Redis主從集羣及哨兵模式

本次實驗環境準備用一臺服務器模擬3臺redis服務器,1主2從

主從集羣搭建

第一步：安裝Redis

安裝Redis,參考前面安裝Redis文章，保證單機使用沒有問題。

第二步：配置服務器文件

定位到安裝後的redis目錄：cd /usr/local/redis

對單機的redis配置文件拷貝出3份出來

cp redis.conf  redis6381.conf

cp redis.conf  redis6382.conf

cp redis.conf  redis6383.conf

清空新拷貝的三份配置文件，命令爲 「> 文件名」

[root@localhost redis]# > redis6381.conf

[root@localhost redis]# > redis6382.conf

[root@localhost redis]# > redis6383.conf

再對三份配置文件分別配置內容

6381端口的配置文件

include /usr/local/redis/redis.conf  #包含redis.conf文件
daemonize yes
port 6381
pidfile /var/run/redis_6381.pid
logfile 6381.log
dbfilename dump6381.rdb

6382端口的配置文件

include /usr/local/redis/redis.conf  #包含redis.conf文件
daemonize yes
port 6382
pidfile /var/run/redis_6382.pid
logfile 6382.log
dbfilename dump6382.rdb
slaveof 127.0.0.1 6381    #說明是從屬於6381端口的主機

6383端口的配置文件

include /usr/local/redis/redis.conf  #包含redis.conf文件
daemonize yes
port 6383
pidfile /var/run/redis_6383.pid
logfile 6383.log
dbfilename dump6383.rdb
slaveof 127.0.0.1 6381  #說明是從屬於6381端口的主機

第三步：啓動redis服務器

模擬啓動三臺redis服務器

[root@localhost redis]# ./bin/redis-server redis6381.conf
[root@localhost redis]# ./bin/redis-server redis6382.conf
[root@localhost redis]# ./bin/redis-server redis6383.conf

查看進程

[root@localhost redis]# ps -ef|grep redis
root      90648      1  0 17:17 ?        00:00:00 ./bin/redis-server 127.0.0.1:6381
root      90652      1  0 17:17 ?        00:00:00 ./bin/redis-server 127.0.0.1:6382
root      90657      1  1 17:17 ?        00:00:00 ./bin/redis-server 127.0.0.1:6383
root      90664   4536  0 17:17 pts/2    00:00:00 grep --color=auto redis

說明3臺服務器已經啓動成功，端口分別是指定的6381,6382,6383

第四步，客戶端鏈接redis服務器

分別打開三個窗口，定位到redis目錄：cd /usr/local/redis

經過客戶端工具鏈接不一樣端口的服務器

如鏈接6381端口服務器

[root@localhost redis]# ./bin/redis-cli -p 6381

查看信息，以下：

127.0.0.1:6381> info replication

# Replication
role:master
connected_slaves:2
slave0:ip=127.0.0.1,port=6382,state=online,offset=253,lag=1
slave1:ip=127.0.0.1,port=6383,state=online,offset=253,lag=1
master_repl_offset:253
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:2
repl_backlog_histlen:252

能夠看到它是主服務器，咱們在前面配置文件中指定它就是主服務器。

由於是主機，它可讀可寫，寫的數據同步到從機。

寫：

127.0.0.1:6381> set key1 v1
OK
127.0.0.1:6381> set key2 v2
OK

讀:

127.0.0.1:6381> get key1
"v1"
127.0.0.1:6381> get key2
"v2"

如鏈接6382端口服務器
[root@localhost redis]# ./bin/redis-cli -p 6382

 查看信息，以下：

127.0.0.1:6382> info replication
# Replication
role:slave
master_host:127.0.0.1
master_port:6381
master_link_status:up
master_last_io_seconds_ago:10
master_sync_in_progress:0
slave_repl_offset:883
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

能夠看到，它是從服務器，咱們在前面配置文件中指定它就是從服務器。

由於是從機，它只讀不可寫。數據只能從主機6381同步。

讀：

127.0.0.1:6382> keys *
1) "key1"
2) "key2"
127.0.0.1:6382> get key2
"v2"

寫：

127.0.0.1:6382> set key3 v3
(error) READONLY You can't write against a read only slave.

