Comment 8 for bug 1827628

Reviewed: https://review.opendev.org/659239
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=c094a6ef0c220ace7f717a07bef6fbd87a019190
Submitter: Zuul
Branch: stable/stein

commit c094a6ef0c220ace7f717a07bef6fbd87a019190
Author: Surya Seetharaman <email address hidden>
Date: Thu May 9 16:22:13 2019 +0200

    Disable limit if affinity(anti)/same(different)host is requested

    When max_placement_results is less than the total number of nodes in
    a deployment it may not be possible to use the affinity, anti-affinity,
    same host or different host filters as there is no guarantee
    for placement to return the expected hosts under such situations. This
    patch disables the max_placement_results parameter when nova queries
    placement for ``GET /allocation_candidates`` if the
    request_spec.scheduler_hints containts any of group, same_host or
    different_host keys.

    Note that due to change If7ea02df42d220c5042947efdef4777509492a0b only
    being in Train the test in the backport calls resources_from_request_spec
    without the context or fake HostManager parameters.

    Change-Id: Ia2d5f80b6db59a8f6da03344aeaa6aa599407672
    Closes-Bug: #1827628
    (cherry picked from commit 2f9e972ba3358fc5bc9bdc06faf47b21d509e20f)