Redis+keepalived实现双机热备
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一． 简介
安装使用centos 5.6(64)
Master 192.168.2.235
Slave 192.168.2.236
Vip 192.168.2.200
编译环境 yum -y install gcc gcc+ gcc-c++ openssl openssl-devel pcre pcre-devel
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，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
二． 安装
Gperftools安装
tar xzvf gperftools-2.1.tar.gz
cd gperftools-2.1
. ./configure --enable-frame-pointers
make
make install
mv /usr/local/lib/libtcmalloc.so.4 /usr/lib64/
Keepalived安装
tar xf keepalived-1.2.12.tar.gz
cd keepalived-1.2.12
./configure
make && make install
cp /usr/local/etc/rc.d/init.d/keepalived /etc/init.d/
cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/
chmod +x /etc/init.d/keepalived
chkconfig –add keepalived
mkdir /etc/keepalived
ln –s /usr/local/sbin/keepalived /usr/sbin
Redis安装
tar xf redis-2.8.10.tar.gz
cd redis2.8.10
mkdir –p /opt/redis
make PREFIX=/opt/redis USE_TCMALLOC=yes FORCE_LIBC_MALLOC=yes install
三 ．配置
创建配置文件夹以及文件
mkdir -p /opt/redis/etc
mkdir -p /opt/redis/run
mkdir -p /opt/redis/data/6379
mkdir -p /opt/redis/log
cp /root/redis-2.8.10/redis.conf /opt/redis/etc/redis.conf
mv /opt/redis/etc/redis.conf /opt/redis/etc/redis_6379.conf
修改配置文件：
vim /opt/redis/etc/redis_6379.conf
daemonize yes
pidfile /opt/redis/run/redis_6379.pid
dir /opt/redis/data/6379
logfile /opt/redis/log/redis_6379.log
创建服务管理脚本
vim /etc/init.d/redis
#!/bin/sh
PATH="/opt/redis/bin:$PATH"
EXEC="/opt/redis/bin/redis-server"
CLIEXEC="/opt/redis/bin/redis-cli"
PIDFILE="/opt/redis/run/redis_6379.pid"
CONF="/opt/redis/etc/redis_6379.conf"
REDISPORT="6379"
case "$1" in
start)
if [ -f $PIDFILE ]
then
echo "$PIDFILE exists, process is already running or crashed."
else
echo "Starting Redis server..."
$EXEC $CONF
fi
;;
stop)
if [ ! -f $PIDFILE ]
then
echo "$PIDFILE does not exist, process is not running."
else
PID=$(cat $PIDFILE)
echo "Stopping ..."
$CLIEXEC -p $REDISPORT shutdown
while [ -x /proc/${PID} ]
do
echo "Waiting for Redis to shutdown ..."
sleep 1
done
echo "Redis stopped."
fi
;;
*)
echo "Usage: $0 {start|stop}" >&2
exit 1
;;
esac
授权 chmod +x /etc/init.d/redis
vim /etc/sysctl.conf
在最后添加以下节点:
vm.overcommit_memory = 1
#sysctl –p
启动redis
/etc/init.d/redis start
验证
ps aux | grep redis
首先在master上创建如下配置
mkdir –p /etc/keepalived
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 eth0 ###监控网卡
virtual_router_id 51
priority 101 ###权重值
authentication {
auth_type PASS ###加密
auth_pass redis ###密码
}
track_script {
chk_redis ###执行上面定义的chk_redis
}
virtual_ipaddress {
192.168.2.200 ###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
}
vim /etc/keepalived/scripts/redis_master.sh
#!/bin/bash
REDISCLI="/opt/redis/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 192.168.2.236(slave) 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
vim /etc/keepalived/scripts/redis_backup.sh
#!/bin/bash
REDISCLI="/opt/redis/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 192.168.2.236(slave) 6379 >> $LOGFILE 2>&1
在slave上创建如下文件：
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 eth0 ###监控网卡
virtual_router_id 51
priority 100 ###比MASTRE权重值低
authentication {
auth_type PASS
auth_pass redis ###密码与MASTRE相同
}
track_script {
chk_redis ###执行上面定义的chk_redis
}
virtual_ipaddress {
192.168.2.200 ###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
}
vim /etc/keepalived/scripts/redis_master.sh
#!/bin/bash
REDISCLI="/opt/redis/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 192.168.2.235(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 SLAVEOF NO ONE >> $LOGFILE 2>&1
vim /etc/keepalived/scripts/redis_backup.sh
#!/bin/bash
REDISCLI="/opt/redis/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 192.168.2.235 6379 >> $LOGFILE 2>&1
以下脚本分别在master和slave上创建
mkdir /etc/keepalived/scripts
vim /etc/keepalived/scripts/redis_check.sh
#!/bin/bash
ALIVE=`/opt/redis/bin/redis-cli PING`
if [ "$ALIVE" == "PONG" ]; then
echo $ALIVE
exit 0
else
echo $ALIVE
exit 1
fi
vim /etc/keepalived/scripts/redis_fault.sh
#!/bin/bash
LOGFILE=/var/log/keepalived-redis-state.log
echo "[fault]" >> $LOGFILE
date >> $LOGFILE
vim /etc/keepalived/scripts/redis_stop.sh
#!/bin/bash
LOGFILE=/var/log/keepalived-redis-state.log
echo "[stop]" >> $LOGFILE
date >> $LOGFILE
授执行权 chmod +x /etc/keepalived/scripts/*.sh
四 ．测试
在msater和slave上分别启动redis；
/etc/init.d/redis start
分别启动keepalived
/etc/init.d/keepalived start
在master上执行 ip a
虚拟IP已经绑定了
在master上执行/etc/init.d/redis stop 查看slave
看到了吧秒级切换。
接下来再吧master上的redis启动起来又切换回来了。
测试redis同步
redis教程：http://www.runoob.com/redis/redis-tutorial.html
本文出自 “Linux_woniu” 博客，请务必保留此出处http://llu1314.blog.51cto.com/5925801/1965311
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