 

 

哨兵模式

配置哨兵配置文件

定位到redis的源文件目錄，將哨兵配置文件sentinel.conf做爲模板，拷貝出3份

[root@localhost local]# cd redis-3.2.9/

[root@localhost redis-3.2.9]# cp sentinel.conf  sentinel26381.conf
[root@localhost redis-3.2.9]# cp sentinel.conf  sentinel26382.conf
[root@localhost redis-3.2.9]# cp sentinel.conf  sentinel26383.conf

分別修改拷貝的配置文件

[root@localhost redis-3.2.9]# vim sentinel26381.conf

將哨兵的工做端口端口26379和監控的redis主機127.0.0.1 6379 2修改成本身定義的值

模板中的兩處要被修改的地方：

port 26379

sentinel monitor mymaster 127.0.0.1 6379 2

我這裏修改成該哨兵端口爲26381，監控的redis主機爲127.0.0.1 6381

port 26381

sentinel monitor mymaster 127.0.0.1 6381 2

其餘兩臺哨兵配置文件也按照這樣修改，只是哨兵的端口要不同，監控的redis主機應該同樣。

啓動哨兵程序

分別打開3個窗口，定爲到/usr/local/redis-3.2.9/src，找到redis-sentinel，配合上步的配置文件啓動

注意須要3個窗口，由於這裏是前臺啓動，須要看監控信息

[root@localhost src]# ./redis-sentinel ../sentinel26381.conf

[root@localhost src]# ./redis-sentinel ../sentinel26382.conf

[root@localhost src]# ./redis-sentinel ../sentinel26383.conf

等3臺哨兵都啓動成功之後，

分別查看監控信息，26381哨兵的監控信息，以下：

[root@localhost src]# ./redis-sentinel ../sentinel26381.conf
94744:X 01 Feb 18:29:03.171 * Increased maximum number of open files to 10032 (it was originally set to 1024).
                _._                                                  
           _.-``__ ''-._                                             
      _.-``    `.  `_.  ''-._           Redis 3.2.9 (00000000/0) 64 bit
  .-`` .-```.  ```\/    _.,_ ''-._                                   
 (    '      ,       .-`  | `,    )     Running in sentinel mode
 |`-._`-...-` __...-.``-._|'` _.-'|     Port: 26381
 |    `-._   `._    /     _.-'    |     PID: 94744
  `-._    `-._  `-./  _.-'    _.-'                                   
 |`-._`-._    `-.__.-'    _.-'_.-'|                                  
 |    `-._`-._        _.-'_.-'    |           http://redis.io        
  `-._    `-._`-.__.-'_.-'    _.-'                                   
 |`-._`-._    `-.__.-'    _.-'_.-'|                                  
 |    `-._`-._        _.-'_.-'    |                                  
  `-._    `-._`-.__.-'_.-'    _.-'                                   
      `-._    `-.__.-'    _.-'                                       
          `-._        _.-'                                           
              `-.__.-'                                               

94744:X 01 Feb 18:29:03.172 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
94744:X 01 Feb 18:29:03.174 # Sentinel ID is 9044885c3cd355b168a93bc68ed4c2b7c78ebca6
94744:X 01 Feb 18:29:03.174 # +monitor master mymaster 127.0.0.1 6381 quorum 2
94744:X 01 Feb 18:29:03.175 * +slave slave 127.0.0.1:6382 127.0.0.1 6382 @ mymaster 127.0.0.1 6381
94744:X 01 Feb 18:29:03.176 * +slave slave 127.0.0.1:6383 127.0.0.1 6383 @ mymaster 127.0.0.1 6381
/usr/local/redis-3.2.9/src/usr/local/redis-3.2.9/src94744:X 01 Feb 18:33:35.645 * +sentinel sentinel 7bc01d8db6cf93c5d1f9d0a146c9967c0c4b339b 127.0.0.1 26382 @ mymaster 127.0.0.1 6381
94744:X 01 Feb 18:34:08.801 * +sentinel sentinel 574de03c2a3e5ace4798af0df4945961398efdf1 127.0.0.1 26383 @ mymaster 127.0.0.1 6381

