Redis集群详解

Redis有三种集群模式，分别是：

1* 主从模式
2
3* Sentinel模式
4
5* Cluster模式

三种集群模式各有特点，关于Redis介绍可以参考这里：NoSQL（二)——Redis

Redis官网：https://redis.io/ ，最新版本5.0.4

主从模式

主从模式介绍

主从模式是三种模式中最简单的，在主从复制中，数据库分为两类：主数据库(master)和从数据库(slave)。

其中主从复制有如下特点：

1* 主数据库可以进行读写操作，当读写操作导致数据变化时会自动将数据同步给从数据库
2
3* 从数据库一般都是只读的，并且接收主数据库同步过来的数据
4
5* 一个master可以拥有多个slave，但是一个slave只能对应一个master
6
7* slave挂了不影响其他slave的读和master的读和写，重新启动后会将数据从master同步过来
8
9* master挂了以后，不影响slave的读，但redis不再提供写服务，master重启后redis将重新对外提供写服务
10
11* master挂了以后，不会在slave节点中重新选一个master

工作机制：

当slave启动后，主动向master发送SYNC命令。master接收到SYNC命令后在后台保存快照（RDB持久化）和缓存保存快照这段时间的命令，然后将保存的快照文件和缓存的命令发送给slave。slave接收到快照文件和命令后加载快照文件和缓存的执行命令。

复制初始化后，master每次接收到的写命令都会同步发送给slave，保证主从数据一致性。

安全设置：

当master节点设置密码后，

1客户端访问master需要密码
2
3启动slave需要密码，在配置文件中配置即可
4
5客户端访问slave不需要密码

缺点：

从上面可以看出，master节点在主从模式中唯一，若master挂掉，则redis无法对外提供写服务。

主从模式搭建

环境准备：

1master节点                  192.168.30.128
2
3slave节点                   192.168.30.129
4
5slave节点                   192.168.30.130

全部下载安装：

1# cd /software
2
3# wget http://download.redis.io/releases/redis-5.0.4.tar.gz
4
5# tar zxf redis-5.0.4.tar.gz && mv redis-5.0.4/ /usr/local/redis
6
7# cd /usr/local/redis && make && make install
8
9# echo $?
100

全部配置成服务：

服务文件

1# vim /usr/lib/systemd/system/redis.service
2
3[Unit]
4Description=Redis persistent key-value database
5After=network.target
6After=network-online.target
7Wants=network-online.target
8
9[Service]
10ExecStart=/usr/local/bin/redis-server /usr/local/redis/redis.conf --supervised systemd
11ExecStop=/usr/libexec/redis-shutdown
12Type=notify
13User=redis
14Group=redis
15RuntimeDirectory=redis
16RuntimeDirectoryMode=0755
17
18[Install]
19WantedBy=multi-user.target

shutdown脚本

1# vim /usr/libexec/redis-shutdown
2
3#!/bin/bash
4#
5# Wrapper to close properly redis and sentinel
6test x"$REDIS_DEBUG" != x && set -x
7
8REDIS_CLI=/usr/local/bin/redis-cli
9
10# Retrieve service name
11SERVICE_NAME="$1"
12if [ -z "$SERVICE_NAME" ]; then
13   SERVICE_NAME=redis
14fi
15
16# Get the proper config file based on service name
17CONFIG_FILE="/usr/local/redis/$SERVICE_NAME.conf"
18
19# Use awk to retrieve host, port from config file
20HOST=`awk '/^[[:blank:]]*bind/ { print $2 }' $CONFIG_FILE | tail -n1`
21PORT=`awk '/^[[:blank:]]*port/ { print $2 }' $CONFIG_FILE | tail -n1`
22PASS=`awk '/^[[:blank:]]*requirepass/ { print $2 }' $CONFIG_FILE | tail -n1`
23SOCK=`awk '/^[[:blank:]]*unixsocket\s/ { print $2 }' $CONFIG_FILE | tail -n1`
24
25# Just in case, use default host, port
26HOST=${HOST:-127.0.0.1}
27if [ "$SERVICE_NAME" = redis ]; then
28    PORT=${PORT:-6379}
29else
30    PORT=${PORT:-26739}
31fi
32
33# Setup additional parameters
34# e.g password-protected redis instances
35[ -z "$PASS"  ] || ADDITIONAL_PARAMS="-a $PASS"
36
37# shutdown the service properly
38if [ -e "$SOCK" ] ; then
39        $REDIS_CLI -s $SOCK $ADDITIONAL_PARAMS shutdown
40else
41        $REDIS_CLI -h $HOST -p $PORT $ADDITIONAL_PARAMS shutdown
42fi

chmod +x /usr/libexec/redis-shutdown

useradd -s /sbin/nologin redis

chown -R redis:redis /usr/local/redis

chown -R redis:redis /data/redis

yum install -y bash-completion && source /etc/profile #命令补全

systemctl daemon-reload

systemctl enable redis

1
2*   修改配置：
3
4192.168.30.128
5

mkdir -p /data/redis

vim /usr/local/redis/redis.conf

bind 192.168.30.128 #监听ip，多个ip用空格分隔 daemonize yes #允许后台启动 logfile "/usr/local/redis/redis.log" #日志路径 dir /data/redis #数据库备份文件存放目录 masterauth 123456 #slave连接master密码，master可省略 requirepass 123456 #设置master连接密码，slave可省略

appendonly yes #在/data/redis/目录生成appendonly.aof文件，将每一次写操作请求都追加到appendonly.aof 文件中

echo 'vm.overcommit_memory=1' >> /etc/sysctl.conf

sysctl -p

1
2192.168.30.129
3

mkdir -p /data/redis

vim /usr/local/redis/redis.conf

bind 192.168.30.129 daemonize yes logfile "/usr/local/redis/redis.log" dir /data/redis replicaof 192.168.30.128 6379 masterauth 123456 requirepass 123456 appendonly yes

echo 'vm.overcommit_memory=1' >> /etc/sysctl.conf

sysctl -p

1
2192.168.30.130
3

mkdir -p /data/redis

vim /usr/local/redis/redis.conf

bind 192.168.30.130 daemonize yes logfile "/usr/local/redis/redis.log" dir /data/redis replicaof 192.168.30.128 6379 masterauth 123456 requirepass 123456 appendonly yes

echo 'vm.overcommit_memory=1' >> /etc/sysctl.conf

sysctl -p

1
2*   全部启动redis：
3

systemctl start redis

1
2*   查看集群状态：
3

redis-cli -h 192.168.30.128 -a 123456

Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.

