Comment 86 for bug 1664931

Reviewed: https://review.openstack.org/523213
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=234ade29a39cf2d51e08157e149e0cbd0c5047be
Submitter: Zuul
Branch: stable/pike

commit 234ade29a39cf2d51e08157e149e0cbd0c5047be
Author: Matt Riedemann <email address hidden>
Date: Fri Nov 17 13:17:16 2017 -0500

    Add regression test for rebuild with new image doubling allocations

    Commit 984dd8ad6add4523d93c7ce5a666a32233e02e34 makes a rebuild
    with a new image go through the scheduler again to validate the
    image against the instance.host (we rebuild to the same host that
    the instance already lives on).

    The problem is that change introduced a regression where the
    FilterScheduler is going to think it's doing a resize to the same
    host and double the allocations for the instance (and usage for the
    compute node provider) in Placement, which is wrong since the
    flavor is the same.

    This adds a regression test to show the bug.

    NOTE(mriedem): Due to cc833359870d3962326c35094adea2f525ec8141 not
    being in Pike, we have to use the MediumFakeDriver until the bug
    is fixed. Also, the ComputeManager._get_nodename method doesn't exist
    in Pike so we have to just get the hypervisor uuid from the os-hypervisors
    API.

    Change-Id: Ie0949b4e6101f0b29ec4542146d523a07a683991
    Related-Bug: #1664931
    (cherry picked from commit cacfd372acb4eb056c4391db3c988bfe91c957df)