keepalived+redis实现高可用，故障自动redis主从切换

2016-07-23 00:45 默认分类狂奔的蜗牛

在A服务器(10.0.11.2),B服务器(10.0.12.2)上均安装redis,keepalived(安装方法略)
A作为默认的master,B作为slave(在redis的配置文件中加上 SLAVEOF 10.0.11.2 6379)即可
A,B上的Redis均开启本地化策略。appendonly yes

## A服务器的配置
keepalived配置文件内容

global_defs {
	notification_email {
	hq@xxx.com
	}
	notification_email_from hq@xxx.com
	smtp_server 127.0.0.1
	smtp_connect_timeout 30
	router_id redis1.xxx.com
	}

vrrp_script chk_redis {
	script "/opt/redis/sh/redis_check.sh"
	interval 2
	}

vrrp_instance VI_1 {
	state MASTER
	interface bond0
	virtual_router_id 51
	priority 101
	advert_int 2
	authentication {
	auth_type PASS
	auth_pass 1111
	}
	track_script {
	chk_redis
	}
	virtual_ipaddress {
	10.0.11.0
	}
	notify_master /opt/redis/sh/redis_master.sh
	notify_backup /opt/redis/sh/redis_backup.sh
	notify_fault /opt/redis/sh/redis_fault.sh
	notify_stop /opt/redis/sh/redis_stop.sh
	}

说明：

global_defs 部分的邮件可以随便写，要实现邮件通知则要按真实填写
	script "/opt/redis/sh/redis_check.sh" #监控脚本的路径
	interval 2 #监控的频率
	state MASTER #默认的状态
	interface bond0 #网卡名
	virtual_router_id 51 #A,B 服务器设置一样即可
	priority 101 #优先级 比B设大即可
	advert_int 2 #貌似广播的频率，不确定
	authentication { #A,B 服务器设置一样即可
	auth_type PASS
	auth_pass 1111
	}
	track_script { #监控的名称，上面设置的
	chk_redis
	}
	virtual_ipaddress { #虚拟IP, 客户端就用这个IP来访问redis
	10.0.11.0
	}
	
	#以下是各个状态下执行的脚本路径
	notify_master /opt/redis/sh/redis_master.sh #成为master
	notify_backup /opt/redis/sh/redis_backup.sh #成为backup
	notify_fault /opt/redis/sh/redis_fault.sh #监控脚本 exit 1 时
	notify_stop /opt/redis/sh/redis_stop.sh #keepalived 服务停止时

`/opt/redis/sh/redis_check.sh`

#!/bin/bash
	ALIVE=`/usr/local/bin/redis-cli PING`
	LOGFILE="/opt/redis/logs/keepalived-redis-state.log"
	if [ "$ALIVE" == "PONG" ]; then
	echo $ALIVE
	#echo "check master pong" >> $LOGFILE
	exit 0
	else
	echo $ALIVE
	exit 1
	fi

`/opt/redis/sh/redis_master.sh`

#!/bin/bash
	REDISCLI="/usr/local/bin/redis-cli"
	LOGFILE="/opt/redis/logs/keepalived-redis-state.log"
	echo "[master]" >> $LOGFILE
	date >> $LOGFILE
	echo "Being master...." >> $LOGFILE 2>&1
	echo "Run SLAVEOF cmd ..." >> $LOGFILE
	$REDISCLI SLAVEOF 10.0.12.2 6379 >> $LOGFILE 2>&1
	sleep 15
	echo "Run SLAVEOF NO ONE cmd ..." >> $LOGFILE
	$REDISCLI SLAVEOF NO ONE
	$REDISCLI SLAVEOF NO ONE >> $LOGFILE 2>&1

`/opt/redis/sh/redis_backup.sh`
 
	REDISCLI="/usr/local/bin/redis-cli"
	LOGFILE="/opt/redis/logs/keepalived-redis-state.log"
	echo "[backup]" >> $LOGFILE
	date >> $LOGFILE
	echo "Being slave...." >> $LOGFILE 2>&1
	sleep 15
	echo "Run SLAVEOF cmd..." >> $LOGFILE
	$REDISCLI SLAVEOF 10.0.12.2 6379 >> $LOGFILE 2>&1

`/opt/redis/sh/redis_fault.sh`

#!/bin/bash
	LOGFILE="/opt/redis/logs/keepalived-redis-state.log"
	echo "[fault]" >> $LOGFILE
	date >> $LOGFILE
	sh /opt/redis/sh/redis_backup.sh

`/opt/redis/sh/redis_stop.sh`

#!/bin/bash
	LOGFILE="/opt/redis/logs/keepalived-redis-state.log"
	echo "[stop]" >> $LOGFILE
	date >> $LOGFILE

