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Redis主从配置及通过Keepalived实现Redis自动切换高可用

2017-04-26 14:52 781 查看

一：环境介绍：

Master: 192.168.1.4

Slave: 192.168.1.5

Virtural IP Address (VIP): 192.168.1.253

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。

三：安装配置前准备工作

1.在主服务器192.168.1.4上面做下面操作

echo "192.168.1.4 test01" >> /etc/hosts

echo "192.168.1.5 test" >> /etc/hosts

2.在从服务器192.168.1.5上面做下面操作

echo "192.168.1.4 test01" >> /etc/hosts

echo "192.168.1.5 test" >> /etc/hosts

四：主服务器配置redis

1.下载安装redis软件包

wget http://download.redis.io/releases/redis-2.8.12.tar.gztar xf redis-2.8.12.tar.gz

cd redis-2.8.12

make && make install

cd src/

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

cd /usr/local/bin

ls -ll

然后将源码中的 redis.conf 复制到 /etc/redis.conf

cp /root/redis-2.8.12/redis.conf /etc/redis.conf

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

就可以默认在后台执行redis-server了。

再制作一个 init.d 的启动脚本：

vim /etc/init.d/redis-server

#!/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

--------------------------------------分割线 --------------------------------------

Ubuntu 14.04下Redis安装及简单测试 http://www.linuxidc.com/Linux/2014-05/101544.htm

Redis集群明细文档 http://www.linuxidc.com/Linux/2013-09/90118.htm

Ubuntu 12.10下安装Redis（图文详解）+ Jedis连接Redis http://www.linuxidc.com/Linux/2013-06/85816.htm

Redis系列-安装部署维护篇 http://www.linuxidc.com/Linux/2012-12/75627.htm

CentOS 6.3安装Redis http://www.linuxidc.com/Linux/2012-12/75314.htm

Redis配置文件redis.conf 详解 http://www.linuxidc.com/Linux/2013-11/92524.htm

CentOS 6.3下Haproxy+Keepalived+Apache配置笔记 http://www.linuxidc.com/Linux/2013-06/85598.htm

Haproxy + KeepAlived 实现WEB群集 on CentOS 6 http://www.linuxidc.com/Linux/2012-03/55672.htm

Keepalived+Haproxy配置高可用负载均衡 http://www.linuxidc.com/Linux/2012-03/56748.htm

Haproxy+Keepalived构建高可用负载均衡 http://www.linuxidc.com/Linux/2012-03/55880.htm

--------------------------------------分割线 --------------------------------------

五：从发服务器配置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 192.168.1.4 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 hello world2

#从服务器

redis-cli -p 6379 get hello

"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.在Master和Slave上安装Keepalived

$ yum install keepalived -y

2.配置文件

默认安装完成keepalived之后是没有配置文件的，因此我们需要手动创建：

首先，在Master上创建如下配置文件：

$ vim /etc/keepalived/keepalived.conf

! 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

}

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 {

192.168.1.253 ######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.然后，在Slave上创建如下配置文件：

$ vim /etc/keepalived/keepalived.conf

! 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

}

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 {

192.168.1.253 ####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

}

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=`/usr/local/bin/redis-cli 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"

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 192.168.1.5 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"

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 192.168.1.5 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"

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 192.168.1.4 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"

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

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

$ /etc/init.d/redis 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 192.168.0.253 INFO

连接成功，Slave也连接上来了。

role:master

slave0:192.168.1.5,6379,online

尝试插入一些数据：

$ redis-cli -h 192.168.0.253 SET Hello Redis

OK

从VIP读取数据

$ redis-cli -h 192.168.0.253 GET Hello

"Redis"

从Master读取数据

$ redis-cli -h 192.168.0.1 GET Hello

"Redis"

从Slave读取数据

$ redis-cli -h 192.168.0.2 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

$ 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]

2014年 07月 07日星期一 16:42:52 CST

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 192.168.1.253 INFO

$ redis-cli -h 192.168.1.5 INFO

role:master

然后我们恢复Master的Redis进程

$ /etc/init.d/redis start

查看Master上的Keepalived日志

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

[master]

2014年 07月 07日星期一 16:48:08 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]

Fri Sep 28 14:16:37 CST 2012

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。

Redis 的详细介绍：请点这里
Redis 的下载地址：请点这里

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