这篇文章给大家介绍Mysql MHA部署中如何手动切换，内容非常详细，感兴趣的小伙伴们可以参考借鉴，希望对大家能有所帮助。
Mysql MHA部署-手动切换
架构说明：
参考：http://www.zhaibibei.cn/mysql/mha/
1 检查从库现有状态(188,223)
---show slave status\G
2 查看管理节点日志(222)
通过如下命令事实查看MHA当前状态
tail -f /etc/mha/manager/mha.log
3 关闭MHA的管理进程(222)
[root@rac4 ~]# masterha_stop -conf=/etc/mha/mha.conf
MHA Manager is not running on mha(2:NOT_RUNNING).
4.手动切换
相关命令如下：
masterha_master_switch -master_state=alive –orig_master_is_new_slave –conf=/etc/mha/mha.conf
-master_state=alive 代表告诉MHA原master还是存活的，不需要将其从配置文件删除
–orig_master_is_new_slave 参数代表原master会自动同步新的master
--还有一些其他的参数如下
-running_updates_limit 如果主库的写操作时间超过了该参数，则退出切换
–interactive=0 代表直接确认，不需要输入YES
切换过程如下：
[root@rac4 ~]# masterha_master_switch -master_state=alive -orig_master_is_new_slave -conf=/etc/mha/mha.conf
Sat Mar 14 22:17:37 2020 - [info] MHA::MasterRotate version 0.56.
Sat Mar 14 22:17:37 2020 - [info] Starting online master switch..
Sat Mar 14 22:17:37 2020 - [info]
Sat Mar 14 22:17:37 2020 - [info] * Phase 1: Configuration Check Phase..
Sat Mar 14 22:17:37 2020 - [info]
Sat Mar 14 22:17:37 2020 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Sat Mar 14 22:17:37 2020 - [info] Reading application default configuration from /etc/mha/mha.conf..
Sat Mar 14 22:17:37 2020 - [info] Reading server configuration from /etc/mha/mha.conf..
Sat Mar 14 22:17:38 2020 - [info] GTID failover mode = 1
Sat Mar 14 22:17:38 2020 - [info] Current Alive Master: rac1(192.168.2.187:3306)
Sat Mar 14 22:17:38 2020 - [info] Alive Slaves:
Sat Mar 14 22:17:38 2020 - [info] rac2(192.168.2.188:3306) Version=5.7.28-log (oldest major version between slaves) log-bin:enabled
Sat Mar 14 22:17:38 2020 - [info] GTID ON
Sat Mar 14 22:17:38 2020 - [info] Replicating from 192.168.2.187(192.168.2.187:3306)
Sat Mar 14 22:17:38 2020 - [info] Primary candidate for the new Master (candidate_master is set)
Sat Mar 14 22:17:38 2020 - [info] rac3(192.168.2.223:3306) Version=5.7.28-log (oldest major version between slaves) log-bin:enabled
Sat Mar 14 22:17:38 2020 - [info] GTID ON
Sat Mar 14 22:17:38 2020 - [info] Replicating from 192.168.2.187(192.168.2.187:3306)
Sat Mar 14 22:17:38 2020 - [info] Not candidate for the new Master (no_master is set)
It is better to execute FLUSH NO_WRITE_TO_BINLOG TABLES on the master before switching. Is it ok to execute on rac1(192.168.2.187:3306)? (YES/no): YES
Sat Mar 14 22:19:01 2020 - [info] Executing FLUSH NO_WRITE_TO_BINLOG TABLES. This may take long time..
Sat Mar 14 22:19:01 2020 - [info] ok.
Sat Mar 14 22:19:01 2020 - [info] Checking MHA is not monitoring or doing failover..
Sat Mar 14 22:19:01 2020 - [info] Checking replication health on rac2..
Sat Mar 14 22:19:01 2020 - [info] ok.
Sat Mar 14 22:19:01 2020 - [info] Checking replication health on rac3..
Sat Mar 14 22:19:01 2020 - [info] ok.
Sat Mar 14 22:19:01 2020 - [info] Searching new master from slaves..
Sat Mar 14 22:19:01 2020 - [info] Candidate masters from the configuration file:
Sat Mar 14 22:19:01 2020 - [info] rac1(192.168.2.187:3306) Version=5.7.28-log log-bin:enabled
Sat Mar 14 22:19:01 2020 - [info] GTID ON
Sat Mar 14 22:19:01 2020 - [info] rac2(192.168.2.188:3306) Version=5.7.28-log (oldest major version between slaves) log-bin:enabled
Sat Mar 14 22:19:01 2020 - [info] GTID ON
Sat Mar 14 22:19:01 2020 - [info] Replicating from 192.168.2.187(192.168.2.187:3306)
Sat Mar 14 22:19:01 2020 - [info] Primary candidate for the new Master (candidate_master is set)
Sat Mar 14 22:19:01 2020 - [info] Non-candidate masters:
Sat Mar 14 22:19:01 2020 - [info] rac3(192.168.2.223:3306) Version=5.7.28-log (oldest major version between slaves) log-bin:enabled
Sat Mar 14 22:19:01 2020 - [info] GTID ON
Sat Mar 14 22:19:01 2020 - [info] Replicating from 192.168.2.187(192.168.2.187:3306)
Sat Mar 14 22:19:01 2020 - [info] Not candidate for the new Master (no_master is set)
Sat Mar 14 22:19:01 2020 - [info] Searching from candidate_master slaves which have received the latest relay log events..
