1.集群環境
1.Linux服務器列表
使用4台CentOS Linux服務器搭建環境,其IP地址如下:
192.168.110.100
192.168.110.101
192.168.110.102
192.168.110.103
2.Redis服務部署環境
192.168.110.100
啟動多個Redis sentinel服務,構成Redis sentinel集群
192.168.110.101
啟動Redis服務,設置成主節點
192.168.110.102
啟動Redis服務,設置成192.168.110.101的從節點
192.168.110.103
啟動Redis服務,設置成192.168.110.101的從節點

2.配置並啟動Redis主從集群
1.修改redis.conf配置文件
主節點的redis配置文件使用默認的配置文件就可以了,
從節點的redis配置文件修改如下:
# Master-Slave replication. Use slaveof to make a Redis instance a copy of
# another Redis server. A few things to understand ASAP about Redis replication.
#
# 1) Redis replication is asynchronous, but you can configure a master to
# stop accepting writes if it appears to be not connected with at least
# a given number of slaves.
# 2) Redis slaves are able to perform a partial resynchronization with the
# master if the replication link is lost for a relatively small amount of
# time. You may want to configure the replication backlog size (see the next
# sections of this file) with a sensible value depending on your needs.
# 3) Replication is automatic and does not need user intervention. After a
# network partition slaves automatically try to reconnect to masters
# and resynchronize with them.
#
# 主從同步。通過 slaveof 配置來實現Redis實例的備份。
# 注意,這里是本地從遠端復制數據。也就是說,本地可以有不同的數據庫文件、綁定不同的IP、監聽不同的端口。
#
# slaveof <masterip> <masterport>
slaveof 192.168.110.1016379
注意:兩台從節點都要改。
2.啟動Redis主從集群
先啟動192.168.110.101主節點,使用默認配置,腳本:
[wch@localhost bin]$ ./redis-server
再啟動192.168.110.102和
192.168.110.103
從節點,使用剛才的配置,腳本:
./redis-server redis.conf
3.查看集群
192.168.110.101主節點
Replication
信息
[wch@localhost bin]$ ./redis-cli -h 192.168.110.101 info Replication
# Replication
role:master
connected_slaves:2
slave0:ip=192.168.110.102,port=6379,state=online,offset=659,lag=1
slave1:ip=192.168.110.103,port=6379,state=online,offset=659,lag=0
master_repl_offset:659
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:2
repl_backlog_histlen:658
192.168.110.102
從節點
Replication
信息
[wch@localhost bin]$ ./redis-cli -h 192.168.110.102 info Replication
# Replication
role:slave
master_host:192.168.110.101
master_port:6379
master_link_status:up
master_last_io_seconds_ago:3
master_sync_in_progress:0
slave_repl_offset:701
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
192.168.110.103
從節點
Replication
信息
[wch@localhost bin]$ ./redis-cli -h 192.168.110.103 info Replication
# Replication
role:slave
master_host:192.168.110.101
master_port:6379
master_link_status:up
master_last_io_seconds_ago:9
master_sync_in_progress:0
slave_repl_offset:715
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
此時,存儲到
192.168.110.101主節點的數據,在從節點中都可以查詢到。從節點會備份主節點的數據。
3.配置sentinel集群並啟動
1.創建sentinel.conf配置文件
port 26379
# sentinel announce-ip <ip>
# sentinel announce-port <port>
dir /tmp
################################# master001 #################################
sentinel monitor master001 192.168.110.10163792
# sentinel auth-pass <master-name> <password>
sentinel down-after-milliseconds master001 30000
sentinel parallel-syncs master001 1
sentinel failover-timeout master001 180000
# sentinel notification-script <master-name> <script-path>
# sentinel client-reconfig-script <master-name> <script-path>
# 可以配置多個master節點
################################# master002 #################################
配置文件說明:
1. port
:當前
Sentinel服務運行的端口
2. dir
:
Sentinel服務運行時使用的臨時文件夾
3.sentinel monitor master001 192.168.110.10163792
:
Sentinel去監視一個名為
master001
的主redis實例,這個主實例的IP地址為本機地址
192.168
.
