Comment 4 for bug 1838041

Please see https://bugs.launchpad.net/charm-percona-cluster/+bug/1949935. The process was simple, just ran the upgrade on the leader unit first, one step at a time. The same error occurred on the remaining two percona-cluster units.

Is it something as simple as the percona cluster packages running the upgrade steps as well as the charm? Could the charm be modified to catch the exception and continue, since it's just the tool reporting that the upgrade step doesn't need to be run?