redis主從+keepalived 高可用 自動切換

一環境介紹

 master：  172.168.1.69

slave  ： 172.168.1.57      

VIP     172.168.1.253   虛擬IP

二。設計思路：

當 Master 與 Slave 均運作正常時, Master負責服務，Slave負責Standby；

當 Master 掛掉，Slave 正時, Slave接管服務，同時關閉主從復制功能；

當 Master 恢復正常，則從Slave同步數據，同步數據之后關閉主從復制功能，恢復Master身份，于此同時Slave等待Master同步數據完成之后，恢復Slave身份。

然后依次循環。

需要注意的是，這樣做需要在Master與Slave上都開啟本地化策略，否則在互相自動切換的過程中，未開啟本地化的一方會將另一方的數據清空，造成數據完全丟失。(配置方式，打開redis的配置文件。找到appendonly。默認是appendonly no。改成appendonly yes。)

 redis配置文件不可設置只讀模式

三。安裝前準備工作

1.在主服務器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.在從服務器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主從 （略）

端口號 ：P ：6379

密碼：123456

 啟動服務：

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

主服務器上執行：

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

從服務器上執行：

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

測試是否已啟動

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

性能測試

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

關閉服務

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

五：安裝配置keepalived （直接yum安裝也可以  方便  簡單粗暴  不用自己裝依賴包）

1.mkdir /root/tools -p

cd /root/tools

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

tar -zxf keepalived*

2.做一個內核連接

[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 

移動啟動腳本和配置文件

[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   啟動腳本中默認指定的配置文件路徑

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

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

執行上述操作后就可以以 /etc/init.d/keepalived 的方式啟動了

/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上創建監控Redis的腳本

$  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.編寫以下負責運作的關鍵腳本：

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

因為Keepalived在轉換狀態時會依照狀態來呼叫：

當進入Master狀態時會呼叫notify_master

當進入Backup狀態時會呼叫notify_backup

當發現異常情況時進入Fault狀態呼叫notify_fault

當Keepalived程序終止時則呼叫notify_stop

1)首先，在Redis Master上創建notity_master與notify_backup腳本：

$  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 #延遲10秒以后待數據同步完成后再取消同步狀態

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 #延遲15秒待數據被對方同步完成之后再切換主從角色

echo "Run SLAVEOF cmd ..." >> $LOGFILE

$REDISCLI SLAVEOF 172.168.1.57 6379 >> $LOGFILE  2>&1

2)在Redis Slave上創建notity_master與notify_backup腳本：

$  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 #延遲10秒以后待數據同步完成后再取消同步狀態

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 #延遲15秒待數據被對方同步完成之后再切換主從角色

echo "Run SLAVEOF cmd ..." >> $LOGFILE

$REDISCLI SLAVEOF 172.168.1.69 6379 >> $LOGFILE  2>&1

3)然后在Master與Slave創建如下相同的腳本：

$  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.在主從服務器上面給腳本都加上可執行權限：

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

7.進行相關功能測試

啟動Master和slave上的Redis

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

啟動Master和slave上的Keepalived

$     

嘗試通過VIP連接Redis:

$ redis-cli -h 172.168.1.253 INFO

連接成功，Slave也連接上來了。

role:master

slave0:172.168.1.57,6379,online

嘗試插入一些數據：

$ redis-cli -h 172.168.1.69 SET Hello Redis

OK

 從VIP讀取數據

$ redis-cli -h 172.168.1.253 GET Hello

"Redis"

從Master讀取數據   

$ redis-cli -h 172.168.1.69 GET Hello

"Redis"

從Slave讀取數據

$ redis-cli -h 172.168.1.57 GET Hello

"Redis"

8.通過模擬相關故障，進行功能測試（）

將Master上的Redis進程殺死：

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

同時Slave上的日志顯示：

$ 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

然后我們可以發現，Slave已經接管服務，并且擔任Master的角色了。

$ redis-cli -h 172.168.1.253 INFO

$ redis-cli -h 172.168.1.57 INFO

role:master

然后我們恢復Master的Redis進程(恢復主redis后，需要重啟keepalived  和從庫的redis  可恢復正常）

$  /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

同時Slave上的日志顯示：

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

[backup]

Being slave....

Run SLAVEOF cmd ...

OK

發現目前的Master已經再次恢復了Master的角色，故障切換以及自動恢復都成功了。