服務器描述：本次搭建是用來測試，所以是在一臺服務器上搭建三個redis服務（一主兩從）

服務角色	端口	Redis.conf名稱	sentinel配置文件名稱	sentinel端口	redis日志路徑	sentinel路勁
主(master)	6379	redis.conf	sentinel.conf	26379	/home/zhangxs/data/redislog/redis_server/master.log	/home/zhangxs/data/redislog/sentinel/sentinel6379.log
從(slave)	6380	redis_slave6380.conf	Sentinel6380.conf	26380	/home/zhangxs/data/redislog/redis_server/slave6380.log	/home/zhangxs/data/redislog/sentinel/sentinel6380.log
從(slave)	6381	redis_slave6381.conf	Sentinel6381.conf	26381	/home/zhangxs/data/redislog/redis_server/slave6381.log	/home/zhangxs/data/redislog/sentinel/sentinel6381.log

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修改配置文件

• 1： redis.conf

修改redis服務日志路徑：logfile "/home/zhangxs/data/redislog/redis_server/master.log"

其他沒有修改，使用的是默認配置

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• 2：redis_slave6380.conf 和redis_slave6381.conf? (copy redis_slave.conf)

設置他們指向的master服務的ip和端口：slaveof 127.0.0.1 6379(兩個文件都配置)

修改redis_slave6380.conf 和redis_slave6381.conf 端口:redis_slave6380.conf? 端口為26380 ; redis_slave6381.conf 端口為26381

設置slave服務日志路徑： logfile /home/zhangxs/data/redislog/redis_server/slave6380.log 和 logfile /home/zhangxs/data/redislog/redis_server/slave6381.log

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• 3：sentinel.conf

修改日志路徑：logfile "/home/zhangxs/data/redislog/sentinel/sentinel6379.log"

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• 4:Sentinel6380.conf 和 Sentinel6381.conf (copy sentinel.conf)

修改端口號：Sentinel6380.conf 改為 26380;?? Sentinel6381.conf 改為 26381;

修改日志路徑：logfile "/home/zhangxs/data/redislog/sentinel/sentinel6380.log" 和?logfile "/home/zhangxs/data/redislog/sentinel/sentinel6381.log"

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上面配置好后，啟動redis服務

• 1：啟動master

src/redis-server redis.conf&

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• 2:啟動從服務(slave6380)

src/redis-server redis_slave6380.conf &

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查看主服務日志，會發現多出來一段

2755:M 29 Jul 00:13:25.469 * Starting BGSAVE for SYNC with target: disk 2755:M 29 Jul 00:13:25.502 * Background saving started by pid 2784 2784:C 29 Jul 00:13:25.608 * DB saved on disk 2784:C 29 Jul 00:13:25.608 * RDB: 6 MB of memory used by copy-on-write 2755:M 29 Jul 00:13:25.677 * Background saving terminated with success 2755:M 29 Jul 00:13:25.677 * Synchronization with slave 127.0.0.1:6380 succeeded //同步到從服務127.0.0.1:6380成功

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查看從服務日志slave6380.log

2780:S 29 Jul 00:13:25.436 * DB loaded from disk: 0.007 seconds 2780:S 29 Jul 00:13:25.436 * Before turning into a slave, using my master parameters to synthesize a cached master: I may be able to synchronize with the new master with just a partial transfer. 2780:S 29 Jul 00:13:25.436 * Ready to accept connections 2780:S 29 Jul 00:13:25.436 * Connecting to MASTER 127.0.0.1:6379 //正在連接master服務 2780:S 29 Jul 00:13:25.436 * MASTER <-> SLAVE sync started //master到slave 啟動同步 2780:S 29 Jul 00:13:25.436 * Non blocking connect for SYNC fired the event. 2780:S 29 Jul 00:13:25.436 * Master replied to PING, replication can continue... 2780:S 29 Jul 00:13:25.436 * Trying a partial resynchronization (request a26696cff5d35f38896c4eb068f71adbb7cfc421:474104). 2780:S 29 Jul 00:13:25.577 * Full resync from master: 541cd938f43b4f144e647881af409fa1884ea5a4:0 //從master全量同步 2780:S 29 Jul 00:13:25.577 * Discarding previously cached master state.//丟棄之前緩存的master狀態 2780:S 29 Jul 00:13:25.677 * MASTER <-> SLAVE sync: receiving 250 bytes from master //slave從master 同步250個字節 2780:S 29 Jul 00:13:25.677 * MASTER <-> SLAVE sync: Flushing old data 2780:S 29 Jul 00:13:25.677 * MASTER <-> SLAVE sync: Loading DB in memory 2780:S 29 Jul 00:13:25.678 * MASTER <-> SLAVE sync: Finished with success ?

