redis主从+keepalived 高可用 自动切换

一环境介绍

 master：  172.168.1.69

slave  ： 172.168.1.57      

VIP     172.168.1.253   虚拟IP

二。设计思路：

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。(配置方式，打开redis的配置文件。找到appendonly。默认是appendonly no。改成appendonly yes。)

 redis配置文件不可设置只读模式

三。安装前准备工作

1.在主服务器172.168.1.69 上面做下面操作

echo "172.168.1.69  test01" >> /etc/hosts

echo "172.168.1.57 test" >> /etc/hosts

2.在从服务器172.168.1.57上面做下面操作

echo "172.168.1.69  test01" >> /etc/hosts

echo "172.168.1.57 test" >> /etc/hosts

四：配置redis主从 （略）

端口号 ：P ：6379

密码：123456

 启动服务：

# /mnt/tools/redis/bin/redis-server /mnt/tools/redis/etc/redis.conf

主服务器上执行：

#/mnt/tools/redis/bin/redis-cli -h 172.168.1.69 -a 123456 set test 123456

从服务器上执行：

#/mnt/tools/redis/bin/redis-cli -h 172.168.1.57 get test

测试是否已启动

# /mnt/tools/redis/bin/redis-cli ping

性能测试

# /mnt/tools/redis/bin/redis-benchmark

关闭服务

#/mnt/tools/redis/bin/redis-cli -p 6379 shutdown

五：安装配置keepalived （直接yum安装也可以  方便  简单粗暴  不用自己装依赖包）

1.mkdir /root/tools -p

cd /root/tools

wget http://www.keepalived.org/software/keepalived-1.1.17.tar.gz

tar -zxf keepalived*

2.做一个内核连接

[root@zjx tools]# uname -r

3.10.0-123.9.3.el7.x86_64

[root@zjx tools]# ln -s /usr/src/kernels/3.10.0-123.9.3.el7.x86_64 /usr/src/linux

cd keepalived-1.1.17

 ./configure      error（yum install -y openssl openssl-devel         yum install popt-devel）

make && make install 

移动启动脚本和配置文件

[root@zjx /]# cp /usr/local/etc/rc.d/init.d/keepalived  /etc/init.d/

[root@zjx /]# cp /usr/local/etc/sysconfig/keepalived  /etc/sysconfig/

[root@zjx /]# mkdir /etc/keepalived   启动脚本中默认指定的配置文件路径

[root@zjx /]# /bin/cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/

[root@zjx /]# /bin/cp /usr/local/sbin/keepalived  /usr/sbin/

执行上述操作后就可以以 /etc/init.d/keepalived 的方式启动了

/etc/init.d/keepalived start

/etc/init.d/keepalived stop

/etc/init.d/keepalived restart

3.master   keepalived.cnf 配置文件

! Configuration File for keepalived

vrrp_script chk_redis {

    script "/etc/keepalived/scripts/redis_check.sh"

    interval 2

    }

vrrp_instance VI_1 {

    state MASTER

    interface eth0

    virtual_router_id 51

    mcast_src_ip 172.168.1.253

    priority 100

    advert_int 1

    authentication {

        auth_type PASS

        auth_pass 1111

    }

track_script {

    chk_redis

    }

virtual_ipaddress {

        172.168.1.253

    }

        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

}

slave：keepalived.cnf 配置文件

! Configuration File for keepalived

vrrp_script chk_redis {

    script "/etc/keepalived/scripts/redis_check.sh"

    interval 2

}

vrrp_instance VI_1 {

    state BACKUP

    interface eth0

    virtual_router_id 51

mcast_src_ip 172.168.1.253

    priority 10

advert_int 1

    authentication {

        auth_type PASS

        auth_pass 1111

    }

track_script {

    chk_redis

    }

virtual_ipaddress {

        172.168.1.253

    }

         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

}

4.在Master和Slave上创建监控Redis的脚本

$  mkdir /etc/keepalived/scripts

$  vim /etc/keepalived/scripts/redis_check.sh

#!/bin/bash

ALIVE=`/mnt/tools/redis/bin/redis-cli -a 123456 PING`

if [ "$ALIVE" == "PONG" ]; then

echo $ALIVE

exit 0

else

echo $ALIVE

exit 1

fi

5.编写以下负责运作的关键脚本：

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

因为Keepalived在转换状态时会依照状态来呼叫：

当进入Master状态时会呼叫notify_master

当进入Backup状态时会呼叫notify_backup

当发现异常情况时进入Fault状态呼叫notify_fault

当Keepalived程序终止时则呼叫notify_stop

1)首先，在Redis Master上创建notity_master与notify_backup脚本：

$  vim /etc/keepalived/scripts/redis_master.sh

#!/bin/bash

REDISCLI="/usr/local/bin/redis-cli -a 123456"

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 172.168.1.57 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="/usr/local/bin/redis-cli -a 123456"

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 172.168.1.57 6379 >> $LOGFILE  2>&1

2)在Redis Slave上创建notity_master与notify_backup脚本：

$  vim /etc/keepalived/scripts/redis_master.sh

#!/bin/bash

REDISCLI="/usr/local/bin/redis-cli -a 123456"

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 172.168.1.69 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="/usr/local/bin/redis-cli -a 123456"

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 172.168.1.69 6379 >> $LOGFILE  2>&1

3)然后在Master与Slave创建如下相同的脚本：

$  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

6.在主从服务器上面给脚本都加上可执行权限：

$  chmod +x /etc/keepalived/scripts/*.sh

7.进行相关功能测试

启动Master和slave上的Redis

$  /mnt/tools/redis/bin/redis-server /mnt/tools/redis/etc/redis.conf

启动Master和slave上的Keepalived

$     

尝试通过VIP连接Redis:

$ redis-cli -h 172.168.1.253 INFO

连接成功，Slave也连接上来了。

role:master

slave0:172.168.1.57,6379,online

尝试插入一些数据：

$ redis-cli -h 172.168.1.69 SET Hello Redis

OK

 从VIP读取数据

$ redis-cli -h 172.168.1.253 GET Hello

"Redis"

从Master读取数据   

$ redis-cli -h 172.168.1.69 GET Hello

"Redis"

从Slave读取数据

$ redis-cli -h 172.168.1.57 GET Hello

"Redis"

8.通过模拟相关故障，进行功能测试（）

将Master上的Redis进程杀死：

killall -9 redis-server

查看Master上的Keepalived日志

查看Master上的Keepalived日志

$ tail -f /var/log/keepalived-redis-state.log

[fault]

Thu Sep 27 08:29:01 CST 2012

同时Slave上的日志显示：

$ tail -f /var/log/keepalived-redis-state.log

[master]

Being master....

Run SLAVEOF cmd ...

OK Already connected to specified master

Run SLAVEOF NO ONE cmd ...

OK

然后我们可以发现，Slave已经接管服务，并且担任Master的角色了。

$ redis-cli -h 172.168.1.253 INFO

$ redis-cli -h 172.168.1.57 INFO

role:master

然后我们恢复Master的Redis进程(恢复主redis后，需要重启keepalived  和从库的redis  可恢复正常）

$  /etc/init.d/redis start

查看Master上的Keepalived日志

$ tail -f /var/log/keepalived-redis-state.log

[master]

Being master....

Run SLAVEOF cmd ...

OK

Run SLAVEOF NO ONE cmd ...

OK

同时Slave上的日志显示：

$ tail -f /var/log/keepalived-redis-state.log

[backup]

Being slave....

Run SLAVEOF cmd ...

OK

发现目前的Master已经再次恢复了Master的角色，故障切换以及自动恢复都成功了。