192.168.30.128:6379> info replication

Replication

role:master connected_slaves:2 slave0:ip=192.168.30.129,port=6379,state=online,offset=168,lag=1 slave1:ip=192.168.30.130,port=6379,state=online,offset=168,lag=1 master_replid:fb4941e02d5032ad74c6e2383211fc58963dbe90 master_replid2:0000000000000000000000000000000000000000 master_repl_offset:168 second_repl_offset:-1 repl_backlog_active:1 repl_backlog_size:1048576 repl_backlog_first_byte_offset:1 repl_backlog_histlen:168

1# redis-cli -h 192.168.30.129 -a 123456 info replication
2
3Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
4# Replication
5role:slave
6master_host:192.168.30.128
7master_port:6379
8master_link_status:up
9master_last_io_seconds_ago:1
10master_sync_in_progress:0
11slave_repl_offset:196
12slave_priority:100
13slave_read_only:1
14connected_slaves:0
15master_replid:fb4941e02d5032ad74c6e2383211fc58963dbe90
16master_replid2:0000000000000000000000000000000000000000
17master_repl_offset:196
18second_repl_offset:-1
19repl_backlog_active:1
20repl_backlog_size:1048576
21repl_backlog_first_byte_offset:1
22repl_backlog_histlen:196 
23```
24
25*   数据演示：
26
27```
28192.168.30.128:6379> keys *
29(empty list or set)
30
31192.168.30.128:6379> set key1 100
32OK
33
34192.168.30.128:6379> set key2 lzx
35OK
36
37192.168.30.128:6379> keys *
381) "key1"
392) "key2"

redis-cli -h 192.168.30.129 -a 123456

Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.

192.168.30.129:6379> keys *

"key2"
"key1"

192.168.30.129:6379> CONFIG GET dir

"dir"
"/data/redis"

192.168.30.129:6379> CONFIG GET dbfilename

"dbfilename"
"dump.rdb"

192.168.30.129:6379> get key1 "100"

192.168.30.129:6379> get key2 "lzx"

192.168.30.129:6379> set key3 aaa (error) READONLY You can't write against a read only replica.

