Comment 69 for bug 1664931

Reviewed: https://review.openstack.org/519684
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=97a51d981bd603b964b04b3568218ce57ac57338
Submitter: Zuul
Branch: stable/newton

commit 97a51d981bd603b964b04b3568218ce57ac57338
Author: Matt Riedemann <email address hidden>
Date: Fri Oct 27 16:03:15 2017 -0400

    Validate new image via scheduler during rebuild

    During a rebuild we bypass the scheduler because we are
    always rebuilding the instance on the same host it's already
    on. However, we allow passing a new image during rebuild
    and that new image needs to be validated to work with the
    instance host by running it through the scheduler filters,
    like the ImagePropertiesFilter. Otherwise the new image
    could violate constraints placed on the host by the admin.

    This change checks to see if there is a new image provided
    and if so, modifies the request spec passed to the scheduler
    so that the new image is validated all while restricting
    the scheduler to still pick the same host that the instance
    is running on. If the image is not valid for the host, the
    scheduler will raise NoValidHost and the rebuild stops.

    A functional test is added to show the recreate of the bug
    and that we probably stop the rebuild now in conductor by
    calling the scheduler to validate the image.

    Co-Authored-By: Sylvain Bauza <email address hidden>

    Closes-Bug: #1664931

    NOTE(mriedem): There were a few changes needed for Newton:

    1. There is no PlacementFixture but it's not needed.
    2. The API client needs to have the microversion set from
       the test.
    3. The enabled_filters config option wasn't in Newton.
    4. The scheduler has to be started before compute otherwise
       we get a MessagingTimeout due to the CastAsCall fixture
       during the compute startup.

    Depends-On: I344d8fdded9b7d5385fcb41b699f1352acb4cda7

    Change-Id: I11746d1ea996a0f18b7c54b4c9c21df58cc4714b
    (cherry picked from commit 984dd8ad6add4523d93c7ce5a666a32233e02e34)
    (cherry picked from commit 9e2d63da94db63d97bd02e373bfc53d95808b833)
    (cherry picked from commit b72105c1c49fcddc94992af63fc2f8078023491a)