redis演练(7) redis Sentinel实现故障转移

中仅仅配置了redis主从环境。分别配置了2个主从结构。分别是1.有向无环，2星型模型。配置起来非常简单。但是，遗留了一个尾巴，没有阐述。如果master宕掉了怎么办？redis如何实现fail-over故障转移？本文，就重点说一下这块。主要内容手动实现fail-over效果
sentinel实现自动fail-over效果
手动实现fail-over效果

日志（6379）2495:M 05 Sep 20:06:23.615 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
2495:M 05 Sep 20:06:23.615 # Server started, Redis version 3.2.3
2495:M 05 Sep 20:06:23.617 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add ‘vm.overcommit_memory = 1’ to /etc/sysctl.conf and then reboot or run the command ‘sysctl vm.overcommit_memory=1’ for this to take effect.
2495:M 05 Sep 20:06:24.815 * DB loaded from append only file: 1.199 seconds
2495:M 05 Sep 20:06:24.816 * The server is now ready to accept connections on port 6379
2495:M 05 Sep 20:06:24.816 – DB 0: 20019 keys (0 volatile) in 32768 slots HT.
2495:M 05 Sep 20:06:24.816 – 0 clients connected (0 slaves), 3764336 bytes in use
2495:M 05 Sep 20:06:29.841 – DB 0: 20019 keys (0 volatile) in 32768 slots HT.
2495:M 05 Sep 20:06:29.841 – 0 clients connected (0 slaves), 3764336 bytes in use
2495:M 05 Sep 20:06:34.867 – DB 0: 20019 keys (0 volatile) in 32768 slots HT.
2495:M 05 Sep 20:06:34.875 – 0 clients connected (0 slaves), 3764336 bytes in use
2495:M 05 Sep 20:06:39.919 – DB 0: 20019 keys (0 volatile) in 32768 slots HT.
2495:M 05 Sep 20:06:39.921 – 0 clients connected (0 slaves), 3764336 bytes in use
2495:M 05 Sep 20:06:44.971 – DB 0: 20019 keys (0 volatile) in 32768 slots HT.
2495:M 05 Sep 20:06:44.971 – 0 clients connected (0 slaves), 3764336 bytes in use
2495:M 05 Sep 20:06:50.022 – DB 0: 20019 keys (0 volatile) in 32768 slots HT.
2495:M 05 Sep 20:06:50.022 – 0 clients connected (0 slaves), 3764336 bytes in use
2495:M 05 Sep 20:06:55.134 – DB 0: 20019 keys (0 volatile) in 32768 slots HT.
2495:M 05 Sep 20:06:55.134 – 0 clients connected (0 slaves), 3764336 bytes in use
2495:M 05 Sep 20:06:58.775 – Accepted 127.0.0.1:44408
2495:M 05 Sep 20:06:58.775 * Slave 127.0.0.1:6380 asks for synchronization
2495:M 05 Sep 20:06:58.775 * Full resync requested by slave 127.0.0.1:6380
2495:M 05 Sep 20:06:58.775 * Starting BGSAVE for SYNC with target: disk
2495:M 05 Sep 20:06:58.776 * Background saving started by pid 2511
2511:C 05 Sep 20:06:58.868 * DB saved on disk
2511:C 05 Sep 20:06:58.870 * RDB: 0 MB of memory used by copy-on-write
2495:M 05 Sep 20:06:58.916 * Background saving terminated with success
2495:M 05 Sep 20:06:58.920 * Synchronization with slave 127.0.0.1:6380 succeeded….2495:M 05 Sep 20:19:19.471 # User requested shutdown…
2495:M 05 Sep 20:19:19.471 * Calling fsync() on the AOF file.
2495:M 05 Sep 20:19:19.471 * Removing the pid file.
2495:M 05 Sep 20:19:19.472 # Redis is now ready to exit, bye bye…
日志（6380）2508:S 05 Sep 20:06:58.714 # Server started, Redis version 3.2.3
2508:S 05 Sep 20:06:58.714 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add ‘vm.overcommit_memory = 1’ to /etc/sysctl.conf and then reboot or run the command ‘sysctl vm.overcommit_memory=1’ for this to take effect.
