centos6上redis+Keepalived实现Redis主从复制
环境：CentOs6.8Master:172.20.52.72
Slave:172.20.52.159
Virtual IP address(VIP):172.20.52.253
应用软件：
1、keepalived-1.2.12.tar.gz
下载地址http://www.keepalived.org/download.html
2、redis-2.8.7.tar.gz
下载地址http://www.oschina.net/news/49449/redis-2-8-7
一、安装配置前准备
yum -y install gcc gcc+ gcc-c++ openssl openssl-devel pcre pcre-devel
Redis属于内存数据库，所以调优都集中到了内存上,需要将 vm.overcommit 设置为1
echo "vm.overcommit_memory=1" >> /etc/sysctl
sysctl -p
1.在主服务器172.20.52.160上面做下面操作
echo " 172.20.52.72node1" >> /etc/hosts
echo " 172.20.52.159 node2" >> /etc/hosts
2.在从服务器10.10.10.204上面做下面操作
echo " 172.20.52.72 node1" >> /etc/hosts
echo " 172.20.52.159 node2" >> /etc/hosts
二、在Master和slave上安装Redis
tar -zxvf redis-2.8.7.tar.gz
cd redis-2.8.7
make && make install
cd src
mkdir -p /usr/local/redis/bin
cp redis-server redis-cli redis-benchmark redis-check-aof redis-check-dump /usr/local/redis/bin
mkdir -p /usr/local/redis/etc
复制源码中的redis.conf至/usr/local/redis/etc/ cp redis.conf /usr/local/redis/etc/
修改 /usr/local/redis/etc/redis.conf里面可以把 daemonize no 修改为daemonize yes
制作一个redisinit.d 的启动脚本：
复制如下代码：
#!/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 startorservice 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
vim /etc/init.d/redis-server
chmod o+x /etc/init.d/redis-server
chkconfig --add redis-server
/etc/init.d/redis-server start
从服务上redis的配置
修改 /etc/redis.conf
slaveof修改为
slaveof 172.20.52.72 6379
然后开启从服务器的redis服务。
start redis-server start
三、进行主从测试
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。
四、安装配置keepalived
1.在Master和Slave上安装Keepalived
$ yum install keepalived -y
2.默认安装完成keepalived之后是有配置文件的，但是我们需要创建合适的配置文件
首先，在Master上创建如下配置文件：
$vim /etc/keepalived/keepalived.conf
vrrp_script chk_redis {
script "/etc/keepalived/scripts/redis_check.sh" ###监控脚本
interval 2 ###监控时间
}
vrrp_instance VI_1 {
state MASTER ###设置为MASTER
interface eth1 ###监控网卡
virtual_router_id 51
priority 100 ###权重值
authentication {
auth_type PASS ###加密
auth_pass 1111 ###密码
}
track_script {
chk_redis ###执行上面定义的chk_redis
}
virtual_ipaddress {
172.20.52.253 ######VIP
}
notify_master /etc/keepalived/scripts/redis_master.sh
notify_backup /etc/keepalived/scripts/redis_backup.sh
notify_fault/etc/keepalived/scripts/redis_fault.sh
notify_stop /etc/keepalived/scripts/redis_stop.sh
}
3.然后，在Slave上创建如下配置文件：
vim /etc/keepalived/keepalived.conf
vrrp_script chk_redis {
script "/etc/keepalived/scripts/redis_check.sh" ###监控脚本
interval 2 ###监控时间
}
vrrp_instance VI_1 {
state BACKUP ###设置为BACKUP
interface eth1 ###监控网卡
virtual_router_id 51
priority 10 ###比MASTRE权重值低
authentication {
auth_type PASS
auth_pass 1111 ###密码与MASTRE相同
}
track_script {
chk_redis ###执行上面定义的chk_redis
}
virtual_ipaddress {
192.168.1.253 ####vip
}
notify_master /etc/keepalived/scripts/redis_master.sh
notify_backup /etc/keepalived/scripts/redis_backup.sh
notify_fault/etc/keepalived/scripts/redis_fault.sh
notify_stop /etc/keepalived/scripts/redis_stop.sh
}
4. 在Master和Slave上创建监控Redis的脚本
mkdir /etc/keepalived/scripts
#!/bin/bash
ALIVE=`/usr/local/bin/redis-cli PING`
