centos7 redis主从复制

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。

一：安装配置前准备工作
1.在主服务器192.168.1.4上面做下面操作
echo “192.168.1.4 test01” >> /etc/hosts
echo “192.168.1.5 test” >> /etc/hosts
2.在从服务器192.168.1.5上面做下面操作
echo “192.168.1.4 test01” >> /etc/hosts
echo “192.168.1.5 test” >> /etc/hosts

防火墙配置
firewall-cmd --zone=public --add-port=6379/tcp --permanent
命令含义：
–zone #作用域
–add-port=80/tcp #添加端口，格式为：端口/通讯协议
–permanent #永久生效，没有此参数重启后失效
重启防火墙使配置生效
systemctl restart firewalld.service
1、运行、停止、禁用firewalld
启动：# systemctl start firewalld
查看状态：# systemctl status firewalld 或者 firewall-cmd --state
停止：# systemctl disable firewalld
禁用：# systemctl stop firewalld

2、配置firewalld
查看版本：$ firewall-cmd --version
查看帮助：$ firewall-cmd --help
查看设置：
显示状态：$ firewall-cmd --state
查看区域信息: $ firewall-cmd --get-active-zones
查看指定接口所属区域：$ firewall-cmd --get-zone-of-interface=eth0
拒绝所有包：# firewall-cmd --panic-on
取消拒绝状态：# firewall-cmd --panic-off
查看是否拒绝：$ firewall-cmd --query-panic

更新防火墙规则：# firewall-cmd --reload

# firewall-cmd --complete-reload

两者的区别就是第一个无需断开连接，就是firewalld特性之一动态添加规则，第二个需要断开连接，类似重启服务

将接口添加到区域，默认接口都在public

# firewall-cmd --zone=public --add-interface=eth0

永久生效再加上 –permanent 然后reload防火墙

设置默认接口区域

# firewall-cmd --set-default-zone=public

立即生效无需重启

打开端口（貌似这个才最常用）
查看所有打开的端口：

# firewall-cmd --zone=dmz --list-ports

加入一个端口到区域：

# firewall-cmd --zone=dmz --add-port=8080/tcp

若要永久生效方法同上

打开一个服务，类似于将端口可视化，服务需要在配置文件中添加，/etc/firewalld 目录下有services文件夹，这个不详细说了，详情参考文档

# firewall-cmd --zone=work --add-service=smtp

移除服务

# firewall-cmd --zone=work --remove-service=smtp

二、下载安装redis软件包

get http://download.redis.io/releases/redis-stable.tar.gz
tar -zxvf redis-stable.tar.gz
mv redis-stable /usr/local/redis3.2.1
cd /usr/local/redis3.2.1
make
make install 
cd /usr/local/bin
ls -ll
然后将源码中的 redis.conf 复制到 /etc/redis.conf
cp /usr/local/redis3.2.1/redis.conf /etc/redis.conf
修改 /etc/redis.conf里面可以把
daemonize yes                   #开启redis守护进程 
pidfile /var/run/redis.pid      #redis守护进程的pid存放位置 
dbfilename dump.rdb             #指定快照文件名  
dir /var/lib/redis              #指定快照文件存储路径
masterauth 123456               #主库认证密码 
requirepass 123456              #客户端连接密码 
注释bind 127.0.0.1
 `
# requirepass foobared 修改为 requirepass 密码
就可以默认在后台执行redis-server了。

再制作一个 init.d 的启动脚本：
vim /etc/init.d/redis-server
#!/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 -a yunee 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 

三、从发服务器配置redis
从服务器，配置一样，只不过 修改/etc/redis.conf 中
slaveof 修改为
slaveof 192.168.1.4 6379
masterauth 修改为主服务器所设置的密码
然后开启从服务器的redis服务。

start redis-server start

四、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 hello world2

从服务器

redis-cli -p 6379 get hello
"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。