1# redis-cli -h 192.168.30.130 -a 123456
2Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
3
4192.168.30.130:6379> keys *
51) "key2"
62) "key1"
7
8192.168.30.130:6379> CONFIG GET dir
91) "dir"
102) "/data/redis"
11
12192.168.30.130:6379> CONFIG GET dbfilename
131) "dbfilename"
142) "dump.rdb"
15
16192.168.30.130:6379> get key1
17"100"
18
19192.168.30.130:6379> get key2
20"lzx"
21
22192.168.30.130:6379> set key3 aaa
23(error) READONLY You can't write against a read only replica. 
24```
25
26可以看到，在master节点写入的数据，很快就同步到slave节点上，而且在slave节点上无法写入数据。
27
28* * *
29
30### [](https://blog.csdn.net/miss1181248983/article/details/90056960)Sentinel模式
31
32#### [](https://blog.csdn.net/miss1181248983/article/details/90056960)Sentinel模式介绍
33
34主从模式的弊端就是不具备高可用性，当master挂掉以后，Redis将不能再对外提供写入操作，因此sentinel应运而生。
35
36sentinel中文含义为哨兵，顾名思义，它的作用就是监控redis集群的运行状况，特点如下：
37
38```
39* sentinel模式是建立在主从模式的基础上，如果只有一个Redis节点，sentinel就没有任何意义
40
41* 当master挂了以后，sentinel会在slave中选择一个做为master，并修改它们的配置文件，其他slave的配置文件也会被修改，比如slaveof属性会指向新的master
42
43* 当master重新启动后，它将不再是master而是做为slave接收新的master的同步数据
44
45* sentinel因为也是一个进程有挂掉的可能，所以sentinel也会启动多个形成一个sentinel集群
46
47* 多sentinel配置的时候，sentinel之间也会自动监控
48
49* 当主从模式配置密码时，sentinel也会同步将配置信息修改到配置文件中，不需要担心
50
51* 一个sentinel或sentinel集群可以管理多个主从Redis，多个sentinel也可以监控同一个redis
52
53* sentinel最好不要和Redis部署在同一台机器，不然Redis的服务器挂了以后，sentinel也挂了 
54```
55
56工作机制：
57
58```
59* 每个sentinel以每秒钟一次的频率向它所知的master，slave以及其他sentinel实例发送一个 PING 命令 
60
61* 如果一个实例距离最后一次有效回复 PING 命令的时间超过 down-after-milliseconds 选项所指定的值， 则这个实例会被sentinel标记为主观下线。 
62
63* 如果一个master被标记为主观下线，则正在监视这个master的所有sentinel要以每秒一次的频率确认master的确进入了主观下线状态
64
65* 当有足够数量的sentinel（大于等于配置文件指定的值）在指定的时间范围内确认master的确进入了主观下线状态， 则master会被标记为客观下线 
66
67* 在一般情况下， 每个sentinel会以每 10 秒一次的频率向它已知的所有master，slave发送 INFO 命令 
68
69* 当master被sentinel标记为客观下线时，sentinel向下线的master的所有slave发送 INFO 命令的频率会从 10 秒一次改为 1 秒一次 
70
71* 若没有足够数量的sentinel同意master已经下线，master的客观下线状态就会被移除；
72  若master重新向sentinel的 PING 命令返回有效回复，master的主观下线状态就会被移除 
73```
74
75当使用sentinel模式的时候，客户端就不要直接连接Redis，而是连接sentinel的ip和port，由sentinel来提供具体的可提供服务的Redis实现，这样当master节点挂掉以后，sentinel就会感知并将新的master节点提供给使用者。
76
77#### [](https://blog.csdn.net/miss1181248983/article/details/90056960)Sentinel模式搭建
78
79*   环境准备：
80
81```
82master节点              192.168.30.128          sentinel端口：26379
83
84slave节点               192.168.30.129          sentinel端口：26379
85
86slave节点               192.168.30.130          sentinel端口：26379 
87```
88
89*   修改配置：
90
91前面已经下载安装了redis，这里省略，直接修改sentinel配置文件。
92
93192.168.30.128
94
95```
96# vim /usr/local/redis/sentinel.conf
97
98daemonize yes
99logfile "/usr/local/redis/sentinel.log"
100dir "/usr/local/redis/sentinel"                 #sentinel工作目录
101sentinel monitor mymaster 192.168.30.128 6379 2                 #判断master失效至少需要2个sentinel同意，建议设置为n/2+1，n为sentinel个数
102sentinel auth-pass mymaster 123456
103sentinel down-after-milliseconds mymaster 30000                 #判断master主观下线时间，默认30s 
104```
105
106这里需要注意，`sentinel auth-pass mymaster 123456`需要配置在`sentinel monitor mymaster 192.168.30.128 6379 2`下面，否则启动报错：
107
108```
109# /usr/local/bin/redis-sentinel /usr/local/redis/sentinel.conf
110
111*** FATAL CONFIG FILE ERROR ***
112Reading the configuration file, at line 104
113>>> 'sentinel auth-pass mymaster 123456'
114No such master with specified name. 
115```
116
117*   全部启动sentinel：
118
119```
120# mkdir /usr/local/redis/sentinel && chown -R redis:redis /usr/local/redis
121
122# /usr/local/bin/redis-sentinel /usr/local/redis/sentinel.conf 
123```
124
125*   任一主机查看日志：
126
127```
128# tail -f /usr/local/redis/sentinel.log
129
13021574:X 09 May 2019 15:32:04.298 # Sentinel ID is 30c417116a8edbab09708037366c4a7471beb770
13121574:X 09 May 2019 15:32:04.298 # +monitor master mymaster 192.168.30.128 6379 quorum 2
13221574:X 09 May 2019 15:32:04.299 * +slave slave 192.168.30.129:6379 192.168.30.129 6379 @ mymaster 192.168.30.128 6379
13321574:X 09 May 2019 15:32:04.300 * +slave slave 192.168.30.130:6379 192.168.30.130 6379 @ mymaster 192.168.30.128 6379
13421574:X 09 May 2019 15:32:16.347 * +sentinel sentinel 79b8d61626afd4d059fb5a6a63393e9a1374e78f 192.168.30.129 26379 @ mymaster 192.168.30.128 6379
13521574:X 09 May 2019 15:32:31.584 * +sentinel sentinel d7b429dcba792103ef0d80827dd0910bd9284d21 192.168.30.130 26379 @ mymaster 192.168.30.128 6379 
136```
137
138Sentinel模式下的几个事件：
139
140```
141·       +reset-master ：主服务器已被重置。
142
143·       +slave ：一个新的从服务器已经被 Sentinel 识别并关联。
144
145·       +failover-state-reconf-slaves ：故障转移状态切换到了 reconf-slaves 状态。
146
147·       +failover-detected ：另一个 Sentinel 开始了一次故障转移操作，或者一个从服务器转换成了主服务器。
148
149·       +slave-reconf-sent ：领头（leader）的 Sentinel 向实例发送了 [SLAVEOF](/commands/slaveof.html) 命令，为实例设置新的主服务器。
150
151·       +slave-reconf-inprog ：实例正在将自己设置为指定主服务器的从服务器，但相应的同步过程仍未完成。
152
153·       +slave-reconf-done ：从服务器已经成功完成对新主服务器的同步。
154
155·       -dup-sentinel ：对给定主服务器进行监视的一个或多个 Sentinel 已经因为重复出现而被移除 —— 当 Sentinel 实例重启的时候，就会出现这种情况。
156
157·       +sentinel ：一个监视给定主服务器的新 Sentinel 已经被识别并添加。
158
159·       +sdown ：给定的实例现在处于主观下线状态。
160
161·       -sdown ：给定的实例已经不再处于主观下线状态。
162
163·       +odown ：给定的实例现在处于客观下线状态。
164
165·       -odown ：给定的实例已经不再处于客观下线状态。
166
167·       +new-epoch ：当前的纪元（epoch）已经被更新。
168
169·       +try-failover ：一个新的故障迁移操作正在执行中，等待被大多数 Sentinel 选中（waiting to be elected by the majority）。
170
171·       +elected-leader ：赢得指定纪元的选举，可以进行故障迁移操作了。
172
173·       +failover-state-select-slave ：故障转移操作现在处于 select-slave 状态 —— Sentinel 正在寻找可以升级为主服务器的从服务器。
174
175·       no-good-slave ：Sentinel 操作未能找到适合进行升级的从服务器。Sentinel 会在一段时间之后再次尝试寻找合适的从服务器来进行升级，又或者直接放弃执行故障转移操作。
176
177·       selected-slave ：Sentinel 顺利找到适合进行升级的从服务器。
178
179·       failover-state-send-slaveof-noone ：Sentinel 正在将指定的从服务器升级为主服务器，等待升级功能完成。
180
181·       failover-end-for-timeout ：故障转移因为超时而中止，不过最终所有从服务器都会开始复制新的主服务器（slaves will eventually be configured to replicate with the new master anyway）。
182
183·       failover-end ：故障转移操作顺利完成。所有从服务器都开始复制新的主服务器了。
184
185·       +switch-master ：配置变更，主服务器的 IP 和地址已经改变。 这是绝大多数外部用户都关心的信息。
186
187·       +tilt ：进入 tilt 模式。
188
189·       -tilt ：退出 tilt 模式。 
190```
191
192*   master宕机演示：
193
194192.168.30.128
195
196```
197# systemctl stop redis
198
199# tail -f /usr/local/redis/sentinel.log
200
20122428:X 09 May 2019 15:51:29.287 # +sdown master mymaster 192.168.30.128 6379
20222428:X 09 May 2019 15:51:29.371 # +odown master mymaster 192.168.30.128 6379 #quorum 2/2
20322428:X 09 May 2019 15:51:29.371 # +new-epoch 1
