一:环境介绍:
Master: 192.168.1.4
Slave: 192.168.1.5
Virtural IP Address (VIP): 192.168.1.253
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。
三: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
四:主服务器配置redis
1.下载安装redis软件包
wget http://download.redis.io/releases/redis-2.8.12.tar.gztar xf redis-2.8.12.tar.gz cd redis-2.8.12 make && make install cd src/ cp redis-server redis-cli redis-benchmark redis-check-aof redis-check-dump /usr/local/bin cd /usr/local/bin ls -ll 然后将源码中的 redis.conf 复制到 /etc/redis.conf cp /root/redis-2.8.12/redis.conf /etc/redis.conf 修改 /etc/redis.conf里面可以把 daemonize no 修改为daemonize yes 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 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 <masterip> <masterport>修改为
slaveof 192.168.1.4 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 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。
七:安装和配置keepalived
1.在Master和Slave上安装Keepalived
$ yum install keepalived -y
2.默认安装完成keepalived之后是没有配置文件的,因此我们需要手动创建:
首先,在Master上创建如下配置文件:
$ vim /etc/keepalived/keepalived.conf
! 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 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 { 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 }
3.然后,在Slave上创建如下配置文件:
$ vim /etc/keepalived/keepalived.conf
! 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 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
$ vim /etc/keepalived/scripts/redis_check.sh
#!/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 "[master]" >> $LOGFILE date >> $LOGFILE echo "Being master...." >> $LOGFILE 2>&1 echo "Run SLAVEOF cmd ..." >> $LOGFILE $REDISCLI SLAVEOF 192.168.1.5 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="/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 192.168.1.5 6379 >> $LOGFILE 2>&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 "[master]" >> $LOGFILE date >> $LOGFILE echo "Being master...." >> $LOGFILE 2>&1 echo "Run SLAVEOF cmd ..." >> $LOGFILE $REDISCLI SLAVEOF 192.168.1.4 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="/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
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 "[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
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 192.168.0.253 INFO
连接成功,Slave也连接上来了。
role:master
slave0:192.168.1.5,6379,online
尝试插入一些数据:
$ redis-cli -h 192.168.0.253 SET Hello Redis
OK
从VIP读取数据
$ redis-cli -h 192.168.0.253 GET Hello
"Redis"
从Master读取数据
$ redis-cli -h 192.168.0.1 GET Hello
"Redis"
从Slave读取数据
$ redis-cli -h 192.168.0.2 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
[fault]
Thu Sep 27 08:29:01 CST 2012
同时Slave上的日志显示:
$ tail -f /var/log/keepalived-redis-state.log
[master]
2014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 192.168.1.253 INFO
$ redis-cli -h 192.168.1.5 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
[master]
2014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
[backup]
Fri Sep 28 14:16:37 CST 2012
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。
参考:http://chwshuang.iteye.com/blog/1881169
redis主从配置及通过keepalived实现redis自动切换高可用