Comment 5 for bug 1854730

Reviewed: https://review.opendev.org/698274
Committed: https://git.openstack.org/cgit/openstack/tripleo-heat-templates/commit/?id=44b6e6b8520bc9660dd1c6ac44d91523c7c7c84a
Submitter: Zuul
Branch: stable/train

commit 44b6e6b8520bc9660dd1c6ac44d91523c7c7c84a
Author: Damien Ciabrini <email address hidden>
Date: Mon Dec 2 13:01:45 2019 +0100

    HA: minor update of arbitrary container image name

    HA services get their container image name from a pacemaker
    resource configuration. This image name is shared between
    all cluster nodes.

    To achieve image update without service disruption, a pacemaker
    resource is configured to use an intermediate image name
    "<registry>/<namespace>/<servicename>:pcmklatest" pointing to
    the real image name configured in Heat. This tag can then be
    updated independently on every node during the minor update.

    In order to support the same rolling update when the <namespace>
    changes in the container image, we need a similar floating
    approach for the prefix part of the container image.

    Introduce a new Heat parameter ClusterCommonTag that, when enabled,
    sets the intermediate image name to
    "cluster-common-tag/<servicename>:pcmklatest". By default, this
    parameter is disabled and the original naming scheme is conserved.

    Note: by introducing this new naming scheme, we stop seeing a
    meaningful image name prefix when doing a "pcs status", but since
    we already can't tell what image ID the :pcmklatest tag points to,
    we don't lose much information really.

    Related-Bug: #1854730

    Change-Id: Id369154d147cd5cf0a6f997bf806084fc7580e01
    (cherry picked from commit a166ec6bcaae078a4f7ed91feb8e431fe031e0cb)