Redis序列之Sentinel

前段时间一直在研究Redis的Sentinel集群，实验几次也没成功过，要么是Master有问题，要么是Mster宕机后，Slave没能自动切换成新的Master，今天突发灵感，实验一次成功，集群配置如上：
Master：127.0.0.1:10001
Slave：127.0.0.1:10002,127.0.0.1:10003
Sentinel：127.0.0.1:26389,127.0.0.1:26489

首先新建10001，10002，10003文件夹，将redis.conf,redid-server分别Copy到文件夹中

longwentaodeMacBook-Pro:redis-cluster longwentao$ ls
10001       10002       10003       sentinel
longwentaodeMacBook-Pro:redis-cluster longwentao$ ls 10001
redis-server    redis.conf

修改redis.conf文件中的端口号和文件夹保持一致

port 10001
port 10002
port 10003

修改10002,10003文件下的redis.conf文件，指定master为127.0.0.1:10001，其他使用默认配置

# slaveof <masterip> <masterport>
slaveof 127.0.0.1 10001

再创建sentinel文件夹，将redis-sentinel,sentinel.conf文件Copy到文件夹中，将sentinel.conf文件重命名为sentinel_26379.conf，修改端口号及需要监控的master

port 26379
sentinel monitor mymaster 127.0.0.1 10001 1

1表示至少一个sentinel同意master宕机后，切换新的master

将sentinel_26379.conf Copy一份成sentinel_26479.conf，并修改端口号为26479，其他不变，最后sentinel文件夹中的内容如下

longwentaodeMacBook-Pro:sentinel longwentao$ ls
redis-sentinel      sentinel_26379.conf sentinel_26479.conf

一个conf文件代表一个sentinel

到这里整个集群配置就完成了，接下来先启动master和sentinel

longwentaodeMacBook-Pro:10001 longwentao$ ./redis-server redis.conf 
longwentaodeMacBook-Pro:sentinel longwentao$ ./redis-sentinel sentinel_26379.conf 
longwentaodeMacBook-Pro:sentinel longwentao$ ./redis-sentinel sentinel_26479.conf 

再启动10002和10003

longwentaodeMacBook-Pro:10002 longwentao$ ./redis-server redis.conf 
longwentaodeMacBook-Pro:10003 longwentao$ ./redis-server redis.conf 

可以看到，sentinel中已经监控到增加了两个slave

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588:X 31 Dec 12:54:52.469 # Sentinel ID is 75e84135f9dddd13910b3e835f6836b0d861dbdb
588:X 31 Dec 12:54:52.469 # +monitor master mymaster 127.0.0.1 10001 quorum 1
588:X 31 Dec 12:54:52.470 * +slave slave 127.0.0.1:10002 127.0.0.1 10002 @ mymaster 127.0.0.1 10001
588:X 31 Dec 12:54:52.470 * +slave slave 127.0.0.1:10003 127.0.0.1 10003 @ mymaster 127.0.0.1 10001

在10001中查看群集信息，10001为Master，有两个slave10002，10003

longwentaodeMacBook-Pro:src longwentao$ ./redis-cli -p 10001
127.0.0.1:10001> info replication
# Replication
role:master
connected_slaves:2
slave0:ip=127.0.0.1,port=10002,state=online,offset=417020,lag=1
slave1:ip=127.0.0.1,port=10003,state=online,offset=417020,lag=1
master_repl_offset:417020
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:2
repl_backlog_histlen:417019

在10002中查看集群信息

longwentaodeMacBook-Pro:src longwentao$ ./redis-cli -p 10002
127.0.0.1:10002> info replication
# Replication
role:slave
master_host:127.0.0.1
master_port:10001
master_link_status:up
master_last_io_seconds_ago:2
master_sync_in_progress:0
slave_repl_offset:424608
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
127.0.0.1:10002> 

宕机验证，将master停掉,sentinel中显示10003自动变成了master

588:X 31 Dec 13:57:38.194 # +switch-master mymaster 127.0.0.1 10001 127.0.0.1 10003
588:X 31 Dec 13:57:38.195 * +slave slave 127.0.0.1:10002 127.0.0.1 10002 @ mymaster 127.0.0.1 10003
588:X 31 Dec 13:57:38.195 * +slave slave 127.0.0.1:10001 127.0.0.1 10001 @ mymaster 127.0.0.1 10003
588:X 31 Dec 13:58:08.268 # +sdown slave 127.0.0.1:10001 127.0.0.1 10001 @ mymaster 127.0.0.1 10003

再查看集群信息，10003为master,有一个10002的slave节点

longwentaodeMacBook-Pro:src longwentao$ ./redis-cli -p 10003
127.0.0.1:10003> info replication
# Replication
role:master
connected_slaves:1
slave0:ip=127.0.0.1,port=10002,state=online,offset=28740,lag=1
master_repl_offset:28874
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:2
repl_backlog_histlen:28873

再将10001启动,sentinel显示增加了一个10001的slave，master为10003

588:X 31 Dec 14:03:23.277 # -sdown slave 127.0.0.1:10001 127.0.0.1 10001 @ mymaster 127.0.0.1 10003
588:X 31 Dec 14:03:33.256 * +convert-to-slave slave 127.0.0.1:10001 127.0.0.1 10001 @ mymaster 127.0.0.1 10003

查看集群信息，master还是10003，10001已经变成了slave

127.0.0.1:10003> info replication
# Replication
role:master
connected_slaves:2
slave0:ip=127.0.0.1,port=10002,state=online,offset=60039,lag=1
slave1:ip=127.0.0.1,port=10001,state=online,offset=60039,lag=1
master_repl_offset:60039
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:2
repl_backlog_histlen:60038
127.0.0.1:10003>