20422428:X 09 May 2019 15:51:29.371 # +try-failover master mymaster 192.168.30.128 6379
20522428:X 09 May 2019 15:51:29.385 # +vote-for-leader 30c417116a8edbab09708037366c4a7471beb770 1
20622428:X 09 May 2019 15:51:29.403 # d7b429dcba792103ef0d80827dd0910bd9284d21 voted for 30c417116a8edbab09708037366c4a7471beb770 1
20722428:X 09 May 2019 15:51:29.408 # 79b8d61626afd4d059fb5a6a63393e9a1374e78f voted for 30c417116a8edbab09708037366c4a7471beb770 1
20822428:X 09 May 2019 15:51:29.451 # +elected-leader master mymaster 192.168.30.128 6379
20922428:X 09 May 2019 15:51:29.451 # +failover-state-select-slave master mymaster 192.168.30.128 6379
21022428:X 09 May 2019 15:51:29.528 # +selected-slave slave 192.168.30.129:6379 192.168.30.129 6379 @ mymaster 192.168.30.128 6379
21122428:X 09 May 2019 15:51:29.528 * +failover-state-send-slaveof-noone slave 192.168.30.129:6379 192.168.30.129 6379 @ mymaster 192.168.30.128 6379
21222428:X 09 May 2019 15:51:29.594 * +failover-state-wait-promotion slave 192.168.30.129:6379 192.168.30.129 6379 @ mymaster 192.168.30.128 6379
21322428:X 09 May 2019 15:51:30.190 # +promoted-slave slave 192.168.30.129:6379 192.168.30.129 6379 @ mymaster 192.168.30.128 6379
21422428:X 09 May 2019 15:51:30.190 # +failover-state-reconf-slaves master mymaster 192.168.30.128 6379
21522428:X 09 May 2019 15:51:30.258 * +slave-reconf-sent slave 192.168.30.130:6379 192.168.30.130 6379 @ mymaster 192.168.30.128 6379
21622428:X 09 May 2019 15:51:30.511 # -odown master mymaster 192.168.30.128 6379
21722428:X 09 May 2019 15:51:31.233 * +slave-reconf-inprog slave 192.168.30.130:6379 192.168.30.130 6379 @ mymaster 192.168.30.128 6379
21822428:X 09 May 2019 15:51:31.233 * +slave-reconf-done slave 192.168.30.130:6379 192.168.30.130 6379 @ mymaster 192.168.30.128 6379
21922428:X 09 May 2019 15:51:31.297 # +failover-end master mymaster 192.168.30.128 6379
22022428:X 09 May 2019 15:51:31.297 # +switch-master mymaster 192.168.30.128 6379 192.168.30.129 6379
22122428:X 09 May 2019 15:51:31.298 * +slave slave 192.168.30.130:6379 192.168.30.130 6379 @ mymaster 192.168.30.129 6379
22222428:X 09 May 2019 15:51:31.298 * +slave slave 192.168.30.128:6379 192.168.30.128 6379 @ mymaster 192.168.30.129 6379
22322428:X 09 May 2019 15:52:31.307 # +sdown slave 192.168.30.128:6379 192.168.30.128 6379 @ mymaster 192.168.30.129 6379 
224```
225
226从日志中可以看到，master已经从192.168.30.128转移到192.168.30.129上
227
228192.168.30.129上查看集群信息
229
230```
231# /usr/local/bin/redis-cli -h 192.168.30.129 -p 6379 -a 123456
232Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
233
234192.168.30.129:6379> info replication
235# Replication
236role:master
237connected_slaves:1
238slave0:ip=192.168.30.130,port=6379,state=online,offset=291039,lag=1
239master_replid:757aff269236ed2707ba584a86a40716c1c76d74
240master_replid2:47a862fc0ff20362be29096ecdcca6d432070ee9
241master_repl_offset:291182
242second_repl_offset:248123
243repl_backlog_active:1
244repl_backlog_size:1048576
245repl_backlog_first_byte_offset:1
246repl_backlog_histlen:291182
247
248192.168.30.129:6379> set key4 linux
249OK 
250```
251
252当前集群中只有一个slave——192.168.30.130，master是192.168.30.129，且192.168.30.129具有写权限。
253
254192.168.30.130上查看redis的配置文件也可以看到`replicaof 192.168.30.129 6379`，这是sentinel在选举master是做的修改。
255
256重新把192.168.30.128上进程启动
257
258```
259# systemctl start redis
260
261# tail -f /usr/local/redis/sentinel.log
262
26322428:X 09 May 2019 15:51:31.297 # +switch-master mymaster 192.168.30.128 6379 192.168.30.129 6379
26422428:X 09 May 2019 15:51:31.298 * +slave slave 192.168.30.130:6379 192.168.30.130 6379 @ mymaster 192.168.30.129 6379
26522428:X 09 May 2019 15:51:31.298 * +slave slave 192.168.30.128:6379 192.168.30.128 6379 @ mymaster 192.168.30.129 6379
26622428:X 09 May 2019 15:52:31.307 # +sdown slave 192.168.30.128:6379 192.168.30.128 6379 @ mymaster 192.168.30.129 6379
26722428:X 09 May 2019 16:01:24.872 # -sdown slave 192.168.30.128:6379 192.168.30.128 6379 @ mymaster 192.168.30.129 6379 
268```
269
270查看集群信息
271
272```
273# /usr/local/bin/redis-cli -h 192.168.30.128 -p 6379 -a 123456
274Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
275
276192.168.30.128:6379> info replication
277# Replication
278role:slave
279master_host:192.168.30.129
280master_port:6379
281master_link_status:up
282master_last_io_seconds_ago:0
283master_sync_in_progress:0
284slave_repl_offset:514774
285slave_priority:100
286slave_read_only:1
287connected_slaves:0
288master_replid:757aff269236ed2707ba584a86a40716c1c76d74
289master_replid2:0000000000000000000000000000000000000000
290master_repl_offset:514774
291second_repl_offset:-1
292repl_backlog_active:1
293repl_backlog_size:1048576
294repl_backlog_first_byte_offset:376528
295repl_backlog_histlen:138247
296
297192.168.30.128:6379> get key4
298"linux"
299
300192.168.30.128:6379> set key5
301(error) ERR wrong number of arguments for 'set' command 
302```
303
304即使192.168.30.128重新启动redis服务，也是作为slave加入redis集群，192.168.30.129仍然是master。
305
306* * *
307
308### [](https://blog.csdn.net/miss1181248983/article/details/90056960)Cluster模式
309
310#### [](https://blog.csdn.net/miss1181248983/article/details/90056960)Cluster模式介绍
311
312sentinel模式基本可以满足一般生产的需求，具备高可用性。但是当数据量过大到一台服务器存放不下的情况时，主从模式或sentinel模式就不能满足需求了，这个时候需要对存储的数据进行分片，将数据存储到多个Redis实例中。cluster模式的出现就是为了解决单机Redis容量有限的问题，将Redis的数据根据一定的规则分配到多台机器。
313
314cluster可以说是sentinel和主从模式的结合体，通过cluster可以实现主从和master重选功能，所以如果配置两个副本三个分片的话，就需要六个Redis实例。因为Redis的数据是根据一定规则分配到cluster的不同机器的，当数据量过大时，可以新增机器进行扩容。
315
316使用集群，只需要将redis配置文件中的`cluster-enable`配置打开即可。每个集群中至少需要三个主数据库才能正常运行，新增节点非常方便。
317
318cluster集群特点：
319
320```
321* 多个redis节点网络互联，数据共享
322
323* 所有的节点都是一主一从（也可以是一主多从），其中从不提供服务，仅作为备用
324
325* 不支持同时处理多个key（如MSET/MGET），因为redis需要把key均匀分布在各个节点上，
326  并发量很高的情况下同时创建key-value会降低性能并导致不可预测的行为
327  
328* 支持在线增加、删除节点
329
330* 客户端可以连接任何一个主节点进行读写 
331```
332
333#### [](https://blog.csdn.net/miss1181248983/article/details/90056960)Cluster模式搭建
334
335*   环境准备：
336
337```
338三台机器，分别开启两个redis服务（端口）
339
340192.168.30.128              端口：7001,7002
341
342192.168.30.129              端口：7003,7004
343
344192.168.30.130              端口：7005,7006 
345```
346
347*   修改配置文件：
348
349192.168.30.128
350
351```
352# mkdir /usr/local/redis/cluster
353
354# cp /usr/local/redis/redis.conf /usr/local/redis/cluster/redis_7001.conf
355
356# cp /usr/local/redis/redis.conf /usr/local/redis/cluster/redis_7002.conf
357
358# chown -R redis:redis /usr/local/redis
359
360# mkdir -p /data/redis/cluster/{redis_7001,redis_7002} && chown -R redis:redis /data/redis