26382哨兵的監控信息，以下：

[root@localhost src]# ./redis-sentinel ../sentinel26382.conf
95009:X 01 Feb 18:33:33.626 * Increased maximum number of open files to 10032 (it was originally set to 1024).
                _._                                                  
           _.-``__ ''-._                                             
      _.-``    `.  `_.  ''-._           Redis 3.2.9 (00000000/0) 64 bit
  .-`` .-```.  ```\/    _.,_ ''-._                                   
 (    '      ,       .-`  | `,    )     Running in sentinel mode
 |`-._`-...-` __...-.``-._|'` _.-'|     Port: 26382
 |    `-._   `._    /     _.-'    |     PID: 95009
  `-._    `-._  `-./  _.-'    _.-'                                   
 |`-._`-._    `-.__.-'    _.-'_.-'|                                  
 |    `-._`-._        _.-'_.-'    |           http://redis.io        
  `-._    `-._`-.__.-'_.-'    _.-'                                   
 |`-._`-._    `-.__.-'    _.-'_.-'|                                  
 |    `-._`-._        _.-'_.-'    |                                  
  `-._    `-._`-.__.-'_.-'    _.-'                                   
      `-._    `-.__.-'    _.-'                                       
          `-._        _.-'                                           
              `-.__.-'                                               

95009:X 01 Feb 18:33:33.627 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
95009:X 01 Feb 18:33:33.648 # Sentinel ID is 7bc01d8db6cf93c5d1f9d0a146c9967c0c4b339b
95009:X 01 Feb 18:33:33.648 # +monitor master mymaster 127.0.0.1 6381 quorum 2
95009:X 01 Feb 18:33:33.649 * +slave slave 127.0.0.1:6382 127.0.0.1 6382 @ mymaster 127.0.0.1 6381
95009:X 01 Feb 18:33:33.651 * +slave slave 127.0.0.1:6383 127.0.0.1 6383 @ mymaster 127.0.0.1 6381
95009:X 01 Feb 18:33:34.651 * +sentinel sentinel 9044885c3cd355b168a93bc68ed4c2b7c78ebca6 127.0.0.1 26381 @ mymaster 127.0.0.1 6381
95009:X 01 Feb 18:34:08.801 * +sentinel sentinel 574de03c2a3e5ace4798af0df4945961398efdf1 127.0.0.1 26383 @ mymaster 127.0.0.1 6381

26383哨兵的監控信息，以下：

[root@localhost src]# ./redis-sentinel ../sentinel26383.conf
95097:X 01 Feb 18:34:06.716 * Increased maximum number of open files to 10032 (it was originally set to 1024).
                _._                                                  
           _.-``__ ''-._                                             
      _.-``    `.  `_.  ''-._           Redis 3.2.9 (00000000/0) 64 bit
  .-`` .-```.  ```\/    _.,_ ''-._                                   
 (    '      ,       .-`  | `,    )     Running in sentinel mode
 |`-._`-...-` __...-.``-._|'` _.-'|     Port: 26383
 |    `-._   `._    /     _.-'    |     PID: 95097
  `-._    `-._  `-./  _.-'    _.-'                                   
 |`-._`-._    `-.__.-'    _.-'_.-'|                                  
 |    `-._`-._        _.-'_.-'    |           http://redis.io        
  `-._    `-._`-.__.-'_.-'    _.-'                                   
 |`-._`-._    `-.__.-'    _.-'_.-'|                                  
 |    `-._`-._        _.-'_.-'    |                                  
  `-._    `-._`-.__.-'_.-'    _.-'                                   
      `-._    `-.__.-'    _.-'                                       
          `-._        _.-'                                           
              `-.__.-'                                               

