MySql双主+高可用

准备工作

系统：Centos7.6 / 64 位
MySql：v5.7.34
Keepalived：v1.2.24
Rpm：http://repo.mysql.com/mysql57-community-release-el7-8.noarch.rpm
二进制：https://downloads.mysql.com/archives/community/

MySql部署规划（双主互备）

实例	IP	端口	备注
MySql	10.88.40.134	3306	主1
MySql	10.88.40.175	3306	主2
keepalived	10.88.40.200	3306	vip

两台服务器安装Mysql（操作一样）

1. 安装mysql

wget http://repo.mysql.com/mysql57-community-release-el7-8.noarch.rpm
rpm -ivh mysql57-community-release-el7-8.noarch.rpm
yum -y install mysql-server

---

2. 启动mysql服务

service mysqld restart

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3. 重置密码

grep "password" /var/log/mysqld.log

mysql -u root -p  回车
密码：xxx

#更改密码策略为LOW
set global validate_password_policy=0;
#更改密码长度
set global validate_password_length=0;

alter user 'root'@'localhost' identified by '123456';
CREATE USER 'ab'@'%' IDENTIFIED BY '123456';
grant all on *.* to 'ab'@'%' identified by '123456'  with grant option;
update mysql.user set host='%' where user='root';
flush privileges;
exit;
service mysqld restart

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4. 关闭防火墙

firewall-cmd --state //查看防火墙状态
systemctl stop firewalld.service //停止firewall
systemctl disable firewalld.service //禁止firewall开机启动

补充一下：

配置文件：/etc/my.cnf 
日志文件：/var/log/mysqld.log 
服务启动脚本：/usr/lib/systemd/system/mysqld.service 
socket文件：/var/run/mysqld/mysqld.pid

设置主从同步

配置主库1my.cnf，末尾追加

# #将复制事件写入binlog，一台服务器既要做主库又要做从库，此选项必须开启
log-slave-updates=true

#### replication ####
replicate-ignore-db=information_schema
replicate-ignore-db=mysql
replicate-ignore-db=performace_schema
#启用二进制日志
log-bin=mysql-bin
#服务器唯一ID，一般取IP最后一段
server-id=134
sql-mode=STRICT_TRANS_TABLES,NO_ENGINE_SUBSTITUTION

service mysqld restart

配置主库2my.cnf，末尾追加

# #将复制事件写入binlog，一台服务器既要做主库又要做从库，此选项必须开启
log-slave-updates=true

#### replication ####
replicate-ignore-db=information_schema
replicate-ignore-db=mysql
replicate-ignore-db=performace_schema
#启用二进制日志
log-bin=mysql-bin
#服务器唯一ID，一般取IP最后一段
server-id=175
sql_mode=STRICT_TRANS_TABLES,NO_ENGINE_SUBSTITUTION

service mysqld restart

查询主1master的状态

show master status;

配置主2服务器

#配置从服务器
mysql>change master to master_host='10.88.40.134',master_port=3306,master_user='ab',master_password='123456',master_log_file='mysql-bin.000002',master_log_pos=4219;
#注意语句中间不要断开，master_port为mysql服务器端口号(无引号)，master_user为执行同步操作的数据库账户，“4219”无单引号(此处的4219就是show master status 中看到的position的值，这里的mysql-bin.000002就是file对应的值)
#启动从服务器复制功能
Mysql>start slave; 
#检查从服务器复制功能状态：
mysql> show slave status\G;

【查询master的状态、配置主库2服务器】两台都要做，先做主1，再做主2
注：Slave_IO及Slave_SQL进程必须正常运行，即YES状态，否则都是错误的状态(如：其中一个NO均属错误)。

校验主从同步

配置keepalived

yum install keepalived

修改配置文件（主1）路径：/etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs {
   router_id MYSQL_HA #标识，双主相同 
}

vrrp_instance VI_1 {
    state BACKUP #两台配置此处均是BACKUP   
    interface ens33
    virtual_router_id 51 #主备相同
    priority 100 #优先级，另一台backup改为90 
    advert_int 1
    nopreempt #不抢占，只在优先级高master的机器上设置即可，优先级低backup的机器不设置
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        10.88.40.239
    }
}

virtual_server 10.88.40.239 3306 {
    delay_loop 6 #每个6秒检查一次real_server状态
    #lb_algo rr #LVS算法，用不到，我们就关闭了
    #lb_kind NAT #LVS模式,如果不关闭，备用服务器不能通过VIP连接主MySQL
    persistence_timeout 60 #会话保持时间，同一IP的连接60秒内被分配到同一台真实服务器
    protocol TCP

    real_server 10.88.40.139 3306 { #检测本地mysql，backup也要写检测本地mysql
        weight 3
        notify_down /etc/keepalived/mysql.sh #当mysq服down时，执行此脚本，杀死keepalived实现切换
        TCP_CHECK {
            connect_timeout 10 #连接超时时间    
            nb_get_retry 3 #重连次数
            delay_before_retry 3 #重连间隔时间
            connect_port 3306 #健康检查端口
        }
    }
}

修改配置文件（主2）

! Configuration File for keepalived

global_defs {
   router_id MYSQL_HA
}

vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        10.88.40.239
    }
}

virtual_server 10.88.40.239 3306 {
    delay_loop 6
    #lb_algo rr
    #lb_kind NAT
    persistence_timeout 60
    protocol TCP

    real_server 10.88.40.181 3306 {
        weight 3
        notify_down /etc/keepalived/mysql.sh
        TCP_CHECK {
            connect_timeout 10
            nb_get_retry 3
            delay_before_retry 3
            connect_port 3306
        }
    }
}

mysql.sh

#!/bin/bash
pkill keepalived

启动

systemctl start keepalived

tail -500f /var/log/messages