Redis的哨兵部署(sentinel)(實驗)
首先感謝“吧喱公路”的引導,打開了我對哨兵的理解思路,再次謝謝。
Redis的哨兵(sentinel)
哨兵適用於非集群結構的redis環境,比如:redis主從環境。
關於哨兵集群,我這裏就不做實驗了,網上有大量的配置方法。
哨兵集群的核心思想,就是解決哨兵的單點故障問題。
個人認為,有做哨兵集群的經費,不如直接做個redis集群了。
環境描述:(主從從結構)
master:192.168.2.100:6379 #單節點sentinel運行在這個環境上
slave:192.168.2.200:6379
savle:192.168.2.201:6379
redis安裝路徑:/usr/local/redis-3.0.6-6379
redis.conf關鍵配置:(這裏不絮訴基本配置了,主從配置參考:http://blog.51cto.com/13690439/2118890)
master:
# vim redis.conf
requirepass "123456" //設置連接master密碼
masterauth "123456" //登錄master時,調用該參數
slave:
# vim etc/redis.conf
slaveof 192.168.2.100 6379 //指定主庫IP和端口
requirepass "123456" //之所以3個redis都這樣寫,是為了故障切換後,info replication顯示slave0信息
masterauth 123456 //登錄master時,調用該參數
哨兵關鍵配置:(sentinel.conf)
# vim sentinel.conf
port 26379 //端口
sentinel monitor mymaster 192.168.2.100 6379 1
//master-name可以自定義、監聽IP:port 幾個sentinel認為故障時,才算真正的故障
sentinel down-after-milliseconds mymaster 3000
//哨兵發送PING消息,等待PONG消息的時間,超過設定時間表示故障;毫秒
sentinel failover-timeout mymaster 10000
//故障轉移(failover)超時時間,超過設定時間表示故障轉移失敗;毫秒
sentinel auth-pass mymaster 123456 //設置連接master需要的密碼
啟動master的redis:
# redis-server redis.conf
啟動哨兵:(新開一個xshell)
# redis-sentinel sentinel.conf
啟動slave的redis:
# redis-server redis.conf
哨兵的輸出:
# Sentinel runid is e49df1197325687d9a40508c00f466a8c6e596db
//哨兵ID
# +monitor master mymaster 192.168.2.100 6379 quorum 1
//+monitor:增加了一個master監控,後面就是master的信息
* +slave slave 192.168.2.200:6379 192.168.2.200 6379 @ mymaster 192.168.2.100 6379
//+salve:增加了一個salve監控,後面是salve的信息
* +slave slave 192.168.2.201:6379 192.168.2.201 6379 @ mymaster 192.168.2.100 6379
//+salve:增加了一個salve監控,後面是salve的信息
master上登錄redis:
# redis-cli -h 192.168.2.100 -p 6379 -a 123456
192.168.2.100:6379> set name zhangsan
OK
192.168.2.100:6379> set age 26
OK
192.168.2.100:6379> set home beijing
OK
192.168.2.100:6379> keys *
1) "name"
2) "home"
3) "age"
salve上登錄redis:(兩個salve登錄查看,數據同步正常)
# redis-cli -h 192.168.2.200 -p 6379 -a 123456
192.168.2.200:6379> keys *
1) "name"
2) "home"
3) "age"
停止master的redis:(註意觀察哨兵的輸出)
# ps -ef |grep redis
root 11467 1 0 17:12 ? 00:00:00 redis-server *:6379
root 11473 4650 0 17:12 pts/1 00:00:00 redis-sentinel *:26379 [sentinel]
root 11513 4339 0 17:16 pts/0 00:00:00 grep --color=auto redis
# kill 11467
哨兵的輸出:
# +sdown master mymaster 192.168.2.100 6379
//+sdown:master節點掛了。後面是master信息
# +odown master mymaster 192.168.2.100 6379 #quorum 1/1
# +new-epoch 14
# +try-failover master mymaster 192.168.2.100 6379
//開始恢復故障
# +vote-for-leader e49df1197325687d9a40508c00f466a8c6e596db 14
//投票選舉節點的哨兵信息,因為我們就一個哨兵,所以就是自己 leader
# +elected-leader master mymaster 192.168.2.100 6379
//選舉節點後替換誰
# +failover-state-select-slave master mymaster 192.168.2.100 6379
//開始為故障的master選舉
# +selected-slave slave 192.168.2.200:6379 192.168.2.200 6379 @ mymaster 192.168.2.100 6379
//節點選舉結果,選中192.168.2.200:6379來替換master
