redis+Keepalived主从热备秒级切换

tongyi007

一 简介
安装使用centos 5.10
Master 192.168.235.135
Slave 192.168.235.152
Vip 192.168.235.200
编译环境 yum -y install gcc gcc+ gcc-c++ openssl openssl-devel pcre pcre-devel

当 Master 与 Slave 均运作正常时, Master负责服务，Slave负责Standby；
当 Master 挂掉，Slave 正常时, Slave接管服务，同时关闭主从复制功能；
当 Master 恢复正常，则从Slave同步数据，同步数据之后关闭主从复制功能，恢复Master身份，于此同时Slave等待Master同步数据完成之后，恢复Slave身份。
然后依次循环。
需要注意的是，这样做需要在Master与Slave上都开启本地化策略，否则在互相自动切换的过程中，未开启本地化的一方会将另一方的数据清空，造成数据完全丢失


二 安装
Redis安装配置->: http://liuyieyer.iyunv.com/blog/2078093
下载安装wget http://www.keepalived.org/software/keepalived-1.2.12.tar.gz
tar xf keepalived-1.2.12.tar.gz
cd keepalived-1.2.12
./configure
make && make install
cp /usr/local/etc/rc.d/init.d/keepalived /etc/init.d/
cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/
chmod +x /etc/init.d/keepalived
chkconfig –add keepalived
mkdir /etc/keepalived
ln –s /usr/local/sbin/keepalived /usr/sbin

三 配置
首先在master上创建如下配置
mkdir –p /etc/keepalived
vim /etc/keepalived/keepalived.conf
//加入如下内容脚本
vrrp_script chk_redis {
                script "/etc/keepalived/scripts/redis_check.sh"   ###监控脚本
                interval 2                                        ###监控时间
}
vrrp_instance VI_1 {
        state MASTER                            ###设置为MASTER
        interface eth0                          ###监控网卡   
        virtual_router_id 51
        priority 101                            ###权重值
        authentication {
                     auth_type PASS             ###加密
                     auth_pass redis            ###密码
        }
        track_script {
                chk_redis                       ###执行上面定义的chk_redis
        }
        virtual_ipaddress {
             192.168.235.200                         ###VIP
        }
        notify_master /etc/keepalived/scripts/redis_master.sh
        notify_backup /etc/keepalived/scripts/redis_backup.sh
        notify_fault  /etc/keepalived/scripts/redis_fault.sh
        notify_stop   /etc/keepalived/scripts/redis_stop.sh
}

vim /etc/keepalived/scripts/redis_master.sh

#!/bin/bash
REDISCLI="/opt/redis/bin/redis-cli"
LOGFILE="/var/log/keepalived-redis-state.log"
echo "[master]" >> $LOGFILE
date >> $LOGFILE
echo "Being master...." >> $LOGFILE 2>&1
echo "Run SLAVEOF cmd ..." >> $LOGFILE
$REDISCLI SLAVEOF 192.168.135.152(slave) 6379 >> $LOGFILE  2>&1
sleep 10 #延迟10秒以后待数据同步完成后再取消同步状态
echo "Run SLAVEOF NO ONE cmd ..." >> $LOGFILE
$REDISCLI SLAVEOF NO ONE >> $LOGFILE 2>&1

vim /etc/keepalived/scripts/redis_backup.sh
#!/bin/bash
REDISCLI="/opt/redis/bin/redis-cli"
LOGFILE="/var/log/keepalived-redis-state.log"
echo "[backup]" >> $LOGFILE
date >> $LOGFILE
echo "Being slave...." >> $LOGFILE 2>&1
sleep 15 #延迟15秒待数据被对方同步完成之后再切换主从角色
echo "Run SLAVEOF cmd ..." >> $LOGFILE
$REDISCLI SLAVEOF 192.168.135.152(slave)  6379 >> $LOGFILE  2>&1

