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    Redis主从配置及使用KeepAlived实现Redis高可用

    Vlix_Liu发表于 2015-07-20 06:21:27
    love 1

    一：环境介绍

    Master: 172.16.206.29

    Slave: 172.16.206.28

    Virtural IP Address (VIP): 172.16.206.250

    二：设计思路：

    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，有写权限，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，同时Slave等待Master同步数据完成之后，恢复Slave身份。

     

    三：安装配置前准备工作

    在主服务器 172.16.206.29 上面做下面操作

    echo “172.16.206.29 osb29″ >> /etc/hosts

    echo “172.16.206.28 osb28″ >> /etc/hosts

    在从服务器 172.16.206.28 上面做下面操作

    echo “172.16.206.29 osb29″ >> /etc/hosts

    echo “172.16.206.28 osb28″ >> /etc/hosts

    四：主服务器配置redis

    1．下载redis 版本2.8.19

    wget http://download.redis.io/releases/redis-2.8.19.tar.gz

    2．解压 tar -zxvf redis-2.8.19.tar.gz

    3．cd redis-2.8.19

    4．make && make install

    5．cp redis.conf /etc/redis.conf

    cd src/

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

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

    目的是可以在后台执行redis-server。

    7．init.d 启动脚本

    vi /etc/init.d/redis-server

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    #!/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

    chmod o+x /etc/init.d/redis-server

    chkconfig –add redis-server

    service redis-server start

    五：从服务器配置redis

    从服务器，配置一样，只不过 修改/etc/redis.conf 中

    slaveof <masterip> <masterport>修改为

    slaveof 172.16.206.28 6379

    然后开启从服务器的redis服务。

    start redis-server start

     

    六：进行redis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 hello2 world2

    #从服务器

    redis-cli -p 6379 get hello2

    “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。

     

    七：安装和配置keepalived

    1． wget http://www.keepalived.org/software/keepalived-1.2.15.tar.gz

    tar -zxvf keepalived-1.2.15.tar.gz

    cd keepalived-1.2.15

    2．  安装openssl-devel和kernel-devel

    yum install openssl-devel

    yum install kernel-devel

    ln -s /usr/src/kernels/2.6.32-431.el6.x86_64 /usr/src/linux

    3． 配置编译安装

    ./configure–prefix=/usr/local/keepalived  –with-kernel-dir=/usr/src/linux   –enable-sha1

    make && make install

    4． 复制keepalived相关文件

    cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/keepalived

    cp /usr/local/keepalived/sbin/keepalived /usr/sbin/keepalived

    cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/keepalived

    mkdir /etc/keepalived

    cp /usr/local/keepalived/etc/keepalived/samples/keepalived.conf.virtualhost

    /etc/keepalived/keepalived.conf

    八：修改配置文件和相关脚本

    1． 在Master上创建配置文件

    vi /etc/keepalived/keepalived.conf

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    ! Configuration File for keepalived
    vrrp_script chk_redis {
        script "/etc/keepalived/scripts/redis_check.sh"    ###监控脚本
        interval 2                                          ###监控时间
        }
    #网卡需要注意，使用ifconfig查看一下当前活动网卡
    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 {
           172.16.206.250        ######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
    }

    2．在Slave上创建如下配置文件

    vim /etc/keepalived/keepalived.conf

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    ! Configuration File for keepalived
    vrrp_script chk_redis {
        script "/etc/keepalived/scripts/redis_check.sh"    ###监控脚本
        interval 2                  ###监控时间
        }
     #同样要注意网卡
    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 {
            172.16.206.250 ####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．在Master和Slave上创建监控Redis的脚本

    $  mkdir /etc/keepalived/scripts

    $  vim /etc/keepalived/scripts/redis_check.sh

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

     

    4．编写关键脚本

    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执行脚本：

    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：

    vi /etc/keepalived/scripts/redis_master.sh

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    #!/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 172.16.206.sl 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

    vi /etc/keepalived/scripts/redis_backup.sh

     

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    #!/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 192.168.1.sl 6379 >> $LOGFILE  2>&1

    在Redis Slave上创建notity_master与notify_backup脚本：

    vi /etc/keepalived/scripts/redis_master.sh

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    #!/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 192.168.1.ma 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

    vi /etc/keepalived/scripts/redis_backup.sh

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    #!/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 192.168.1.4 6379 >> $LOGFILE  2>&1

    然后在Master与Slave创建如下相同的脚本：

     

    vi /etc/keepalived/scripts/redis_fault.sh

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

    vi /etc/keepalived/scripts/redis_stop.sh

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

    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

    九：相关功能测试

    启动Master和slave上的Redis

    service redis-server 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 172.16.206.250 INFO

    连接成功，可以看到主从机的信息，例如：

    role:master

    slave0:172.16.206.28,6379,online

     

    尝试插入一些数据：

    $ redis-cli -h 172.16.206.250 SET hello3 world3

    OK

     

    从VIP读取数据

    $ redis-cli -h 172.16.206.250 GET hello3

    “world3″

    从Master读取数据

    $ redis-cli -h 172.16.206.29 GET hello3

    “world3″

    从Slave读取数据

    $ redis-cli -h 172.16.206.28 GET hello3

    “world3″

     

    将Master上的Redis进程杀死：

    $ service redis-server stop

    查看Master上的Keepalived日志

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

    [fault]

    Mon Jan  5 14:06:22 CST 2015

     

    同时Slave上的日志显示：

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

    [master]

    Mon Jan  5 14:13:52 CST 2015

    Being master….

    Run SLAVEOF cmd …

    OK Already connected to specified master

    Run SLAVEOF NO ONE cmd …

    OK

    现在，Slave已经接管服务，并且拥有Master的角色

    $ redis-cli -h 172.16.206.250 INFO

    $ redis-cli -h 172.16.206.28 INFO

    role:master

     

    然后恢复Master的Redis进程

    $  service redis-server start

    查看Master上的Keepalived日志

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

     

    [master]

    2015年 01月 05日 星期一 15:48:08 CST

    Being master….

    Run SLAVEOF cmd …

    OK

    Run SLAVEOF NO ONE cmd …

    OK

    同时Slave上的日志显示：

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

    [backup]

    Mon Jan  5 14:53:16 CST 2015

    Being slave….

    Run SLAVEOF cmd …

    OK

     

    Master已经再次恢复了Master角色



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