if [ "$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：
$vim /etc/keepalived/scripts/redis_master.sh
#!/bin/bash
REDISCLI="/usr/local/bin/redis-cli"
LOGFILE="/var/log/keepalived-redis-state.log"
echo "" >> $LOGFILE
date >> $LOGFILE
echo "Being master...." >> $LOGFILE 2>&1
echo "Run SLAVEOF cmd ..." >> $LOGFILE
$REDISCLI SLAVEOF 172.20.52.159 6379 >> $LOGFILE2>&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
vim /etc/keepalived/scripts/redis_backup.sh
#!/bin/bash
REDISCLI="/usr/local/bin/redis-cli"
LOGFILE="/var/log/keepalived-redis-state.log"
echo "" >> $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 172.20.52.159 6379 >> $LOGFILE2>&1
2)在Redis Slave上创建notity_master与notify_backup脚本：
vim /etc/keepalived/scripts/redis_master.sh
#!/bin/bash
REDISCLI="/usr/local/bin/redis-cli"
LOGFILE="/var/log/keepalived-redis-state.log"
echo "" >> $LOGFILE
date >> $LOGFILE
echo "Being master...." >> $LOGFILE 2>&1
echo "Run SLAVEOF cmd ..." >> $LOGFILE
$REDISCLI SLAVEOF 172.20.52.72 6379 >> $LOGFILE2>&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
vim /etc/keepalived/scripts/redis_backup.sh
#!/bin/bash
REDISCLI="/usr/local/bin/redis-cli"
LOGFILE="/var/log/keepalived-redis-state.log"
echo "" >> $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 172.20.52.726379 >> $LOGFILE2>&1
3)然后在Master与Slave创建如下相同的脚本：
vim /etc/keepalived/scripts/redis_fault.sh
#!/bin/bash
LOGFILE=/var/log/keepalived-redis-state.log
echo "" >> $LOGFILE
date >> $LOGFILE
vim /etc/keepalived/scripts/redis_stop.sh
#!/bin/bash
LOGFILE=/var/log/keepalived-redis-state.log
echo "" >> $LOGFILE
date >> $LOGFILE
6.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
7.
.进行相关功能测试
启动Master和slave上的Redis
$/etc/init.d/redis 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 172.20.52.253 INFO
连接成功，Slave也连接上来了。
role:master
slave0:172.20.52.159,6379,online
尝试插入一些数据：
$ redis-cli -h 172。20.52.253 SET Hello Redis
OK
从VIP读取数据
$ redis-cli -h 172.20.52.253 GET Hello
"Redis"
从Master读取数据
$ redis-cli -h 172.20.52.72 GET Hello
"Redis"
从Slave读取数据
$ redis-cli -h 172.20.52.159 GET Hello
"Redis"
8.通过模拟相关故障，进行功能测试
将Master上的Redis进程杀死：
$killall -9 redis-server
查看Master上的Keepalived日志
$ tail -f /var/log/keepalived-redis-state.log
Thu Sep 27 08:29:01 CST 2016
同时Slave上的日志显示：
$ tail -f /var/log/keepalived-redis-state.log
2016年 07月 07日 星期一 16:42:52 CST
Being master....
Run SLAVEOF cmd ...
OK Already connected to specified master
Run SLAVEOF NO ONE cmd ...
OK
然后我们可以发现，Slave已经接管服务，并且担任Master的角色了。
$ redis-cli -h 172.20.52.253 INFO
$ redis-cli -h 172.20.52.159 INFO
role:master
然后我们恢复Master的Redis进程
$/etc/init.d/redis start
查看Master上的Keepalived日志
$ tail -f /var/log/keepalived-redis-state.log
2016年 07月 07日 星期一 16:48:08 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
Fri Sep 28 14:16:37 CST 2016
Being slave....
Run SLAVEOF cmd ...
OK
发现目前的Master已经再次恢复了Master的角色，故障切换以及自动恢复都成功了。
1.问题：刚使用redis-cli -h 172.20.52.253 INFO
说连接失败，没有路由。
此时我的解决办法是iptables -F
2.VIP的添加
ifconfig eth1:0 172.20.52.253 netmask 172.20.52.253 up
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