2508:S 05 Sep 20:06:58.775 * DB loaded from disk: 0.060 seconds
2508:S 05 Sep 20:06:58.775 * The server is now ready to accept connections on port 6380
2508:S 05 Sep 20:06:58.775 * Connecting to MASTER 127.0.0.1:6379
2508:S 05 Sep 20:06:58.775 * MASTER SLAVE sync started
2508:S 05 Sep 20:06:58.775 * Non blocking connect for SYNC fired the event.
2508:S 05 Sep 20:06:58.775 * Master replied to PING, replication can continue…
2508:S 05 Sep 20:06:58.775 * Partial resynchronization not possible (no cached master)
2508:S 05 Sep 20:06:58.802 * Full resync from master: 8d0d86237c36a8d6ace4eed9b5f6e5871b40da29:1
2508:S 05 Sep 20:06:58.917 * MASTER SLAVE sync: receiving 489615 bytes from master
2508:S 05 Sep 20:06:58.922 * MASTER SLAVE sync: Flushing old data
2508:S 05 Sep 20:06:58.938 * MASTER SLAVE sync: Loading DB in memory
2508:S 05 Sep 20:06:58.969 * MASTER SLAVE sync: Finished with success
2508:S 05 Sep 20:06:59.788 * Slave 127.0.0.1:6381 asks for synchronization
2508:S 05 Sep 20:06:59.788 * Full resync requested by slave 127.0.0.1:6381
2508:S 05 Sep 20:06:59.788 * Starting BGSAVE for SYNC with target: disk
2508:S 05 Sep 20:06:59.788 * Background saving started by pid 2512
2512:C 05 Sep 20:06:59.832 * DB saved on disk
2512:C 05 Sep 20:06:59.832 * RDB: 0 MB of memory used by copy-on-write
2508:S 05 Sep 20:06:59.896 * Background saving terminated with success
2508:S 05 Sep 20:06:59.899 * Synchronization with slave 127.0.0.1:6381 succeeded
2508:S 05 Sep 20:10:46.786 * 10000 changes in 60 seconds. Saving…
2508:S 05 Sep 20:10:46.786 * Background saving started by pid 2595
2595:C 05 Sep 20:10:46.800 * DB saved on disk
2595:C 05 Sep 20:10:46.801 * RDB: 0 MB of memory used by copy-on-write
2508:S 05 Sep 20:10:46.887 * Background saving terminated with success
2508:S 05 Sep 20:19:19.472 # Connection with master lost.
2508:S 05 Sep 20:19:19.472 * Caching the disconnected master state.
2508:S 05 Sep 20:19:19.594 * Connecting to MASTER 127.0.0.1:6379
2508:S 05 Sep 20:19:19.595 * MASTER SLAVE sync started
2508:S 05 Sep 20:19:19.595 # Error condition on socket for SYNC: Connection refused
2508:S 05 Sep 20:19:20.619 * Connecting to MASTER 127.0.0.1:6379
2508:S 05 Sep 20:19:20.619 * MASTER SLAVE sync started…
2508:S 05 Sep 20:20:49.783 # Error condition on socket for SYNC: Connection refused
2508:M 05 Sep 20:20:50.283 * Discarding previously cached master state.
