keepalived实现redis主从高可用

Redis  /  管理员 发布于 3年前   327

方案说明

两台机器（称为A和B），以统一的VIP对外提供服务
1.正常情况下，A和B都启动，B会把A的数据同步过来（B is slave of A）
2.当A挂了后，VIP漂移到B；B的keepalived 通知redis 执行：slaveof no one，由B提供服务
3.当A起来后，VIP不切换，仍在B上面；而A的keepalived 通知redis 执行slaveof B，开始把B的数据同步过来（A is slave of B）
4.依此循环

也就是说：
当两台机器都正常时，一个为master，一个为slave；
当master挂掉时，slave升级为master；
当原master再次起来时，它不会抢占，而是作为slave；依此循环


机器

10.75.201.67:/home/redis
10.75.201.66: /home/redis
初次启动时，10.75.201.67为master，10.75.201.66为slave

配置

//A机器vrrp_script chk_nutcraker {                script "/home/redis/redis/bin/redis_check.sh"                interval 2}vrrp_instance VI_2 {        state BACKUP        #both BACKUP        interface eth1        virtual_router_id 12        priority 101    #101 on master, 100 on backup        nopreempt       #both nopreempt        track_script {                chk_nutcraker        }        virtual_ipaddress {             10.75.201.3        }        notify /home/redis/redis/bin/redis_notify.sh}

//B机器vrrp_script chk_nutcraker {                script "/home/redis/redis/bin/redis_check.sh"                interval 2}vrrp_instance VI_2 {        state BACKUP        #both BACKUP        interface eth1        virtual_router_id 12        priority 100    #101 on master, 100 on backup        nopreempt       #both nopreempt        track_script {                chk_nutcraker        }        virtual_ipaddress {             10.75.201.3        }        notify /home/redis/redis/bin/redis_notify.sh}

检测redis是否正常的脚本：
[root@redhat1 ~]# cat /home/redis/redis/bin/redis_check.sh

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

redis根据keepalived状态转移而更新自己的状态：进入master时slaveof no one，进入backup时，slaveof另一台机器：
[root@redhat1 ~]# cat /home/redis/redis/bin/redis_notify.sh

#!/bin/bashREMOTE=10.75.201.67  #在10.75.201.67机器上则为10.75.201.66PORT=6379REDIS_HOME=/home/redis/redisREDISCLI="$REDIS_HOME/bin/redis-cli"LOGFILE="$REDIS_HOME/logs/redis_notify.log"DATE_TIME=`date "+%Y-%m-%d %H:%M:%S"`TYPE=$1NAME=$2STATE=$3case $STATE in        "MASTER")                   echo "$DATE_TIME:became master:" >> $LOGFILE                  $REDISCLI SLAVEOF NO ONE >> $LOGFILE 2>&1                   exit 0                  ;;        "BACKUP")                    echo "$DATE_TIME:became slave:" >> $LOGFILE                  $REDISCLI SLAVEOF $REMOTE $PORT >> $LOGFILE  2>&1                  exit 0                  ;;        "FAULT")                    echo "$DATE_TIME:[fault]" >> $LOGFILE                  exit 0                  ;;        *)        echo "unknown state"                  exit 1                  ;;Esac