Comment 16 for bug 1856313

Reviewed: https://review.opendev.org/708343
Committed: https://git.openstack.org/cgit/openstack/tripleo-heat-templates/commit/?id=0cd97e44cd4027805b74240a04a6475d5f2eaaa2
Submitter: Zuul
Branch: stable/train

commit 0cd97e44cd4027805b74240a04a6475d5f2eaaa2
Author: Jose Luis Franco Arza <email address hidden>
Date: Thu Jan 30 10:54:58 2020 +0100

    Force facts cache refreshing after OS upgrade.

    When upgrading from Rocky to Stein, an upgrade of the operating system is
    performed. This upgrade from RHEL7 to RHEL8 implies the removal of the
    default /usr/bin/python binary. As the facts cache is enabled, Ansible's
    strategy does not consider to upgrade facts and therefore we try to run the
    ansible playbook using the old python binary when running the upgrade.
    This fails with the error: /usr/bin/python: No such file or directory.

    This patch makes use of the setup task in combination with clear_facts
    right after rebooting to upgrade the operating system, to ensure that
    the facts are gathered and refreshed for the Overcloud node just upgraded.
    This way, we make sure that we are using the right python binary.

    Closes-Bug: #1856313
    Change-Id: Ia1fa60c22e482ab14a509730cf93634772e077a7
    (cherry picked from commit 598cf6977fcc37b1b4bcc1463b6c7e80f7037b5e)