galera-formula/metadata/service/ssl/slave.yml

parameters:
  _param:
    mysql_ssl_key_file: /etc/mysql/ssl/key.pem
    mysql_ssl_cert_file: /etc/mysql/ssl/cert.pem
    mysql_ssl_ca_file: /etc/mysql/ssl/ca.pem
  galera:
    slave:
      ssl:
        enabled: True
        key_file: ${_param:mysql_ssl_key_file}
        cert_file: ${_param:mysql_ssl_cert_file}
        ca_file: ${_param:mysql_ssl_ca_file}