---
fixes:
  - |
    There had been `bug 1777591`_ that placement filters out the specified
    target host when deploying an instance by the random limitation. In
    previous releases the bug has been worked around by unlimiting the results
    from the Placement service if the target host is specified. From this
    release, the Nova scheduler uses more optimized path retrieving only the
    target host information from placement. Note that it still uses the unlimit
    workaround if a target host is specified without a specific node and
    multiple nodes are found for the target host. This can happen in some of
    the virt drivers such as the Ironic driver.

    .. _bug 1777591: https://bugs.launchpad.net/nova/+bug/1777591
