Comment 2 for bug 1617520

Reviewed: https://review.openstack.org/358626
Committed: https://git.openstack.org/cgit/openstack/tripleo-heat-templates/commit/?id=63421ca73de8ed9a0033706c190bf9a6eca4b582
Submitter: Jenkins
Branch: master

commit 63421ca73de8ed9a0033706c190bf9a6eca4b582
Author: Michele Baldessari <email address hidden>
Date: Fri Aug 26 16:46:44 2016 +0200

    Add a function to upgrade from full HA to NG HA

    This is the initial work to have a function that migrates a full HA
    architecture as deployed in Mitaka to the HA architecture as deployed in
    Newton where only a few resources are managed by pacemaker.

    The sequence is the following:
    1) We remove the desired services from pacemaker's control. The services
       at this point are still running normally via the systemd service as
       invoked by pacemaker
    2) We do a "systemctl stop <service>" on all controllers for all the
       services that were removed from pacemaker's control. We do this to make
       sure that during the yum upgrade, the %post sections that call
       "systemctl try-restart" do not take ages, because at this point during
       the upgrade rabbit is down. The only exceptions are "openstack-core"
       and "delay" which are dummy pacemaker resources that do not exist on
       the system
    3) We do a "systemctl start <service>" on all nodes for all the services
       mentioned above.

    We should probably merge this patch only when newton has branched as it
    is very specific to the M/N upgrade.

    Closes-Bug: 1617520
    Change-Id: I4c409ce58c1a57b6e0decc3cf168b62698b32e39