• 3:啟動從服務(slave6381)

src/redis-server redis_slave6381.conf &

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查看主服務日志，會發現多出來一段

//從服務127.0.0.1:6381發送同步請求
2755:M 29 Jul 00:26:46.531 * Slave 127.0.0.1:6381 asks for synchronization //接受127.0.1:6381的部分重同步請求。從偏移量1開始發送積壓的1106字節 2755:M 29 Jul 00:26:46.531 * Partial resynchronization request from 127.0.0.1:6381 accepted. Sending 1106 bytes of backlog starting from offset 1.

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查看從服務日志slave6381.log

2809:S 29 Jul 00:26:46.531 * DB loaded from disk: 0.000 seconds 2809:S 29 Jul 00:26:46.531 * Before turning into a slave, using my master parameters to synthesize a cached master: I may be able to synchronize with the new master with just a partial transfer. 2809:S 29 Jul 00:26:46.531 * Ready to accept connections 2809:S 29 Jul 00:26:46.531 * Connecting to MASTER 127.0.0.1:6379 2809:S 29 Jul 00:26:46.531 * MASTER <-> SLAVE sync started 2809:S 29 Jul 00:26:46.531 * Non blocking connect for SYNC fired the event. 2809:S 29 Jul 00:26:46.531 * Master replied to PING, replication can continue... 2809:S 29 Jul 00:26:46.531 * Trying a partial resynchronization (request 541cd938f43b4f144e647881af409fa1884ea5a4:1). 2809:S 29 Jul 00:26:46.531 * Successful partial resynchronization with master. 2809:S 29 Jul 00:26:46.532 * MASTER <-> SLAVE sync: Master accepted a Partial Resynchronization

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• 4：測試數據同步功能（使用redis-cli 連接服務器）

1：連接master

[root@vm1 src]# redis-cli -h 127.0.0.1 -p 6379 127.0.0.1:6379> set name fj

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2:連接slave6380

[root@vm1 src]# redis-cli -h 127.0.0.1 -p 6380 127.0.0.1:6380> get name "fj" 127.0.0.1:6380>

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3:連接slave6381

[root@vm1 src]# redis-cli -h 127.0.0.1 -p 6381 127.0.0.1:6381> get name "fj" 127.0.0.1:6381>

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Ok 主從同步沒有問題。

默認情況下從服務是不允許set數據的，測試下

127.0.0.1:6380> set name hello (error) READONLY You can't write against a read only slave. 127.0.0.1:6380> 127.0.0.1:6381> set name hello (error) READONLY You can't write against a read only slave. 127.0.0.1:6381>

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啟動各個服務的sentinel

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• 啟動sentinel6379

src/redis-sentinel sentinel.conf &

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• 查看Sentinel6379.log

2908:X 29 Jul 01:01:32.838 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo 2908:X 29 Jul 01:01:32.839 # Redis version=4.0.10, bits=64, commit=00000000, modified=0, pid=2908, just started 2908:X 29 Jul 01:01:32.839 # Configuration loaded 2908:X 29 Jul 01:01:32.839 * Increased maximum number of open files to 10032 (it was originally set to 1024). 2908:X 29 Jul 01:01:32.840 * Running mode=sentinel, port=26379. 2908:X 29 Jul 01:01:32.840 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128. 2908:X 29 Jul 01:01:32.855 # Sentinel ID is 1a77392638e41bb0ea0a865ffc93b8de6335227f 2908:X 29 Jul 01:01:32.855 # +monitor master mymaster 127.0.0.1 6379 quorum 2 //一個新的從服務器已經被sentinel識別并關聯 2908:X 29 Jul 01:01:32.856 * +slave slave 127.0.0.1:6380 127.0.0.1 6380 @ mymaster 127.0.0.1 6379 2908:X 29 Jul 01:01:32.858 * +slave slave 127.0.0.1:6381 127.0.0.1 6381 @ mymaster 127.0.0.1 6379

