Redis+Sentinel哨兵模式安装与配置
机器环境有限，搭建一个伪集群。
1.环境介绍
集群机器 redis服务 哨兵(sentinel) 节点描述
虚拟机：172.17.199.70 端口6400 安装sentinel服务,端口26400 主节点
虚拟机：172.17.199.70 端口6401 安装sentinel服务,端口26401 从节点
虚拟机：172.17.199.70 端口6402 安装sentinel服务,端口26402 从节点
2.配置主从关系
2.1.主redis.conf 配置 #日志和数据文件地址自行修改
daemonize yes
pidfile "/usr/redis/redis-2.8.19/redis_6400.pid"
port 6400
tcp-backlog 65535
bind 0.0.0.0
timeout 0
tcp-keepalive 0
loglevel notice
logfile "/usr/redis/redis-2.8.19/redis_6400.log"
maxmemory 8gb
maxmemory-policy allkeys-lru
databases 16
save 900 1
save 300 10
save 60 10000
stop-writes-on-bgsave-error yes
rdbcompression yes
rdbchecksum yes
dbfilename "dump.rdb"
dir "/usr/redis/redis-2.8.19/data"
slave-serve-stale-data yes
slave-read-only yes
repl-disable-tcp-nodelay no
slave-priority 100
appendonly no
appendfilename "appendonly.aof"
appendfsync everysec
no-appendfsync-on-rewrite no
auto-aof-rewrite-percentage 100
auto-aof-rewrite-min-size 64mb
lua-time-limit 5000
slowlog-log-slower-than 10000
slowlog-max-len 128
notify-keyspace-events ""
hash-max-ziplist-entries 512
hash-max-ziplist-value 64
list-max-ziplist-entries 512
list-max-ziplist-value 64
set-max-intset-entries 512
zset-max-ziplist-entries 128
2.2.从redis.conf 配置 #相比于主多了一行slaveof
daemonize yes
pidfile "/usr/redis/redis-slave1/redis_6401.pid"
port 6401
tcp-backlog 65535
bind 0.0.0.0
timeout 0
tcp-keepalive 0
loglevel notice
logfile "/usr/redis/redis-slave1/redis_6401.log"
maxmemory 8gb
maxmemory-policy allkeys-lru
databases 16
save 900 1
save 300 10
save 60 10000
stop-writes-on-bgsave-error yes
rdbcompression yes
rdbchecksum yes
dbfilename "dump.rdb"
dir "/usr/redis/redis-slave1/data"
slave-serve-stale-data yes
slave-read-only yes
repl-disable-tcp-nodelay no
slave-priority 100
appendonly no
appendfilename "appendonly.aof"
appendfsync everysec
no-appendfsync-on-rewrite no
auto-aof-rewrite-percentage 100
auto-aof-rewrite-min-size 64mb
lua-time-limit 5000
slowlog-log-slower-than 10000
slowlog-max-len 128
notify-keyspace-events ""
hash-max-ziplist-entries 512
hash-max-ziplist-value 64
list-max-ziplist-entries 512
list-max-ziplist-value 64
set-max-intset-entries 512
zset-max-ziplist-entries 128
slaveof 172.17.199.70 6400
2.3启动
./src/redis-server redis.conf
2.4.查询主从关系
2.4.1主
[root@iZ2zeemywxjdx93lap023pZ redis-slave1]# ./src/redis-cli -h 172.17.199.70 -p 6400 info Replication
# Replication
role:master
connected_slaves:2
slave0:ip=172.17.199.70,port=6401,state=online,offset=15596870,lag=1
slave1:ip=172.17.199.70,port=6402,state=online,offset=15597011,lag=0
master_repl_offset:15597011
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:14548436
repl_backlog_histlen:1048576
2.4.2从
[root@iZ2zeemywxjdx93lap023pZ redis-slave1]# ./src/redis-cli -h 172.17.199.70 -p 6401 info Replication
# Replication
role:slave
master_host:172.17.199.70
master_port:6400
master_link_status:up
master_last_io_seconds_ago:0
master_sync_in_progress:0
slave_repl_offset:15606951
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
3.配置哨兵Sentinel
port 26400
daemonize yes
dir "/usr/redis/redis-2.8.19/sentinel"
sentinel monitor mymaster 172.17.199.70 6400 2
sentinel down-after-milliseconds mymaster 3000
sentinel failover-timeout mymaster 10000
sentinel config-epoch mymaster 0
sentinel leader-epoch mymaster 0
sentinel known-slave mymaster 172.17.199.70 6401
sentinel known-slave mymaster 172.17.199.70 6402
# Generated by CONFIG REWRITE
sentinel known-sentinel mymaster 172.17.199.70 26401 b0adf1633ee389f66794961751f069041b838471
sentinel known-sentinel mymaster 172.17.199.70 26402 c331f278bc5f54ba3e83007ef8af50eccf51e252
sentinel current-epoch 0
port 26401
daemonize yes
dir "/usr/redis/redis-slave1/sentinel"
sentinel monitor mymaster 172.17.199.70 6400 2
sentinel down-after-milliseconds mymaster 3000
sentinel failover-timeout mymaster 10000
