MySQL8.0 一主二从

1. 系统环境

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cat /etc/redhat-release
CentOS Linux release 7.9.2009 (Core)

192.168.183.137     mysql-master
192.168.183.153     mysql-slave-1
192.168.183.154     mysql-slave-2

# 关闭SELINUX
sed -i 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config
setenforce 0

# 关闭防火墙
systemctl stop firewalld
systemctl disable firewalld

2. 安装MySQL

三台机器均执行

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wget  https://dev.mysql.com/get/mysql80-community-release-el7-7.noarch.rpm
yum -y install  mysql80-community-release-el7-7.noarch.rpm
yum clean all && yum makecache
yum -y  install mysql-community-server
systemctl start mysqld
systemctl enable mysqld

# 查看root密码
grep 'temporary password' /var/log/mysqld.log
mysql -uroot -ppassword

# 修改root密码
ALTER USER 'root'@'localhost' IDENTIFIED BY 'password';
FLUSH PRIVILEGES;

3. mysql-master配置文件修改

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vim /etc/my.cnf
# 加入以下内容
server_id=137      # server_id需要保证唯一性，不可与其他从服务器相同 如果为0会拒绝所有从服务器连接
log-bin=mysql-bin  # 设置同步的binary log二进制日志文件名前缀，默认是binlog
binlog_ignore_db = information_schema # 不需要同步的数据库
binlog_ignore_db = performance_schema # 不需要同步的数据库
innodb_flush_log_at_trx_commit=1  # 我们每次事务的结束都会触发Log Thread 将log buffer中的数据写入文件并通知文件系统同步文件。这个设置是最安全的设置，能够保证不论是MySQL Crash 还是OS Crash或者是主机断电都不会丢失任何已经提交的数据。

4. mysql-slave-1配置文件修改

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vim /etc/my.cnf
# 加入以下内容
server_id=153      
log-bin=mysql-bin 
binlog_ignore_db = information_schema 
binlog_ignore_db = performance_schema 
innodb_flush_log_at_trx_commit=1

5. mysql-slave-2配置文件修改

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vim /etc/my.cnf
# 加入以下内容
server_id=154     
log-bin=mysql-bin 
binlog_ignore_db = information_schema 
binlog_ignore_db = performance_schema 
innodb_flush_log_at_trx_commit=1

修改完成之后全部重启systemctl restart mysqld

6. 主库创建复制用户

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mysql -uroot -ppassworn

# 创建同步账户master节点 执行

mysql> CREATE USER slave@'%' IDENTIFIED BY 'QAZqaz1234@';
mysql> GRANT ALL PRIVILEGES ON *.* TO 'slave'@'%'WITH GRANT OPTION;
mysql> CHANGE MASTER TO GET_MASTER_PUBLIC_KEY=1;
mysql> FLUSH PRIVILEGES;
mysql> SHOW MASTER STATUS;

mysql> show master status;
+------------------+----------+--------------+---------------------------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB                      | Executed_Gtid_Set |
+------------------+----------+--------------+---------------------------------------+-------------------+
| mysql-bin.000001 |      873 |              | information_schema,performance_schema |                   |
+------------------+----------+--------------+---------------------------------------+-------------------+

7. 配置从库

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mysql -uroot -ppassworn

# slave-1和slave-2都是同样的操作
mysql> change master to
master_host='192.168.183.137',master_user='slave',master_password='QAZqaz1234@',
master_log_file='master-bin.000001',master_log_pos=873;

# 启动同步
mysql> START SLAVE;
mysql> FLUSH PRIVILEGES;

mysql> SHOW SLAVE STATUS\G

Slave_IO_Running: Connecting，

报错：Error connecting to source 'slave@192.168.183.137:3306'. This was attempt 5/86400, with a delay of 60 seconds between attempts. Message: Authentication plugin 'caching_sha2_password' reported error: Authentication requires secure connection.

发生这个问题的原因是在 mysql 8.0 以后，caching_sha2_password是默认的身份验证插件，而不是以往的mysql_native_password。在 MySQL Command Line 工具下修改 mysql 的默认身份验证插件即可。

登录主库

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ALTER USER slave@'%' IDENTIFIED WITH mysql_native_password BY 'QAZqaz1234@';

FLUSH PRIVILEGES;

然后从库重新同步

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# slave-1和slave-2都是同样的操作
mysql> STOP SLAVE;

mysql> change master to
master_host='192.168.183.137',master_user='slave',master_password='QAZqaz1234@',
master_log_file='master-bin.000001',master_log_pos=1323;

# 启动同步
mysql> RESET SLAVE;
mysql> START SLAVE;
mysql> FLUSH PRIVILEGES;

再次查看同步状况可以看到已经成功：

mysql> SHOW SLAVE STATUS\G

8. 测试

在master节点上执行SQL语句

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create database db_test;
show databases;

在从库上面查看

在master的db_test库里面创建表

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use db_test;
# 创建一个my_user表：
CREATE TABLE `my_user` (
  `id` tinyint(4) NOT NULL AUTO_INCREMENT,
  `account` varchar(255) DEFAULT NULL,
  `passwd` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
);

# 插入数据：
INSERT INTO `my_user` VALUES ('1', 'admin', 'admin');
INSERT INTO `my_user` VALUES ('2', 'pu', '12345');
INSERT INTO `my_user` VALUES ('3', 'system', 'system');

# 查看插入数据
select * from db_test.my_user;

到从库上都能查到则说明没问题。