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• 啟動sentinel6380

src/redis-sentinel sentinel6380.conf &

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• 查看 Sentinel6380.log

2937:X 29 Jul 01:08:14.325 # Redis version=4.0.10, bits=64, commit=00000000, modified=0, pid=2937, just started 2937:X 29 Jul 01:08:14.325 # Configuration loaded 2937:X 29 Jul 01:08:14.327 * Increased maximum number of open files to 10032 (it was originally set to 1024). 2937:X 29 Jul 01:08:14.377 * Running mode=sentinel, port=26380. 2937:X 29 Jul 01:08:14.377 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128. 2937:X 29 Jul 01:08:14.379 # Sentinel ID is 4a6aebffdd1301bf054e722c34e8a6611418ba8a 2937:X 29 Jul 01:08:14.379 # +monitor master mymaster 127.0.0.1 6379 quorum 2 2937:X 29 Jul 01:08:14.380 * +slave slave 127.0.0.1:6380 127.0.0.1 6380 @ mymaster 127.0.0.1 6379 2937:X 29 Jul 01:08:14.381 * +slave slave 127.0.0.1:6381 127.0.0.1 6381 @ mymaster 127.0.0.1 6379 //一個新的sentinel（監控）已經被識別并關聯 2937:X 29 Jul 01:08:14.919 * +sentinel sentinel 1a77392638e41bb0ea0a865ffc93b8de6335227f 127.0.0.1 26379 @ mymaster 127.0.0.1 6379

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• Sentinel6380啟動后會發現，Sentinel6379.log 加了一段日志

//一個新的sentinel（監控）已經被識別并關聯 2908:X 29 Jul 01:08:16.367 * +sentinel sentinel 4a6aebffdd1301bf054e722c34e8a6611418ba8a 127.0.0.1 26380 @ mymaster 127.0.0.1 6379

新啟動一個sentinel，會通過發布訂閱功能自動發現監控相同master下的其他sentinel。這一功能是通過向頻道 sentinel:hello 發送信息來實現的。

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• 啟動sentinel6381

[root@vm1 redis-4.0.10]# src/redis-sentinel sentinel6381.conf &

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查看 Sentinel6381.log

2961:X 29 Jul 01:11:09.823 # Configuration loaded 2961:X 29 Jul 01:11:09.823 * Increased maximum number of open files to 10032 (it was originally set to 1024). 2961:X 29 Jul 01:11:09.852 * Running mode=sentinel, port=26381. 2961:X 29 Jul 01:11:09.852 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128. 2961:X 29 Jul 01:11:09.853 # Sentinel ID is 1db1a4dcdf0ecca00b64d9362c2a2dd338da0030 2961:X 29 Jul 01:11:09.853 # +monitor master mymaster 127.0.0.1 6379 quorum 2 2961:X 29 Jul 01:11:09.853 * +slave slave 127.0.0.1:6380 127.0.0.1 6380 @ mymaster 127.0.0.1 6379 2961:X 29 Jul 01:11:09.855 * +slave slave 127.0.0.1:6381 127.0.0.1 6381 @ mymaster 127.0.0.1 6379 2961:X 29 Jul 01:11:10.334 * +sentinel sentinel 1a77392638e41bb0ea0a865ffc93b8de6335227f 127.0.0.1 26379 @ mymaster 127.0.0.1 6379 2961:X 29 Jul 01:11:11.446 * +sentinel sentinel 4a6aebffdd1301bf054e722c34e8a6611418ba8a 127.0.0.1 26380 @ mymaster 127.0.0.1 6379

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• 新加入的sentinel6381， sentinel6379和sentinel6380 都會收到通知(//一個新的sentinel（監控）已經被識別并關聯)

2908:X 29 Jul 01:11:11.880 * +sentinel sentinel 1db1a4dcdf0ecca00b64d9362c2a2dd338da0030 127.0.0.1 26381 @ mymaster 127.0.0.1 6379

2937:X 29 Jul 01:11:11.878 * +sentinel sentinel 1db1a4dcdf0ecca00b64d9362c2a2dd338da0030 127.0.0.1 26381 @ mymaster 127.0.0.1 6379

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sentinel的狀態都會記錄到sentinel.conf文件中，用于啟動后恢復狀態，查看下各個sentinel.conf 文件 變動后的部分

• sentinel.conf

啟動前：無???? 啟動后：sentinel myid 1a77392638e41bb0ea0a865ffc93b8de6335227f //自己的sentinel myid

