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redis主从+keepalived实现高可用

redis主从+keepalived实现高可用

作者: 彩色的炮灰 | 来源:发表于2021-08-25 11:21 被阅读0次

Redis是我们当下比较流行使用的非关系数据库，可支持多样化的数据类型，多线程高并发支持，redis运行在内存拥有更快的读写。因为redis的表现如此出色，如何能保障redis在运行中能够应对宕机故障，

Redis支持数据的备份，即master-slave模式的数据备份。
性能极高 – Redis能读的速度是100K+次/s,写的速度是80K+次/s
原子 – Redis的所有操作都是原子性的，同时Redis还支持对几个操作全并后的原子性执行。

准备环境

Centos7 --> 10.0.0.7 -->主Redis -->主Keepalived
Centos7 --> 10.0.0.8 -->从Redis -->备Keepalived
VIP --> 10.0.0.122 (此IP必须和主备2台机器同网段但没有被使用)
redis-4.0.0
下载路径：http://download.redis.io/releases/redis-6.0.8.tar.gz
KeepAlived（直接使用yum安装）

Redis编译安装

1、提前准备好的redis软件放在/opt目录下：redis-4.0.0.tar.gz

cd /opt
tar -zxvf redis-4.0.0.tar.gz
mv redis-4.0.0 redis
cd redis
makeMALLOC=libc
make PREFIX=/usr/local/redis install

2、配置redis启动脚本

vim /etc/init.d/redis

#!/bin/sh
#chkconfig:2345 80 90
# Simple Redisinit.d script conceived to work on Linux systems
# as it doesuse of the /proc filesystem.

#配置redis端口号
REDISPORT=6379
#配置redis启动命令路径
EXE=/usr/local/redis/bin/redis-server
#配置redis连接命令路径
CLIEXE=/usr/local/redis/bin/redis-cli
#配置redis运行PID路径
PIDFILE=/var/run/redis_6379.pid
#配置redis的配置文件路径
CONF="/etc/redis/redis.conf"
#配置redis的连接认证密码
REDISPASSWORD=123456

function start () {
        if [ -f $PIDFILE ]

        then
                echo "$PIDFILE exists,process is already running or crashed"
        else
                echo "Starting Redisserver..."
                $EXE $CONF &
        fi
}

function stop () {
        if [ ! -f $PIDFILE ]
        then
                echo "$PIDFILE does not exist, process is not running"
        else
                PID=$(cat $PIDFILE)
                echo "Stopping ..."
                $CLIEXE -p $REDISPORT -a $REDISPASSWORD shutdown
                while [ -x /proc/${PID} ]
                do
                    echo "Waiting forRedis to shutdown ..."
                    sleep 1
                done
                echo "Redis stopped"
        fi
}

function restart () {
        stop
        sleep 3
        start
}

case "$1" in
    start)
    start
    ;;
    stop)
    stop
    ;;
    restart)
    restart
    ;;
    *)
    echo -e "\e[31m Please use $0 [start|stop|restart] asfirst argument \e[0m"
    ;;
esac

授予执行权限：chmod +x /etc/init.d/redis
添加开机启动：
chkconfig --add redis
chkconfig redis on
查看：chkconfig --list | grep redis

此次试验事先关闭了防火墙和selinux，生产环境建议开启防火墙。

3、添加redis命令环境变量

#vi /etc/profile
#添加下一行参数
exportPATH="$PATH:/usr/local/redis/bin"
#环境变量生效
source /etc/profile

4、启动redis服务

systemctl start  redis 
#检查启动情况
ps -ef | grep redis
image.png

注：在我们两台服务器上先执行同样的操作安装完成redis，接下来安装完成后，就直接进入配置主从环境。

Redis主从配置

我们的思路是以10.0.0.7作为主，10.0.0.8作为从，10.0.0.122作为VIP漂移地址，应用通过10.0.0.122的6379端口访问redis数据库。

正常运行下，当主节点10.0.0.7宕机后，VIP飘逸到10.0.0.8上，这时10.0.0.8就会接管10.0.0.7成为主节点，10.0.0.7就会成为从节点，继续提供读写操作。

当10.0.0.7恢复正常后，这时10.0.0.7会与10.0.0.8进行一次数据同步，10.0.0.7原有的数据不会丢失，还会同步宕机之间已经写入到10.0.0.8的数据，数据同步完成之后，

VIP会因为权重的原因重新回到10.0.0.7节点上并成为主节点，10.0.0.8会因为失去VIP会重新成为从节点，恢复到初始状态继续提供不间断的读写服务。

1、配置redis的配置文件
Master-10.0.0.7配置文件

vim /etc/redis/redis.conf
    bind 0.0.0.0
    port 6379
    daemonize yes
    requirepass 123456
    slave-serve-stale-data yes
    slave-read-only no

Slave-10.0.0.8配置文件

vim /etc/redis/redis.conf
    bind 0.0.0.0
    port 6379
    daemonize yes
    slaveof 10.0.0.7 6379
    masterauth 123456
    slave-serve-stale-data yes
    slave-read-only no

2、配置完成后重启redis服务！验证主从是否正常。
主节点10.0.0.7终端登录测试：
[root@localhost ~]# redis-cli -a 123456
127.0.0.1:6379> INFO