95097:X 01 Feb 18:34:06.717 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
95097:X 01 Feb 18:34:06.719 # Sentinel ID is 574de03c2a3e5ace4798af0df4945961398efdf1
95097:X 01 Feb 18:34:06.719 # +monitor master mymaster 127.0.0.1 6381 quorum 2
95097:X 01 Feb 18:34:06.719 * +slave slave 127.0.0.1:6382 127.0.0.1 6382 @ mymaster 127.0.0.1 6381
95097:X 01 Feb 18:34:06.721 * +slave slave 127.0.0.1:6383 127.0.0.1 6383 @ mymaster 127.0.0.1 6381
95097:X 01 Feb 18:34:07.784 * +sentinel sentinel 9044885c3cd355b168a93bc68ed4c2b7c78ebca6 127.0.0.1 26381 @ mymaster 127.0.0.1 6381
95097:X 01 Feb 18:34:08.425 * +sentinel sentinel 7bc01d8db6cf93c5d1f9d0a146c9967c0c4b339b 127.0.0.1 26382 @ mymaster 127.0.0.1 6381

 模擬故障，讓主從自動切換

主動讓redis的主服務器6381關掉，模擬主機掛機的情況

127.0.0.1:6381> shutdown

觀看哨兵服務器，會發現如下信息

[root@localhost src]# ./redis-sentinel ../sentinel26382.conf
95009:X 01 Feb 18:33:33.626 * Increased maximum number of open files to 10032 (it was originally set to 1024).
                _._                                                  
           _.-``__ ''-._                                             
      _.-``    `.  `_.  ''-._           Redis 3.2.9 (00000000/0) 64 bit
  .-`` .-```.  ```\/    _.,_ ''-._                                   
 (    '      ,       .-`  | `,    )     Running in sentinel mode
 |`-._`-...-` __...-.``-._|'` _.-'|     Port: 26382
 |    `-._   `._    /     _.-'    |     PID: 95009
  `-._    `-._  `-./  _.-'    _.-'                                   
 |`-._`-._    `-.__.-'    _.-'_.-'|                                  
 |    `-._`-._        _.-'_.-'    |           http://redis.io        
  `-._    `-._`-.__.-'_.-'    _.-'                                   
 |`-._`-._    `-.__.-'    _.-'_.-'|                                  
 |    `-._`-._        _.-'_.-'    |                                  
  `-._    `-._`-.__.-'_.-'    _.-'                                   
      `-._    `-.__.-'    _.-'                                       
          `-._        _.-'                                           
              `-.__.-'                                               

