写在前面的话：
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对于redis来讲，它有四种部署模式，分别是单机模式、主从模式、哨兵模式和集群模式，他们的使用场景有些区别，固然也是愈来愈复杂，可靠性愈来愈高。css
本文从实际操做的角度，来介绍和讲解下，这几种模式的特色，鉴于篇幅的问题，文章分红两篇，一篇用来介绍：单机模式、主从模式和哨兵模式；本篇文章是，另一个模式的介绍：集群模式。html
1、集群模式解决什么问题呢？
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集群模式用来解决Redis的在线扩容的问题，缘由是：Redis容量受限于单机配置的问题，而且前面的几种模式并不能很好的作到这一点。node
集群模式有三种方式：客户端实现、Proxy代理层、服务端实现。nginx
本文章主要讲解服务端实现方式，服务端的实现方式就是标准的集群(分区分片)模式，RedisCluster是Redis在3.0版本后推出的分布式解决方案。redis
Cluster模式实现了Redis的分布式存储，即每台节点存储不一样的内容，来解决在线扩容的问题。算法
2、Cluster模式的工做机制是什么？sql
在Redis的每一个节点上，都有一个插槽（slot），总共16384个哈希槽，取值范围为0-16383。采用Slot的设计(一个集群有多个主从节点，一个主从节点上会分配多个Slot槽，每一个槽点上存的是Key-Value数据):数据库
当咱们存取key的时候，Redis会根据CRC16的算法得出一个结果，而后把结果对16384求余数，这样每一个key都会对应一个编号在0-16383之间的哈希槽，经过这个值，去找到对应的插槽所对应的节点，而后直接自动跳转到这个对应的节点上进行存取操做。如图所示：
1.为了保证高可用，Cluster模式也引入主从复制模式，一个主节点对应一个或者多个从节点，当主节点宕机的时候，就会启用从节点。（备注：这里的从节点只是作备份来用，不做为读写分离来操做。）2.当其它主节点ping一个主节点A时，若是半数以上的主节点与A通讯超时，那么认为主节点A宕机了。若是主节点A和它的从节点都宕机了，那么该集群就没法再提供服务了。
备注：Cluster模式集群节点最小配置6个节点(3主3从，由于须要半数以上)
3、集群部署实际操做
1. 配置和启动集群
1）修改配置文件，这里分别启动7001～7006六个redis服务：
#修改为本身对应的端口号port 7001 #指定了记录日志的文件。logfile #数据目录，数据库的写入会在这个目录。rdb、aof文件也会写在这个目录dir #是否开启集群cluster-enabled#集群配置文件的名称，每一个节点都有一个集群相关的配置文件，持久化保存集群的信息。#这个文件并不须要手动配置，这个配置文件由Redis生成并更新，每一个Redis集群节点须要一个单独的配置文件，请确保与实例运行的系统中配置文件名称不冲突(建议配对应端口号)cluster-config-file nodes-7001.conf#节点互连超时的阀值。集群节点超时毫秒数cluster-node-timeout 15000 #默认redis使用的是rdb方式持久化，这种方式在许多应用中已经足够用了。#可是redis若是中途宕机，会致使可能有几分钟的数据丢失，根据save来策略进行持久化，Append Only File是另外一种持久化方式，能够提供更好的持久化特性。#Redis会把每次写入的数据在接收后都写入 appendonly.aof 文件，每次启动时Redis都会先把这个文件的数据读入内存里，先忽略RDB文件。appendonly yesprotected-mode no #保护模式 yes改成nobind 127.0.0.1 #本机试验，使用这个ip,这里也能够指定为集群的IPdaemonize yes #用来指定redis是否要用守护线程的方式启动,yes表示后台启动
2）启动redis-server:
按照下面的命令来分别启动7001～7006六个服务：
$ redis-server /usr/local/etc/redis7005.conf14903:C 05 Jan 2021 11:50:05.601 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo14903:C 05 Jan 2021 11:50:05.601 # Redis version=5.0.5, bits=64, commit=00000000, modified=0, pid=14903, just started14903:C 05 Jan 2021 11:50:05.601 # Configuration loaded
显示启动的redis-server:
ps -ef | grep redis 501 14867 1 0 11:45上午 ?? 0:00.66 redis-server 127.0.0.1:7001 [cluster] 501 14884 1 0 11:48上午 ?? 0:00.17 redis-server 127.0.0.1:7002 [cluster] 501 14887 1 0 11:49上午 ?? 0:00.08 redis-server 127.0.0.1:7003 [cluster] 501 14890 1 0 11:49上午 ?? 0:00.06 redis-server 127.0.0.1:7004 [cluster] 501 28799 1 0 171120 ?? 45:20.39 redis-server 127.0.0.1:7005 [cluster] 501 28801 1 0 171120 ?? 47:39.12 redis-server 127.0.0.1:7006 [cluster] 501 13669 841 0 10:11上午 ttys002 0:00.01 redis-cli -h 127.0.0.1 -p 7001 501 14897 14516 0 11:49上午 ttys007 0:00.00 grep redis
3)设置为cluster集群模式：
