使用keepalived实现redis主从切换

安装keepalived和redis主从的过程不再赘述，可参见本人其他部署文章。

主机名	IP地址	所安装软件
jia3.ty.com	192.168.10.103	keepalived(backup-高优先级),redis(master)
jia4.ty.com	192.168.10.104	keepalived(backup-低优先级),redis(slave)

192.168.10.103和192.168.10.104的keepalived配置如下:

[[email protected] keepalived]# more /etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs {
   notification_email {
     [email protected]
   }
   notification_email_from [email protected]
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id REDIS_KEEPALIVED
}

vrrp_script chk_redis {
    script "/etc/keepalived/script/chk_redis.sh"
    interval 3
}

vrrp_instance REDIS_1 {
    state BACKUP
    nopreempt
    interface eth1
    virtual_router_id 51
    priority 200          #192.168.10.104该项配置值为100，其他都一样
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass redis
    }
    track_script {
        chk_redis
    }
    virtual_ipaddress {
        192.168.10.111/24
    }
    notify_master "/etc/keepalived/script/become_master.sh"
}

涉及到的两个脚本内容如下：

[[email protected] keepalived]# more /etc/keepalived/script/chk_redis.sh

#!/bin/bash

A=`/app/redis/bin/redis-cli -h 127.0.0.1 -p 6379 PING`
if [ "$A"x != "PONG"x ]
then 
        /app/redis/bin/redis-server /app/redis/conf/redis.conf
        sleep 2
        if [ "`/app/redis/bin/redis-cli -h 127.0.0.1 -p 6379 PING`"x != "PONG"x ]
        then
                /etc/init.d/keepalived stop
        fi
fi

[[email protected] keepalived]# more /etc/keepalived/script/become_master.sh

#!/bin/bash
/app/redis/bin/redis-cli -h 127.0.0.1 -p 6379 slaveof no one

说明：

	1.keepalived使用双Backup非抢占模式
	2.redis主从切换的实现是通过检测本机redis进程，当服务不可用时停止keepalived服务做VIP切换，当获得VIP时让Redis执行slaveof no one命令变成主。
	3.需要检测keepalived状态，当发现VIP切换后需要尽快恢复至初始状态。

测试：

查看当前状态

192.168.10.103现在是redis master和VIP的所有者，如下图：

使用keepalived实现redis主从切换