2508:M 05 Sep 20:20:50.283 * MASTER MODE enabled (user request from ‘id=6 addr=127.0.0.1:54717 fd=8 name= age=696 idle=0 flags=N db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=32768 obl=0 oll=0 omem=0 events=r cmd=slaveof’)
2508:M 05 Sep 20:25:47.073 * 1 changes in 900 seconds. Saving…
2508:M 05 Sep 20:25:47.074 * Background saving started by pid 2722
2722:C 05 Sep 20:25:47.087 * DB saved on disk
2722:C 05 Sep 20:25:47.088 * RDB: 0 MB of memory used by copy-on-write
2508:M 05 Sep 20:25:47.176 * Background saving terminated with success
2508:M 05 Sep 20:40:48.064 * 1 changes in 900 seconds. Saving…
2508:M 05 Sep 20:40:48.064 * Background saving started by pid 2813
2813:C 05 Sep 20:40:48.075 * DB saved on disk
2813:C 05 Sep 20:40:48.075 * RDB: 0 MB of memory used by copy-on-write
2508:M 05 Sep 20:40:48.165 * Background saving terminated with success
6381日志
2503:S 05 Sep 20:06:54.667 * DB loaded from disk: 0.087 seconds
2503:S 05 Sep 20:06:54.667 * The server is now ready to accept connections on port 6381
2503:S 05 Sep 20:06:54.667 * Connecting to MASTER 127.0.0.1:6380
2503:S 05 Sep 20:06:54.667 * MASTER SLAVE sync started
2503:S 05 Sep 20:06:54.667 # Error condition on socket for SYNC: Connection refused
2503:S 05 Sep 20:0 香港云主机6:55.691 * Connecting to MASTER 127.0.0.1:6380
2503:S 05 Sep 20:06:55.692 * MASTER SLAVE sync started
2503:S 05 Sep 20:06:55.692 # Error condition on socket for SYNC: Connection refused
2503:S 05 Sep 20:06:56.716 * Connecting to MASTER 127.0.0.1:6380
2503:S 05 Sep 20:06:56.717 * MASTER SLAVE sync started
2503:S 05 Sep 20:06:56.717 # Error condition on socket for SYNC: Connection refused
2503:S 05 Sep 20:06:57.741 * Connecting to MASTER 127.0.0.1:6380
2503:S 05 Sep 20:06:57.742 * MASTER SLAVE sync started
2503:S 05 Sep 20:06:57.742 # Error condition on socket for SYNC: Connection refused
2503:S 05 Sep 20:06:58.764 * Connecting to MASTER 127.0.0.1:6380
2503:S 05 Sep 20:06:58.764 * MASTER SLAVE sync started
2503:S 05 Sep 20:06:58.764 * Non blocking connect for SYNC fired the event.
2503:S 05 Sep 20:06:58.775 * Master replied to PING, replication can continue…
2503:S 05 Sep 20:06:58.775 * Partial resynchronization not possible (no cached master)
2503:S 05 Sep 20:06:58.776 * Master does not support PSYNC or is in error state (reply: -ERR Can’t SYNC while not connected with my master)
2503:S 05 Sep 20:06:58.776 * Retrying with SYNC…
2503:S 05 Sep 20:06:58.803 # MASTER aborted replication with an error: ERR Can’t SYNC while not connected with my master
2503:S 05 Sep 20:06:59.786 * Connecting to MASTER 127.0.0.1:6380
2503:S 05 Sep 20:06:59.787 * MASTER SLAVE sync started
2503:S 05 Sep 20:06:59.787 * Non blocking connect for SYNC fired the event.
2503:S 05 Sep 20:06:59.787 * Master replied to PING, replication can continue…
2503:S 05 Sep 20:06:59.787 * Partial resynchronization not possible (no cached master)
2503:S 05 Sep 20:06:59.788 * Full resync from master: e1bfca531c87795977333fca30c7a75eea64a1de:1
2503:S 05 Sep 20:06:59.897 * MASTER SLAVE sync: receiving 489615 bytes from master