sentinel config-epoch mymaster 0
sentinel leader-epoch mymaster 0
sentinel known-slave mymaster 172.17.199.70 6400
sentinel known-slave mymaster 172.17.199.70 6402
# Generated by CONFIG REWRITE
sentinel known-sentinel mymaster 172.17.199.70 26400 57ec8c95e8292ccbcc4da37202f2bdada5208936
sentinel known-sentinel mymaster 172.17.199.70 26402 c331f278bc5f54ba3e83007ef8af50eccf51e252
sentinel current-epoch 0
port 26402
daemonize yes
dir "/usr/redis/redis-slave2/sentinel"
sentinel monitor mymaster 172.17.199.70 6400 2
sentinel down-after-milliseconds mymaster 3000
sentinel failover-timeout mymaster 10000
sentinel config-epoch mymaster 0
sentinel leader-epoch mymaster 0
sentinel known-slave mymaster 172.17.199.70 6401
sentinel known-slave mymaster 172.17.199.70 6400
# Generated by CONFIG REWRITE
sentinel known-sentinel mymaster 172.17.199.70 26401 b0adf1633ee389f66794961751f069041b838471
sentinel known-sentinel mymaster 172.17.199.70 26400 57ec8c95e8292ccbcc4da37202f2bdada5208936
sentinel current-epoch 0
配置文件说明：
1. port :当前Sentinel服务运行的端口
2. dir : Sentinel服务运行时使用的临时文件夹
3.sentinel monitor master001 192.168.110.10163792:Sentinel去监视一个名为master001的主redis实例，这个主实例的IP地址为本机地址192.168.110.101，端口号为6379，而将这个主实例判断为失效至少需要2个 Sentinel进程的同意，只要同意Sentinel的数量不达标，自动failover就不会执行
4.sentinel down-after-milliseconds master001 30000:指定了Sentinel认为Redis实例已经失效所需的毫秒数。当实例超过该时间没有返回PING，或者直接返回错误，那么Sentinel将这个实例标记为主观下线。只有一个 Sentinel进程将实例标记为主观下线并不一定会引起实例的自动故障迁移：只有在足够数量的Sentinel都将一个实例标记为主观下线之后，实例才会被标记为客观下线，这时自动故障迁移才会执行
5.sentinel parallel-syncs master001 1：指定了在执行故障转移时，最多可以有多少个从Redis实例在同步新的主实例，在从Redis实例较多的情况下这个数字越小，同步的时间越长，完成故障转移所需的时间就越长
6.sentinel failover-timeout master001 180000：如果在该时间（ms）内未能完成failover操作，则认为该failover失败
7.sentinel notification-script ：指定sentinel检测到该监控的redis实例指向的实例异常时，调用的报警脚本。该配置项可选，但是很常用
4.测试sentinel集群
4.1.停止6400主
[root@iZ2zeemywxjdx93lap023pZ redis-slave2]# ./src/redis-cli -h 127.0.0.1 -p 6400 info Replication
Could not connect to Redis at 127.0.0.1:6400: Connection refused
[root@iZ2zeemywxjdx93lap023pZ redis-slave2]# ./src/redis-cli -h 127.0.0.1 -p 6401 info Replication
# Replication
role:slave
master_host:172.17.199.70
master_port:6402
master_link_status:up
master_last_io_seconds_ago:0
master_sync_in_progress:0
slave_repl_offset:11952
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
#可以看到6400不能连接，6402成为了主节点
4.2启动6400
[root@iZ2zeemywxjdx93lap023pZ redis-2.8.19]# ./src/redis-server redis.conf
[root@iZ2zeemywxjdx93lap023pZ redis-2.8.19]# ./src/redis-cli -h 127.0.0.1 -p 6400 info Replication
# Replication
role:slave
master_host:172.17.199.70
master_port:6402
master_link_status:up
master_last_io_seconds_ago:0
master_sync_in_progress:0
slave_repl_offset:26737
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
#发现主节点还是6402，6400变成了从节点
4.3只保留一个哨兵sentinel，停止6402主节点
[root@iZ2zeemywxjdx93lap023pZ redis-2.8.19]# ./src/redis-cli -h 127.0.0.1 -p 6402 info Replication
Could not connect to Redis at 127.0.0.1:6402: Connection refused
[root@iZ2zeemywxjdx93lap023pZ redis-2.8.19]# ./src/redis-cli -h 127.0.0.1 -p 6400 info Replication
# Replication
role:slave
master_host:172.17.199.70
master_port:6402
master_link_status:down
master_last_io_seconds_ago:-1
master_sync_in_progress:0
slave_repl_offset:163317
master_link_down_since_seconds:11
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@iZ2zeemywxjdx93lap023pZ redis-2.8.19]# ./src/redis-cli -h 127.0.0.1 -p 6401 info Replication
# Replication
role:slave
master_host:172.17.199.70
master_port:6402
master_link_status:down
master_last_io_seconds_ago:-1
master_sync_in_progress:0
slave_repl_offset:163317
master_link_down_since_seconds:14
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
#发现6402主已经连接不上，集群中也不存在主节点，原因是因为sentinel.conf中配置 sentinel monitor mymaster 172.17.199.70 6400 2 随后一个配置的是2
