Comment 1 for bug 2049857

Regarding mysql-router-k8s, the `upgrade-version-a-relation-changed` error is (from searching for "Uncaught exception while in charm code" in the logs)

`mysqlsh.DBError: MySQL Error (2003): Shell.connect: Can\'t connect to MySQL server on \'cinder-mysql-primary.openstack.svc.cluster.local:3306\' (111)`

mysql-router-k8s rev 86+ improves the UX for this situation (https://github.com/canonical/mysql-router-k8s-operator/pull/190)

It appears that the issue here is something with MySQL Server—since even at the end of the logs, MySQL Router is unable to connect to MySQL Server