CentOS7下MySQL5.7主从配置

1、一主一从分配

环境：CentOS7 + Percona-Server-server-57-5.7.32
MySQL安装请参考博文：CentOS7下MySQL(Percona-Server-5.7)安装及简单使用。
主：192.168.178.130
从：192.168.178.150

2、主数据库master配置

1.修改mysql配置

找到主数据库的配置文件my.cnf(或者my.ini)，我的在/etc/percona-server.conf.d/mysqld.cnf下，相关配置项如下：

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# 开启二进制日志 
log_bin=mysql-bin 
binlog_format=ROW 
# 设置server-id 
server-id=130 
# 同步的数据库
binlog-do-db=test 
# 不同步哪些数据库 
binlog-ignore-db = mysql 
binlog-ignore-db = information_schema 
datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock 
symbolic-links=0 
log-error=/var/log/mysqld.log

修改完后需要重启mysql：

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systemctl restart mysql

2.创建用于同步的用户账号

打开mysql会话:

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mysql -uroot -p123456

创建用户并授权:

用户：repl 密码：123456

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mysql> CREATE USER 'repl'@'localhost' IDENTIFIED BY '123456'; 
mysql> GRANT REPLICATION SLAVE ON *.* TO 'repl'@'localhost'; 
mysql> flush privileges;

3.查看master状态

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mysql> show master status;

记录二进制文件名(mysql-bin.000001)和位置(763)。

3、从服务器slave配置

1.修改mysql配置

同样找到my.cnf配置文件，server-id=150，最终配置如下：

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[mysqld] 
log_bin=mysql-bin 
binlog_format=ROW 
server-id=150 
#打开MySQL中继日志 
#relay-log-index=slave-relay-bin.index 
#relay-log=slave-relay-bin 
datadir=/var/lib/mysql 
socket=/var/lib/mysql/mysql.sock 
symbolic-links=0 
log-error=/var/log/mysqld.log 
pid-file=/var/run/mysqld/mysqld.pid

修改配置后重启mysql。

2.执行同步SQL语句

打开mysql会话，执行同步SQL语句(需要主服务器主机名，登陆账号，二进制文件的名称和位置)：

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mysql> CHANGE MASTER TO MASTER_HOST='192.168.178.130',MASTER_USER='repl',MASTER_PASSWORD='123456',MASTER_LOG_FILE='mysql-bin.000001',MASTER_LOG_POS=763;

3.启动slave同步进程：

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mysql> start slave;

4.查看slave状态

mysql> show slave status\G;

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mysql> show slave status\G;
 
*************************** 1. row ***************************
 
Slave_IO_State:
 
Master_Host: 192.168.178.130
 
Master_User: repl
 
Master_Port: 3306
 
Connect_Retry: 60
 
Master_Log_File: mysql-bin.000004
 
Read_Master_Log_Pos: 154
 
Relay_Log_File: 192-relay-bin.000001
 
Relay_Log_Pos: 4
 
Relay_Master_Log_File: mysql-bin.000004
 
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: 154
 
Relay_Log_Space: 154
 
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: 1593
 
Last_IO_Error: Fatal error: The slave I/O thread stops because master and slave have equal MySQL server UUIDs; these UUIDs must be different for replication to work.
 
Last_SQL_Errno: 0
 
Last_SQL_Error:
 
Replicate_Ignore_Server_Ids:
 
Master_Server_Id: 130
 
Master_UUID:
 
Master_Info_File: /var/lib/mysql/master.info
 
SQL_Delay: 0
 
SQL_Remaining_Delay: NULL
 
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
 
Master_Retry_Count: 86400
 
Master_Bind:
 
Last_IO_Error_Timestamp: 210102 23:03:33
 
Last_SQL_Error_Timestamp:
 
Master_SSL_Crl:
 
Master_SSL_Crlpath:
 
Retrieved_Gtid_Set:
 
Executed_Gtid_Set:
 
Auto_Position: 0
 
Replicate_Rewrite_DB:
 
Channel_Name:
 
Master_TLS_Version:
 
1 row in set (0.00 sec)

检查从库是否同步成功：

‘Slave_IO_Running: Yes’ (负责与主库同步IO通信)

‘Slave_SQL_Running: Yes’ (负责自身slave mysql进程)

上面有一处异常：

Last_IO_Error: Fatal error: The slave I/O thread stops because master and slave have equal MySQL server UUIDs; these UUIDs must be different for replication to work.

原因分析：

mysql 5.7的复制引入了uuid的概念，各个复制结构中的server_uuid得保证不一样，但是查看到直接copy data文件夹后server_uuid是相同的
mysql> show variables like ‘%server_uuid%’;

解决方法：

找到data文件夹下的auto.cnf文件，修改里面的uuid值，保证各个db的uuid不一样，重启mysql即可。

再次查看slave状态：

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mysql> show slave status\G;
 
*************************** 1. row ***************************
 
Slave_IO_State: Waiting for master to send event
 
Master_Host: 192.168.178.130
 
Master_User: repl
 
Master_Port: 3306
 
Connect_Retry: 60
 
Master_Log_File: mysql-bin.000004
 
Read_Master_Log_Pos: 154
 
Relay_Log_File: 192-relay-bin.000003
 
Relay_Log_Pos: 320
 
Relay_Master_Log_File: mysql-bin.000004
 
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_Errno: 0
 
Last_Error:
 
Skip_Counter: 0
 
Exec_Master_Log_Pos: 154
 
Relay_Log_Space: 525
 
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:
 
Last_SQL_Errno: 0
 
Last_SQL_Error:
 
Replicate_Ignore_Server_Ids:
 
Master_Server_Id: 130
 
Master_UUID: fb6c6f2b-4ca3-11eb-9e30-000c293fa755
 
Master_Info_File: /var/lib/mysql/master.info
 
SQL_Delay: 0
 
SQL_Remaining_Delay: NULL
 
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
 
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
 
Replicate_Rewrite_DB:
 
Channel_Name:
 
Master_TLS_Version:
 
1 row in set (0.02 sec)

4、主从同步测试

登录主mysql（192.168.178.130）, 创建数据库test:

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mysql> create database test;

登录从mysql（192.168.178.150），查看数据库：

在主mysql上test数据库中新建表tb_user；

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CREATE TABLE `tb_user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `user_name` varchar(20) DEFAULT '',
  `passwd` varchar(20) DEFAULT NULL,
  `age` smallint(6) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

查看从mysql test数据库下的表：

在主mysql上tb_user上新增一条数据：

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INSERT INTO tb_user (id, user_name, passwd, age) VALUES (1, 'xiaowang', '123456', 18);

在从数据库上查看：

会看到主数据库上的操作都同步到了从数据库上。

按照目前的配置，从数据库也是可以写入数据的，但从的写入不会同步到主，会导致主从数据不一致;

从库上限制用户写入数据，在从服务中将read_only参数的值设为1：

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mysql> set global read_only=1;

生产上建议在主库上写数据，从库上读数据，这样就可以做到读写分离。

MySQL
#CentOS #MySQL #主从
CentOS7下MySQL5.7主从配置
https://river106.cn/posts/c90c9699.html
作者
river106
发布于
2021年1月3日
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