搜诶符合你 发表于 2018-11-5 09:46:21

实现Redis高可用

  利用keepalived实现redis高可用
  环境介绍:
  master: 192.168.0.100
  slave: 192.168.0.101
  vip(keepvlied虚拟IP): 192.168.0.200
  注:这里有一个坑
  就是在同一网段之间的Keepalived的配置文件中需要把 virtual_router_id 后面的值设置不同(范围是0-255),否则,keepalived在主从切换的时间会有问题,而且在/var/log/messages日志中
  会不断的写入日志,会把服务器写爆。
virtual_router_id 每一套都需要设置不同(范围是0-255)  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,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
在Master和Slave上安装Keepalived
yum install -y keepalived  首先,在Master上创建如下配置文件:
! Configuration File for keepalived  
global_defs {
  
   router_id redis100
  
}
  
vrrp_script chk_redis
  
{
  
   script "/etc/keepalived/scripts/redis_check.sh 127.0.0.1 6379"
  
   interval 2
  
   timeout 2
  
   fall 3
  
}
  
vrrp_instance redis {
  
   state MASTER # master set to SLAVE also
  
   interface eth0
  
   virtual_router_id 50
  
   priority150
  
   nopreempt # 非抢占模式,注:主与从必须同时设置为BACKUP
  
   advert_int 1
  
authentication {   #all node must same
  
         auth_type PASS
  
         auth_pass 1111
  
    }
  
    virtual_ipaddress {
  
192.168.0.200/24
  
    }
  
    track_script {
  
         chk_redis
  
    }
  
   notify_master "/etc/keepalived/scripts/redis_master.sh 127.0.0.1 192.168.0.101 6379"
  
   notify_backup "/etc/keepalived/scripts/redis_backup.sh 127.0.0.1 192.168.0.101 6379"
  
   notify_fault /etc/keepalived/scripts/redis_fault.sh
  
   notify_stop /etc/keepalived/scripts/redis_stop.sh
  
}
  然后,在Slave上创建如下配置文件:
! Configuration File for keepalived  

  
global_defs {
  
   router_id redis101
  
}
  
vrrp_script chk_redis
  
{
  
   script "/etc/keepalived/scripts/redis_check.sh 127.0.0.1 6379"
  
   interval 2
  
   timeout 2
  
   fall 3
  
}
  
vrrp_instance redis {
  
    state BACKUP
  
    interface eth0
  
    virtual_router_id 50
  
    priority100
  
    advert_int 1
  
authentication {   #all node must same
  
      auth_type PASS
  
      auth_pass 1111
  
    }
  
    virtual_ipaddress {
  
    192.168.0.200/24
  
    }
  
    track_script {
  
         chk_redis
  
    }
  
    notify_master "/etc/keepalived/scripts/redis_master.sh 127.0.0.1 192.168.0.100 6379"
  
    notify_backup "/etc/keepalived/scripts/redis_backup.sh 127.0.0.1 192.168.0.100 6379"
  
    notify_fault /etc/keepalived/scripts/redis_fault.sh
  
    notify_stop /etc/keepalived/scripts/redis_stop.sh
  
}
  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/redis/redis-cli -h $1 -p $2 PING`
  
LOGFILE="/var/log/keepalived-redis-check.log"
  
echo "" >> $LOGFILE
  
date >> $LOGFILE
  
if [ $ALIVE == "PONG" ]; then :
  
   echo "Success: redis-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
  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
  首先,在Redis Master上创建notity_master与notify_backup脚本:
  cat /etc/keepalived/scripts/redis_master.sh
#!/bin/bash  
REDISCLI="/usr/redis/redis-cli -h $1 -p $3"
  
LOGFILE="/var/log/keepalived-redis-state.log"
  
echo "" >> $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
  cat /etc/keepalived/scripts/redis_backup.sh
#!/bin/bash  
REDISCLI="/usr/redis/redis-cli"
  
LOGFILE="/var/log/keepalived-redis-state.log"
  
echo "" >> $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
  接着,在Redis Slave上创建notity_master与notify_backup脚本:
  cat /etc/keepalived/scripts/redis_master.sh
#!/bin/bash  
REDISCLI="/usr/redis/redis-cli -h $1 -p $3"
  
LOGFILE="/var/log/keepalived-redis-state.log"
  
echo "" >> $LOGFILE
  
date >> $LOGFILE
  
echo "Being master...." >> $LOGFILE 2>&1
  
echo "Run SLAVEOF cmd ... " >> $LOGFILE
  
$REDISCLI SLAVEOF $2 $3 >> $LOGFILE2>&1
  
#echo "SLAVEOF $2 cmd can't excute ... " >> $LOGFILE
  
sleep 10 ##delay 15 s wait data sync exchange role
  
echo "Run SLAVEOF NO ONE cmd ..." >> $LOGFILE
  
$REDISCLI SLAVEOF NO ONE >> $LOGFILE 2>&1
  cat /etc/keepalived/scripts/redis_backup.sh
#!/bin/bash  
REDISCLI="/usr/redis/redis-cli"
  
LOGFILE="/var/log/keepalived-redis-state.log"
  
echo "" >> $LOGFILE
  
date >> $LOGFILE
  
echo "Being slave...." >> $LOGFILE 2>&1
  
echo "Run SLAVEOF cmd ..." >> $LOGFILE 2>&1
  
$REDISCLI SLAVEOF $2 $3 >> $LOGFILE
  
sleep 100 #delay 10 s wait data async cancel sync
  
exit(0)
  然后在Master与Slave创建如下相同的脚本:
  cat /etc/keepalived/scripts/redis_fault.sh
#!/bin/bash  
LOGFILE=/var/log/keepalived-redis-state.log
  
echo "" >> $LOGFILE
  
date >> $LOGFILE
  cat /etc/keepalived/scripts/redis_stop.sh
#!/bin/bash  
LOGFILE=/var/log/keepalived-redis-state.log
  
echo "" >> $LOGFILE
  
date >> $LOGFILE
  给脚本都加上可执行权限:
chmod +x /etc/keepalived/scripts/*.sh  脚本创建完成以后,我们开始按照如下流程进行测试:
  1.启动Master上的Redis
$ /etc/init.d/redis start  2.启动Slave上的Redis
$ /etc/init.d/redis start  3.启动Master上的Keepalived
$ /etc/init.d/keepalived start  4.启动Slave上的Keepalived
$ /etc/init.d/keepalived start  5.尝试通过VIP连接Redis:
$ redis-cli -h 10.6.1.200 INFO  连接成功,Slave也连接上来了。
role:master  
slave0:192.168.0.101,6379,online
  6.尝试插入一些数据:
$ redis-cli -h 10.6.1.200 SET Hello Redis  
OK
  从VIP读取数据
$ redis-cli -h 10.6.1.200 GET Hello  
"Redis"
  从Master读取数据
$ redis-cli -h 10.6.1.143 GET Hello  
"Redis"
  从Slave读取数据
$ redis-cli -h 10.6.1.144 GET Hello  
"Redis"
  下面,模拟故障产生:
  将Master上的Redis停了
  本方来自:http://blog.csdn.net/huwei2003/article/details/41894197


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