vim /usr/local/redis/cluster/redis_7001.conf

bind 192.168.30.128 port 7001 daemonize yes pidfile "/var/run/redis_7001.pid" logfile "/usr/local/redis/cluster/redis_7001.log" dir "/data/redis/cluster/redis_7001" #replicaof 192.168.30.129 6379 masterauth 123456 requirepass 123456 appendonly yes cluster-enabled yes cluster-config-file nodes_7001.conf cluster-node-timeout 15000

1# vim /usr/local/redis/cluster/redis_7002.conf
2
3bind 192.168.30.128
4port 7002
5daemonize yes
6pidfile "/var/run/redis_7002.pid"
7logfile "/usr/local/redis/cluster/redis_7002.log"
8dir "/data/redis/cluster/redis_7002"
9#replicaof 192.168.30.129 6379
10masterauth "123456"
11requirepass "123456"
12appendonly yes
13cluster-enabled yes
14cluster-config-file nodes_7002.conf
15cluster-node-timeout 15000 
16```
17
18其它两台机器配置与192.168.30.128一致，此处省略
19
20*   启动redis服务：
21
22```
23# redis-server /usr/local/redis/cluster/redis_7001.conf
24
25# tail -f /usr/local/redis/cluster/redis_7001.log
26
27# redis-server /usr/local/redis/cluster/redis_7002.conf
28
29# tail -f /usr/local/redis/cluster/redis_7002.log 
30```
31
32其它两台机器启动与192.168.30.128一致，此处省略
33
34*   安装ruby并创建集群（低版本）：
35
36如果redis版本比较低，则需要安装ruby。任选一台机器安装ruby即可
37
38```
39# yum -y groupinstall "Development Tools"
40
41# yum install -y gdbm-devel libdb4-devel libffi-devel libyaml libyaml-devel ncurses-devel openssl-devel readline-devel tcl-devel
42
43# mkdir -p ~/rpmbuild/{BUILD,BUILDROOT,RPMS,SOURCES,SPECS,SRPMS}
44
45# wget http://cache.ruby-lang.org/pub/ruby/2.2/ruby-2.2.3.tar.gz -P ~/rpmbuild/SOURCES
46
47# wget http://raw.githubusercontent.com/tjinjin/automate-ruby-rpm/master/ruby22x.spec -P ~/rpmbuild/SPECS
48
49# rpmbuild -bb ~/rpmbuild/SPECS/ruby22x.spec
50
51# rpm -ivh ~/rpmbuild/RPMS/x86_64/ruby-2.2.3-1.el7.x86_64.rpm
52
53# gem install redis                 #目的是安装这个，用于配置集群

