slave-relation-changed hook fails when deploying a master/slave pair

[barryprice]

Hi,

Deploying the latest charm from this repo (cs:mysql is outdated) to a local LXD provider results in hook failures:

charm-mysql{master}$ juju deploy . mysql --series bionic
charm-mysql{master}$ juju deploy . mysql-slave --series bionic
charm-mysql{master}$ juju add-relation mysql:master mysql-slave:slave

Unit status:

mysql-slave/0* error idle 1 10.36.239.140 3306/tcp hook failed: "slave-relation-changed"

Log error line:

2019-10-04 08:23:25 DEBUG slave-relation-changed ERROR 1794 (HY000) at line 1: Slave is not configured or failed to initialize properly. You must at least set --server-id to enable either a master or a slave. Additional error messages can be found in the MySQL error log.

[barryprice]

On closer inspection, this does the same thing with "--series xenial", and I see the same error from cs:mysql (on xenial) as well, again with the local LXD provider.

Tried again deploying on an Openstack provider, with the same results.

So I'm not sure it's currently possible to deploy a master/slave pair, at least as described on the charm's main page.