centos6上redis+Keepalived实现Redis主从复制

2021-08-05 19:58:44

环境：CentOs6.8

Master:172.20.52.72

Slave:172.20.52.159

Virtual IP address(VIP):172.20.52.253

应用软件：

1、keepalived-1.2.12.tar.gz

下载地址http://www.keepalived.org/download.html

2、redis-2.8.7.tar.gz

下载地址http://www.oschina.net/news/49449/redis-2-8-7

一、安装配置前准备

yum -y install gcc gcc+ gcc-c++ openssl openssl-devel pcre pcre-devel

            Redis属于内存数据库，所以调优都集中到了内存上,需要将 vm.overcommit 设置为1
            echo "vm.overcommit_memory=1" >> /etc/sysctl
            sysctl -p

            1.在主服务器172.20.52.160上面做下面操作
                echo " 172.20.52.72 node1" >> /etc/hosts
                echo " 172.20.52.159 node2" >> /etc/hosts
            2.在从服务器10.10.10.204上面做下面操作
                echo " 172.20.52.72 node1" >> /etc/hosts
                echo " 172.20.52.159 node2" >> /etc/hosts

二、在Master和slave上安装Redis

tar -zxvf redis-2.8.7.tar.gz

cd redis-2.8.7

make && make install

cd src

mkdir -p /usr/local/redis/bin

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

mkdir -p /usr/local/redis/etc

复制源码中的redis.conf至/usr/local/redis/etc/ cp redis.conf /usr/local/redis/etc/

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

制作一个redis init.d 的启动脚本：

复制如下代码：

#!/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

    vim /etc/init.d/redis-server
    chmod o+x /etc/init.d/redis-server
    chkconfig --add redis-server
    /etc/init.d/redis-server start

从服务上redis的配置

修改 /etc/redis.conf

slaveof <masterip> <masterport>修改为

slaveof 172.20.52.72 6379

然后开启从服务器的redis服务。

start redis-server start

三、进行主从测试

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。

四、安装配置keepalived

1.在Master和Slave上安装Keepalived

$ yum install keepalived -y

2.默认安装完成keepalived之后是有配置文件的，但是我们需要创建合适的配置文件

首先，在Master上创建如下配置文件：

$ 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 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 {

        172.20.52.253        ######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

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
#!/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 172.20.52.159 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 172.20.52.159 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 172.20.52.72   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 172.20.52.72  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

.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 172.20.52.253 INFO

连接成功，Slave也连接上来了。

role:master

slave0:172.20.52.159,6379,online

尝试插入一些数据：

$ redis-cli -h 172。20.52.253 SET Hello Redis

从VIP读取数据

$ redis-cli -h 172.20.52.253 GET Hello

"Redis"

从Master读取数据

$ redis-cli -h 172.20.52.72 GET Hello

"Redis"

从Slave读取数据

$ redis-cli -h 172.20.52.159 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 2016

同时Slave上的日志显示：

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

[master]

2016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 ...

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 172.20.52.253 INFO

$ redis-cli -h 172.20.52.159 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]

2016年 07月 07日星期一 16:48:08 CST

Being master....

Run SLAVEOF cmd ...

Run SLAVEOF NO ONE cmd ...

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 2016

Being slave....

Run SLAVEOF cmd ...

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。

1.问题：刚使用redis-cli -h 172.20.52.253 INFO

说连接失败，没有路由。

此时我的解决办法是iptables -F

2.VIP的添加

ifconfig eth1:0 172.20.52.253 netmask 172.20.52.253 up

本文转自 ping9527 51CTO博客，原文链接：http://blog.51cto.com/babyhanggege/1910105，如需转载请自行联系原作者

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