啟動前：無???? 啟動后： # Generated by CONFIG REWRITE #master下得兩個從服務 sentinel known-slave mymaster 127.0.0.1 6380 sentinel known-slave mymaster 127.0.0.1 6381 #master下其他兩個sentinel sentinel known-sentinel mymaster 127.0.0.1 26380 4a6aebffdd1301bf054e722c34e8a6611418ba8a sentinel known-sentinel mymaster 127.0.0.1 26381 1db1a4dcdf0ecca00b64d9362c2a2dd338da0030 sentinel current-epoch 0

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Sentinel6380.conf和Sentinel6381.conf改動和sentinel.conf 基本一樣。不一樣的就是 記錄自己sentinel myid和master下其他兩個sentinel不一樣，大同小異。

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測試故障遷移

Sentinel 故障遷移我使用的是默認配置(不需要再配置，可以自定義修改)

//判斷master失效，至少有兩個sentinel同意才會執行故障遷移
sentinel monitor mymaster 127.0.0.1 6379 2 //如果在10秒內sentinel 都收到master的一次有效回復，就認為該master主觀下線 sentinel down-after-milliseconds mymaster 60000 sentinel failover-timeout mymaster 180000
//在執行故障轉移時，同時只有一個slave能對新的master進行數據同步
sentinel parallel-syncs mymaster 1
sentinel monitor resque 192.168.1.3 6380 4
sentinel down-after-milliseconds resque 10000
sentinel failover-timeout resque 180000
sentinel parallel-syncs resque 5

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• 1：查看redis的相關服務

root 2755 2551 0 00:11 pts/2 00:00:06 src/redis-server 127.0.0.1:6379 root 2780 2551 0 00:13 pts/2 00:00:06 src/redis-server 127.0.0.1:6380 root 2809 2551 0 00:26 pts/2 00:00:05 src/redis-server 127.0.0.1:6381 root 2816 2529 0 00:30 pts/1 00:00:00 redis-cli -h 127.0.0.1 -p 6379 root 2822 2530 0 00:33 pts/0 00:00:00 redis-cli -h 127.0.0.1 -p 6380 root 2841 2823 0 00:34 pts/6 00:00:00 redis-cli -h 127.0.0.1 -p 6381 root 2908 2551 0 01:01 pts/2 00:00:07 src/redis-sentinel *:26379 [sentinel] root 2937 2551 0 01:08 pts/2 00:00:06 src/redis-sentinel *:26380 [sentinel] root 2961 2551 0 01:11 pts/2 00:00:06 src/redis-sentinel *:26381 [sentinel] root 3000 2551 0 01:50 pts/2 00:00:00 grep --color=auto redis

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• 2：查看整個備份狀態

127.0.0.1:6379> info# Server # Clients # Memory # Persistence # Stats # Replication role:master connected_slaves:2 slave0:ip=127.0.0.1,port=6380,state=online,offset=544591,lag=0 slave1:ip=127.0.0.1,port=6381,state=online,offset=544591,lag=0 master_replid:541cd938f43b4f144e647881af409fa1884ea5a4 master_replid2:0000000000000000000000000000000000000000 master_repl_offset:544857 second_repl_offset:-1 repl_backlog_active:1 repl_backlog_size:1048576 repl_backlog_first_byte_offset:1 repl_backlog_histlen:544857 # CPU# Cluster# Keyspace

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其他信息我都刪掉了，只留下【Replication】的信息，其他信息可以在redis-cli 命令行中使用【info】命令查看

可以看到，6379是master角色，master下有兩個從服務port=6380，port=6381

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• 3: Kill 掉 master，觀察日志

kill -9 2755

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master被干掉了，所以master.log 沒有日志，看其他兩個從服務日志（截取部分）

