Comment 2 for bug 1742683

This appears to be a race with a telegraf subordinate:

<snip>
    units:
      mysql/0:
        workload-status:
          current: error
          message: 'hook failed: "db-admin-relation-changed" for telegraf:mysql'
</snip>

I think this existing telegraf + juju core bugs are likely related:

https://bugs.launchpad.net/telegraf-charm/+bug/1718259
https://bugs.launchpad.net/charm-percona-cluster/+bug/1717590