cp /usr/local/redis/src/redis-trib.rb /usr/bin/

redis-trib.rb create --replicas 1 192.168.30.128:7001 192.168.30.128:7002 192.168.30.129:7003 192.168.30.129:7004 192.168.30.130:7005 192.168.30.130:7006

1
2*   创建集群：
3
4我这里是redis5.0.4，所以不需要安装ruby，直接创建集群即可
5

redis-cli -a 123456 --cluster create 192.168.30.128:7001 192.168.30.128:7002 192.168.30.129:7003 192.168.30.129:7004 192.168.30.130:7005 192.168.30.130:7006 --cluster-replicas 1

Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.

Performing hash slots allocation on 6 nodes... Master[0] -> Slots 0 - 5460 Master[1] -> Slots 5461 - 10922 Master[2] -> Slots 10923 - 16383 Adding replica 192.168.30.129:7004 to 192.168.30.128:7001 Adding replica 192.168.30.130:7006 to 192.168.30.129:7003 Adding replica 192.168.30.128:7002 to 192.168.30.130:7005 M: 80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001 slots:[0-5460] (5461 slots) master S: b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002 replicates 6788453ee9a8d7f72b1d45a9093838efd0e501f1 M: 4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003 slots:[5461-10922] (5462 slots) master S: b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004 replicates 80c80a3f3e33872c047a8328ad579b9bea001ad8 M: 6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005 slots:[10923-16383] (5461 slots) master S: 277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006 replicates 4d74ec66e898bf09006dac86d4928f9fad81f373 Can I set the above configuration? (type 'yes' to accept): yes #输入yes，接受上面配置 Nodes configuration updated Assign a different config epoch to each node Sending CLUSTER MEET messages to join the cluster

1
2可以看到，
3

192.168.30.128:7001是master，它的slave是192.168.30.129:7004；

192.168.30.129:7003是master，它的slave是192.168.30.130:7006；

192.168.30.130:7005是master，它的slave是192.168.30.128:7002

1
2自动生成nodes.conf文件：
3

ls /data/redis/cluster/redis_7001/

appendonly.aof dump.rdb nodes-7001.conf

vim /data/redis/cluster/redis_7001/nodes-7001.conf

6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557454406312 5 connected 10923-16383 277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557454407000 6 connected b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557454408371 5 connected 80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 myself,master - 0 1557454406000 1 connected 0-5460 b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557454407366 4 connected 4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557454407000 3 connected 5461-10922 vars currentEpoch 6 lastVoteEpoch 0

1
2#### [](https://blog.csdn.net/miss1181248983/article/details/90056960)集群操作
3
4*   登录集群：
5

redis-cli -c -h 192.168.30.128 -p 7001 -a 123456 # -c，使用集群方式登录

1
2*   查看集群信息：
3

192.168.30.128:7001> CLUSTER INFO #集群状态

cluster_state:ok cluster_slots_assigned:16384 cluster_slots_ok:16384 cluster_slots_pfail:0 cluster_slots_fail:0 cluster_known_nodes:6 cluster_size:3 cluster_current_epoch:6 cluster_my_epoch:1 cluster_stats_messages_ping_sent:580 cluster_stats_messages_pong_sent:551 cluster_stats_messages_sent:1131 cluster_stats_messages_ping_received:546 cluster_stats_messages_pong_received:580 cluster_stats_messages_meet_received:5 cluster_stats_messages_received:1131

1
2*   列出节点信息：
3

192.168.30.128:7001> CLUSTER NODES #列出节点信息

6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557455176000 5 connected 10923-16383 277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557455174000 6 connected b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557455175000 5 connected 80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 myself,master - 0 1557455175000 1 connected 0-5460 b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557455174989 4 connected 4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557455175995 3 connected 5461-10922

1
2这里与nodes.conf文件内容相同
3
4*   写入数据：
5

192.168.30.128:7001> set key111 aaa -> Redirected to slot [13680] located at 192.168.30.130:7005 #说明数据到了192.168.30.130:7005上 OK

192.168.30.130:7005> set key222 bbb -> Redirected to slot [2320] located at 192.168.30.128:7001 #说明数据到了192.168.30.128:7001上 OK

192.168.30.128:7001> set key333 ccc -> Redirected to slot [7472] located at 192.168.30.129:7003 #说明数据到了192.168.30.129:7003上 OK

192.168.30.129:7003> get key111 -> Redirected to slot [13680] located at 192.168.30.130:7005 "aaa"

192.168.30.130:7005> get key333 -> Redirected to slot [7472] located at 192.168.30.129:7003 "ccc"

