Mysql master-master replication hints

• tested mariadb 10.3 and mysql8
• this is working configuration for basic running
• next hints will be added if some problems found)

port listening

• don't forget to adjust bind-address option. E.g.

bind-address            = 0.0.0.0

Master servers settings

Server 1 configuration:

[mysqld]
...
server-id               = 1
report_host             = master1
log_bin                 = /var/lib/mysql/mariadb-bin.log
log_bin_index           = /var/lib/mysql/mariadb-bin.index
relay_log               = /var/lib/mysql/relay-bin
relay_log_index         = /var/lib/mysql/relay-bin.index
expire_logs_days        = 10

auto_increment_increment = 2
auto_increment_offset = 1
slave-skip-errors=all

Server 2 configuration:

[mysqld]
...
server-id               = 2
report_host             = master2
log_bin                 = /var/lib/mysql/mariadb-bin.log
log_bin_index           = /var/lib/mysql/mariadb-bin.index
relay_log               = /var/lib/mysql/relay-bin
relay_log_index         = /var/lib/mysql/relay-bin.index
expire_logs_days        = 10

auto_increment_increment = 2
auto_increment_offset = 2
slave-skip-errors=all

Server 1 create replication user + privileges:

MariaDB [none]> create user 'master1'@'%' identified by 'test';
MariaDB [none]> grant replication slave on *.* to 'master1'@'%';

Server 2 create replication user + privileges:

MariaDB [none]> create user 'master2'@'%' identified by 'test';
MariaDB [none]> grant replication slave on *.* to 'master2'@'%';

Server 1 get master status (will be used in the Server 2 slave setting):

MariaDB [none]> show master status;
+--------------------+----------+--------------+------------------+
| File               | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+--------------------+----------+--------------+------------------+
| mariadb-bin.000004 | 52234945 |              |                  |
+--------------------+----------+--------------+------------------+
1 row in set (0.104 sec)

Server 2 get master status (will be used in the Server 1 slave setting):

MariaDB [none]> show master status;
+--------------------+----------+--------------+------------------+
| File               | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+--------------------+----------+--------------+------------------+
| mariadb-bin.000005 | 12214311 |              |                  |
+--------------------+----------+--------------+------------------+
1 row in set (0.000 sec)

Server 1 set slave setting (use master status from server 2):

MariaDB [none]> stop slave;
MariaDB [none]> CHANGE MASTER TO MASTER_HOST='10.133.1.91', MASTER_USER='master2', MASTER_PASSWORD='test',MASTER_LOG_FILE='mariadb-bin.000005', MASTER_LOG_POS=12214311;
MariaDB [none]> start slave;

Server 2 set slave setting (use master status from server 1):

MariaDB [none]> stop slave;
MariaDB [none]> CHANGE MASTER TO MASTER_HOST='10.133.1.90', MASTER_USER='master1', MASTER_PASSWORD='test',MASTER_LOG_FILE='mariadb-bin.000004', MASTER_LOG_POS=52234945;
MariaDB [none]> start slave;

Slave status from Server 1 (Important: Slave_SQL_Running: Yes)

MariaDB [none]> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 10.133.1.91
                  Master_User: master2
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mariadb-bin.000005
          Read_Master_Log_Pos: 12272564
               Relay_Log_File: relay-bin.000006
                Relay_Log_Pos: 10099727
        Relay_Master_Log_File: mariadb-bin.000005
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
              Replicate_Do_DB: 
          Replicate_Ignore_DB: 
           Replicate_Do_Table: 
       Replicate_Ignore_Table: 
      Replicate_Wild_Do_Table: 
  Replicate_Wild_Ignore_Table: 
                   Last_Errno: 0
                   Last_Error: 
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 12272564
              Relay_Log_Space: 10100331
              Until_Condition: None
               Until_Log_File: 
                Until_Log_Pos: 0
           Master_SSL_Allowed: No
           Master_SSL_CA_File: 
           Master_SSL_CA_Path: 
              Master_SSL_Cert: 
            Master_SSL_Cipher: 
               Master_SSL_Key: 
        Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 0
                Last_IO_Error: 
               Last_SQL_Errno: 0
               Last_SQL_Error: 
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 2
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
                   Using_Gtid: No
                  Gtid_IO_Pos: 
      Replicate_Do_Domain_Ids: 
  Replicate_Ignore_Domain_Ids: 
                Parallel_Mode: conservative
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it
             Slave_DDL_Groups: 7325
Slave_Non_Transactional_Groups: 3
   Slave_Transactional_Groups: 6447
1 row in set (0.000 sec)