redis_slave6380.log

///一分鐘內 2780:S 29 Jul 01:58:53.414 # Connection with master lost. 2780:S 29 Jul 01:58:53.414 * Caching the disconnected master state. 2780:S 29 Jul 01:58:54.163 * Connecting to MASTER 127.0.0.1:6379 2780:S 29 Jul 01:58:54.163 * MASTER <-> SLAVE sync started 2780:S 29 Jul 01:58:54.164 # Error condition on socket for SYNC: Connection refused 2780:S 29 Jul 01:58:55.168 * Connecting to MASTER 127.0.0.1:6379 2780:S 29 Jul 01:58:55.169 * MASTER <-> SLAVE sync started .... ... ... 2780:S 29 Jul 01:59:22.381 # Error condition on socket for SYNC: Connection refused 2780:S 29 Jul 01:59:23.389 * Connecting to MASTER 127.0.0.1:6379 2780:S 29 Jul 01:59:23.389 * MASTER <-> SLAVE sync started 2780:S 29 Jul 01:59:23.389 # Error condition on socket for SYNC: Connection refused ///一分鐘后 2780:S 29 Jul 01:59:24.321 * SLAVE OF 127.0.0.1:6381 enabled (user request from 'id=8 addr=127.0.0.1:52556 fd=11 name=sentinel-4a6aebff-cmd age=3070 idle=0 flags=x db=0 sub=0 psub=0 multi=3 qbuf=133 qbuf-free=32635 obl=36 oll=0 omem=0 events=r cmd=exec') 2780:S 29 Jul 01:59:24.323 # CONFIG REWRITE executed with suc 2780:S 29 Jul 01:59:24.399 * Connecting to MASTER 127.0.0.1:6381 2780:S 29 Jul 01:59:24.399 * MASTER <-> SLAVE sync started 2780:S 29 Jul 01:59:24.399 * Non blocking connect for SYNC fired the event. 2780:S 29 Jul 01:59:24.399 * Master replied to PING, replication can continue... 2780:S 29 Jul 01:59:24.399 * Trying a partial resynchronization (request 541cd938f43b4f144e647881af409fa1884ea5a4:617714). 2780:S 29 Jul 01:59:24.400 * Successful partial resynchronization with master. 2780:S 29 Jul 01:59:24.400 # Master replication ID changed to 514edab0972b4b6e5388edc4f14fbdb4d223d39e 2780:S 29 Jul 01:59:24.400 * MASTER <-> SLAVE sync: Master accepted a Partial Resynchronization.

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從01:58:53.414 到01:59:23.389 這一分鐘內一直在嘗試連接master，一分鐘內沒有連接成功后，sentinel 就會master判斷為主觀下線，看日志

Sentinel6379.log

//判定master 主觀下線 2908:X 29 Jul 01:59:23.492 # +sdown master mymaster 127.0.0.1 6379 //當前的紀元（epoch）已經被更新。 2908:X 29 Jul 01:59:23.546 # +new-epoch 1 //開始給sentinel6380投票,誰來主導這次故障轉移 2908:X 29 Jul 01:59:23.549 # +vote-for-leader 4a6aebffdd1301bf054e722c34e8a6611418ba8a 1 //判定master 客觀觀下線,已經有2個sentinel同意 2908:X 29 Jul 01:59:23.569 # +odown master mymaster 127.0.0.1 6379 #quorum 3/2 2908:X 29 Jul 01:59:23.569 # Next failover delay: I will not start a failover before Sun Jul 29 02:05:23 2018 2908:X 29 Jul 01:59:24.328 # +config-update-from sentinel 4a6aebffdd1301bf054e722c34e8a6611418ba8a 127.0.0.1 26380 @ mymaster 127.0.0.1 6379 2908:X 29 Jul 01:59:24.328 # +switch-master mymaster 127.0.0.1 6379 127.0.0.1 6381 2908:X 29 Jul 01:59:24.328 * +slave slave 127.0.0.1:6380 127.0.0.1 6380 @ mymaster 127.0.0.1 6381 2908:X 29 Jul 01:59:24.328 * +slave slave 127.0.0.1:6379 127.0.0.1 6379 @ mymaster 127.0.0.1 6381 2908:X 29 Jul 01:59:54.333 # +sdown slave 127.0.0.1:6379 127.0.0.1 6379 @ mymaster 127.0.0.1 6381