五、配置keepalived

下载地址：http://www.keepalived.org/software/keepalived-1.2.23.tar.gz
上传到/usr/local/source-gz目录

tar -zxvf keepalived-1.2.23.tar.gz
mv keepalived-1.2.23 /usr/local/keepalived-1.2.23

yum安装opensslyum install -y openssl openssl-devel

./configure 
make && make install 

转移keepalived的配置文件 
cp /usr/local/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/
#用于keepalived服务点的启动  
cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/
#这个是用于查看keepalived相关的帮助文档
如keepalived –help或者man keepalived
mkdir /etc/keepalived
cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/  
#将keepalived配置文件做备份
cp /usr/local/sbin/keepalived /usr/sbin/
mkdir /etc/keepalived
vi /etc/keepalived/keepalived.conf
配置内容如下：
! 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
}

vrrp_instance VI_1 {
    state MASTER                 ###设置为MASTER
    interface eno16777736                ###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 {
        192.168.255.129         ######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
}

在Master和Slave上创建监控Redis的脚本
mkdir /etc/keepalived/scripts
vi /etc/keepalived/scripts/redis_check.sh
编辑内容如下：
#!/bin/bash
ALIVE=`/usr/local/bin/redis-cli -a yunee PING`
if [ "$ALIVE" == "PONG" ]; then
echo $ALIVE
exit 0
else
echo $ALIVE
exit 1
fi

5.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

1）首先，在Redis Master上创建notity_master与notify_backup脚本：

vi /etc/keepalived/scripts/redis_master.sh

#!/bin/bash
REDISCLI="/usr/local/bin/redis-cli"
LOGFILE="/var/log/keepalived-redis-state.log"
MASTER="192.168.255.134"
PASSWD="yunee"

echo "[master]" >> $LOGFILE
date >> $LOGFILE
echo "Being master...." >> $LOGFILE 2>&1

echo "Run SLAVEOF cmd ..." >> $LOGFILE
$REDISCLI -a $PASSWD SLAVEOF $MASTER 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 -a $PASSWD SLAVEOF NO ONE >> $LOGFILE 2>&1

vi /etc/keepalived/scripts/redis_backup.sh

#!/bin/bash
REDISCLI="/usr/local/bin/redis-cli"
LOGFILE="/var/log/keepalived-redis-state.log"
MASTER="192.168.255.134"
PASSWD="yunee"

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 -a $PASSWD SLAVEOF $MASTER 6379 >> $LOGFILE 2>&1

2）在Redis Slave上创建notity_master与notify_backup脚本：

vi /etc/keepalived/scripts/redis_master.sh

#!/bin/bash
REDISCLI="/usr/local/bin/redis-cli"
LOGFILE="/var/log/keepalived-redis-state.log"
MASTER="192.168.255.137"
PASSWD="yunee"

echo "[master]" >> $LOGFILE
date >> $LOGFILE
echo "Being master...." >> $LOGFILE 2>&1

echo "Run SLAVEOF cmd ..." >> $LOGFILE
$REDISCLI -a $PASSWD SLAVEOF $MASTER 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 -a $PASSWD SLAVEOF NO ONE >> $LOGFILE 2>&1

vi /etc/keepalived/scripts/redis_backup.sh

#!/bin/bash
REDISCLI="/usr/local/bin/redis-cli"
LOGFILE="/var/log/keepalived-redis-state.log"
MASTER="192.168.255.137"
PASSWD="yunee"

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 -a $PASSWD SLAVEOF $MASTER 6379 >> $LOGFILE 2>&1

3)然后在Master与Slave创建如下相同的脚本：

vi /etc/keepalived/scripts/redis_fault.sh

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

vi /etc/keepalived/scripts/redis_stop.sh

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

4）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

禁用防火墙
systemctl stop firewalld

查看状态
firewall-cmd --state

查看日志
tail -f /var/log/keepalived-redis-state.log