MySQL Replication

        MySQL提供了Replication功能,可以实现将一个数据库的数据同步到多台其他数据库。前者通常称之为主库(master),后者则被称从库(slave)。MySQL复制过程采用异步方式,但延时非常小,秒级同步。

同步复制数据基本原理

1.在主库上发生的数据变化记录到二进制日志Binlog
2.从库的IO线程将主库的Binlog复制到自己的中继日志Relay log
3.从库的SQL线程通过读取、重放中继日志实现数据复制

mysql

        MySQL的复制有三种模式:Statement Level、Row Level、Mixed Level。复制级别的不同,会导致Master端二进制日志文件的生成形式的不同。

环境

环境版本
Docker26.1.4
CentOS7
Mysql5.7

步骤

一、创建容器

docker run -p 3307:3306 --name mysql-master \
-v /mydata/mysql-cluster/mysql-master1/log:/var/log/mysql \
-v /mydata/mysql-cluster/mysql-master1/data:/var/lib/mysql \
-v /mydata/mysql-cluster/mysql-master1/conf:/etc/mysql \
-v /mydata/mysql-cluster/mysql-master1/mysql-files:/var/lib/mysql-files \
-e MYSQL_ROOT_PASSWORD=root \
-d mysql:5.7

docker run -p 3317:3306 --name mysql-master2 \
-v /mydata/mysql-cluster/mysql-master2/log:/var/log/mysql \
-v /mydata/mysql-cluster/mysql-master2/data:/var/lib/mysql \
-v /mydata/mysql-cluster/mysql-master2/conf:/etc/mysql \
-v /mydata/mysql-cluster/mysql-master2/mysql-files:/var/lib/mysql-files \
-e MYSQL_ROOT_PASSWORD=root \
-d mysql:5.7

docker run -p 3327:3306 --name mysql-slave1 \
-v /mydata/mysql-cluster/mysql-slave1/log:/var/log/mysql \
-v /mydata/mysql-cluster/mysql-slave1/data:/var/lib/mysql \
-v /mydata/mysql-cluster/mysql-slave1/conf:/etc/mysql \
-v /mydata/mysql-cluster/mysql-slave1/mysql-files:/var/lib/mysql-files \
-e MYSQL_ROOT_PASSWORD=root \
-d mysql:5.7

docker run -p 3337:3306 --name mysql-slave2 \
-v /mydata/mysql-cluster/mysql-slave2/log:/var/log/mysql \
-v /mydata/mysql-cluster/mysql-slave2/data:/var/lib/mysql \
-v /mydata/mysql-cluster/mysql-slave2/conf:/etc/mysql \
-v /mydata/mysql-cluster/mysql-slave2/mysql-files:/var/lib/mysql-files \
-e MYSQL_ROOT_PASSWORD=root \
-d mysql:5.7

二、创建配置文件

分别创建配置文件并写入对应的配置:

master配置

修改mydata/mysql-cluster/mysql-master1/conf/my.cnf,把以下配置写入到my.cnf

[client]
default-character-set=utf8
[mysql]
default-character-set=utf8
[mysqld]
init_connect='SET collation_connection = utf8_unicode_ci' 
init_connect='SET NAMES utf8' 
character-set-server=utf8
collation-server=utf8_unicode_ci
skip-character-set-client-handshake
skip-name-resolve
[mysqld]
server_id=1
log-bin=mysql-bin
read-only=0

binlog-do-db=admin

replicate-ignore-db=mysql
replicate-ignore-db=sys
replicate-ignore-db=information_schema
replicate-ignore-db=performance_schema

binlog_cache_size=1M  
binlog_format=mixed  
log-slave-updates 
expire_logs_days=7  
slave_skip_errors=1062

slave配置

修改mydata/mysql-cluster/mysql-slave1/conf/my.cnf,把以下配置写入到my.cnf

[client]
default-character-set=utf8
[mysql]
default-character-set=utf8
[mysqld]
init_connect='SET collation_connection = utf8_unicode_ci'
init_connect='SET NAMES utf8' 
character-set-server=utf8
collation-server=utf8_unicode_ci
skip-character-set-client-handshake
skip-name-resolve

server_id=4
log-bin=mysql-bin
read-only=1
binlog-do-db=admin

replicate-ignore-db=mysql
replicate-ignore-db=sys
replicate-ignore-db=information_schema
replicate-ignore-db=performance_schema

*注意

每个配置文件server_id必须唯一

若不配置读写分离read-only无需设置

log-bin=mysql-bin:mysql5.7默认不开启bin_log日志,需要此配置开启

binlog-do-db:指定同步的数据库名

replicate-ignore-db:指定不同步的数据库名

三、启动容器

docker start mysql-master mysql-master2 mysql-slave1 mysql-slave2

四、主从关联

配置master

1.进入容器

docker exec -it mysql-master /bin/bash

2.登录

mysql -uroot -proot

3.查看是否开启远程访问(可选)

mysql> select user,host from mysql.user;
+---------------+-----------+
| user          | host      |
+---------------+-----------+
| root          | %         |
| mysql.session | localhost |
| mysql.sys     | localhost |
| root          | localhost |
+---------------+-----------+
4 rows in set (0.01 sec)

