下文内容主要给大家带来mysql双主配置讲义，这里所讲到的知识，与书籍略有不同，都是专业技术人员在与用户接触过程中，总结出来的，具有一定的经验分享价值，希望给广大读者带来帮助。

结尾2

1.数据库架构图：

2.安装环境信息：
master1 172.16.90.13    CentOS 7.2  Keepalived读  VIP：172.16.90.15
master2 172.16.90.14    CentOS 7.2  Keepalived读  VIP：172.16.90.16

3.MySQL双主配置

master1修改my.cnf,新增如下配置：

server-id=13
log-bin=mysql-bin
sync-binlog=1
binlog-checksum=none
binlog-format=mixed
auto-increment-increment=2
auto-increment-offset=1
log-slave-updates
slave-skip-errors=all

master2修改my.cnf,新增如下配置：

server-id=14
log-bin=mysql-bin
sync-binlog=1
binlog-checksum=none
binlog-format=mixed
auto-increment-increment=2
auto-increment-offset=1
log-slave-updates
slave-skip-errors=all

在master1中为mysql从库账户授权：

grant replication slave on . to 'sync'@'%' identified by 'syncpwd';
flush privileges;
show master status; #当前主库状态,即master1
show master status;
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000004 |      599 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+

在master2中为mysql从库账户授权：

grant replication slave on . to 'sync'@'%' identified by 'syncpwd';
flush privileges;
show master status; #当前主库状态,即master2
show master status;
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000002 |      468 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+

在maste1中指定master2为主库：

stop slave;
change master to master_host='172.16.90.14',master_user='sync',master_password='syncpwd',master_log_file='mysql-bin.000002',master_log_pos=468;
flush privileges;
SET GLOBAL SQL_SLAVE_SKIP_COUNTER=1; START SLAVE;
start slave;

在maste2中指定master1为主库：

stop slave;
change master to master_host='172.16.90.13',master_user='sync',master_password='syncpwd',master_log_file='mysql-bin.000004',master_log_pos=599;
flush privileges;
SET GLOBAL SQL_SLAVE_SKIP_COUNTER=1; START SLAVE;
start slave;

MySQL双主配置完成，验证配置成功：

show slave status\G #master1中显示的信息
1. row
Slave_IO_State: Waiting for master to send event
Master_Host: 172.16.90.13
Master_User: sync
Master_Port: 3306
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
show slave status\G #master2中显示的信息
1. row
Slave_IO_State: Waiting for master to send event
Master_Host: 172.16.90.14
Master_User: sync
Master_Port: 3306
Slave_IO_Running: Yes
Slave_SQL_Running: Yes

4.Keepalived高可用配置

安装：yum install -y keepalived
启动：systemctl stop keepalived
说明：
当两台云服务器都正常的时候
用户写数据默认访问服务器A，如果A有异常则访问B服务器。
用户读数据默认访问服务器B，如果B有异常则访问A服务器。

服务器A的写数据初始权重为100，B为90
服务器A的读数据初始权重为90，B为100
检测进程检测到异常时，会使得本机的权重下降20

服务器A

vrrp_script chk_master1 {
    script "/opt/context/keepalive_check/chk_mysql.sh"
    interval 2            
    weight -20 
}

vrrp_instance VI_MASTER1 {
    state MASTER
    interface eno16780032
    virtual_router_id 51
    priority 100
    mcast_src_ip 172.16.90.13
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 5678
    }
    virtual_ipaddress {
        172.16.90.15
    }

    track_script {
        chk_master1
    }
}

vrrp_instance VI_MASTER2 {
    state BACKUP
    interface eno16780032
    virtual_router_id 52
    priority 90
    mcast_src_ip 172.16.90.13
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 15678
    }
    virtual_ipaddress {
        172.16.90.16
    }
}

服务器B

vrrp_script chk_master2 {
    script "/opt/context/keepalive_check/chk_mysql.sh"
    interval 2
    weight -20
}

vrrp_instance VI_MASTER1 {
    state BACKUP
    interface eno16780032
    virtual_router_id 51
    priority 90
    mcast_src_ip 172.16.90.14
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 5678
    }
    virtual_ipaddress {
        172.16.90.15
    }
}

vrrp_instance VI_MASTER2 {
    state MASTER
    interface eno16780032
    virtual_router_id 52
    priority 100
    mcast_src_ip 172.16.90.14
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 15678
    }
    virtual_ipaddress {
        172.16.90.16
    }

    track_script {
        chk_master2
    }
}

检测脚本

#!/bin/bash
counter=$(netstat -na|grep "LISTEN"|grep "3306"|wc -l)
if [ "${counter}" -eq 0 ]; then
    systemctl stop keepalived
fi
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