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Sentinel6380.log

//判定master 主觀下線 2937:X 29 Jul 01:59:23.459 # +sdown master mymaster 127.0.0.1 6379 //判定master 客觀觀下線,已經有2個sentinel同意 2937:X 29 Jul 01:59:23.536 # +odown master mymaster 127.0.0.1 6379 #quorum 2/2 2937:X 29 Jul 01:59:23.537 # +new-epoch 1 //嘗試故障轉移master 2937:X 29 Jul 01:59:23.537 # +try-failover master mymaster 127.0.0.1 6379 //開始給sentinel6380投票,誰來主導這次故障轉移 2937:X 29 Jul 01:59:23.540 # +vote-for-leader 4a6aebffdd1301bf054e722c34e8a6611418ba8a 1 //其他兩個sentinel 都投票給4a6aebffdd1301bf054e722c34e8a6611418ba8a 【6380sentinel】 2937:X 29 Jul 01:59:23.549 # 1db1a4dcdf0ecca00b64d9362c2a2dd338da0030 voted for 4a6aebffdd1301bf054e722c34e8a6611418ba8a 1 2937:X 29 Jul 01:59:23.549 # 1a77392638e41bb0ea0a865ffc93b8de6335227f voted for 4a6aebffdd1301bf054e722c34e8a6611418ba8a 1 //6379這個服務贏得選舉可以進行故障轉移 2937:X 29 Jul 01:59:23.619 # +elected-leader master mymaster 127.0.0.1 6379 //發現6379這個服務是故障轉移狀態，就開始選擇master下得從服務 2937:X 29 Jul 01:59:23.619 # +failover-state-select-slave master mymaster 127.0.0.1 6379 //故障轉移操作現在處于 select-slave 狀態 —— Sentinel 正在尋找可以升級為主服務器的從服務器。(選擇mymaster 127.0.0.1 6379 下 6381 的從服務) 2937:X 29 Jul 01:59:23.710 # +selected-slave slave 127.0.0.1:6381 127.0.0.1 6381 @ mymaster 127.0.0.1 6379 //Sentinel 正在將6379下的從服務器6381升級為主服務器，等待升級功能完成。 2937:X 29 Jul 01:59:23.710 * +failover-state-send-slaveof-noone slave 127.0.0.1:6381 127.0.0.1 6381 @ mymaster 127.0.0.1 6379 //master下的從服務 6381 等待升級 2937:X 29 Jul 01:59:23.769 * +failover-state-wait-promotion slave 127.0.0.1:6381 127.0.0.1 6381 @ mymaster 127.0.0.1 6379 //升級master下從服務6381 2937:X 29 Jul 01:59:24.251 # +promoted-slave slave 127.0.0.1:6381 127.0.0.1 6381 @ mymaster 127.0.0.1 6379 //故障轉移狀態切換到了 reconf-slaves 狀態。（再次確認從服務器轉為主服務器） 2937:X 29 Jul 01:59:24.251 # +failover-state-reconf-slaves master mymaster 127.0.0.1 6379 //牽頭的sentinel 向6380從服務器發送slaveof 指令，將它設置為新的master 2937:X 29 Jul 01:59:24.321 * +slave-reconf-sent slave 127.0.0.1:6380 127.0.0.1 6380 @ mymaster 127.0.0.1 6379 //6379不再處于客觀下線狀態，客觀下線狀態只用于master服務，6379已經不是master了 2937:X 29 Jul 01:59:24.653 # -odown master mymaster 127.0.0.1 6379 //6380服務正在將自己設置為6381主服務的從服務器，還未完成 2937:X 29 Jul 01:59:25.270 * +slave-reconf-inprog slave 127.0.0.1:6380 127.0.0.1 6380 @ mymaster 127.0.0.1 6379 //從服務器6380已經完成對新master服務的同步 2937:X 29 Jul 01:59:25.271 * +slave-reconf-done slave 127.0.0.1:6380 127.0.0.1 6380 @ mymaster 127.0.0.1 6379 //master6379 故障轉移結束，所有的從服務器開始同步新的master 2937:X 29 Jul 01:59:25.347 # +failover-end master mymaster 127.0.0.1 6379 //配置變更主服務器的ip地址已經改變， 選擇master 為6381 2937:X 29 Jul 01:59:25.347 # +switch-master mymaster 127.0.0.1 6379 127.0.0.1 6381 //6381下的兩個從服務（新的從服務被識別并關聯） 2937:X 29 Jul 01:59:25.347 * +slave slave 127.0.0.1:6380 127.0.0.1 6380 @ mymaster 127.0.0.1 6381 2937:X 29 Jul 01:59:25.347 * +slave slave 127.0.0.1:6379 127.0.0.1 6379 @ mymaster 127.0.0.1 6381 //添加master下從服務6379 為客觀下線 2937:X 29 Jul 01:59:55.401 # +sdown slave 127.0.0.1:6379 127.0.0.1 6379 @ mymaster 127.0.0.1 6381

