Previously we required the operator to run two separate commands for
the "prepare" and "run" phases of operating system upgrade. This
commit refactors the upgrade_tasks with these tags so that running the
whole system upgrade is possible via a single command with `--tags
system_upgrade`.
Allowing to run in a single command requires being more careful about
what can happen in which step number in the upgrade tasks. The upgrade
steps for system upgrade are now explicitly documented in composable
services readme.
The existing system_upgrade_run and system_upgrade_prepare tasks were
checked and moved into the appropriate steps. In the case of
pacemaker, it required moving the cluster stop/destroy action into a
single file with removing all containers, to guarantee that the
cluster is stopped before the container removal, otherwise pacemaker
would try to spawn new containers.
Change-Id: I3cd78de8d07be46ee01006dd7e039c285991d14a
Partial-Bug: #1831690
206625d4f5