如果没有'root'@'%'记录就执行

grant all privileges on *.* to 'root'@'%' identified by 'root' with grant option;
flush privileges;

4.配置权限

grant replication slave on *.* to 'backup'@'%' identified by 'root';

5.查看状态

File和Position这两个参数后面会用到

mysql> show master status\G;
*************************** 1. row ***************************
             File: mysql-bin.000001
         Position: 439
     Binlog_Do_DB: admin
 Binlog_Ignore_DB: 
Executed_Gtid_Set: 
1 row in set (0.00 sec)

 配置Slave

重复配置master的1、2、3(可选)步骤

4.配置主从复制

change master to master_host='192.168.56.11',master_user='backup',master_password='root',master_log_file='mysql-bin.000001',master_log_pos=439,master_port=3307;

‌        change master命令用于配置和改变Slave服务器用于连接Master服务器的参数,以便Slave服务器读取Master服务器的binlog及Slave服务器的relay log。‌ 这个命令同时更新master.info及relay-log.info信息。在执行该命令之前,如果Slave服务器上的IO线程和SQL线程已经启动,需要先停止这些线程(执行stop slave命令)。

change master命令的参数‌包括但不限于:

  • MASTER_HOST‌ 和 ‌MASTER_PORT‌:指定Master服务器的IP地址和端口号。
  • MASTER_USER‌ 和 ‌MASTER_PASSWORD‌:用于认证的Master服务器用户名和密码。
  • MASTER_LOG_FILE‌ 和 ‌MASTER_LOG_POS‌:指定从哪个binlog文件以及从该文件的哪个位置开始复制数据。
  • MASTER_CONNECT_RETRY‌、‌MASTER_RETRY_COUNT‌、‌MASTER_DELAY‌、‌MASTER_HEARTBEAT_PERIOD‌ 等:这些参数用于控制连接重试、延迟和心跳等行为。
  • MASTER_AUTO_POSITION‌:设置为1时,Slave服务器可以自动确定应该从Master服务器的哪个binlog文件和位置开始复制数据。
  • RELAY_LOG_FILE‌ 和 ‌RELAY_LOG_POS‌:如果设置了,这些参数用于指定中继日志的文件名和位置。
  • MASTER_SSL‌ 和相关SSL参数:用于配置SSL加密连接。

5.开启同步

start slave;

如果Slave_IO_RunningSlave_SQL_Running显示为Yes,开启成功,如果为Connecting说明出现错误,排查网络是否畅通、mysql配置文件、防火墙、master账号的连接权限、change master参数

 master执行记录

[root@10 conf]# docker exec -it mysql-master /bin/bash
root@1275b7c6c4d6:/# mysql -uroot -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.36-log MySQL Community Server (GPL)

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> select user,host from mysql.user;
+---------------+-----------+
| user          | host      |
+---------------+-----------+
| root          | %         |
| mysql.session | localhost |
| mysql.sys     | localhost |
| root          | localhost |
+---------------+-----------+
4 rows in set (0.01 sec)

mysql> grant replication slave on *.* to 'backup'@'%' identified by 'root';
Query OK, 0 rows affected, 1 warning (0.02 sec)

mysql> show master status\G;
*************************** 1. row ***************************
             File: mysql-bin.000001
         Position: 439
     Binlog_Do_DB: admin
 Binlog_Ignore_DB: 
Executed_Gtid_Set: 
1 row in set (0.00 sec)

slave执行记录

mysql> change master to master_host='192.168.56.11',master_user='backup',master_password='root',master_log_file='mysql-bin.000001',master_log_pos=439,master_port=3307;
Query OK, 0 rows affected, 2 warnings (0.11 sec)

mysql> start slave;
Query OK, 0 rows affected (0.01 sec)

mysql> show slave status\G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.56.11
                  Master_User: backup
                  Master_Port: 3307
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000001
          Read_Master_Log_Pos: 439
               Relay_Log_File: 9cd2f3cd957f-relay-bin.000002
                Relay_Log_Pos: 320
        Relay_Master_Log_File: mysql-bin.000001
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
              Replicate_Do_DB: 
          Replicate_Ignore_DB: mysql,sys,information_schema,performance_schema
           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: 439
              Relay_Log_Space: 534
              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: 2
                  Master_UUID: 534ec559-61e3-11ef-a009-0242ac110009
             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 (0.00 sec)

五、双主关联

两个master互为主从

master1

mysql> change master to master_host='192.168.56.11',master_user='backup',master_password='root',master_log_file='mysql-bin.000001',master_log_pos=439,master_port=3317;
Query OK, 0 rows affected, 2 warnings (0.01 sec)

master2

mysql> change master to master_host='192.168.56.11',master_user='backup',master_password='root',master_log_file='mysql-bin.000001',master_log_pos=369,master_port=3307;
Query OK, 0 rows affected, 2 warnings (0.12 sec)

至此,Msql集群搭建完成

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