A typical scenario of when this is useful is if you have set up a new version of MariaDB as a slave, for example for testing, and want to upgrade your master to the new version.

In MariaDB replication, a slave should be of a version same or newer than the master. _ref.

Stopping the Original Master

Manually Take Down the Master

-- set the master to read only to ensure that there are no new updates on the master
FLUSH TABLES WITH READ LOCK;

-- check the current position of the master:
SHOW MASTER STATUS;

+--------------------+----------+--------------+------------------+
| File               | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+--------------------+----------+--------------+------------------+
| mariadb-bin.000006 |      790 |              |                  |
+--------------------+----------+--------------+------------------+

-- When slave is up to date, you can then take the MASTER down.
SHUTDOWN;

Preparing the Slave to be a Master

Wait until you have the same position on the slave. The most important information to watch are Master_Log_File and Exec_Master_Log_Pos as when this matches the master, it signals that all transactions has been committed on the slave.

SHOW SLAVE STATUS \G
...
                   Master_User: repl
                   Master_Port: 3306
                 Connect_Retry: 60
               Master_Log_File: mariadb-bin.000006
           Read_Master_Log_Pos: 790
                Relay_Log_File: mysqld-relay-bin.000010
                 Relay_Log_Pos: 557
         Relay_Master_Log_File: mariadb-bin.000006
              Slave_IO_Running: Yes
             Slave_SQL_Running: Yes
  ...
                    Last_Errno: 0
                    Last_Error:
                  Skip_Counter: 0
           Exec_Master_Log_Pos: 790 -- matches the master
               Relay_Log_Space: 867
               Until_Condition: None

Stop all old connections to the old master(s) and reset read only mode, if you had it enabled.

-- Stop all connections to master
STOP ALL SLAVES;
RESET SLAVE ALL;

-- reset read only mode,
SET @@global.read_only=0;