192.168.30.129:7003>

1
2可以看出redis cluster集群是去中心化的，每个节点都是平等的，连接哪个节点都可以获取和设置数据。
3
4当然，平等指的是master节点，因为slave节点根本不提供服务，只是作为对应master节点的一个备份。
5
6*   增加节点：
7
8192.168.30.129上增加一节点：
9

cp /usr/local/redis/cluster/redis_7003.conf /usr/local/redis/cluster/redis_7007.conf

vim /usr/local/redis/cluster/redis_7007.conf

bind 192.168.30.129 port 7007 daemonize yes pidfile "/var/run/redis_7007.pid" logfile "/usr/local/redis/cluster/redis_7007.log" dir "/data/redis/cluster/redis_7007" #replicaof 192.168.30.129 6379 masterauth "123456" requirepass "123456" appendonly yes cluster-enabled yes cluster-config-file nodes_7007.conf cluster-node-timeout 15000

mkdir /data/redis/cluster/redis_7007

chown -R redis:redis /usr/local/redis && chown -R redis:redis /data/redis

redis-server /usr/local/redis/cluster/redis_7007.conf

1
2192.168.30.130上增加一节点：
3

cp /usr/local/redis/cluster/redis_7005.conf /usr/local/redis/cluster/redis_7008.conf

vim /usr/local/redis/cluster/redis_7007.conf

bind 192.168.30.130 port 7008 daemonize yes pidfile "/var/run/redis_7008.pid" logfile "/usr/local/redis/cluster/redis_7008.log" dir "/data/redis/cluster/redis_7008" #replicaof 192.168.30.130 6379 masterauth "123456" requirepass "123456" appendonly yes cluster-enabled yes cluster-config-file nodes_7008.conf cluster-node-timeout 15000

mkdir /data/redis/cluster/redis_7008

chown -R redis:redis /usr/local/redis && chown -R redis:redis /data/redis

redis-server /usr/local/redis/cluster/redis_7008.conf

1
2集群中增加节点：
3

192.168.30.129:7003> CLUSTER MEET 192.168.30.129 7007 OK

192.168.30.129:7003> CLUSTER NODES

4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 myself,master - 0 1557457361000 3 connected 5461-10922 80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master - 0 1557457364746 1 connected 0-5460 277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557457362000 6 connected b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557457363000 4 connected b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557457362000 5 connected e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557457362729 0 connected 6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557457363739 5 connected 10923-16383

1192.168.30.129:7003> CLUSTER MEET 192.168.30.130 7008
2OK
3
4192.168.30.129:7003> CLUSTER NODES
5
64d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 myself,master - 0 1557457489000 3 connected 5461-10922
780c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master - 0 1557457489000 1 connected 0-5460
8277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557457489000 6 connected
9b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557457488000 4 connected
10b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557457489472 5 connected
111a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 master - 0 1557457489259 0 connected
12e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557457489000 0 connected
136788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557457490475 5 connected 10923-16383 
14```
15
16可以看到，新增的节点都是以master身份加入集群的
17
18*   更换节点身份：
19
20将新增的192.168.30.130:7008节点身份改为192.168.30.129:7007的slave
21
22```
23# redis-cli -c -h 192.168.30.130 -p 7008 -a 123456 cluster replicate e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 
24```
25
26`cluster replicate`后面跟node\_id，更改对应节点身份。也可以登入集群更改
27
28```
29# redis-cli -c -h 192.168.30.130 -p 7008 -a 123456
30
31192.168.30.130:7008> CLUSTER REPLICATE e51ab166bc0f33026887bcf8eba0dff3d5b0bf14
32OK
33
34192.168.30.130:7008> CLUSTER NODES
35
36277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557458316881 3 connected
3780c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master - 0 1557458314864 1 connected 0-5460
384d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557458316000 3 connected 5461-10922
396788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557458315872 5 connected 10923-16383
40b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557458317890 5 connected
411a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 myself,slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557458315000 7 connected
42b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557458315000 1 connected
43e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557458314000 0 connected 
44```
45
46查看相应的nodes.conf文件，可以发现有更改，它记录当前集群的节点信息
47
48```
49# cat /data/redis/cluster/redis_7001/nodes-7001.conf
50
511a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557458236169 7 connected
526788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557458235000 5 connected 10923-16383
53277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557458234103 6 connected
54b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557458235129 5 connected
5580c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 myself,master - 0 1557458234000 1 connected 0-5460
56b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557458236000 4 connected
57e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557458236000 0 connected
584d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557458233089 3 connected 5461-10922
59vars currentEpoch 7 lastVoteEpoch 0 
60```
61
62*   删除节点：
63
64```
65192.168.30.130:7008> CLUSTER FORGET 1a1c7f02fce87530bd5abdfc98df1cffce4f1767
66(error) ERR I tried hard but I can't forget myself...               #无法删除登录节点
67
68192.168.30.130:7008> CLUSTER FORGET e51ab166bc0f33026887bcf8eba0dff3d5b0bf14
69(error) ERR Can't forget my master!                 #不能删除自己的master节点
70
71192.168.30.130:7008> CLUSTER FORGET 6788453ee9a8d7f72b1d45a9093838efd0e501f1
72OK              #可以删除其它的master节点
73
74192.168.30.130:7008> CLUSTER NODES
75
76277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557458887328 3 connected
7780c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master - 0 1557458887000 1 connected 0-5460
784d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557458886000 3 connected 5461-10922
79b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave - 0 1557458888351 5 connected
801a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 myself,slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557458885000 7 connected
81b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557458883289 1 connected
82e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557458885310 0 connected
83
84192.168.30.130:7008> CLUSTER FORGET b4d3eb411a7355d4767c6c23b4df69fa183ef8bc
85OK              #可以删除其它的slave节点
86
87192.168.30.130:7008> CLUSTER NODES
88
89277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557459031397 3 connected
9080c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master - 0 1557459032407 1 connected 0-5460
914d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557459035434 3 connected 5461-10922
926788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557459034000 5 connected 10923-16383
931a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 myself,slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557459032000 7 connected
94b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557459034000 1 connected
95e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557459034427 0 connected 
96```
97
98*   保存配置：
99
100```
101192.168.30.130:7008> CLUSTER SAVECONFIG                 #将节点配置信息保存到硬盘
102OK
103 
104# cat /data/redis/cluster/redis_7001/nodes-7001.conf
105
1061a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557458236169 7 connected
1076788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557458235000 5 connected 10923-16383
108277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557458234103 6 connected
109b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557458235129 5 connected
11080c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 myself,master - 0 1557458234000 1 connected 0-5460
111b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557458236000 4 connected
112e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557458236000 0 connected
1134d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557458233089 3 connected 5461-10922
114vars currentEpoch 7 lastVoteEpoch 0
115
116# redis-cli -c -h 192.168.30.130 -p 7008 -a 123456
117Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
118
119192.168.30.130:7008> CLUSTER NODES
120277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557459500741 3 connected
12180c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master - 0 1557459500000 1 connected 0-5460
1224d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557459501000 3 connected 5461-10922
1236788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557459500000 5 connected 10923-16383
124b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557459499737 5 connected
1251a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 myself,slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557459499000 7 connected
126b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557459501750 1 connected
127e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557459498000 0 connected 
128```
129
130可以看到，之前删除的节点又恢复了，这是因为对应的配置文件没有删除，执行`CLUSTER SAVECONFIG`恢复。
131
132*   模拟master节点挂掉：
133
134192.168.30.128
135
136```
137# netstat -lntp |grep 7001
138tcp        0      0 192.168.30.128:17001    0.0.0.0:*               LISTEN      6701/redis-server 1 
139tcp        0      0 192.168.30.128:7001     0.0.0.0:*               LISTEN      6701/redis-server 1 
140
141# kill 6701