2503:S 05 Sep 20:06:59.900 * MASTER SLAVE sync: Flushing old data
2503:S 05 Sep 20:06:59.917 * MASTER SLAVE sync: Loading DB in memory
2503:S 05 Sep 20:06:59.969 * MASTER SLAVE sync: Finished with success2.sentinel实现fail-over自动切换参照http://www.redis.cn/topics/sentinel.html使用sentinel 监控(正常初始化状态，使用sentinel监控如下）2.1 Master状态
127.0.0.1:26379> sentinel masters
1) 1) “name”
2) “mymaster”
3) “ip”
4) “127.0.0.1”
5) “port”
6) “6379”
7) “runid”
8) “4d2b8e087e297f5d6347e1599a37c4998ad056d6”
9) “flags”
10) “master”
11) “link-pending-commands”
12) “0”
13) “link-refcount”
14) “1”
15) “last-ping-sent”
16) “0”
17) “last-ok-ping-reply”
18) “410”
19) “last-ping-reply”
20) “410”
21) “down-after-milliseconds”
22) “5000”
23) “info-refresh”
24) “7817”
25) “role-reported”
26) “master”
27) “role-reported-time”
28) “58045”
29) “config-epoch”
30) “0”
31) “num-slaves”
32) “2”
33) “num-other-sentinels”
34) “0”
35) “quorum”
36) “1”
37) “failover-timeout”
38) “180000”
39) “parallel-syncs”
40) “1”可以知道Master的端口，备节点等信息。
2.2 查看初始的Slave信息
127.0.0.1:26379> sentinel slaves mymaster
1) 1) “name”
2) “127.0.0.1:6380”
3) “ip”
4) “127.0.0.1”
5) “port”
6) “6380”
7) “runid”
8) “c344769d6d1cfd814437034b39f04b17851dca66”
9) “flags”
10) “slave”
11) “link-pending-commands”
12) “0”
13) “link-refcount”
14) “1”
15) “last-ping-sent”
16) “0”
17) “last-ok-ping-reply”
18) “693”
19) “last-ping-reply”
20) “693”
21) “down-after-milliseconds”
22) “5000”
23) “info-refresh”
24) “6445”
25) “role-reported”
26) “slave”
27) “role-reported-time”
28) “96788”
29) “master-link-down-time”
30) “0”
31) “master-link-status”
32) “ok”
33) “master-host”
34) “127.0.0.1”
35) “master-port”
36) “6379”
37) “slave-priority”
38) “100”
39) “slave-repl-offset”
40) “6058”
2) 1) “name”
2) “127.0.0.1:6381”
3) “ip”
4) “127.0.0.1”
5) “port”
6) “6381”
7) “runid”
8) “9f8666ce6e7b30d01449f6fb10d8556030a96186”
9) “flags”
10) “slave”
11) “link-pending-commands”
12) “0”
13) “link-refcount”
14) “1”
15) “last-ping-sent”
16) “0”
17) “last-ok-ping-reply”
18) “693”
19) “last-ping-reply”
20) “693”
21) “down-after-milliseconds”
22) “5000”
23) “info-refresh”
24) “6444”
25) “role-reported”
26) “slave”
27) “role-reported-time”
28) “96788”
29) “master-link-down-time”
30) “0”
31) “master-link-status”
32) “ok”
33) “master-host”
34) “127.0.0.1”
35) “master-port”
36) “6379”
37) “slave-priority”
38) “100”
39) “slave-repl-offset”
40) “6058”

此时，sentinel日志风平浪静2847:X 07 Sep 21:01:27.567 # Sentinel ID is 1b9d1d720b11ecf5568c3dc0194305e86c47ed9a
2847:X 07 Sep 21:01:27.567 # +monitor master mymaster 127.0.0.1 6379 quorum 12.3 模拟Master6379宕机）127.0.0.1:6379> debug sleep 100
OK
2.4 sentinel自动进行failover切换
观看sentinel日志(sentinel具体工作详情)2847:X 07 Sep 21:01:27.567 # +monitor master mymaster 127.0.0.1 6379 quorum 1
2847:X 07 Sep 21:03:49.117 # +sdown master mymaster 127.0.0.1 6379
2847:X 07 Sep 21:03:49.117 # +odown master mymaster 127.0.0.1 6379 #quorum 1/1
2847:X 07 Sep 21:03:49.117 # +new-epoch 4
2847:X 07 Sep 21:03:49.117 # +try-failover master mymaster 127.0.0.1 6379
2847:X 07 Sep 21:03:49.128 # +vote-for-leader 1b9d1d720b11ecf5568c3dc0194305e86c47ed9a 4