## **B服务器的配置**

keepalived配置文件内容

global_defs {
	notification_email {
	hq@xxx.com
	}
	notification_email_from hq@xxx.com
	smtp_server 127.0.0.1
	smtp_connect_timeout 30
	router_id redis2.xxx.com
	}

vrrp_script chk_redis {
	script "/opt/redis/sh/redis_check.sh"
	interval 2
	}

vrrp_instance VI_1 {
	state BACKUP
	interface bond0
	virtual_router_id 51
	priority 99
	authentication {
	auth_type PASS
	auth_pass 1111
	}
	track_script {
	chk_redis
	}
	virtual_ipaddress {
	10.0.11.0
	}
	notify_master /opt/redis/sh/redis_master.sh
	notify_backup /opt/redis/sh/redis_backup.sh
	notify_fault /opt/redis/sh/redis_fault.sh
	notify_stop /opt/redis/sh/redis_stop.sh
	}

`/opt/redis/sh/redis_check.sh`

#!/bin/bash
	ALIVE=`/usr/local/bin/redis-cli -h 10.0.11.2 -p 6379 PING`
	LOGFILE="/opt/redis/logs/keepalived-redis-state.log"
	if [ "$ALIVE" != "PONG" ]; then
	echo $ALIVE
	exit 0
	else
	echo $ALIVE
	exit 1
	fi
	
`/opt/redis/sh/redis_master.sh`

#!/bin/bash
	REDISCLI="/usr/local/bin/redis-cli"
	LOGFILE="/opt/redis/logs/keepalived-redis-state.log"
	echo "[master]" >> $LOGFILE
	date >> $LOGFILE
	echo "Being master...." >> $LOGFILE 2>&1
	##echo "master Run SLAVEOF 10.0.11.2 cmd ..." >> $LOGFILE
	##REDISCLI SLAVEOF 10.0.11.2 6379 >> $LOGFILE 2>&1
	#sleep 10
	echo "Run SLAVEOF NO ONE cmd ..." >> $LOGFILE
	$REDISCLI SLAVEOF NO ONE >> $LOGFILE 2>&1

`/opt/redis/sh/redis_backup.sh`

#!/bin/bash
	REDISCLI="/usr/local/bin/redis-cli"
	LOGFILE="/opt/redis/logs/keepalived-redis-state.log"
	echo "[backup]" >> $LOGFILE
	date >> $LOGFILE
	echo "Being slave...." >> $LOGFILE 2>&1
	#sleep 10
	echo "backup Run SLAVEOF 10.0.11.2 cmd..." >> $LOGFILE
	$REDISCLI SLAVEOF 10.0.11.2 6379 >> $LOGFILE 2>&1

`/opt/redis/sh/redis_fault.sh`

#!/bin/bash
	LOGFILE="/opt/redis/logs/keepalived-redis-state.log"
	echo "[fault]" >> $LOGFILE
	date >> $LOGFILE
	sh /opt/redis/sh/redis_slave.sh

`/opt/redis/sh/redis_stop.sh`

#!/bin/bash
	LOGFILE="/opt/redis/logs/keepalived-redis-state.log"
	echo "[stop]" >> $LOGFILE
	date >> $LOGFILE

`/opt/redis/sh/redis_slave.sh`

#!/bin/bash
	REDISCLI="/usr/local/bin/redis-cli"
	LOGFILE="/opt/redis/logs/keepalived-redis-state.log"
	echo "[slave]" >> $LOGFILE
	echo "Being slave...." >> $LOGFILE 2>&1
	sleep 35
	date >> $LOGFILE
	echo "slave Run SLAVEOF 10.0.11.2 cmd..." >> $LOGFILE
	$REDISCLI SLAVEOF 10.0.11.2 6379 >> $LOGFILE 2>&1

redis_slave.sh 中的sleep 35 说明，因为A服务器上的redis服务起来后 B变成fault状态，同时A服务器在变成master,如果次是B太快同步A的话(比A从B同步数据早)会造成数据丢失。这样做的目的是A起来后先从B同步数据，B在slaveof A,

## 脚本说明：
脚本的逻辑就是当A，B上的redis服务正常是A为master,B为slave
如果检测到A服务不正常则B成为master, "/usr/local/bin/redis-cli SLAVEOF NO ONE" 这个命令就是关闭数据同步，变成Redis 的master.
如果A服务起来后，A切回master,在变成master前从B上同步最新的数据。同时在B上要 执行 "/usr/local/bin/redis-cli SLAVEOF 10.0.11.2 6379"
让B再做为A的slave,不然B还是master.
在redis的主从架构中，可以用"/usr/local/bin/redis-cli -h 10.0.11.2 INFO" 来查看各个当前的状态。 看当前服务器是master还是slave;

在命令行下
`tail -30 /opt/redis/logs/keepalived-redis-state.log `查看keepalived的状态转换

`tail -30 /var/log/messages` 查看 keepalived虚拟IP的变化。

以上是在实际生产环境中测试过的，虽然有的的地方可能不大合理，但故障转移可以实现，数据也不会丢。之前按网上的教程做的vip可以切换，但数据这块有问题，所以改成这样。
如有更好的方法请告知，多谢！

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