命令： redis-cli --cluster create 127.0.0.1:7001 127.0.0.1:7002 127.0.0.1:7003 127.0.0.1:7004 127.0.0.1:7005 127.0.0.1:7006 --cluster-replicas 1
# 1表示每一个主节点至少一个备份
redis-cli --cluster create 127.0.0.1:7001 127.0.0.1:7002 127.0.0.1:7003 127.0.0.1:7004 127.0.0.1:7005 127.0.0.1:7006 --cluster-replicas 1>>> Performing hash slots allocation on 6 nodes... -> Slots 0 - 5460 -> Slots 5461 - 10922 -> Slots 10923 - 16383Adding replica 127.0.0.1:7005 to 127.0.0.1:7001Adding replica 127.0.0.1:7006 to 127.0.0.1:7002Adding replica 127.0.0.1:7004 to 127.0.0.1:7003 Trying to optimize slaves allocation for anti-affinity Some slaves are in the same host as their masterM: 4359ede424a92c7f249fb6524c6cc3f6dc46fb60 127.0.0.1:7001 slots:[0-5460] (5461 slots) masterM: 2c779d5cc0b786af908d1c76dd3d4968e15796b3 127.0.0.1:7002 slots:[5461-10922] (5462 slots) masterM: 62c2ac721e402a27f017be49589bc06532548cdd 127.0.0.1:7003 slots:[10923-16383] (5461 slots) masterS: 2b51a786e6f204c292dc349b45aa8b515637382c 127.0.0.1:7004 replicates 62c2ac721e402a27f017be49589bc06532548cddS: 357221f17c5f5bf11d0551506fbff245ed0c047b 127.0.0.1:7005 replicates 4359ede424a92c7f249fb6524c6cc3f6dc46fb60S: 2ecce47670970e13a034a37dd425154d298dc480 127.0.0.1:7006 replicates 2c779d5cc0b786af908d1c76dd3d4968e15796b3Can I set the above configuration? (type 'yes' to accept): yes Nodes configuration updated Assign a different config epoch to each node Sending CLUSTER MEET messages to join the clusterWaiting for the cluster to join..... Performing Cluster Check (using node 127.0.0.1:7001)M: 4359ede424a92c7f249fb6524c6cc3f6dc46fb60 127.0.0.1:7001 slots:[0-5460] (5461 slots) master 1 additional replica(s)S: 2ecce47670970e13a034a37dd425154d298dc480 127.0.0.1:7006 slots: (0 slots) slave replicates 2c779d5cc0b786af908d1c76dd3d4968e15796b3M: 2c779d5cc0b786af908d1c76dd3d4968e15796b3 127.0.0.1:7002 slots:[5461-10922] (5462 slots) master 1 additional replica(s)S: 2b51a786e6f204c292dc349b45aa8b515637382c 127.0.0.1:7004 slots: (0 slots) slave replicates 62c2ac721e402a27f017be49589bc06532548cddM: 62c2ac721e402a27f017be49589bc06532548cdd 127.0.0.1:7003 slots:[10923-16383] (5461 slots) master 1 additional replica(s)S: 357221f17c5f5bf11d0551506fbff245ed0c047b 127.0.0.1:7005 slots: (0 slots) slave replicates 4359ede424a92c7f249fb6524c6cc3f6dc46fb60 All nodes agree about slots configuration. Check for open slots... Check slots coverage... All 16384 slots covered.
备注：这一步碰到的问题：
$ redis-cli --cluster create 127.0.0.1:7001 127.0.0.1:7002 127.0.0.1:7003 127.0.0.1:7004 127.0.0.1:7005 127.0.0.1:7006 --cluster-replicas 1[ERR] Node 127.0.0.1:7003 is not empty. Either the node already knows other nodes (check with CLUSTER NODES) or contains some key in database 0.
