Comment 10 for bug 1721652

Reviewed: https://review.openstack.org/511759
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=1657b8721d82056cb6e9b2ec7ae7690ca215cb14
Submitter: Zuul
Branch: stable/pike

commit 1657b8721d82056cb6e9b2ec7ae7690ca215cb14
Author: Balazs Gibizer <email address hidden>
Date: Fri Oct 6 18:25:17 2017 +0200

    Reproduce bug 1721652 in the functional test env

    When bug 1709902 was fixed in I0df401a7c91f012fdb25cb0e6b344ca51de8c309
    the fix assumed that when the _destroy_evacuated_instances() is called
    during the init of the nova-compute service the resource tracker
    already knows the compute node ids associated to the given compute
    host. This is not true and therefore _destroy_evacuated_instances fails
    with an exception and does not clean up the evacuated instance.

    The solution for the original bug included a functional regression
    test. However the functional test env is not capable of fully simulate
    a nova-compute service restart. The service only stopped then started
    again. This allows some in memory state of the compute service to
    survive the simulated restart. This caused that the functional test
    was not able to catch that the above described assumption is not
    correct.

    Related-Bug: #1721652
    Related-Bug: #1709902
    Change-Id: Icaf1bae8cb040b939f916a19ce026031ddb84af7
    (cherry picked from commit a3c556963eaf408a29b27a1f6fc44bc424e48efc)