CentOS7操作系统下实现mysql数据库的主主复制

时间：2022-09-15 08:30:38

CentOS7操作系统下实现mysql主主复制
实验环境：两台主机，172.18.24.107,172,18.24.27
操作系统为Centos7.3
安装mariadb服务，源码编译安装或者yum安装都可，这里选择yum安装
172.18.24.107主机上：
停掉mariadb服务，修改配置文件

[root@node1 ~]#systemctl stop mariadb.srevice 
vim /etc/my.cnf.d/server.cnf 
[server]
skip_name_resolve=ON        #跳过解析过程
innodb_file_per_table=ON   
max_connection=20000        #最大连接数
log_bin=master-log          #开启二进制日志 
server_id=1                 #服务器di号
relay_log=relay-log         #开启中继日志
auto_increment_offset=1
auto_increment_increment=2
[root@node1 ~]#systemctl start mariadb.service #开启服务
[root@node1 ~]#mysql
MariaDB [(none)]> SHOW MASTER STATUS;
MariaDB [(none)]> STOP SLAVE;
MariaDB [(none)]> GRANT REPLICATION SLAVE,REPLICATION CLIENT ON *.* TO 'repluser'@'172.18.24.%' IDENTIFIED BY 'replpass';

查看172.18.24.27主机上二进制日志文件记录的位置：

MariaDB [test]> SHOW BINARY LOGS;
+-------------------+-----------+
| Log_name | File_size | +-------------------+-----------+
| master-log.000001 |     30824 |
| master-log.000002 |   1069459 |
| master-log.000003 | 507 | +-------------------+-----------+
从上面可以看到172.18.24.27主机上二进制记录的结束位置是507，那么需要从507开始复制

回到在172.18.24.107主机上：

MariaDB [test]>CHANGE MASTER TO MASTER_HOST='172.18.24.107',MASTER_USER='repluser',MASTER_PASSWORD='replpass',MASTER_LOG_FILE='masterlog.000003',MASTER_LOG_POS=507;
MariaDB [test]>START SLAVE;
MariaDB [test]>SHOW SLAVE STATUS\G;
*************************** 1. row ***************************
 Slave_IO_State: Waiting for master to send event
 Master_Host: 172.18.24.107
 Master_User: repluser
 Master_Port: 3306
 Connect_Retry: 60
 Master_Log_File: master-log.000003
 Read_Master_Log_Pos: 723
 Relay_Log_File: relay-log.000002
 Relay_Log_Pos: 746
 Relay_Master_Log_File: master-log.000003
 Slave_IO_Running: Yes
 Slave_SQL_Running: Yes

172.18.24.107节点上：

systemctl stop mariadb.srevice 
vim /etc/my.cnf.d/server.cnf 
    [server]
    skip_name_resolve=ON    #跳过解析过程
    innodb_file_per_table=ON  
    max_connection=20000   #最大连接数

    log_bin=master-log   #开启二进制日志 
    server_id=1          #服务器di号
    relay_log=relay-log  #开启中继日志

    auto_increment_offset=2   #初始值
    auto_increment_increment=2   #步进值 
systemctl start mariadb.service 
mysql 
>SHOW MASTER STATUS;
MariaDB [test]> GRANT REPLICATION SLAVE,REPLICATION CLIENT ON *.* TO 'repluser'@'172.18.24.%' IDENTIFIED BY 'replpass';
MariaDB [(none)]> CHANGE MASTER TO MASTER_HOST='172.18.24.27',MASTER_USER='repluser',
MASTER_PASSWORD='replpass',MASTER_LOG_FILE='master-log.000003',MASTER_LOG_POS=507; 
MariaDB [(none)]> STOP SLAVE;
MariaDB [(none)]> SHOW SLAVE STATUS\G;
*************************** 1. row ***************************
               Slave_IO_State: 
                  Master_Host: 172.18.24.27
                  Master_User: repluser
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: master-log.000003
          Read_Master_Log_Pos: 507
               Relay_Log_File: relay-log.000001
                Relay_Log_Pos: 4
        Relay_Master_Log_File: master-log.000003
             Slave_IO_Running: No
            Slave_SQL_Running: No
MariaDB [(none)]> START SLAVE;
MariaDB [(none)]> SHOW SLAVE STATUS\G;
*************************** 1. row ***************************
 Slave_IO_State: Waiting for master to send event
 Master_Host: 172.18.24.27
 Master_User: repluser
 Master_Port: 3306
 Connect_Retry: 60
 Master_Log_File: master-log.000003
 Read_Master_Log_Pos: 507
 Relay_Log_File: relay-log.000002
 Relay_Log_Pos: 530
 Relay_Master_Log_File: master-log.000003
 Slave_IO_Running: Yes
 Slave_SQL_Running: Yes

配置完成，开始测试：
在172.18.24.107上

MariaDB [test]> show tables;   #107上测试数据库test中没有表
Empty set (0.00 sec)

在172.18.24.27上

ariaDB [(none)]> use test;
Database changed
MariaDB [test]> show tables;  #27上测试数据库test中没有表
Empty set (0.00 sec)
MariaDB [test]> CREATE TABLE students(id INT UNSIGNED PRIMARY KEY,name CHAR(30) NOT NULL,age TINYINT UNSIGNED,gender ENUM('F','M'));    #在27上创建数据库

在172.18.24.107上查看测试数据库中是否同步了172.18.24.27上的表students

MariaDB [test]> show tables;
+----------------+
| Tables_in_test | +----------------+
| students | +----------------+
1 row in set (0.00 sec)

查看表结构，根27上的表一样，说明172.1824.107主机上同步了172.18.24.27主机

MariaDB [test]> DESC students;
+--------+---------------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra | +--------+---------------------+------+-----+---------+-------+
| id     | int(10) unsigned    | NO   | PRI | NULL    |       |
| name   | char(30)            | NO   |     | NULL    |       |
| age    | tinyint(3) unsigned | YES  |     | NULL    |       |
| gender | enum('F','M') | YES | | NULL | | +--------+---------------------+------+-----+---------+-------+
4 rows in set (0.01 sec)

如上，我们可以确定，172.18.24.107主机上的数据库同步了172.18.24.27上的数据库

然后，我们在172.1824.107主机上插入数据如下：

MariaDB [test]> INSERT INTO students VALUE (1,'xiaoming',22,'M');
Query OK, 1 row affected (0.01 sec)

MariaDB [test]> SELECT * FROM students;
+----+----------+------+--------+
| id | name | age | gender | +----+----------+------+--------+
| 1 | xiaoming | 22 | M | +----+----------+------+--------+
1 row in set (0.00 sec)

在172.18.24.27主机上查看是否同步了172.1824.107主机上的插入更改：

MariaDB [test]> select * from students;
+----+----------+------+--------+
| id | name | age | gender | +----+----------+------+--------+
| 1 | xiaoming | 22 | M | +----+----------+------+--------+
1 row in set (0.00 sec)

如上，我们可以确定，172.18.24.27主机上的数据库同步了172.18.24.107上的数据库。

由此，我们实现了两台主机的互相复制，互为主从！

总结：主主复制是在主从复制上衍生过来的，自己是别人的从也同时是别人的主，做为主数据库，需要有写的权限，并且二进制日志需要开启，从数据库只需要有读的权限，但是我们这里是主主，即两台主机都需要开启读写权限。在生产中，我们需要不停机的状态下中途搭建主主复制模式，那么之前的数据就需要全量备份到从数据库中，然后再开启复制。

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