* +failover-state-send-slaveof-noone slave 192.168.2.200:6379 192.168.2.200 6379 @ mymaster 192.168.2.100 6379
//確認節點選舉結果
* +failover-state-wait-promotion slave 192.168.2.200:6379 192.168.2.200 6379 @ mymaster 192.168.2.100 6379
//選中的節點正在升級為master
# +promoted-slave slave 192.168.2.200:6379 192.168.2.200 6379 @ mymaster 192.168.2.100 6379
//選中的節點已成功升級為master
# +failover-state-reconf-slaves master mymaster 192.168.2.100 6379
//切換故障master的狀態
* +slave-reconf-sent slave 192.168.2.201:6379 192.168.2.201 6379 @ mymaster 192.168.2.100 6379
//
* +slave-reconf-inprog slave 192.168.2.201:6379 192.168.2.201 6379 @ mymaster 192.168.2.100 6379
//其他節點同步故障master信息
* +slave-reconf-done slave 192.168.2.201:6379 192.168.2.201 6379 @ mymaster 192.168.2.100 6379
//其他節點完成故障master的同步
# +failover-end master mymaster 192.168.2.100 6379
//故障恢復完成
# +switch-master mymaster 192.168.2.100 6379 192.168.2.200 6379
//master從192.168.2.100:6379 變為 192.168.2.200:6379
* +slave slave 192.168.2.201:6379 192.168.2.201 6379 @ mymaster 192.168.2.200 6379
//其他節點指定新的master
* +slave slave 192.168.2.100:6379 192.168.2.100 6379 @ mymaster 192.168.2.200 6379
//故障master指定新的master
# +sdown slave 192.168.2.100:6379 192.168.2.100 6379 @ mymaster 192.168.2.200 6379
//192.168.2.100:6379宕機,待恢復
啟動master的redis(註意觀察哨兵的輸出)
# redis-server redis.conf
哨兵的輸出:
# -sdown slave 192.168.2.100:6379 192.168.2.100 6379 @ mymaster 192.168.2.200 6379
//故障master節點已經恢復
* +convert-to-slave slave 192.168.2.100:6379 192.168.2.100 6379 @ mymaster 192.168.2.200 6379
//故障master節點變為salve,他的master為192.168.2.200:6379
現在我們查看主從的狀態:
192.168.2.100上查看:
# redis-cli -h 192.168.2.100 -p 6379 -a 123456
192.168.2.100:6379> info replication
# Replication
role:slave
master_host:192.168.2.200
master_port:6379
master_link_status:up
192.168.2.100:6379> set ab 123
(error) READONLY You can't write against a read only slave.
192.168.2.100:6379> get name
"zhagnsan"
192.168.2.201上查看:
# redis-cli -h 192.168.2.201 -p 6379 -a 123456
192.168.2.201:6379> info replication
# Replication
role:slave
master_host:192.168.2.200
master_port:6379
master_link_status:up
192.168.2.201:6379> set ab 123
(error) READONLY You can't write against a read only slave.
192.168.2.201:6379> get name
"zhagnsan"
192.168.2.200上查看:
# redis-cli -h 192.168.2.200 -p 6379 -a 123456
192.168.2.200:6379> info replication
# Replication
role:master
connected_slaves:2
slave0:ip=192.168.2.201,port=6379,state=online,offset=24990,lag=1
slave1:ip=192.168.2.100,port=6379,state=online,offset=24990,lag=0
192.168.2.200:6379> set ab 123
OK
192.168.2.200:6379> keys *
1) "name"
2) "home"
3) "age"
4) "ab"
總結:通過哨兵(sentinel)實現了主從從環境高可用效果。
master在宕機後,通過哨兵自動將其中一個salve提升為master,切換過程中,數據保存完整。
但我們也發現,原master不能繼續插入key了, 而客戶端連接還是會連原master,
這時,我們就需要在數據庫連接池做一些規則設置了。
由於目前我能力有限,無法解釋連接池問題,還請見諒。
Redis的哨兵部署(sentinel)(實驗)