多机MySQL一主双从详细安装主从复制

多机MySQL一主双从详细安装

一、复制的工作原理

要想实现AB复制，那么前提是master上必须要开启二进制日志

1.首先master将数据更新记录到二进制日志文件
2.从slave start开始，slave通过I/O线程向master请求二进制日志文件指定位置之后的内容
3.master接收到slave的io请求之后，就会从相应的位置点开始，给slave传日志
4.slave接收到日志后，会写入本地的中继日志中
5.slave通过sql线程读取中继日志的内容，在数据库中执行相应的操作，到此为止，master和slave上的数据一致，之后slave服务器进入等待状态，等待master的后续更新

 

 

二、主从复制配置

172.20.28.36	MySQL-master	yum install mysql mysql-server -y
172.20.28.37	MySQL-slave1	yum install mysql mysql-server -y
172.20.28.38	MySQL-slave2	yum install mysql mysql-server -y
小结：mysql服务是yum安装的，配置文件：/etc/my.cnf  数据存放目录：/var/lib/mysql

2.1 修改主库和从库的配置文件

master	Slave1	Slave2
[root@i-t27hedd8 ~]# cat /etc/my.cnf [mysqld] datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock user=mysql # Disabling symbolic-links is recommended to prevent assorted security risks symbolic-links=0 server-id=1 log-bin=/var/lib/mysql/mysql-bin [mysqld_safe] log-error=/var/log/mysqld.log pid-file=/var/run/mysqld/mysqld.pid	[mysqld] datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock user=mysql # Disabling symbolic-links is recommended to prevent assorted security risks symbolic-links=0 server-id=3 [mysqld_safe] log-error=/var/log/mysqld.log pid-file=/var/run/mysqld/mysqld.pid	[mysqld] datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock user=mysql # Disabling symbolic-links is recommended to prevent assorted security risks symbolic-links=0 server-id=5 [mysqld_safe] log-error=/var/log/mysqld.log pid-file=/var/run/mysqld/mysqld.pid
小结： 1、主库开启binlog日志 2、主从server-id不同 3、从库服务器能连通主库

2.2 在master端查看

mysql> show variables like "log_bin"; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | log_bin       | ON    | +---------------+-------+ 1 row in set (0.00 sec)   mysql> show master status; +------------------+----------+--------------+------------------+ | File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | +------------------+----------+--------------+------------------+ | mysql-bin.000001 |      341 |              |                  | +------------------+----------+--------------+------------------+ 1 row in set (0.00 sec)

2.3在主库创建复制用户

mysql> grant replication slave on *.* to 'oldboy123'@'172.20.28.%' identified by 'oldboy123'; Query OK, 0 rows affected (0.00 sec) mysql> flush privileges; Query OK, 0 rows affected (0.00 sec)

mysql> select user,host,password  from mysql.user; +-----------+-------------+-------------------------------------------+ | user      | host        | password                                  | +-----------+-------------+-------------------------------------------+ | root      | localhost   | *FE28814B4A8B3309DAC6ED7D3237ADED6DA1E515 | | root      | i-t27hedd8  |                                           | | root      | 127.0.0.1   |                                           | |           | localhost   |                                           | |           | i-t27hedd8  |                                           | | oldboy123 | 172.20.28.* | *FE28814B4A8B3309DAC6ED7D3237ADED6DA1E515 | +-----------+-------------+-------------------------------------------+

2.4 分别在两台从库上操作

mysql> change master to  master_host='172.20.28.36', master_port=3306, master_user='oldboy123', master_password='oldboy123', master_log_file='mysql-bin.000001', master_log_pos=714; mysql> flush privileges；

2.5 分别开启两台从库

mysql> start slave;

2.6 分别查看两台从库的信息

show slave status\G; *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: 172.20.28.36 Master_User: oldboy123 Master_Port: 3306 Connect_Retry: 60 Master_Log_File: mysql-bin.000001 Read_Master_Log_Pos: 1130 Relay_Log_File: mysqld-relay-bin.000002 Relay_Log_Pos: 667 Relay_Master_Log_File: mysql-bin.000001              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_Error: Skip_Counter: 0 Exec_Master_Log_Pos: 1130 Relay_Log_Space: 823 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:

至此，MySQL一主双从就配置完成了。