Sat Mar 14 22:19:01 2020 - [info]
From:
rac1(192.168.2.187:3306) (current master)
+--rac2(192.168.2.188:3306)
+--rac3(192.168.2.223:3306)
To:
rac2(192.168.2.188:3306) (new master)
+--rac3(192.168.2.223:3306)
+--rac1(192.168.2.187:3306)
Starting master switch from rac1(192.168.2.187:3306) to rac2(192.168.2.188:3306)? (yes/NO): yes
Sat Mar 14 22:19:32 2020 - [info] Checking whether rac2(192.168.2.188:3306) is ok for the new master..
Sat Mar 14 22:19:32 2020 - [info] ok.
Sat Mar 14 22:19:32 2020 - [info] rac1(192.168.2.187:3306): SHOW SLAVE STATUS returned empty result. To check replication filtering rules, temporarily executing CHANGE MASTER to a dummy host.
Sat Mar 14 22:19:32 2020 - [info] rac1(192.168.2.187:3306): Resetting slave pointing to the dummy host.
Sat Mar 14 22:19:32 2020 - [info] ** Phase 1: Configuration Check Phase completed.
Sat Mar 14 22:19:32 2020 - [info]
Sat Mar 14 22:19:32 2020 - [info] * Phase 2: Rejecting updates Phase..
Sat Mar 14 22:19:32 2020 - [info]
Sat Mar 14 22:19:32 2020 - [info] Executing master ip online change script to disable write on the current master:
Sat Mar 14 22:19:32 2020 - [info] /etc/mha/script/master_ip_online_change --command=stop --orig_master_host=rac1 --orig_master_ip=192.168.2.187 --orig_master_port=3306 --orig_master_user='monitor' --orig_master_password='123456' --new_master_host=rac2 --new_master_ip=192.168.2.188 --new_master_port=3306 --new_master_user='monitor' --new_master_password='123456' --orig_master_ssh_user=root --new_master_ssh_user=root --orig_master_is_new_slave
Sat Mar 14 22:19:32 2020 756531 Set read_only on the new master.. ok.
Sat Mar 14 22:19:32 2020 761639 Set read_only=1 on the orig master.. ok.
Sat Mar 14 22:19:32 2020 763740 Killing all application threads..
Sat Mar 14 22:19:32 2020 763785 done.
Disabling the VIP an old master: rac1
eth0:2: ERROR while getting interface flags: No such device
Sat Mar 14 22:19:33 2020 - [info] ok.
Sat Mar 14 22:19:33 2020 - [info] Locking all tables on the orig master to reject updates from everybody (including root):
Sat Mar 14 22:19:33 2020 - [info] Executing FLUSH TABLES WITH READ LOCK..
Sat Mar 14 22:19:33 2020 - [info] ok.
Sat Mar 14 22:19:33 2020 - [info] Orig master binlog:pos is mysql-bin.000009:194.
Sat Mar 14 22:19:33 2020 - [info] Waiting to execute all relay logs on rac2(192.168.2.188:3306)..
Sat Mar 14 22:19:33 2020 - [info] master_pos_wait(mysql-bin.000009:194) completed on rac2(192.168.2.188:3306). Executed 0 events.
Sat Mar 14 22:19:33 2020 - [info] done.
Sat Mar 14 22:19:33 2020 - [info] Getting new master's binlog name and position..
Sat Mar 14 22:19:33 2020 - [info] mysql-bin.000006:3938
Sat Mar 14 22:19:33 2020 - [info] All other slaves should start replication from here. Statement should be: CHANGE MASTER TO MASTER_HOST='rac2 or 192.168.2.188', MASTER_PORT=3306, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='xxx';
Sat Mar 14 22:19:33 2020 - [info] Executing master ip online change script to allow write on the new master:
Sat Mar 14 22:19:33 2020 - [info] /etc/mha/script/master_ip_online_change --command=start --orig_master_host=rac1 --orig_master_ip=192.168.2.187 --orig_master_port=3306 --orig_master_user='monitor' --orig_master_password='123456' --new_master_host=rac2 --new_master_ip=192.168.2.188 --new_master_port=3306 --new_master_user='monitor' --new_master_password='123456' --orig_master_ssh_user=root --new_master_ssh_user=root --orig_master_is_new_slave
Sat Mar 14 22:19:33 2020 227880 Set read_only=0 on the new master.
