msyql 主从切换

从库是192.168.1.70 ，主库是192.168.1.64，主从切换一次

即：主库是192.168.1.70，从库是192.168.1.64

1、从库上执行，修改为主

修改从库为非只读库
修改配置 /etc/my.cnf
read_only = 1
重启mysql
service mysqld_3306 restart

mysql> stop slave io_thread;
Query OK, 0 rows affected (0.07 sec)

mysql> show slave status\G;
*************************** 1. row ***************************
Slave_IO_State:
Master_Host: 192.168.1.64
Master_User: zabbix64
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000147
Read_Master_Log_Pos: 49072513
Relay_Log_File: relay-bin-3306.000179
Relay_Log_Pos: 17594196
Relay_Master_Log_File: mysql-bin.000147
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: 49072513
Relay_Log_Space: 17594368
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: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 101
Master_UUID: 9a5386d8-cd13-11e8-96cb-c68297e2a5d7
Master_Info_File: /home/mysql_data/3306/master.info
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
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
1 row in set (0.00 sec)

ERROR:
No query specified

mysql> stop slave;
Query OK, 0 rows affected (0.05 sec)

mysql> show slave status\G;
*************************** 1. row ***************************
Slave_IO_State:
Master_Host: 192.168.1.64
Master_User: zabbix64
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000147
Read_Master_Log_Pos: 49072513
Relay_Log_File: relay-bin-3306.000179
Relay_Log_Pos: 17594196
Relay_Master_Log_File: mysql-bin.000147
Slave_IO_Running: No
Slave_SQL_Running: No
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: 49072513
Relay_Log_Space: 17594368
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: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 101
Master_UUID: 9a5386d8-cd13-11e8-96cb-c68297e2a5d7
Master_Info_File: /home/mysql_data/3306/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State:
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
1 row in set (0.00 sec)

ERROR:
No query specified

mysql> reset master;
Query OK, 0 rows affected (0.28 sec)

mysql> grant replication slave on *.* to 'repl'@'192.168.1.64' identified by '123456';
Query OK, 0 rows affected (0.05 sec)

2、主上执行（修改为从）

mysql> change master to master_host='192.168.1.70',master_user='repl',master_password='123456';
Query OK, 0 rows affected, 2 warnings (0.31 sec)

mysql> start slave;
Query OK, 0 rows affected (0.05 sec)

参考来源 ：https://www.cnblogs.com/gomysql/p/3663146.html