解决方法：
1)将每一个节点下aof、rdb、nodes.conf本地备份文件删除；
2)172.168.63.201:7001> flushdb #清空当前数据库(可省略)
$redis-cli -p 7000
127.0.0.1:7000> flushall
127.0.0.1:7000> cluster reset
127.0.0.1:7000> exit
3)以后再执行脚本，成功执行
详情能够参考：
https://www.jianshu.com/p/338bc2a74300
https://stackoverflow.com/questions/37206993/redis-server-cluster-not-working
2. 集群检查
1) 查看集群信息以及slot分配信息:
$ redis-cli -h 127.0.0.1 -p 7001 cluster node(error) ERR Unknown subcommand or wrong number of arguments for 'node'. Try CLUSTER HELP. cluster nodes2ecce47670970e13a034a37dd425154d298dc480 127.0.0.1:7006@17006 slave 2c779d5cc0b786af908d1c76dd3d4968e15796b3 0 1609823130000 6 connected2c779d5cc0b786af908d1c76dd3d4968e15796b3 127.0.0.1:7002@17002 master - 0 1609823129000 2 connected 5461-109222b51a786e6f204c292dc349b45aa8b515637382c 127.0.0.1:7004@17004 slave 62c2ac721e402a27f017be49589bc06532548cdd 0 1609823128000 4 connected4359ede424a92c7f249fb6524c6cc3f6dc46fb60 127.0.0.1:7001@17001 myself,master - 0 1609823128000 1 connected 0-546062c2ac721e402a27f017be49589bc06532548cdd 127.0.0.1:7003@17003 master - 0 1609823130975 3 connected 10923-16383357221f17c5f5bf11d0551506fbff245ed0c047b 127.0.0.1:7005@17005 slave 4359ede424a92c7f249fb6524c6cc3f6dc46fb60 0 1609823129000 5 connected
介绍：能够根据以上得出总共有3个master节点，每一个节点有一个slave节点，三个master节点分别分配了0-5460、5461-1092二、10923-16383三个slot范围，7001这个master节点的slave节点为7005节点，其id为4359ede424a92c7f249fb6524c6cc3f6dc46fb60
2）添加数据，数据会根hash而后存到对应的slot槽，会存到slot槽对应的节点上
$ redis-cli -c -h 127.0.0.1 -p 7001 // -c 是集群方式启动127.0.0.1:7001> set 122 11 // hash在本机7001OK127.0.0.1:7001> set 1221 222 // hash到了7003-> Redirected to slot [13341] located at 127.0.0.1:7003OK127.0.0.1:7003> set 12233 222 // hash到了7002-> Redirected to slot [6669] located at 127.0.0.1:7002OK127.0.0.1:7002> set 12233 111 // hash到了7003OK127.0.0.1:7002> keys *1) "12233"127.0.0.1:7002>
备注：
127.0.0.1:7002> set 6666 6 (error) MOVED 1491 127.0.0.1:7001 // 提示这个错误是由于没有按照集群启动redis-cli
3.宕机测试
测试步骤：关掉7001，查看集群，发现7001的slave变成master，重启7001，发现7001变成7005的salve。
1）关掉7001
kill 14867$ ps -ef | grep redis 501 14884 1 0 11:48上午 ?? 0:14.18 redis-server 127.0.0.1:7002 [cluster] 501 14887 1 0 11:49上午 ?? 0:13.94 redis-server 127.0.0.1:7003 [cluster] 501 14890 1 0 11:49上午 ?? 0:14.02 redis-server 127.0.0.1:7004 [cluster] 501 14904 1 0 11:50上午 ?? 0:13.84 redis-server 127.0.0.1:7005 [cluster] 501 14907 1 0 11:50上午 ?? 0:13.65 redis-server 127.0.0.1:7006 [cluster] 501 13669 841 0 10:11上午 ttys002 0:00.01 redis-cli -h 127.0.0.1 -p 7001 501 15295 7048 0 1:26下午 ttys004 0:00.02 redis-cli -c -h 127.0.0.1 -p 7001 501 15319 14516 0 1:32下午 ttys007 0:00.00 grep redis
2) 7005变成master