在slave上创建如下文件：
vim /etc/keepalived/keepalived.conf
vrrp_script chk_redis {
                script "/etc/keepalived/scripts/redis_check.sh"   ###监控脚本
                interval 2                                        ###监控时间
}
vrrp_instance VI_1 {
        state BACKUP                                ###设置为BACKUP
        interface eth0                              ###监控网卡
        virtual_router_id 51
        priority 100                                ###比MASTRE权重值低
        authentication {
                     auth_type PASS
                     auth_pass redis                ###密码与MASTRE相同
        }
        track_script {
                chk_redis                       ###执行上面定义的chk_redis
        }
        virtual_ipaddress {
             192.168.235.200                         ###VIP
        }
        notify_master /etc/keepalived/scripts/redis_master.sh
        notify_backup /etc/keepalived/scripts/redis_backup.sh
        notify_fault  /etc/keepalived/scripts/redis_fault.sh
        notify_stop   /etc/keepalived/scripts/redis_stop.sh
}

vim /etc/keepalived/scripts/redis_master.sh
#!/bin/bash
REDISCLI="/opt/redis/bin/redis-cli"
LOGFILE="/var/log/keepalived-redis-state.log"
echo "[master]" >> $LOGFILE
date >> $LOGFILE
echo "Being master...." >> $LOGFILE 2>&1
echo "Run SLAVEOF cmd ..." >> $LOGFILE
$REDISCLI SLAVEOF 192.168.235.135(master) 6379 >> $LOGFILE  2>&1
sleep 10 #延迟10秒以后待数据同步完成后再取消同步状态
echo "Run SLAVEOF NO ONE cmd ..." >> $LOGFILE
$REDISCLI SLAVEOF NO ONE >> $LOGFILE 2>&1
vim /etc/keepalived/scripts/redis_backup.sh
#!/bin/bash
REDISCLI="/opt/redis/bin/redis-cli"
LOGFILE="/var/log/keepalived-redis-state.log"
echo "[backup]" >> $LOGFILE
date >> $LOGFILE
echo "Being slave...." >> $LOGFILE 2>&1
sleep 15 #延迟15秒待数据被对方同步完成之后再切换主从角色
echo "Run SLAVEOF cmd ..." >> $LOGFILE
$REDISCLI SLAVEOF 10.6.1.143 6379 >> $LOGFILE  2>&1

以下脚本分别在master和slave上创建
mkdir /etc/keepalived/scripts
vim /etc/keepalived/scripts/redis_check.sh
#!/bin/bash

ALIVE=`/opt/redis/bin/redis-cli PING`
if [ "$ALIVE" == "PONG" ]; then
  echo $ALIVE
  exit 0
else
  echo $ALIVE
  exit 1
fi
vim /etc/keepalived/scripts/redis_fault.sh
#!/bin/bash
LOGFILE=/var/log/keepalived-redis-state.log
echo "[fault]" >> $LOGFILE
date >> $LOGFILE
vim /etc/keepalived/scripts/redis_stop.sh
#!/bin/bash
LOGFILE=/var/log/keepalived-redis-state.log
echo "[stop]" >> $LOGFILE
date >> $LOGFILE

授执行权  chmod +x /etc/keepalived/scripts/*.sh

测试
在msater和slave上分别启动redis；
Service redis start
分别启动keepalived
Service keepalived start
在master上执行 ip a
http://dl2.iyunv.com/upload/attachment/0097/9840/ee4e888e-a8c7-3f9c-8526-61fbb38c943f.jpg

虚拟IP已经绑定了
在master上执行service redis stop 查看slave

http://dl2.iyunv.com/upload/attachment/0097/9842/a09552b4-ed4d-32da-a875-7ef0aa6d4941.jpg
看到了吧秒级切换。
接下来再吧master上的redis启动起来


http://dl2.iyunv.com/upload/attachment/0097/9844/ad5c99ee-932b-3c67-a16b-5427620cbb4d.jpg
又切换回来了。
测试redis同步

http://dl2.iyunv.com/upload/attachment/0097/9846/d2301a94-f2f5-3e05-9538-604e563cd064.jpg


到此安装完成了。