1、大家可以先看我的单台Redis安装教程,链接在此点击Redis在CentOS for LInux上安装详细教程

2、第一台redis配置,是正常配置。作为MASTER主服务器,第二台redis的配置文件中

  加  一行代码 slaveof    主redis的IP  6379

  例如我的主redis的ip是192.168.1.2

       我在从redis配置文件中加一行   

        从:       slaveof 192.168.1.2 6379

3、然后启动从redis服务器,主从复制就搭建好了。当然你的配置文件中,如果对日志文件有要求,可以这样修改

     主:  logfile  "/var/log/redis/redis_master.log"

     从:  logfile "/var/log/redis/redis_slava.log"

4、此时如果主master服务器宕机了,此时主从复制就彻底垮掉了,如果你的项目挂载了redis主从复制,则项目就会出错。

5、解决redis主从复制,主服务器宕机,从服务器充当主服务器,即主从双机热备技术。使用的技术服务是Keepalived高可用。

6、Linux for CentOS 下的 keepalived 安装与卸载以及相关命令操作之详细教程 点击链接进入Keepalived的安装教程。

7、环境准备工作

      准备两台Linux服务器:

                 1. redis主服务器地址:192.168.1.10   并且该服务器已经安装Keepalived服务

                 2.redis从服务器地址:192.168.1.11   并且该服务器已经安装Keepalived服务

                 3.备用一个虚拟IP地址:192.168.1.20(用来做IP地址漂移)

                 4.此两台服务器已经做好主从复制的配置。

8.登录主redis服务器 192.168.1.10

9.进入/etc/keepalived/keepalived.conf编辑配置文件

global_defs {
   router_id redis1
   script_user root
   enable_script_security
}
vrrp_script chk_redis 
{ 
     script "/etc/keepalived/scripts/redis_check.sh 127.0.0.1 6379" 
     interval 2 
     timeout 2
     fall 3
     weight -20
}

vrrp_instance redis {
     state MASTER
     interface eth0  
     virtual_router_id 100 
     priority  100       
     #nopreempt # no seize,must add
     advert_int 1
         authentication {   #all node must same
         auth_type PASS
         auth_pass 1111
    }   
    
    unicast_src_ip 192.168.1.10
    unicast_peer {
        192.168.1.11
    }    

    virtual_ipaddress {  
        192.168.1.20
    }
    track_script { 
         chk_redis 
    } 

     notify_master "/etc/keepalived/scripts/redis_master.sh 127.0.0.1  192.168.1.11 6379"
     notify_backup "/etc/keepalived/scripts/redis_backup.sh 127.0.0.1  192.168.1.11 6379"
     notify_fault /etc/keepalived/scripts/redis_fault.sh 
     notify_stop /etc/keepalived/scripts/redis_stop.sh 
}

10. 建立目录  make   /etc/keepalived/scripts 用来存放脚本

         redis_backup.sh

         redis_check.sh

         redis_fault.sh

         redis_master.sh

          redis_stop.sh

 每个脚本代码如下:

【redis_backup.sh】

#!/bin/bash 
REDISCLI="/usr/local/bin/redis-cli -h $1 -p $3" 
LOGFILE="/etc/keepalived/log/keepalived-redis-state.log" 
echo "[backup]" >> $LOGFILE 
date >> $LOGFILE 
echo "Run SLAVEOF cmd ..." >> $LOGFILE 
$REDISCLI SLAVEOF $2 $3 >> $LOGFILE 2>&1 
# echo "Being slave...." >> $LOGFILE 2>&1 
sleep 15 
#delay 15 s wait data sync exchange role



【redis_check.sh】

#!/bin/bash
ALIVE=`/usr/local/bin/redis-cli -h $1 -p $2 PING`
LOGFILE="/etc/keepalived/log/keepalived-redis-check.log"
echo "[CHECK]" >> $LOGFILE
date >> $LOGFILE

if [[ $ALIVE == "PONG"  ]]; then :
 echo "SUCCESS:reidis-cli -h $1 -p $2 PING $ALIVE" >> $LOGFILE 2>&1
 exit 0
else
 echo "FAILED:redis-cli -h $1 -p $2 PING $ALIVE" >> $LOGFILE 2>&1
 exit 1
fi



【redis_fault.sh】

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




【redis_master.sh】

#!/bin/bash 
REDISCLI="/usr/local/bin/redis-cli -h $1 -p $3" 
LOGFILE="/etc/keepalived/log/keepalived-redis-state.log" 
echo "[master]" >> $LOGFILE 
date >> $LOGFILE 
echo "Being master...." >> $LOGFILE 2>&1  
echo "Run MASTER cmd ..." >> $LOGFILE 2>&1
$REDISCLI SLAVEOF $2 $3 >> $LOGFILE  
sleep 10 
#delay 10 s wait data async cancel sync

echo "Run SLAVEOF NO ONE cmd ..." >> $LOGFILE
$REDISCLI SLAVEOF NO ONE >> $LOGFILE 2>&1


【redis_stop.sh】

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

注释:脚本代码,如果和你路径不一样,可根据自己的适当修改

给脚本赋执行权限:chmod a+x /etc/keepalived/scripts/*.sh 

 

11.登录从redis服务器 192.168.1.11

12.进入/etc/keepalived/keepalived.conf编辑配置文件

global_defs {
   router_id redis1
   script_user root
   enable_script_security
}
vrrp_script chk_redis 
{ 
     script "/etc/keepalived/scripts/redis_check.sh 127.0.0.1 6379" 
     interval 2 
     timeout 2
     fall 3
     weight -20
}

vrrp_instance redis {
     state BACKUP
     interface eth0  
     virtual_router_id 100 
     priority  90       
     #nopreempt # no seize,must add
     advert_int 1
         authentication {   #all node must same
         auth_type PASS
         auth_pass 1111
    }   
    
    unicast_src_ip 192.168.1.11
    unicast_peer {
          192.168.1.10
    }    

    virtual_ipaddress {  
         192.168.1.20
    }
    track_script { 
         chk_redis 
    } 

     notify_master "/etc/keepalived/scripts/redis_master.sh 127.0.0.1  192.168.1.10 6379"
     notify_backup "/etc/keepalived/scripts/redis_backup.sh 127.0.0.1  192.168.1.10 6379"
     notify_fault /etc/keepalived/scripts/redis_fault.sh 
     notify_stop /etc/keepalived/scripts/redis_stop.sh 
}

 

 主服务器的脚本,在从服务器这边也要复制一份过来。

注释:脚本代码,如果和你路径不一样,可根据自己的适当修改

         给脚本赋执行权限:chmod a+x /etc/keepalived/scripts/*.sh 

 温馨提示:

1.keepalived的主备状态与state值设置无关,是简单的标识;
2.主备机由priority值和vrrp_script中的weight值之和决定,大的为主;
3.主备比较权值=priority值+weight值*标志位,当vrrp_script检测脚本为true时标志位为1,反之为0;
4.为保证正常的主备切换,weight值应大于主备priority值之差。

 

此时启动redis 和keepalived服务吧!

然后再主服务器输入:  ip  add  查看虚拟ip目前是否在主服务器上。

。。。。。

下面就开始做测试了,比如把主服务器的redis关闭,测试从服务器redis的读写情况。

开启主服务器redis,看看从服务器redis此时会主备切换不。

 

  

相信自己,一切皆有可能!