Enabling the VIP 192.168.2.189 on the new master: rac2
SIOCSIFADDR: No such device
eth0:2: ERROR while getting interface flags: No such device
SIOCSIFNETMASK: No such device
arping: Device eth0 not available.
Sat Mar 14 22:19:33 2020 - [info] ok.
Sat Mar 14 22:19:33 2020 - [info]
Sat Mar 14 22:19:33 2020 - [info] * Switching slaves in parallel..
Sat Mar 14 22:19:33 2020 - [info]
Sat Mar 14 22:19:33 2020 - [info] -- Slave switch on host rac3(192.168.2.223:3306) started, pid: 12424
Sat Mar 14 22:19:33 2020 - [info]
Sat Mar 14 22:19:34 2020 - [info] Log messages from rac3 ...
Sat Mar 14 22:19:34 2020 - [info]
Sat Mar 14 22:19:33 2020 - [info] Waiting to execute all relay logs on rac3(192.168.2.223:3306)..
Sat Mar 14 22:19:33 2020 - [info] master_pos_wait(mysql-bin.000009:194) completed on rac3(192.168.2.223:3306). Executed 0 events.
Sat Mar 14 22:19:33 2020 - [info] done.
Sat Mar 14 22:19:33 2020 - [info] Resetting slave rac3(192.168.2.223:3306) and starting replication from the new master rac2(192.168.2.188:3306)..
Sat Mar 14 22:19:33 2020 - [info] Executed CHANGE MASTER.
Sat Mar 14 22:19:33 2020 - [info] Slave started.
Sat Mar 14 22:19:34 2020 - [info] End of log messages from rac3 ...
Sat Mar 14 22:19:34 2020 - [info]
Sat Mar 14 22:19:34 2020 - [info] -- Slave switch on host rac3(192.168.2.223:3306) succeeded.
Sat Mar 14 22:19:34 2020 - [info] Unlocking all tables on the orig master:
Sat Mar 14 22:19:34 2020 - [info] Executing UNLOCK TABLES..
Sat Mar 14 22:19:34 2020 - [info] ok.
Sat Mar 14 22:19:34 2020 - [info] Starting orig master as a new slave..
Sat Mar 14 22:19:34 2020 - [info] Resetting slave rac1(192.168.2.187:3306) and starting replication from the new master rac2(192.168.2.188:3306)..
Sat Mar 14 22:19:34 2020 - [info] Executed CHANGE MASTER.
Sat Mar 14 22:19:34 2020 - [info] Slave started.
Sat Mar 14 22:19:34 2020 - [info] All new slave servers switched successfully.
Sat Mar 14 22:19:34 2020 - [info]
Sat Mar 14 22:19:34 2020 - [info] * Phase 5: New master cleanup phase..
Sat Mar 14 22:19:34 2020 - [info]
Sat Mar 14 22:19:34 2020 - [info] rac2: Resetting slave info succeeded.
Sat Mar 14 22:19:34 2020 - [info] Switching master to rac2(192.168.2.188:3306) completed successfully.
5.切换阶段
执行master_ip_online_change时当前master不可写
新的主库设置只读
旧的主库设置只读
禁用原主库VIP
旧主库设全局锁
获取新主库master信息
新主库设置VIP
新主库取消只读
异步从库重新同步至新主库
原主库释放全局锁
原主库同步至新主库
6.查看切换后状态
---223
mysql> show slave status \G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.2.188
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000006
Read_Master_Log_Pos: 3938
Relay_Log_File: mysql-relay.000005
Relay_Log_Pos: 454
Relay_Master_Log_File: mysql-bin.000006
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
----187
mysql> show slave status \G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: rac2
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000006
Read_Master_Log_Pos: 3938
Relay_Log_File: mysql-relay.000007
Relay_Log_Pos: 454
Relay_Master_Log_File: mysql-bin.000006
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
......
7.数据测试
---188：
mysql> use jumptest
mysql> insert into cjc01 values(3000);
Query OK, 1 row affected (0.02 sec)
mysql> select * from cjc01;
+------+
| id |
+------+
| 100 |
| 3 |
| 3000 |
+------+
3 rows in set (0.00 sec)
---187：
mysql> select * from cjc01;
+------+
| id |
+------+
| 100 |
| 3 |
| 3000 |
+------+
3 rows in set (0.01 sec)
---223：
mysql> select * from cjc01;
+------+
| id |
+------+
| 100 |
| 3 |
| 3000 |
+------+
3 rows in set (0.01 sec)
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