Use galera_new_cluster instead. systemctl start mariadb@bootstrap
will generate error message, use_galera_new_cluster.conf is the name
of the file that will generate this error.

Output:

Job for mariadb@bootstrap.service failed. See "systemctl status
mariadb@bootstrap.service" and "journalctl -xe" for details.

● mariadb@bootstrap.service - MariaDB database server
   Loaded: loaded (/usr/lib/systemd/system/mariadb@.service; disabled;
vendor preset: disabled)
  Drop-In: /usr/lib/systemd/system/mariadb@bootstrap.service.d
           └─use_galera_new_cluster.conf
   Active: failed (Result: exit-code) since Thu 2015-10-15 19:27:52
CEST; 5s ago
  Process: 24334 ExecStart=/usr/bin/false (code=exited,
status=1/FAILURE)
  Process: 24330 ExecStart=/usr/bin/echo Please use galera_new_cluster
to start the mariadb service with --wsrep-new-cluster (code=exited,
status=0/SUCCESS)
 Main PID: 24334 (code=exited, status=1/FAILURE)

Oct 15 19:27:52 spaceman systemd[1]: Starting MariaDB database server...
Oct 15 19:27:52 spaceman systemd[1]: mariadb@bootstrap.service: main
process exited, code=exited, status=1/FAILURE
Oct 15 19:27:52 spaceman systemd[1]: Failed to start MariaDB database
server.
Oct 15 19:27:52 spaceman systemd[1]: Unit mariadb@bootstrap.service
entered failed state.
Oct 15 19:27:52 spaceman systemd[1]: mariadb@bootstrap.service failed.