cluster nodes2b51a786e6f204c292dc349b45aa8b515637382c 127.0.0.1:7004@17004 slave 62c2ac721e402a27f017be49589bc06532548cdd 0 1609824784402 4 connected357221f17c5f5bf11d0551506fbff245ed0c047b 127.0.0.1:7005@17005 master - 0 1609824786425 7 connected 0-54602c779d5cc0b786af908d1c76dd3d4968e15796b3 127.0.0.1:7002@17002 master - 0 1609824785000 2 connected 5461-1092262c2ac721e402a27f017be49589bc06532548cdd 127.0.0.1:7003@17003 myself,master - 0 1609824780000 3 connected 10923-163834359ede424a92c7f249fb6524c6cc3f6dc46fb60 127.0.0.1:7001@17001 master,fail - 1609824748365 1609824746000 1 disconnected2ecce47670970e13a034a37dd425154d298dc480 127.0.0.1:7006@17006 slave 2c779d5cc0b786af908d1c76dd3d4968e15796b3 0 1609824785413 6 connected
3)重启7001，变成7005的salve
redis-server /usr/local/etc/redis7001.conf15354:C 05 Jan 2021 13:39:21.856 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo15354:C 05 Jan 2021 13:39:21.856 # Redis version=5.0.5, bits=64, commit=00000000, modified=0, pid=15354, just started15354:C 05 Jan 2021 13:39:21.856 # Configuration loaded ps -ef | grep redis 501 14884 1 0 11:48上午 ?? 0:16.23 redis-server 127.0.0.1:7002 [cluster] 501 14887 1 0 11:49上午 ?? 0:15.99 redis-server 127.0.0.1:7003 [cluster] 501 14890 1 0 11:49上午 ?? 0:16.05 redis-server 127.0.0.1:7004 [cluster] 501 14904 1 0 11:50上午 ?? 0:15.88 redis-server 127.0.0.1:7005 [cluster] 501 14907 1 0 11:50上午 ?? 0:15.70 redis-server 127.0.0.1:7006 [cluster] 501 15355 1 0 1:39下午 ?? 0:00.02 redis-server 127.0.0.1:7001 [cluster] 501 13669 841 0 10:11上午 ttys002 0:00.01 redis-cli -h 127.0.0.1 -p 7001 501 15295 7048 0 1:26下午 ttys004 0:00.02 redis-cli -c -h 127.0.0.1 -p 7001 501 15360 14516 0 1:39下午 ttys007 0:00.00 grep red
cluster nodes查看：
cluster nodes2b51a786e6f204c292dc349b45aa8b515637382c 127.0.0.1:7004@17004 slave 62c2ac721e402a27f017be49589bc06532548cdd 0 1609825212544 4 connected357221f17c5f5bf11d0551506fbff245ed0c047b 127.0.0.1:7005@17005 master - 0 1609825211000 7 connected 0-54602c779d5cc0b786af908d1c76dd3d4968e15796b3 127.0.0.1:7002@17002 master - 0 1609825209000 2 connected 5461-1092262c2ac721e402a27f017be49589bc06532548cdd 127.0.0.1:7003@17003 myself,master - 0 1609825208000 3 connected 10923-163834359ede424a92c7f249fb6524c6cc3f6dc46fb60 127.0.0.1:7001@17001 slave 357221f17c5f5bf11d0551506fbff245ed0c047b 0 1609825210000 7 connected2ecce47670970e13a034a37dd425154d298dc480 127.0.0.1:7006@17006 slave 2c779d5cc0b786af908d1c76dd3d4968e15796b3 0 1609825211533 6 connected
4.水平拓展
场景是集群能力不够的时候，扩容用的，下面新增7007，7008来演示下。
1) 新增集群配置 7007和7008，按照前面方法操做，启动以下：
ps -ef | grep redis 501 14884 1 0 11:48上午 ?? 0:19.85 redis-server 127.0.0.1:7002 [cluster] 501 14887 1 0 11:49上午 ?? 0:19.64 redis-server 127.0.0.1:7003 [cluster] 501 14890 1 0 11:49上午 ?? 0:19.64 redis-server 127.0.0.1:7004 [cluster] 501 14904 1 0 11:50上午 ?? 0:19.51 redis-server 127.0.0.1:7005 [cluster] 501 14907 1 0 11:50上午 ?? 0:19.29 redis-server 127.0.0.1:7006 [cluster] 501 15355 1 0 1:39下午 ?? 0:03.61 redis-server 127.0.0.1:7001 [cluster] 501 15426 1 0 1:54下午 ?? 0:00.61 redis-server 127.0.0.1:7007 [cluster] 501 15430 1 0 1:54下午 ?? 0:00.59 redis-server 127.0.0.1:7008 [cluster] 501 13669 841 0 10:11上午 ttys002 0:00.01 redis-cli -h 127.0.0.1 -p 7001 501 15295 7048 0 1:26下午 ttys004 0:00.02 redis-cli -c -h 127.0.0.1 -p 7001 501 15446 14516 0 1:57下午 ttys007 0:00.00 grep redis