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Sentinel6381.log

//判定master 主觀下線
2961:X 29 Jul 01:59:23.459 # +sdown master mymaster 127.0.0.1 6379 2961:X 29 Jul 01:59:23.545 # +new-epoch 1
//開始給6380投票 2961:X 29 Jul 01:59:23.548 # +vote-for-leader 4a6aebffdd1301bf054e722c34e8a6611418ba8a 1 2961:X 29 Jul 01:59:24.325 # +config-update-from sentinel 4a6aebffdd1301bf054e722c34e8a6611418ba8a 127.0.0.1 26380 @ mymaster 127.0.0.1 6379 2961:X 29 Jul 01:59:24.325 # +switch-master mymaster 127.0.0.1 6379 127.0.0.1 6381 2961:X 29 Jul 01:59:24.325 * +slave slave 127.0.0.1:6380 127.0.0.1 6380 @ mymaster 127.0.0.1 6381 2961:X 29 Jul 01:59:24.325 * +slave slave 127.0.0.1:6379 127.0.0.1 6379 @ mymaster 127.0.0.1 6381 2961:X 29 Jul 01:59:54.348 # +sdown slave 127.0.0.1:6379 127.0.0.1 6379 @ mymaster 127.0.0.1 6381

可以看到在 01:59:23秒 也就是一分鐘之后，三個監控master的sentinel 都判定了master為主觀下線(sdown)，我們配置的至少有2個sentinel 同意master 主觀下線，master就會被切換到客觀下線(odown) 【+odown master mymaster 127.0.0.1 6379 #quorum 2/2】。當判斷master為客觀下線后，sentinel 就開始選舉出新的master，可以看到Sentinel6380.log 日志要比其他的sentinel.log多，因為整個選舉的過程是Sentinel6380 在牽頭執行。

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4：在6381下查看整個服務的備份狀態

# Replication role:master connected_slaves:1 slave0:ip=127.0.0.1,port=6380,state=online,offset=1125775,lag=0 master_replid:514edab0972b4b6e5388edc4f14fbdb4d223d39e master_replid2:541cd938f43b4f144e647881af409fa1884ea5a4 master_repl_offset:1125775 second_repl_offset:617714 repl_backlog_active:1 repl_backlog_size:1048576 repl_backlog_first_byte_offset:77200 repl_backlog_histlen:1048576

可以看到6381的角色成為了master，只有一個slave，因為另一個掛了。

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5：再次啟動6379服務

查看6379服務的日志

3037:S 29 Jul 02:46:47.753 # CONFIG REWRITE executed with success.
3037:S 29 Jul 02:46:48.359 * Connecting to MASTER 127.0.0.1:6381
3037:S 29 Jul 02:46:48.360 * MASTER <-> SLAVE sync started
3037:S 29 Jul 02:46:48.360 * Non blocking connect for SYNC fired the event.
3037:S 29 Jul 02:46:48.361 * Master replied to PING, replication can continue...
3037:S 29 Jul 02:46:48.362 * Trying a partial resynchronization (request 7b0dc6ac9c2188e3c92eb29eea200ea6c572619c:1).
3037:S 29 Jul 02:46:48.608 * Full resync from master: 514edab0972b4b6e5388edc4f14fbdb4d223d39e:1178142
3037:S 29 Jul 02:46:48.608 * Discarding previously cached master state.
3037:S 29 Jul 02:46:48.708 * MASTER <-> SLAVE sync: receiving 253 bytes from master
3037:S 29 Jul 02:46:48.708 * MASTER <-> SLAVE sync: Flushing old data
3037:S 29 Jul 02:46:48.708 * MASTER <-> SLAVE sync: Loading DB in memory
3037:S 29 Jul 02:46:48.708 * MASTER <-> SLAVE sync: Finished with success
3037:S 29 Jul 02:46:48.709 * Background append only file rewriting started by pid 3042
3037:S 29 Jul 02:46:48.750 * AOF rewrite child asks to stop sending diffs.
3042:C 29 Jul 02:46:48.750 * Parent agreed to stop sending diffs. Finalizing AOF...
3042:C 29 Jul 02:46:48.750 * Concatenating 0.00 MB of AOF diff received from parent.
3042:C 29 Jul 02:46:48.750 * SYNC append only file rewrite performed
3042:C 29 Jul 02:46:48.750 * AOF rewrite: 6 MB of memory used by copy-on-write
3037:S 29 Jul 02:46:48.781 * Background AOF rewrite terminated with success
3037:S 29 Jul 02:46:48.782 * Residual parent diff successfully flushed to the rewritten AOF (0.00 MB)
3037:S 29 Jul 02:46:48.782 * Background AOF rewrite finished successfully

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看到啟動后重寫配置文件，然后自動連接6381這個新的master服務，開始從master 上全量同步數據

