利用ProxySQL实现读写分离

1. 环境准备：
   准备三台主机，一台ProxySQL服务器:192.168.8.7，另外两台主机实现主从复制192.168.8.17,27

   注意：slave节点需要设置read_only=1

2. 安装ProxySQL，并向ProxySQL中添加MySQL节点，以下操作不需要use main也可成功

MySQL> show tables;
MySQL > select * from sqlite_master where name='mysql_servers'\G
MySQL > select * from mysql_servers;   
MySQL > insert into mysql_servers(hostgroup_id,hostname,port) 
values(10,'192.168.8.17',3306); 
MySQL > insert into mysql_servers(hostgroup_id,hostname,port) 
values(10,'192.168.8.27',3306);
MySQL > load mysql servers to runtime;
MySQL > save mysql servers to disk;

3. 添加监控后端节点的用户，连接每个节点的read_only值来自动调整主从节点是属于读组还是写组

#在master上执行
MySQL> grant replication client on *.* to monitor@'192.168.8.%' identified 
by 'magedu';
#ProxySQL上配置监控
MySQL