192.168.30.130:7008> CLUSTER NODES

277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557461178000 3 connected 80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master,fail - 1557460950483 1557460947145 1 disconnected 4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557461174922 3 connected 5461-10922 6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557461181003 5 connected 10923-16383 b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557461179993 5 connected 1a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 myself,slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557461176000 7 connected b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 master - 0 1557461178981 8 connected 0-5460 e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557461179000 0 connected

1
2对应7001的一行可以看到，master fail，状态为disconnected；而对应7004的一行，slave已经变成master。
3
4*   重新启动7001节点：
5

redis-server /usr/local/redis/cluster/redis_7001.conf

192.168.30.130:7008> CLUSTER NODES

277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557461307000 3 connected 80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 slave b6331cbc986794237c83ed2d5c30777c1551546e 0 1557461305441 8 connected 4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557461307962 3 connected 5461-10922 6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557461304935 5 connected 10923-16383 b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557461306000 5 connected 1a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 myself,slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557461305000 7 connected b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 master - 0 1557461308972 8 connected 0-5460 e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557461307000 0 connected

1
2可以看到，7001节点启动后为slave节点，并且是7004的slave节点。即master节点如果挂掉，它的slave节点变为新master节点继续对外提供服务，而原来的master节点如果重启，则变为新master节点的slave节点。
3
4另外，如果这里是拿7007节点做测试的话，会发现7008节点并不会切换，这是因为7007节点上根本没数据。集群数据被分为三份，采用哈希槽 (hash slot)的方式来分配16384个slot的话，它们三个节点分别承担的slot 区间是：
5

节点7004覆盖0－5460 节点7003覆盖5461－10922 节点7005覆盖10923－16383

1
2* * *
3
4更多参考：
5
6[Redis集群常用命令](https://www.cnblogs.com/gossip/p/5993922.html)
7
8 
9
10  
11
12本文转自 [https://blog.csdn.net/miss1181248983/article/details/90056960](https://blog.csdn.net/miss1181248983/article/details/90056960)，如有侵权，请联系删除。

Redis集群详解

Redis集群详解

主从模式

主从模式介绍

主从模式搭建

chmod +x /usr/libexec/redis-shutdown

useradd -s /sbin/nologin redis

chown -R redis:redis /usr/local/redis

chown -R redis:redis /data/redis

yum install -y bash-completion && source /etc/profile #命令补全

systemctl daemon-reload

systemctl enable redis

mkdir -p /data/redis

vim /usr/local/redis/redis.conf

echo 'vm.overcommit_memory=1' >> /etc/sysctl.conf

sysctl -p

mkdir -p /data/redis

vim /usr/local/redis/redis.conf

echo 'vm.overcommit_memory=1' >> /etc/sysctl.conf

sysctl -p

mkdir -p /data/redis

vim /usr/local/redis/redis.conf

echo 'vm.overcommit_memory=1' >> /etc/sysctl.conf

sysctl -p

systemctl start redis

redis-cli -h 192.168.30.128 -a 123456

Replication

redis-cli -h 192.168.30.129 -a 123456

vim /usr/local/redis/cluster/redis_7001.conf

cp /usr/local/redis/src/redis-trib.rb /usr/bin/

redis-trib.rb create --replicas 1 192.168.30.128:7001 192.168.30.128:7002 192.168.30.129:7003 192.168.30.129:7004 192.168.30.130:7005 192.168.30.130:7006

redis-cli -a 123456 --cluster create 192.168.30.128:7001 192.168.30.128:7002 192.168.30.129:7003 192.168.30.129:7004 192.168.30.130:7005 192.168.30.130:7006 --cluster-replicas 1

ls /data/redis/cluster/redis_7001/

vim /data/redis/cluster/redis_7001/nodes-7001.conf

redis-cli -c -h 192.168.30.128 -p 7001 -a 123456 # -c，使用集群方式登录

cp /usr/local/redis/cluster/redis_7003.conf /usr/local/redis/cluster/redis_7007.conf

vim /usr/local/redis/cluster/redis_7007.conf

mkdir /data/redis/cluster/redis_7007

chown -R redis:redis /usr/local/redis && chown -R redis:redis /data/redis

redis-server /usr/local/redis/cluster/redis_7007.conf

cp /usr/local/redis/cluster/redis_7005.conf /usr/local/redis/cluster/redis_7008.conf

vim /usr/local/redis/cluster/redis_7007.conf

mkdir /data/redis/cluster/redis_7008

chown -R redis:redis /usr/local/redis && chown -R redis:redis /data/redis

redis-server /usr/local/redis/cluster/redis_7008.conf

redis-server /usr/local/redis/cluster/redis_7001.conf

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