With PKI role in place in most cases you don't need to explicitly provide path to the CA file because PKI role ensures that CA is trusted by the system overall. In the meanwhile in PyMySQL [1] you must either provide CA file or cert/key or enable verify. Since current behaviour is to provide path to the custom CA we expect certificate being trusted overall. Thus we enable cert verification when galera_use_ssl is True. [1] https://github.com/PyMySQL/PyMySQL/blob/78f0cf99e5d5351df0821442e4dc35c49a6390c6/pymysql/connections.py#L267 Change-Id: I933e1edbd4260e2bd61bcceec3ddad8aea85353c