2847:X 07 Sep 21:03:49.129 # +elected-leader master mymaster 127.0.0.1 6379
2847:X 07 Sep 21:03:49.129 # +failover-state-select-slave master mymaster 127.0.0.1 6379
2847:X 07 Sep 21:03:49.185 # +selected-slave slave 127.0.0.1:6381 127.0.0.1 6381 @ mymaster 127.0.0.1 6379
2847:X 07 Sep 21:03:49.185 * +failover-state-send-slaveof-noone slave 127.0.0.1:6381 127.0.0.1 6381 @ mymaster 127.0.0.1 6379
2847:X 07 Sep 21:03:49.252 * +failover-state-wait-promotion slave 127.0.0.1:6381 127.0.0.1 6381 @ mymaster 127.0.0.1 6379
2847:X 07 Sep 21:03:50.262 # +promoted-slave slave 127.0.0.1:6381 127.0.0.1 6381 @ mymaster 127.0.0.1 6379
2847:X 07 Sep 21:03:50.262 # +failover-state-reconf-slaves master mymaster 127.0.0.1 6379
2847:X 07 Sep 21:03:50.315 * +slave-reconf-sent slave 127.0.0.1:6380 127.0.0.1 6380 @ mymaster 127.0.0.1 6379
2847:X 07 Sep 21:03:51.308 * +slave-reconf-inprog slave 127.0.0.1:6380 127.0.0.1 6380 @ mymaster 127.0.0.1 6379
2847:X 07 Sep 21:03:51.308 * +slave-reconf-done slave 127.0.0.1:6380 127.0.0.1 6380 @ mymaster 127.0.0.1 6379
2847:X 07 Sep 21:03:51.365 # +failover-end master mymaster 127.0.0.1 6379
2847:X 07 Sep 21:03:51.365 # +switch-master mymaster 127.0.0.1 6379 127.0.0.1 6381
2847:X 07 Sep 21:03:51.365 * +slave slave 127.0.0.1:6380 127.0.0.1 6380 @ mymaster 127.0.0.1 6381
2847:X 07 Sep 21:03:51.365 * +slave slave 127.0.0.1:6379 127.0.0.1 6379 @ mymaster 127.0.0.1 6381
2847:X 07 Sep 21:03:56.399 # +sdown slave 127.0.0.1:6379 127.0.0.1 6379 @ mymaster 127.0.0.1 6381
2847:X 07 Sep 21:05:23.708 # -sdown slave 127.0.0.1:6379 127.0.0.1 6379 @ mymaster 127.0.0.1 6381
2847:X 07 Sep 21:05:33.730 * +convert-to-slave slave 127.0.0.1:6379 127.0.0.1 6379 @ mymaster 127.0.0.1 6381
2.6 failover切换后监控信息127.0.0.1:26379> sentinel masters
1) 1) “name”
2) “mymaster”
3) “ip”
4) “127.0.0.1”
5) “port”
6) “6381” （这儿变成了6381）
7) “runid”
8) “9f8666ce6e7b30d01449f6fb10d8556030a96186”
9) “flags”
10) “master”
11) “link-pending-commands”
12) “0”
13) “link-refcount”
14) “1”
15) “last-ping-sent”
16) “0”
17) “last-ok-ping-reply”
18) “190”
19) “last-ping-reply”
20) “190”
21) “down-after-milliseconds”
22) “5000”
23) “info-refresh”
24) “1905”
25) “role-reported”
26) “master”
27) “role-reported-time”
28) “42128”
29) “config-epoch”
30) “4”
31) “num-slaves”
32) “2”
33) “num-other-sentinels”
34) “0”
35) “quorum”
36) “1”
37) “failover-timeout”
38) “180000”
39) “parallel-syncs”
40) “1”
备库信息
127.0.0.1:26379> sentinel slaves mymaster
1) 1) “name”
2) “127.0.0.1:6379”
3) “ip”
4) “127.0.0.1”
5) “port”
6) “6379”
7) “runid”
8) “”
9) “flags”
10) “s_down,slave”（此时6379 还处在sleep状态，过了休眠时间会更新该状态）
11) “link-pending-commands”
12) “44”
13) “link-refcount”
14) “1”
15) “last-ping-sent”
16) “48488”
17) “last-ok-ping-reply”
18) “48488”
19) “last-ping-reply”
20) “48488”
21) “s-down-time”
22) “43454”
23) “down-after-milliseconds”
24) “5000”
25) “info-refresh”
26) “1473253479853”
27) “role-reported”
28) “slave”
29) “role-reported-time”
30) “48488”
31) “master-link-down-time”
32) “0”
33) “master-link-status”
34) “err”
35) “master-host”
36) “?”