95009:X 01 Feb 18:33:33.627 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
95009:X 01 Feb 18:33:33.648 # Sentinel ID is 7bc01d8db6cf93c5d1f9d0a146c9967c0c4b339b
95009:X 01 Feb 18:33:33.648 # +monitor master mymaster 127.0.0.1 6381 quorum 2
95009:X 01 Feb 18:33:33.649 * +slave slave 127.0.0.1:6382 127.0.0.1 6382 @ mymaster 127.0.0.1 6381
95009:X 01 Feb 18:33:33.651 * +slave slave 127.0.0.1:6383 127.0.0.1 6383 @ mymaster 127.0.0.1 6381
95009:X 01 Feb 18:33:34.651 * +sentinel sentinel 9044885c3cd355b168a93bc68ed4c2b7c78ebca6 127.0.0.1 26381 @ mymaster 127.0.0.1 6381
95009:X 01 Feb 18:34:08.801 * +sentinel sentinel 574de03c2a3e5ace4798af0df4945961398efdf1 127.0.0.1 26383 @ mymaster 127.0.0.1 6381
95009:X 01 Feb 18:59:42.232 # +sdown master mymaster 127.0.0.1 6381
95009:X 01 Feb 18:59:42.316 # +odown master mymaster 127.0.0.1 6381 #quorum 2/2
95009:X 01 Feb 18:59:42.316 # +new-epoch 1
95009:X 01 Feb 18:59:42.316 # +try-failover master mymaster 127.0.0.1 6381
95009:X 01 Feb 18:59:42.325 # +vote-for-leader 7bc01d8db6cf93c5d1f9d0a146c9967c0c4b339b 1
95009:X 01 Feb 18:59:42.363 # 9044885c3cd355b168a93bc68ed4c2b7c78ebca6 voted for 7bc01d8db6cf93c5d1f9d0a146c9967c0c4b339b 1
95009:X 01 Feb 18:59:42.363 # 574de03c2a3e5ace4798af0df4945961398efdf1 voted for 7bc01d8db6cf93c5d1f9d0a146c9967c0c4b339b 1
95009:X 01 Feb 18:59:42.379 # +elected-leader master mymaster 127.0.0.1 6381
95009:X 01 Feb 18:59:42.379 # +failover-state-select-slave master mymaster 127.0.0.1 6381
95009:X 01 Feb 18:59:42.470 # +selected-slave slave 127.0.0.1:6383 127.0.0.1 6383 @ mymaster 127.0.0.1 6381
95009:X 01 Feb 18:59:42.470 * +failover-state-send-slaveof-noone slave 127.0.0.1:6383 127.0.0.1 6383 @ mymaster 127.0.0.1 6381
95009:X 01 Feb 18:59:42.522 * +failover-state-wait-promotion slave 127.0.0.1:6383 127.0.0.1 6383 @ mymaster 127.0.0.1 6381
95009:X 01 Feb 18:59:43.315 # +promoted-slave slave 127.0.0.1:6383 127.0.0.1 6383 @ mymaster 127.0.0.1 6381
95009:X 01 Feb 18:59:43.315 # +failover-state-reconf-slaves master mymaster 127.0.0.1 6381
95009:X 01 Feb 18:59:43.376 * +slave-reconf-sent slave 127.0.0.1:6382 127.0.0.1 6382 @ mymaster 127.0.0.1 6381
95009:X 01 Feb 18:59:44.363 * +slave-reconf-inprog slave 127.0.0.1:6382 127.0.0.1 6382 @ mymaster 127.0.0.1 6381
95009:X 01 Feb 18:59:44.363 * +slave-reconf-done slave 127.0.0.1:6382 127.0.0.1 6382 @ mymaster 127.0.0.1 6381
95009:X 01 Feb 18:59:44.422 # +failover-end master mymaster 127.0.0.1 6381
95009:X 01 Feb 18:59:44.422 # +switch-master mymaster 127.0.0.1 6381 127.0.0.1 6383
95009:X 01 Feb 18:59:44.422 * +slave slave 127.0.0.1:6382 127.0.0.1 6382 @ mymaster 127.0.0.1 6383
95009:X 01 Feb 18:59:44.422 * +slave slave 127.0.0.1:6381 127.0.0.1 6381 @ mymaster 127.0.0.1 6383
95009:X 01 Feb 19:00:14.465 # +sdown slave 127.0.0.1:6381 127.0.0.1 6381 @ mymaster 127.0.0.1 6383

說明集羣的主服務器已經切換到了6383上，即原來的從機6383變爲了主機

咱們去看一下6383的信息

127.0.0.1:6383>  info replication
# Replication
role:master
connected_slaves:1
slave0:ip=127.0.0.1,port=6382,state=online,offset=19848,lag=1
master_repl_offset:19981
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:2
repl_backlog_histlen:19980

確實角色爲master,它下面掛載一臺從機6382

它如今升級爲主機，因此能夠讀寫，驗證以下：

127.0.0.1:6383> set key5 v5
OK
127.0.0.1:6383> get key5
"v5"

再去看下一6382從機的信息

127.0.0.1:6382> info replication
# Replication
role:slave
master_host:127.0.0.1
master_port:6383
master_link_status:up
master_last_io_seconds_ago:0
master_sync_in_progress:0
slave_repl_offset:17440
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

說明它確實從屬的主機爲6383

它仍是隻能讀，數據只能從主機同步

127.0.0.1:6382> set key6 v6
(error) READONLY You can't write against a read only slave.
127.0.0.1:6382> get key5
"v5"

假設原來的6381服務器已經恢復正常了，咱們來啓動它

能夠看到，6381啓動後，自動變爲了從機，主機仍是後來的6383，說明原來的主機恢復後，不會恢復它原來的地位。

由於它已是從機，因此只能讀，不能寫

再看主服務器6383的信息，它已經有兩個從機了，6381是後來恢復後自動掛載上的

哨兵服務器26381上看到對應的自動掛載信息

哨兵服務器26382上看到對應的自動掛載信息

哨兵服務器26383上看到對應的自動掛載信息