110.101
,端口號為
6379
,而將這個主實例判斷為失效至少需要
2
個 Sentinel進程的同意,只要同意Sentinel的數量不達標,自動failover就不會執行
4.sentinel down-after-milliseconds master001 30000
:
指定了Sentinel認為Redis實例已經失效所需的毫秒數。
當實例超過該時間沒有返回PING,或者直接返回錯誤,那么Sentinel將這個實例標記為主觀下線。只有一個 Sentinel進程將實例標記為主觀下線並不一定會引起實例的自動故障遷移:只有在足夠數量的Sentinel都將一個實例標記為主觀下線之后,實例才會被標記為客觀下線,這時自動故障遷移才會執行
5.sentinel parallel-syncs master001 1
:指定了在執行故障轉移時,最多可以有多少個從Redis實例在同步新的主實例,在從Redis實例較多的情況下這個數字越小,同步的時間越長,完成故障轉移所需的時間就越長
6.sentinel failover-timeout master001 180000
:如果在該時間(ms)內未能完成failover操作,則認為該failover失敗
7.sentinel notification-script <master-name> <script-path>
:
指定sentinel檢測到該監控的redis實例指向的實例異常時,調用的報警腳本。該配置項可選,但是很常用
2.啟動
sentinel集群
創建3個sentinel.conf配置文件:
sentinel001.conf、
sentinel002.conf、
sentinel003.conf並修改端口號分別為:
26379
、
36379
、
46379
,並啟動服務:
./redis-sentinel sentinel001.conf
./redis-sentinel sentinel002.conf
./redis-sentinel sentinel003.conf
啟動三個
sentinel
服務后會在其控制台看到如下信息:
./
redis
-
sentinel sentinel001
.
conf
,端口:
26379
[7743]01Oct06:20:38.162# Sentinel runid is ba6c42e1accc31290e11d5876275e1562564295d
[7743]01Oct06:20:38.162# +monitor master master001 192.168.110.101 6379 quorum 2
[7743]01Oct06:20:39.110*+slave slave 192.168.110.102:6379192.168.110.1026379@ master001 192.168.110.1016379
[7743]01Oct06:20:39.111*+slave slave 192.168.110.103:6379192.168.110.1036379@ master001 192.168.110.1016379
[7743]01Oct06:25:07.595*+sentinel sentinel 192.168.110.100:36379192.168.110.10036379@ master001 192.168.110.1016379
[7743]01Oct06:26:11.170*+sentinel sentinel 192.168.110.100:46379192.168.110.10046379@ master001 192.168.110.1016379
./
redis
-
sentinel sentinel002
.
conf
,端口:
36379
[7795]01Oct06:25:05.538# Sentinel runid is 52c14768b15837fb601b26328acf150c6bd30682
[7795]01Oct06:25:05.538# +monitor master master001 192.168.110.101 6379 quorum 2
[7795]01Oct06:25:06.505*+slave slave 192.168.110.102:6379192.168.110.1026379@ master001 192.168.110.1016379
[7795]01Oct06:25:06.515*+slave slave 192.168.110.103:6379192.168.110.1036379@ master001 192.168.110.1016379
[7795]01Oct06:25:07.557*+sentinel sentinel 192.168.110.100:26379192.168.110.10026379@ master001 192.168.110.1016379
[7795]01Oct06:26:11.168*+sentinel sentinel 192.168.110.100:46379192.168.110.10046379@ master001 192.168.110.1016379
./
redis
-
sentinel sentinel003
.
conf
,端口:
46379
[7828]01Oct06:26:09.076# Sentinel runid is c8509594be4a36660b2122b3b81f4f74060c9b04
[7828]01Oct06:26:09.076# +monitor master master001 192.168.110.101 6379 quorum 2
[7828]01Oct06:26:10.063*+slave slave 192.168.110.102:6379192.168.110.1026379@ master001 192.168.110.1016379
[7828]01Oct06:26:10.071*+slave slave 192.168.110.103:6379192.168.110.1036379@ master001 192.168.110.1016379
[7828]01Oct06:26:11.516*+sentinel sentinel 192.168.110.100:26379192.168.110.10026379@ master001 192.168.110.1016379
[7828]01Oct06:26:11.674*+sentinel sentinel 192.168.110.100:36379192.168.110.10036379@ master001 192.168.110.1016379
每個sentinel服務能知道其他所有的服務!
