Now that dbctl is in place, we should build some automation around automatically upgrading databases (mysql, kernel...).
Ideally the script should:
- Check if the host can be depooled (min_number of hosts in a section)
- depool
- Stop MySQL
- Upgrade the host
- Reboot it if that's the desire
- Start mysql
- Run mysql_upgrade
- Start replication
- Once replication is up-to-date use the dbctl -p option to slowly repool the host back in production