. image.png

从节点10.0.0.8终端登录测试：
[root@localhost ~]# redis-cli -a 123456
127.0.0.1:6379> info

image.png

3、同步测试

主节点10.0.0.7


image.png

从节点10.0.0.8


image.png

到此redis的主从已经完成！

KeepAlived配置实现双机热备

使用Keepalived实现VIP，并且通过notify_master、notify_backup、notify_fault、notify_stop来实现容灾。

1、配置Keepalived配置文件

主Keepalived配置文件

vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   notification_email {
     acassen@firewall.loc
     failover@firewall.loc
     sysadmin@firewall.loc
   }
   notification_email_from Alexandre.Cassen@firewall.loc
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id redis01
}

vrrp_script chk_redis {
    script "/etc/keepalived/script/redis_check.sh"
    interval 2
}

vrrp_instance VI_1 {
    state MASTER
    interface eno16777984
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }

    track_script {
        chk_redis
    }
    virtual_ipaddress {
        10.0.0.122
    }

    notify_master /etc/keepalived/script/redis_master.sh
    notify_backup /etc/keepalived/script/redis_backup.sh
    notify_fault  /etc/keepalived/script/redis_fault.sh  
    notify_stop   /etc/keepalived/script/redis_stop.sh
}

备用Keepalived配置文件

vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   notification_email {
     acassen@firewall.loc
     failover@firewall.loc
     sysadmin@firewall.loc
   }
   notification_email_from Alexandre.Cassen@firewall.loc
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id redis02
}

vrrp_script chk_redis {
    script "/etc/keepalived/script/redis_check.sh"
    interval 2
}

vrrp_instance VI_1 {
    state BACKUP
    interface eno16777984
    virtual_router_id 51
    priority 99
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }

    track_script {
        chk_redis
    }
    virtual_ipaddress {
        10.0.0.122
    }

    notify_master /etc/keepalived/script/redis_master.sh
    notify_backup /etc/keepalived/script/redis_backup.sh
    notify_fault  /etc/keepalived/script/redis_fault.sh  
    notify_stop  /etc/keepalived/script/redis_stop.sh
}

2、配置脚本
Master KeepAlived --10.0.0.7

创建存放脚本目录：mkdir -p /etc/keepalived/script/
cd /etc/keepalived/script/
[root@localhost script]# cat redis_check.sh 

#!/bin/bash 
ALIVE=`/usr/local/redis/bin/redis-cli -a 123456 PING` 
if [ "$ALIVE" == "PONG" ];then
echo $ALIVE 
exit 0 
else
echo $ALIVE 
exit 1 
fi

[root@localhost script]# cat redis_master.sh 

#!/bin/bash
REDISCLI="/usr/local/redis/bin/redis-cli -a 123456"
LOGFILE="/var/log/keepalived-redis-state.log"
sleep 15
echo "[master]" >> $LOGFILE
date >> $LOGFILE
echo "Being master...." >>$LOGFILE 2>&1
echo "Run SLAVEOF cmd ...">> $LOGFILE
$REDISCLI SLAVEOF 10.0.0.8 6379 >>$LOGFILE  2>&1
if [ $? -ne 0 ];then
    echo "data rsync fail." >>$LOGFILE 2>&1
else
    echo "data rsync OK." >> $LOGFILE  2>&1
fi
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
if [ $? -ne 0 ];then
    echo "Run SLAVEOF NO ONE cmd fail." >>$LOGFILE 2>&1
else
    echo "Run SLAVEOF NO ONE cmd OK." >> $LOGFILE  2>&1
fi

[root@localhost script]# cat redis_backup.sh 

#!/bin/bash 
REDISCLI="/usr/local/redis/bin/redis-cli -a 123456"
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
$REDISCLI SLAVEOF 10.0.0.8 6379 >>$LOGFILE  2>&1

[root@localhost script]# cat redis_fault.sh 

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

[root@localhost script]# cat redis_stop.sh 

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

Slave KeepAlived -- 10.0.0.8

创建存放脚本目录：mkdir -p /etc/keepalived/script/
cd /etc/keepalived/script/
[root@localhost script]# cat redis_check.sh 

#!/bin/bash 
ALIVE=`/usr/local/redis/bin/redis-cli -a 123456 PING` 
if [ "$ALIVE" == "PONG" ]; then
echo $ALIVE 
exit 0 
else
echo $ALIVE 
exit 1 
fi

[root@localhost script]# cat redis_master.sh 

#!/bin/bash 
REDISCLI="/usr/local/redis/bin/redis-cli -a 123456"
LOGFILE="/var/log/keepalived-redis-state.log"
echo "[master]" >> $LOGFILE
date >> $LOGFILE
echo "Being master...." >>$LOGFILE 2>&1
echo "Run SLAVEOF cmd ...">> $LOGFILE
$REDISCLI SLAVEOF 10.0.0.7 6379 >>$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

[root@localhost script]# cat redis_backup.sh 

#!/bin/bash 
REDISCLI="/usr/local/redis/bin/redis-cli -a 123456"
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
$REDISCLI SLAVEOF 10.0.0.7 6379 >>$LOGFILE  2>&1

[root@localhost script]# cat redis_fault.sh 

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

[root@localhost script]# cat redis_stop.sh 

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

3、启动服务

systemctl start keepalived
systemctl enable keepalived

4、测试服务是否正常

ps -ef | grep keepalived
image 
ping 172.16.81.139
image

查看VIP地址

image

测试连接redis是否正常

redis-cli -h 172.16.81.139 -p 6379 -a 123456

image

Keepalived测试完成！！

测试故障转移情况

关闭主redis服务，查看从redis是否会接管VIP变成主？然后再新的主redis141上插入数据，测试当140恢复，数据是否存在？141的是否会变成从节点？

1、主140关闭redis

service redis stop

2、查看141状态

测试VIP连接远程连接

image

通过INFO可以查看状态信息

image

可以看到从节点的141已经变成master节点了。

3、插入数据

image

4、开启140主节点

service redis start

5、查看140和141的主从状态
141的状态，变回了从


image

140的状态，变回了主

image

我们在140上查看刚刚在141上插入的新数据

image

数据存在，证明主从切换是正常的！！！

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