主从配置：

#主服务器
mysql> show master logs;
+---------------+-----------+-----------+
| Log_name      | File_size | Encrypted |
+---------------+-----------+-----------+
| C8-bin.000001 |       179 | No        |
| C8-bin.000002 |       156 | No        |
+---------------+-----------+-----------+
2 rows in set (0.00 sec)

create user 'repl'@'192.168.88.%' identified by '123456';
grant replication slave on *.* to 'repl'@'192.168.88.%';


#从服务器

mysql> CHANGE MASTER TO MASTER_HOST='192.168.88.8',
    -> MASTER_USER='repl',
    -> MASTER_PASSWORD='123456',
    -> MASTER_LOG_FILE='C8-bin.000002',
    -> MASTER_LOG_POS=156;
Query OK, 0 rows affected, 8 warnings (0.02 sec)

mysql> start slave;
Query OK, 0 rows affected, 1 warning (0.00 sec)


mysql> show slave status \G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for source to send event
                  Master_Host: 192.168.88.8
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: C8-bin.000002
          Read_Master_Log_Pos: 681
               Relay_Log_File: relay-log.000002
                Relay_Log_Pos: 846
        Relay_Master_Log_File: C8-bin.000002
             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: 681
              Relay_Log_Space: 1049
              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: 8
                  Master_UUID: b1b80462-3088-11ec-b2b1-000c29ce6816
             Master_Info_File: mysql.slave_master_info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Replica has read all relay log; waiting for more updates
           Master_Retry_Count: 86400
                  Master_Bind:
      Last_IO_Error_Timestamp:
     Last_SQL_Error_Timestamp:
               Master_SSL_Crl:
           Master_SSL_Crlpath:
           Retrieved_Gtid_Set:
            Executed_Gtid_Set:
                Auto_Position: 0
         Replicate_Rewrite_DB:
                 Channel_Name:
           Master_TLS_Version:
       Master_public_key_path:
        Get_master_public_key: 0
            Network_Namespace:
1 row in set, 1 warning (0.00 sec)

#主服务器测试 主从同步
create database test1;

#从服务器测试
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
| test1              |
+--------------------+
5 rows in set (0.01 sec)

主主配置

#C8主服务器
mysql> show master logs;
+---------------+-----------+-----------+
| Log_name      | File_size | Encrypted |
+---------------+-----------+-----------+
| C8-bin.000001 |       179 | No        |
| C8-bin.000002 |       156 | No        |
+---------------+-----------+-----------+
2 rows in set (0.00 sec)

create user 'repl'@'192.168.88.%' identified by '123456';
grant replication slave on *.* to 'repl'@'192.168.88.%';


#C18主服务器
mysql> CHANGE MASTER TO MASTER_HOST='192.168.88.8',
    -> MASTER_USER='repl',
    -> MASTER_PASSWORD='123456',
    -> MASTER_LOG_FILE='C8-bin.000002',
    -> MASTER_LOG_POS=156;

mysql> start slave;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> show slave status \G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for source to send event
                  Master_Host: 192.168.88.8
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: C8-bin.000002
          Read_Master_Log_Pos: 691
               Relay_Log_File: C8-relay-bin.000002
                Relay_Log_Pos: 856
        Relay_Master_Log_File: C8-bin.000002
             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: 691
              Relay_Log_Space: 1062
              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: 8
                  Master_UUID: 2a686138-30a7-11ec-9877-000c29ce6816
             Master_Info_File: mysql.slave_master_info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Replica has read all relay log; waiting for more updates
           Master_Retry_Count: 86400
                  Master_Bind:
      Last_IO_Error_Timestamp:
     Last_SQL_Error_Timestamp:
               Master_SSL_Crl:
           Master_SSL_Crlpath:
           Retrieved_Gtid_Set:
            Executed_Gtid_Set:
                Auto_Position: 0
         Replicate_Rewrite_DB:
                 Channel_Name:
           Master_TLS_Version:
       Master_public_key_path:
        Get_master_public_key: 0
            Network_Namespace:
1 row in set, 1 warning (0.01 sec)


#C8主服务器
mysql> CHANGE MASTER TO MASTER_HOST='192.168.88.18',
    -> MASTER_USER='repl',
    -> MASTER_PASSWORD='123456',
    -> MASTER_LOG_FILE='C18-bin.000002',
    -> MASTER_LOG_POS=156;
Query OK, 0 rows affected, 8 warnings (0.01 sec)

mysql> start slave;
Query OK, 0 rows affected, 1 warning (0.01 sec)

mysql> show slave status \G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for source to send event
                  Master_Host: 192.168.88.18
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: C18-bin.000002
          Read_Master_Log_Pos: 705
               Relay_Log_File: C18-relay-bin.000002
                Relay_Log_Pos: 321
        Relay_Master_Log_File: C18-bin.000002
             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: 705
              Relay_Log_Space: 527
              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: 18
                  Master_UUID: 2e24e15b-30a7-11ec-b26f-000c2912723d
             Master_Info_File: mysql.slave_master_info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Replica has read all relay log; waiting for more updates
           Master_Retry_Count: 86400
                  Master_Bind:
      Last_IO_Error_Timestamp:
     Last_SQL_Error_Timestamp:
               Master_SSL_Crl:
           Master_SSL_Crlpath:
           Retrieved_Gtid_Set:
            Executed_Gtid_Set:
                Auto_Position: 0
         Replicate_Rewrite_DB:
                 Channel_Name:
           Master_TLS_Version:
       Master_public_key_path:
        Get_master_public_key: 0
            Network_Namespace:
1 row in set, 1 warning (0.01 sec)


#测试
在 C8 上创建db1
mysql> create database db1;

#C18
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| db1                |
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
5 rows in set (0.00 sec)

mysql> create database db2;
Query OK, 1 row affected (0.01 sec)

#C8
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| db1                |
| db2                |
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
6 rows in set (0.01 sec)