37) “master-port”
38) “0”
39) “slave-priority”
40) “100”
41) “slave-repl-offset”
42) “0”
2) 1) “name”
2) “127.0.0.1:6380”
3) “ip”
4) “127.0.0.1”
5) “port”
6) “6380”
7) “runid”
8) “c344769d6d1cfd814437034b39f04b17851dca66”
9) “flags”
10) “slave”
11) “link-pending-commands”
12) “0”
13) “link-refcount”
14) “1”
15) “last-ping-sent”
16) “0”
17) “last-ok-ping-reply”
18) “308”
19) “last-ping-reply”
20) “308”
21) “down-after-milliseconds”
22) “5000”
23) “info-refresh”
24) “8265”
25) “role-reported”
26) “slave”
27) “role-reported-time”
28) “48488”
29) “master-link-down-time”
30) “0”
31) “master-link-status”
32) “ok”
33) “master-host”
34) “127.0.0.1”
35) “master-port”
36) “6381”
37) “slave-priority”
38) “100”
39) “slave-repl-offset”
40) “11780”
127.0.0.1:26379> sentinel slaves mymaster
1) 1) “name”
2) “127.0.0.1:6379”
3) “ip”
4) “127.0.0.1”
5) “port”
6) “6379”
7) “runid”
8) “4d2b8e087e297f5d6347e1599a37c4998ad056d6”
9) “flags”
10) “slave” s_down没有了
11) “link-pending-commands”
12) “0”
13) “link-refcount”
14) “1”
15) “last-ping-sent”
16) “0”
17) “last-ok-ping-reply”
18) “869”
19) “last-ping-reply”
20) “869”
21) “down-after-milliseconds”
22) “5000”
23) “info-refresh”
24) “3426”
25) “role-reported”
26) “slave”
27) “role-reported-time”
28) “3426”
29) “master-link-down-time”
30) “0”
31) “master-link-status”
32) “ok”
33) “master-host”
34) “127.0.0.1”
35) “master-port”
36) “6381”
37) “slave-priority”
38) “100”
39) “slave-repl-offset”
40) “16556”
…手动切换failover
2847:X 07 Sep 21:46:46.793 # +switch-master mymaster 127.0.0.1 6381 127.0.0.1 6379
2847:X 07 Sep 21:46:46.794 * +slave slave 127.0.0.1:6380 127.0.0.1 6380 @ mymaster 127.0.0.1 6379
2847:X 07 Sep 21:46:46.794 * +slave slave 127.0.0.1:6381 127.0.0.1 6381 @ mymaster 127.0.0.1 6379
2847:X 07 Sep 21:46:56.910 * +convert-to-slave slave 127.0.0.1:6381 127.0.0.1 6381 @ mymaster 127.0.0.1 6379
sentinel 发生failover，会更新对应主备库的redis.conf文件。6379对应的配置文件，添加了slaveof参数
[root@hadoop2 redis]# cat redis.conf | grep slaveof
# Master-Slave replication. Use slaveof to make a Redis instance a copy of
# slaveof
slaveof 127.0.0.1 63816380对应的配置文件，修改了slaveof参数[root@hadoop2 redis]# cat redis6380.conf | grep slaveof
# Master-Slave replication. Use slaveof to make a Redis instance a copy of
slaveof 127.0.0.1 6381

至此演练结束3其他3.1 重要的quorum参数。演练设置quorum=1，纯粹为了简单，线上环境不能重要。http://redis.io/topics/sentinel 中提供了讨论了4个场景，在以后慢慢演练讨论下。复制sentinel.conf时，需要处理sentinel生成的信息如sentinel myid 575cb680ff3d3cbad55cdb978c1d6b5962abe7ac否则，sentinel之间通信存在问题

相关推荐: 怎么使用ES6的class模仿Vue写一个双向绑定

这篇文章主要介绍“怎么使用ES6的class模仿Vue写一个双向绑定”的相关知识，小编通过实际案例向大家展示操作过程，操作方法简单快捷，实用性强，希望这篇“怎么使用ES6的class模仿Vue写一个双向绑定”文章能帮助大家解决问题。最终效果如下：构造器(con…

免责声明：本站发布的图片视频文字，以转载和分享为主，文章观点不代表本站立场，本站不承担相关法律责任；如果涉及侵权请联系邮箱：360163164@qq.com举报，并提供相关证据，经查实将立刻删除涉嫌侵权内容。