Comment 17 for bug 1837955

Reviewed: https://review.opendev.org/673567
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=26ec2cbe5975f1687cce3e6b81b448ed51569cd6
Submitter: Zuul
Branch: stable/queens

commit 26ec2cbe5975f1687cce3e6b81b448ed51569cd6
Author: Matt Riedemann <email address hidden>
Date: Mon Jul 29 15:36:42 2019 -0400

    Add functional regression test for bug 1837955

    This adds a functional regression recreate test for
    bug 1837955 which was introduced with change
    Iae904afb6cb4fcea8bb27741d774ffbe986a5fb4 in the Queens
    release.

    In this scenario, the primary (and potentially alternate)
    hosts for a server build fail and reschedule to conductor.
    Eventually all alternate hosts are exhausted and specifically
    trying to claim allocations against the alternates fails,
    probably because between the time of initial scheduling and
    rescheduling something else took up the spare capacity on the
    alternate host.

    When this happens, MaxRetriesExceeded is raised but the
    instance is stuck in BUILD status rather than set to ERROR
    status with a fault message.

    NOTE(mriedem): In this backport the test is changed slighty
    since change Iea283322124cb35fc0bc6d25f35548621e8c8c2f is not
    in Queens so ProviderUsageBaseTestCase is still in test_servers.py.

    Change-Id: I4ca64dd60d883356880680fb1f04cee4136c2e00
    Related-Bug: #1837955
    (cherry picked from commit 5cc39fc51eee6e39f584394283f009aa6809d17b)
    (cherry picked from commit 0d2e27fd018e08617964dc38321ebfa8f1a5a4f9)
    (cherry picked from commit f292a92a89b452c66b5799ac309a5f623ee7b16c)