简介

MySQL Router是处于应用client和dbserver之间的轻量级代理程序，它能检测，分析和转发查询到后端数据库实例，并把结果返回给client，是mysql-proxy的一个替代品

Router可以实现读写分离，程序不是直接连接数据库IP，而是固定连接到mysql router，MySQL Router对前端应用是透明的，应用程序把MySQL Router当作是普通的mysql实例，把查询发给MySQL Router,而MySQL Router会把查询结果返回给前端的应用程序

当从数据库服务器故障时，业务也可以正常运行，MySQL Router可实现自动下线不可用服务器，程序配置不需要任何修改

若主数据库发生故障，由MySQL Router来决定主从自动切换，业务同样可以正常访问，程序配置不需要做任何修改

读写分离(Read/Write Splitting)

让一部分数据库服务器处理事务性增、改、删操作(INSERT、UPDATE、DELETE)，另一部分数据库服务器处理SELECT查询操作

前期准备

准备四台Centos7虚拟机，配置IP地址和hostname，关闭seLinux和防火墙，同步系统时间，修改IP地址和hostname映射

ip

hostname

部署服务

192.168.29.132

master

mysql

192.168.29.138

bak1

mysql

192.168.29.131

bak2

mysql

192.168.29.133

mid

mysql mysql-router

四台虚拟机部署mysql服务

[[email protected] ~]# yum install mysql-server mysql -y

[[email protected]~]# yum install mysql-server mysql -y

[[email protected]~]# yum install mysql-server mysql -y

[[email protected] ~]# yum install mysql-server mysql -y

mid结点部署mysql-router

从官网下载rpm包

[[email protected] ~]# yum localinstall mysql-router-community-8.0.21-1.el7.x86_64.rpm -y

master结点和两个bak结点配置主从复制

详细配置步骤可参考：https://blog.51cto.com/14832653/2500735

启动MySQL服务

[[email protected] ~]# systemctl start mysqld

[[email protected]~]# systemctl start mysqld

[[email protected]~]# systemctl start mysqld

[[email protected] ~]# systemctl start mysqld

配置mysql-router

[[email protected] ~]# vi /etc/mysqlrouter/mysqlrouter.conf

#添加高可用标签,配置master结点为写结点

[routing:failover]

bind_address = 0.0.0.0

bind_port = 7001

max_connections = 1024

mode = read-write

#实际MySQL地址

destinations = 192.168.29.132:3306

#轮询标签，从库进行负载均衡的轮询访问

[routing:balancing]

bind_address = 0.0.0.0

bind_port = 7002

max_connections = 1024

mode = read-only

#实际MySQL地址

destinations = 192.168.29.138:3306,192.168.29.131:3306

启动服务

[[email protected] ~]# systemctl start mysqlrouter.service

测试验证

查看服务情况

[[email protected] ~]# netstat -tnlp |grep mysql

tcp 0 0 0.0.0.0:7001 0.0.0.0:* LISTEN 32715/mysqlrouter

tcp 0 0 0.0.0.0:7002 0.0.0.0:* LISTEN 32715/mysqlrouter

测试连接主库

[[email protected] ~]# mysql -u root -h 192.168.29.133 -p -P 7001

#master结点查看连接情况

mysql>select SUBSTRING_INDEX(host,':',1) as ip , count(*) from information_schema.processlist group by ip;

+-----------+----------+

| ip | count(*) |

+-----------+----------+

| mid | 1 |

+-----------+----------+

测试从库负载均衡

[[email protected] ~]# mysql -u root -h 192.168.29.133 -p -P 7002

#bak1结点查看情况

mysql>select SUBSTRING_INDEX(host,':',1) as ip , count(*) from information_schema.processlist group by ip;

+-----------+----------+

| ip | count(*) |

+-----------+----------+

| mid | 1 |

+-----------+----------+

#再次连接

[[email protected] ~]# mysql -u root -h 192.168.29.133 -p -P 7002

#bak2结点查看情况

mysql>select SUBSTRING_INDEX(host,':',1) as ip , count(*) from information_schema.processlist group by ip;

+-----------+----------+

| ip | count(*) |

+-----------+----------+

| mid | 1 |

+-----------+----------+