4.測試sentinel集群
1.停止192.168.110.101主節點
停止192.168.110.101Redis主節點后,在查看
Replication
信息如下:
[wch@localhost bin]$ ./redis-cli -h 192.168.110.101 info Replication
Could not connect to Redis at 192.168.110.101:6379:Connection refused
[wch@localhost bin]$ ./redis-cli -h 192.168.110.102 info Replication
# Replication
role:slave
master_host:192.168.110.103
master_port:6379
master_link_status:up
master_last_io_seconds_ago:1
master_sync_in_progress:0
slave_repl_offset:29128
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
[wch@localhost bin]$ ./redis-cli -h 192.168.110.103 info Replication
# Replication
role:master
connected_slaves:1
slave0:ip=192.168.110.102,port=6379,state=online,offset=30456,lag=1
master_repl_offset:30456
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:2
repl_backlog_histlen:30455
[wch@localhost bin]$
發現
192.168.110.101Redis主節點已經不能連接,
192.168
.
110.103
成了主節點!
2.再啟動
192.168.110.101主節點
再啟動192.168.110.101Redis主節點后,在查看
Replication
信息如下:
### 啟動腳本,仍然使用默認配置
[wch@localhost bin]$ ./redis-server
[wch@localhost bin]$ ./redis-cli -h 192.168.110.101 info Replication
# Replication
role:slave
master_host:192.168.110.103
master_port:6379
master_link_status:up
master_last_io_seconds_ago:1
master_sync_in_progress:0
slave_repl_offset:57657
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
[wch@localhost bin]$ ./redis-cli -h 192.168.110.102 info Replication
# Replication
role:slave
master_host:192.168.110.103
master_port:6379
master_link_status:up
master_last_io_seconds_ago:0
master_sync_in_progress:0
slave_repl_offset:60751
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
[wch@localhost bin]$ ./redis-cli -h 192.168.110.103 info Replication
# Replication
role:master
connected_slaves:2
slave0:ip=192.168.110.102,port=6379,state=online,offset=63247,lag=1
slave1:ip=192.168.110.101,port=6379,state=online,offset=63247,lag=1
master_repl_offset:63393
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:2
repl_backlog_histlen:63392
[wch@localhost bin]$
發現
192.168
.
110.101
節點啟動后還再集群中,只不過成了從節點,
192.168
.
110.103
仍然是主節點,但是現在又有兩個從節點了!
3.只留下一個sentinel服務,再停止192.168.110.103主節點,查看Redis集群是否出現新的主節點
停止sentinel服務,
只留下一個sentinel服務,再停止Redis主節點,
查看
Replication
信息如下:
[wch@localhost bin]$ ./redis-cli -h 192.168.110.101 info Replication
# Replication
role:slave
master_host:192.168.110.103
master_port:6379
master_link_status:down
master_last_io_seconds_ago:-1
master_sync_in_progress:0
slave_repl_offset:184231
master_link_down_since_seconds:43
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
[wch@localhost bin]$ ./redis-cli -h 192.168.110.102 info Replication
# Replication
role:slave
master_host:192.168.110.103
master_port:6379
master_link_status:down
master_last_io_seconds_ago:-1
master_sync_in_progress:0
slave_repl_offset:184231
master_link_down_since_seconds:52
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
[wch@localhost bin]$ ./redis-cli -h 192.168.110.103 info Replication
Could not connect to Redis at 192.168.110.103:6379:Connection refused
發現
192.168
.
110.103
主節點已經不能連接了,也
不存在Redis主節點,集群中無主節點了!!!分析原因是:sentinel.conf
配置的
sentinel monitor master001
192.168
.
110.101
6379
2
最后一個參數是2導致,若是但節點此配置的最后一個參數要使用是1。(此原因我已證實)
注意:
在生產環境下建議
sentinel節點的數量能在3個以上,並且最好不要在同一台機器上(使用同一網卡)。
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