Comment 11 for bug 1784705

Reviewed: https://review.openstack.org/587921
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=cc8167a1914a70ea7b336856285df2571a754ca0
Submitter: Zuul
Branch: stable/queens

commit cc8167a1914a70ea7b336856285df2571a754ca0
Author: Matt Riedemann <email address hidden>
Date: Tue Jul 31 16:00:28 2018 -0400

    Add recreate test for RT.stats bug 1784705

    With change I6827137f35c0cb4f9fc4c6f753d9a035326ed01b in
    Ocata, we changed the ComputeManager to manage a single
    ResourceTracker and that single ResourceTracker will
    manage multiple compute nodes. The only time a single
    nova-compute service hosts multiple compute nodes is for
    ironic where there is a compute node per instance. The
    problem is the ResourceTracker.stats variable, unlike the
    ResourceTracker.compute_nodes variable, is not node-specific
    so it's possible for node stats to leak across nodes based
    on how the stats are used (and copied).

    This change adds a functional recreate test to show the issue
    before it's fixed. The fixture setup had to be tweaked a
    bit to avoid modifying class variables by reference between
    test cases.

    Conflicts:
          nova/tests/functional/compute/test_resource_tracker.py

    NOTE(mriedem): Conflicts are due to not having change
    I433700e833f97c0fec946dafc2cdda9d49e1100b or change
    I075785abcd4f4a8e180959daeadf215b9cd175c8 in Queens.

    Change-Id: Icc5f615baa1042347ec1699eb84ba0670445b995
    Related-Bug: #1784705
    (cherry picked from commit fc05626d43571733da0803df0fd9a7c69766b8fd)