本文实例讲述了mha实现mysql主从数据库手动切换的方法，分享给大家供大家参考。具体方法如下：
一、准备工作
1、分别在master和slave执行如下,方便mha检查复制:
复制代码 代码如下:grant all privileges on *.* toidentified by 'rootpass';
grant all privileges on *.* to identified by 'rootpass';
grant replication slave on *.* to identified by 'jppasswd';
grant replication slave on *.* to identified by 'jppasswd';
flush privileges;
2、将master设置为只读
复制代码 代码如下:mysql> set global read_only=1;
query ok, 0 rows affected (0.00 sec)
mysql> show variables like 'read_only';
+---------------+-------+
| variable_name | value |
+---------------+-------+
| read_only | on |
+---------------+-------+
1 row in set (0.00 sec)
交互模式:
复制代码 代码如下:#masterha_master_switch --master_state=alive --conf=/etc/masterha/app1.cnf --new_master_host=10.1.1.231 --new_master_port=63306
或非交互模式:
复制代码 代码如下:#masterha_master_switch --master_state=alive --conf=/etc/masterha/app1.cnf --new_master_host=10.1.1.231 --new_master_port=63306 —interactive=0
二、切换完以后，如何让10.1.1.231为主，10.1.1.234为从，操作步骤:
1、主上执行:
复制代码 代码如下:mysql> show master status;
+-------------------------+----------+--------------+--------------------------------------+-------------------+
| file | position | binlog_do_db | binlog_ignore_db | executed_gtid_set |
+-------------------------+----------+--------------+--------------------------------------+-------------------+
| mysql-master-bin.000013 | 120 | denovo_ng | mysql,denovo,test,information_schema | |
+-------------------------+----------+--------------+--------------------------------------+-------------------+
1 row in set (0.00 sec)
2、在10.1.1.234上执行如下sql命令；
复制代码 代码如下:change master to master_host='10.1.1.231',master_port=63306,master_user='jpsync',
master_password='jppasswd', master_log_file='mysql-master-bin.000013',master_log_pos=120;
mysql> show slave status＼g;
*************************** 1. row ***************************
slave_io_state: waiting for master to send event
master_host: 10.1.1.231
master_user: jpsync
master_port: 63306
connect_retry: 60
master_log_file: mysql-master-bin.000013
read_master_log_pos: 120
relay_log_file: compute-0-52-relay-bin.000002
relay_log_pos: 290
relay_master_log_file: mysql-master-bin.000013
slave_io_running: yes
slave_sql_running: yes
3、查看master状态，并测试
复制代码 代码如下:mysql> show slave hosts;
+-----------+------+-------+-----------+--------------------------------------+
| server_id | host | port | master_id | slave_uuid |
+-----------+------+-------+-----------+--------------------------------------+
| 1052 | | 63306 | 1025 | e25a3e4a-39c0-11e4-80cb-00259086c4b6 |
+-----------+------+-------+-----------+--------------------------------------+
1 row in set (0.00 sec)
主库10.1.1.231上插入记录
复制代码 代码如下:mysql> insert into test_slave_002 values(555551111,1,55555,99999,44.11,2222,91919);
query ok, 1 row affected (0.00 sec)
从库查询记录已经存在
复制代码 代码如下:mysql> select * from test_slave_002 where id=555551111;
+-----------+-----+-----------+--------------+----------+----------------+--------------+
| id | tag | ticket_id | candidate_id | duration | source_file_id | source_start |
+-----------+-----+-----------+--------------+----------+----------------+--------------+
| 555551111 | 1 | 55555 | 99999 | 44.11 | 2222 | 91919 |
+-----------+-----+-----------+--------------+----------+----------------+--------------+
1 row in set (0.00 sec)
4、更新配置文件:
更新主库my.cnf配置添加
复制代码 代码如下:skip_slave_start
注意:防止重启数据库，启动slave进程，导致数据不一致。
更新从库my.cnf配置添加，设置slave库为只读:
复制代码 代码如下:read_only=1
relay_log_purge=0
然后重启主库和从库,观察库的信息:
主库信息:
复制代码 代码如下:mysql> show processlist;
+----+--------+------------------+------+-------------+------+-----------------------------------------------------------------------+------------------+
| id | user | host | db | command | time | state | info |
+----+--------+------------------+------+-------------+------+-----------------------------------------------------------------------+------------------+
| 1 | jpsync | 10.1.1.234:49085 | null | binlog dump | 17 | master has sent all binlog to slave; waiting for binlog to be updated | null |
| 2 | root | localhost | null | query | 0 | init | show processlist |
+----+--------+------------------+------+-------------+------+-----------------------------------------------------------------------+------------------+
2 rows in set (0.00 sec)
mysql> show master status;
+-------------------------+----------+--------------+--------------------------------------+-------------------+
| file | position | binlog_do_db | binlog_ignore_db | executed_gtid_set |
+-------------------------+----------+--------------+--------------------------------------+-------------------+
| mysql-master-bin.000014 | 120 | denovo_ng | mysql,denovo,test,information_schema | |
+-------------------------+----------+--------------+--------------------------------------+-------------------+
1 row in set (0.00 sec)
从库信息:
复制代码 代码如下:mysql> show slave status＼g;
*************************** 1. row ***************************
slave_io_state: waiting for master to send event
master_host: 10.1.1.231
master_user: jpsync
master_port: 63306
connect_retry: 60
master_log_file: mysql-master-bin.000014
read_master_log_pos: 120
relay_log_file: compute-0-52-relay-bin.000005
relay_log_pos: 290
relay_master_log_file: mysql-master-bin.000014
slave_io_running: yes
slave_sql_running: yes
mysql> show processlist;
+----+-------------+-----------+------+---------+------+-----------------------------------------------------------------------------+------------------+
| id | user | host | db | command | time | state | info |
+----+-------------+-----------+------+---------+------+-----------------------------------------------------------------------------+------------------+
| 1 | system user | | null | connect | 58 | waiting for master to send event | null |
| 2 | system user | | null | connect | 58 | slave has read all relay log; waiting for the slave i/o thread to update it | null |
| 3 | root | localhost | null | query | 0 | init | show processlist |
+----+-------------+-----------+------+---------+------+-----------------------------------------------------------------------------+------------------+
3 rows in set (0.00 sec)
希望本文所述对大家的mysql数据库程序设计有所帮助。
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