Redis主从配置及使用KeepAlived实现Redis高可用

一：环境介绍

Master: 172.16.206.29

Slave: 172.16.206.28

Virtural IP Address (VIP): 172.16.206.250

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 正常时, Slave接管服务，有写权限，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，同时Slave等待Master同步数据完成之后，恢复Slave身份。

三：安装配置前准备工作

在主服务器 172.16.206.29 上面做下面操作

echo “172.16.206.29 osb29” >> /etc/hosts

echo “172.16.206.28 osb28” >> /etc/hosts

在从服务器 172.16.206.28 上面做下面操作

echo “172.16.206.29 osb29” >> /etc/hosts

echo “172.16.206.28 osb28” >> /etc/hosts

四：主服务器配置redis

1．下载redis 版本2.8.19

wget http://download.redis.io/releases/redis-2.8.19.tar.gz

2．解压 tar -zxvf redis-2.8.19.tar.gz

3．cd redis-2.8.19

4．make && make install

5．cp redis.conf /etc/redis.conf

cd src/

cp redis-server redis-cli redis-benchmark redis-check-aofredis-check-dump /usr/local/bin

6．修改 /etc/redis.conf里面可以把daemonize no 修改为daemonize yes

目的是可以在后台执行redis-server。

7．init.d 启动脚本

    vi /etc/init.d/redis-server

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#!/usr/bin/env bash # # redis start up the redis server daemon # # chkconfig: 345 99 99 # description: redis service in /etc/init.d/redis #            chkconfig --add redis or chkconfig --list redis #            service redis start  or  service redis stop # processname: redis-server # config: /etc/redis.conf PATH = / usr / local / bin : / sbin : / usr / bin : / bin REDISPORT = 6379 EXEC = / usr / local / bin / redis - server REDIS_CLI = / usr / local / bin / redis - cli   PIDFILE = / var / run / redis . pid CONF = "/etc/redis.conf" #make sure some dir exist if [ ! - d / var / lib / redis ] ; then     mkdir - p / var / lib / redis     mkdir - p / var / log / redis   fi   case "$1" in     status )         ps - A | grep redis         ; ;     start )         if [ - f $ PIDFILE ]         then                 echo "$PIDFILE exists, process is already running or crashed"         else                 echo "Starting Redis server..."                 $ EXEC $ CONF         fi         if [ "$?" = "0" ]         then               echo "Redis is running..."         fi         ; ;     stop )         if [ ! - f $ PIDFILE ]         then                 echo "$PIDFILE does not exist, process is not running"         else                 PID = $ ( cat $ PIDFILE )                 echo "Stopping ..."                 $ REDIS_CLI - p $ REDISPORT SHUTDOWN                 while [ - x $ { PIDFILE } ]               do                     echo "Waiting for Redis to shutdown ..."                     sleep 1                 done                 echo "Redis stopped"         fi         ; ;   restart | force - reload )         $ { 0 } stop         $ { 0 } start         ; ;   * )     echo "Usage: /etc/init.d/redis {start|stop|restart|force-reload}" > & 2     exit 1   esac

chmod o+x /etc/init.d/redis-server

chkconfig –add redis-server

service redis-server start

五：从服务器配置redis

从服务器，配置一样，只不过 修改/etc/redis.conf 中

slaveof <masterip> <masterport>修改为

slaveof 172.16.206.28 6379

然后开启从服务器的redis服务。

start redis-server start

 

六：进行redis主从测试

#主服务器

redis-cli -p 6379 set hello world

#从服务器

redis-cli -p 6379 get hello

“world”

 

#主服务器

redis-cli -p 6379 set hello2 world2

#从服务器

redis-cli -p 6379 get hello2

“world2”

redis-cli -p 6379 set hello world

(error) READONLY You can’t write against a read only slave.

成功配置主从redis服务器，由于配置中有一条从服务器是只读的，所以从服务器没法设置数据，只可以读取数据。

 

七：安装和配置keepalived

1． wget http://www.keepalived.org/software/keepalived-1.2.15.tar.gz

tar -zxvf keepalived-1.2.15.tar.gz

cd keepalived-1.2.15

2．  安装openssl-devel和kernel-devel

yum install openssl-devel

yum install kernel-devel

ln -s /usr/src/kernels/2.6.32-431.el6.x86_64 /usr/src/linux

3． 配置编译安装

./configure–prefix=/usr/local/keepalived  –with-kernel-dir=/usr/src/linux   –enable-sha1

