1.环境信息
    在三台主机上,ct6601为redis master,ct6602为redis slave,
   ct6601,ct6602,ct6604各装一个sentinel
    redis version:2.8.20
   hsot:ct6601 192.108.56.117
       ct6602 192.108.56.119
       ct6604 192.108.56.120

   master：   192.108.56.117 6379
   slave1:    192.108.56.119 6379

   sentinel1: 192.108.56.117 26379
   sentinel2: 192.108.56.119 26379
   sentinel3: 192.108.56.120 26379
2.配置
#在ct6601,ct6602,ct6604安装redis
   [root@ct6601 ~]# tar -xzvf redis-2.8.20.tar.gz
   [root@ct6601 ~]# cd /root/redis-2.8.20
   [root@ct6601 ~]# make
   [root@ct6601 ~]# make install
   [root@ct6601 redis-2.8.20]# mkdir /usr/local/redis

#在ct6601,ct6602中复制默认的redis.conf文件
   [root@ct6601 redis-2.8.20]# cp /root/redis-2.8.20/redis.conf /usr/local/redis/redis.conf

#修改ct6601的redis.conf配置文件
   [root@ct6601 redis-2.8.20]# vi /usr/local/redis/redis.conf
   修改:daemonize yes

#修改ct6602的redis.conf配置文件
   [root@ct6602 redis-2.8.20]# vim /usr/local/redis/redis.conf
   修改:daemonize yes
   修改:slaveof 192.108.56.117 6379

#在ct6601,ct6602上启动redis服务
   [root@ct6601 redis]# redis-server /usr/local/redis/redis.conf

#在ct6601,ct6602上查看验证master-slave
   [root@ct6601 redis]# redis-cli
   127.0.0.1:6379> info replication
   # Replication
   role:master
   connected_slaves:1
   slave0:ip=192.108.56.119,port=6379,state=online,offset=225,lag=1
   master_repl_offset:225
   repl_backlog_active:1
   repl_backlog_size:1048576
   repl_backlog_first_byte_offset:2
   repl_backlog_histlen:224
   127.0.0.1:6379> set mykey hello,select~
   OK

   [root@ct6602 redis-2.8.20]# redis-cli
   127.0.0.1:6379> info replication
   # Replication
   role:slave
   master_host:192.108.56.117
   master_port:6379
   master_link_status:up
   master_last_io_seconds_ago:1
   master_sync_in_progress:0
   slave_repl_offset:334
   slave_priority:100
   slave_read_only:1
   connected_slaves:0
   master_repl_offset:0
   repl_backlog_active:0
   repl_backlog_size:1048576
   repl_backlog_first_byte_offset:0
   repl_backlog_histlen:0
   127.0.0.1:6379> get mykey
   "hello,select~"

#在ct6601,ct6602,ct6604上配置redis sentinel
   [root@ct6601 redis]# cp /root/redis-2.8.20/sentinel.conf /usr/local/redis/sentinel.conf
   [root@ct6601 redis]# vi /usr/local/redis/sentinel.conf
   加入:daemonize yes
   修改:sentinel monitor mymaster 192.108.56.117 6379 2

   [root@ct6601 redis]# redis-sentinel /usr/local/redis/sentinel.conf

#查看验证redis sentinel
   [root@ct6601 redis]# redis-cli -p 26379 info sentinel
   # Sentinel
   sentinel_masters:1
   sentinel_tilt:0
   sentinel_running_scripts:0
   sentinel_scripts_queue_length:0
   master0:name=mymaster,status=ok,address=192.108.56.117:6379,slaves=1,sentinels=3

   #关闭ct6601的redis服务
   [root@ct6601 redis]# redis-cli
   127.0.0.1:6379> info replication
   # Replication
   role:master
   connected_slaves:1
   slave0:ip=192.108.56.119,port=6379,state=online,offset=45753,lag=0
   master_repl_offset:45896
   repl_backlog_active:1
   repl_backlog_size:1048576
   repl_backlog_first_byte_offset:2
   repl_backlog_histlen:45895
   127.0.0.1:6379> shutdown
   not connected> exit
   #ct6602上的redis变为master角色
   [root@ct6602 redis-2.8.20]# redis-cli
   127.0.0.1:6379> info replication
   # Replication
   role:master
   connected_slaves:0
   master_repl_offset:0
   repl_backlog_active:0
   repl_backlog_size:1048576
   repl_backlog_first_byte_offset:0
   repl_backlog_histlen:0

   #重新开启ct6601上的redis服务,可以看到ct6601上的redis已经变为slave角色
   [root@ct6601 redis]# redis-server /usr/local/redis/redis.conf
   [root@ct6601 redis]# redis-cli
   127.0.0.1:6379> info replication
   # Replication
   role:slave
   master_host:192.108.56.119
   master_port:6379
   master_link_status:up
   master_last_io_seconds_ago:0
   master_sync_in_progress:0
   slave_repl_offset:2040
   slave_priority:100
   slave_read_only:1
   connected_slaves:0
   master_repl_offset:0
   repl_backlog_active:0
   repl_backlog_size:1048576
   repl_backlog_first_byte_offset:0
   repl_backlog_histlen:0

   [root@ct6602 redis-2.8.20]# redis-cli
   127.0.0.1:6379> info replication
   # Replication
   role:master
   connected_slaves:1
   slave0:ip=192.108.56.117,port=6379,state=online,offset=9089,lag=0
   master_repl_offset:9089
   repl_backlog_active:1
   repl_backlog_size:1048576
   repl_backlog_first_byte_offset:2
   repl_backlog_histlen:9088

3.备注
   经测试,redis sentinel需要最少3个实例,否则如果一台主机redis和redis sentinel都down掉,无法自动切换.

redis sentinel 配置