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查看6381這個新master日志

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//響應6379的同步請求
2809:M 29 Jul 02:46:48.362 * Slave 127.0.0.1:6379 asks for synchronization //不接受同步部分數據請求 2809:M 29 Jul 02:46:48.362 * Partial resynchronization not accepted: Replication ID mismatch (Slave asked for '7b0dc6ac9c2188e3c92eb29eea200ea6c572619c', my replication IDs are '514edab0972b4b6e5388edc4f14fbdb4d223d39e' and '541cd938f43b4f144e647881af409fa1884ea5a4') //開始同步 2809:M 29 Jul 02:46:48.362 * Starting BGSAVE for SYNC with target: disk 2809:M 29 Jul 02:46:48.607 * Background saving started by pid 3041 3041:C 29 Jul 02:46:48.607 * DB saved on disk #6m內存用于寫復制 3041:C 29 Jul 02:46:48.608 * RDB: 6 MB of memory used by copy-on-write //后臺保存成功 2809:M 29 Jul 02:46:48.708 * Background saving terminated with success 2809:M 29 Jul 02:46:48.708 * Synchronization with slave 127.0.0.1:6379 succeeded

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查看sentinel日志

6379sentinel.log

//減去6379服務的主觀下線狀態 2908:X 29 Jul 02:46:37.610 # -sdown slave 127.0.0.1:6379 127.0.0.1 6379 @ mymaster 127.0.0.1 6381 //轉換為master6381 下的從服務 2908:X 29 Jul 02:46:47.628 * +convert-to-slave slave 127.0.0.1:6379 127.0.0.1 6379 @ mymaster 127.0.0.1 6381

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6380sentinel.log

2937:X 29 Jul 02:46:37.767 # -sdown slave 127.0.0.1:6379 127.0.0.1 6379 @ mymaster 127.0.0.1 6381

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6381sentinel.log

2961:X 29 Jul 02:46:38.023 # -sdown slave 127.0.0.1:6379 127.0.0.1 6379 @ mymaster 127.0.0.1 6381

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再看下6381這個新master的整個備份信息

# Replication role:master connected_slaves:2 slave0:ip=127.0.0.1,port=6380,state=online,offset=1348132,lag=0 slave1:ip=127.0.0.1,port=6379,state=online,offset=1348132,lag=0 master_replid:514edab0972b4b6e5388edc4f14fbdb4d223d39e master_replid2:541cd938f43b4f144e647881af409fa1884ea5a4 master_repl_offset:1348132 second_repl_offset:617714 repl_backlog_active:1 repl_backlog_size:1048576 repl_backlog_first_byte_offset:299557 repl_backlog_histlen:1048576

新的master 增加了一個slave6379 從服務

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我們再搭建前做的redis配置，當故障轉移成功后，這些配置會被重寫，重寫的內容基本都在配置文件的最后

Redis.conf配置文件，多了

# Generated by CONFIG REWRITE slaveof 127.0.0.1 6381

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Redis6381.conf配置文件沒有變

# Master-Slave replication. Use slaveof to make a Redis instance a copy of # slaveof <masterip> <masterport> slaveof 127.0.0.1 6381

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新的master配置，也就是redis_slave6381.conf 已經沒有了slaveof 配置

# Master-Slave replication. Use slaveof to make a Redis instance a copy of # slaveof <masterip> <masterport>

Sentinel.conf 也會發生變化，可以自己去看看

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6：再次測試故障轉移后的 同步功能

之前的master已經不再支持set

127.0.0.1:6379> set name zhangxs (error) READONLY You can't write against a read only slave.

新master set成功

127.0.0.1:6381> set name zhangxs OK 127.0.0.1:6379> get name "zhangxs" 127.0.0.1:6380> get name "zhangxs"

同步沒問題。

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轉移后的服務器變成了

服務角色	端口	Redis.conf名稱	sentinel配置文件名稱	sentinel端口	redis日志路徑	sentinel路勁
從(master)	6379	redis.conf	sentinel.conf	26379	/home/zhangxs/data/redislog/redis_server/master.log	/home/zhangxs/data/redislog/sentinel/sentinel6379.log
從(slave)	6380	redis_slave6380.conf	Sentinel6380.conf	26380	/home/zhangxs/data/redislog/redis_server/slave6380.log	/home/zhangxs/data/redislog/sentinel/sentinel6380.log
主(slave)	6381	redis_slave6381.conf	Sentinel6381.conf	26381	/home/zhangxs/data/redislog/redis_server/slave6381.log	/home/zhangxs/data/redislog/sentinel/sentinel6381.log

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參考文檔：http://www.redis.cn/topics

轉載于:https://www.cnblogs.com/zhangXingSheng/p/9385885.html

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