-By: melanie witt <email address hidden>

    Closes-Bug: 1404867
    Closes-Bug: 1408527

    Change-Id: I2192ef513a2cd15d21e9d5d5fe22c5a5fbae0941