问题描述：mysql查看从库状态时，报错”The slave I/O thread stops because master and slave have equal MySQL server UUIDs”，如下所示：

数据库：mysql 5.7.21

1、问题重现

mysql> show slave status \G

*************************** 1. row ***************************

               Slave_IO_State:

                  Master_Host: 192.168.133.136

                  Master_User: repl

                  Master_Port: 3306

                Connect_Retry: 60

              Master_Log_File: binlog.000005

          Read_Master_Log_Pos: 154

               Relay_Log_File: WIN-12HQ2SAA8ON-relay-bin.000001

                Relay_Log_Pos: 4

        Relay_Master_Log_File: binlog.000005

             Slave_IO_Running: No

            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: 154

              Relay_Log_Space: 154

              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: NULL

Master_SSL_Verify_Server_Cert: No

                Last_IO_Errno: 1593

                Last_IO_Error: Fatal error: The slave I/O thread stops because master and slave have equal MySQL server UUIDs; these UUIDs must be dif

ferent for replication to work.

               Last_SQL_Errno: 0

               Last_SQL_Error:

  Replicate_Ignore_Server_Ids:

             Master_Server_Id: 1

                  Master_UUID:

             Master_Info_File: C:\ProgramData\MySQL\MySQL Server 5.7\Data\master.info

                    SQL_Delay: 0

          SQL_Remaining_Delay: NULL

      Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates

           Master_Retry_Count: 86400

                  Master_Bind:

      Last_IO_Error_Timestamp: 230521 17:06:18

     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:

1 row in set (0.00 sec)

2、异常原因

replication架构中需保证每个实例UUID唯一，其保存在datadir目录下的auto.cnf文件中，就跟server_id一样需要保证唯一性.之所以会出现该问题，是因为该环境中从库为主库的克隆.

3、问题解决

停备库实例，删除从库datadir 文件夹下的的 auto.cnf 文件，启动备库实例，此时从库会产生新的 auto.cnf 文件，进而产生新UUID.

4、数据验证

mysql> show slave status \G

*************************** 1. row ***************************

               Slave_IO_State: Waiting for master to send event

                  Master_Host: 192.168.133.136

                  Master_User: repl

                  Master_Port: 3306

                Connect_Retry: 60

              Master_Log_File: binlog.000005

          Read_Master_Log_Pos: 154

               Relay_Log_File: WIN-12HQ2SAA8ON-relay-bin.000003

                Relay_Log_Pos: 317

        Relay_Master_Log_File: binlog.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: 154

              Relay_Log_Space: 534

              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: 1

                  Master_UUID: a1db5f5d-f722-11ed-84af-000c29a2bafe

             Master_Info_File: C:\ProgramData\MySQL\MySQL Server 5.7\Data\master.info

                    SQL_Delay: 0

          SQL_Remaining_Delay: NULL

      Slave_SQL_Running_State: Slave 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:

1 row in set (0.00 sec)

 

说明：如上所示，告警不在出现.

参考网址：https://blog.csdn.net/lihuarongaini/article/details/101299351