make && make install

4． 复制keepalived相关文件

cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/keepalived

cp /usr/local/keepalived/sbin/keepalived /usr/sbin/keepalived

cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/keepalived

mkdir /etc/keepalived

cp /usr/local/keepalived/etc/keepalived/samples/keepalived.conf.virtualhost

/etc/keepalived/keepalived.conf

八：修改配置文件和相关脚本

1． 在Master上创建配置文件

vi /etc/keepalived/keepalived.conf

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! Configuration File for keepalived   vrrp_script chk_redis {       script "/etc/keepalived/scripts/redis_check.sh"    ###监控脚本      interval 2                                          ###监控时间     }   #网卡需要注意，使用ifconfig查看一下当前活动网卡   vrrp_instance VI_1 {     state MASTER                ###设置为MASTER      interface eth1                ###监控网卡        virtual_router_id 51     priority 100            ###权重值      authentication {         auth_type PASS        ###加密          auth _pass 1111        ###密码     }     track_script {           chk _redis            ###执行上面定义的chk_redis      }     virtual_ipaddress {         172.16.206.250         ######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   }

2．在Slave上创建如下配置文件

vim /etc/keepalived/keepalived.conf

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! Configuration File for keepalived     vrrp_script chk_redis {     script "/etc/keepalived/scripts/redis_check.sh"    ###监控脚本      interval 2                  ###监控时间     }     #同样要注意网卡   vrrp_instance VI_1 {     state BACKUP        ###设置为BACKUP      interface eth1      ###监控网卡     virtual_router_id 51     priority 10          ###比MASTRE权重值低      authentication {         auth_type PASS         auth _pass 1111        ###密码与MASTRE相同      }   track_script {     chk _redis        ###执行上面定义的chk_redis      }     virtual_ipaddress {         172.16.206.250 ####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 }

 

3．在Master和Slave上创建监控Redis的脚本

$  mkdir /etc/keepalived/scripts

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

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#!/bin/bash    ALIVE = ` / usr / local / bin / redis - cli PING `  if [ "$ALIVE" == "PONG" ] ; then echo $ ALIVE  exit 0  else echo $ ALIVE  exit 1  fi

 

4．编写关键脚本

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执行脚本：

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

当程序终止时则呼叫notify_stop

 

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

vi /etc/keepalived/scripts/redis_master.sh

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#!/bin/bash   REDISCLI = "/usr/local/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 172.16.206.sl 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

vi /etc/keepalived/scripts/redis_backup.sh

 

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#!/bin/bash    REDISCLI = "/usr/local/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 192.168.1.sl 6379 >> $ LOGFILE  2 > & 1

在Redis Slave上创建notity_master与notify_backup脚本：

vi /etc/keepalived/scripts/redis_master.sh

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#!/bin/bash    REDISCLI = "/usr/local/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 192.168.1.ma 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

vi /etc/keepalived/scripts/redis_backup.sh

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#!/bin/bash    REDISCLI = "/usr/local/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 192.168.1.4 6379 >> $ LOGFILE  2 > & 1

然后在Master与Slave创建如下相同的脚本：

 

vi /etc/keepalived/scripts/redis_fault.sh

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

vi /etc/keepalived/scripts/redis_stop.sh

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

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

九：相关功能测试

启动Master和slave上的Redis

service redis-server start

启动Master和slave上的Keepalived

/etc/init.d/keepalived start

尝试通过VIP连接Redis:

$ redis-cli -h 172.16.206.250 INFO

连接成功，可以看到主从机的信息，例如：

role:master

slave0:172.16.206.28,6379,online

 

尝试插入一些数据：

$ redis-cli -h 172.16.206.250 SET hello3 world3

OK

 

从VIP读取数据

$ redis-cli -h 172.16.206.250 GET hello3

“world3”

从Master读取数据

$ redis-cli -h 172.16.206.29 GET hello3

“world3”

从Slave读取数据

$ redis-cli -h 172.16.206.28 GET hello3

“world3”

 

将Master上的Redis进程杀死：

$ service redis-server stop

查看Master上的Keepalived日志

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

[fault]

Mon Jan  5 14:06:22 CST 2015

 

同时Slave上的日志显示：

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

[master]

Mon Jan  5 14:13:52 CST 2015

Being master….

Run SLAVEOF cmd …

OK Already connected to specified master

Run SLAVEOF NO ONE cmd …

OK

现在，Slave已经接管服务，并且拥有Master的角色

$ redis-cli -h 172.16.206.250 INFO

$ redis-cli -h 172.16.206.28 INFO

role:master

 

然后恢复Master的Redis进程

$  service redis-server start

查看Master上的Keepalived日志

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

 

[master]

2015年 01月 05日 星期一 15:48:08 CST

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]

Mon Jan  5 14:53:16 CST 2015

Being slave….

Run SLAVEOF cmd …

OK

 

Master已经再次恢复了Master角色

from：http://abcve.com/redis-keepalived/