尽管7007，7008启动了，可是集群中并无这两个服务
cluster nodes2b51a786e6f204c292dc349b45aa8b515637382c 127.0.0.1:7004@17004 slave 62c2ac721e402a27f017be49589bc06532548cdd 0 1609827727127 4 connected357221f17c5f5bf11d0551506fbff245ed0c047b 127.0.0.1:7005@17005 master - 0 1609827726116 7 connected 0-54602c779d5cc0b786af908d1c76dd3d4968e15796b3 127.0.0.1:7002@17002 master - 0 1609827724000 2 connected 5461-1092262c2ac721e402a27f017be49589bc06532548cdd 127.0.0.1:7003@17003 myself,master - 0 1609827724000 3 connected 10923-163834359ede424a92c7f249fb6524c6cc3f6dc46fb60 127.0.0.1:7001@17001 slave 357221f17c5f5bf11d0551506fbff245ed0c047b 0 1609827725104 7 connected2ecce47670970e13a034a37dd425154d298dc480 127.0.0.1:7006@17006 slave 2c779d5cc0b786af908d1c76dd3d4968e15796b3 0 1609827724094 6 connected
2）7007加入到集群中，并把他变为master
增长主节点7007，其中7002是集群里面随便选择的一个master节点。
redis-cli --cluster add-node 127.0.0.1:7007 127.0.0.1:7002 Adding node 127.0.0.1:7007 to cluster 127.0.0.1:7002 Performing Cluster Check (using node 127.0.0.1:7002)M: 2c779d5cc0b786af908d1c76dd3d4968e15796b3 127.0.0.1:7002 slots:[5461-10922] (5462 slots) master 1 additional replica(s)S: 2b51a786e6f204c292dc349b45aa8b515637382c 127.0.0.1:7004 slots: (0 slots) slave replicates 62c2ac721e402a27f017be49589bc06532548cddM: 62c2ac721e402a27f017be49589bc06532548cdd 127.0.0.1:7003 slots:[10923-16383] (5461 slots) master 1 additional replica(s)S: 4359ede424a92c7f249fb6524c6cc3f6dc46fb60 127.0.0.1:7001 slots: (0 slots) slave replicates 357221f17c5f5bf11d0551506fbff245ed0c047bM: 357221f17c5f5bf11d0551506fbff245ed0c047b 127.0.0.1:7005 slots:[0-5460] (5461 slots) master 1 additional replica(s)S: 2ecce47670970e13a034a37dd425154d298dc480 127.0.0.1:7006 slots: (0 slots) slave replicates 2c779d5cc0b786af908d1c76dd3d4968e15796b3 All nodes agree about slots configuration. Check for open slots... Check slots coverage... All 16384 slots covered. Send CLUSTER MEET to node 127.0.0.1:7007 to make it join the cluster.[OK] New node added correctly.
检查7007是否成功加入，可是发现7007没有index
$ redis-cli -c -h 127.0.0.1 -p 7001 cluster nodes357221f17c5f5bf11d0551506fbff245ed0c047b 127.0.0.1:7005@17005 master - 0 1609827919000 7 connected 0-546062c2ac721e402a27f017be49589bc06532548cdd 127.0.0.1:7003@17003 master - 0 1609827920739 3 connected 10923-163832ecce47670970e13a034a37dd425154d298dc480 127.0.0.1:7006@17006 slave 2c779d5cc0b786af908d1c76dd3d4968e15796b3 0 1609827917706 6 connected2c779d5cc0b786af908d1c76dd3d4968e15796b3 127.0.0.1:7002@17002 master - 0 1609827919728 2 connected 5461-109222b51a786e6f204c292dc349b45aa8b515637382c 127.0.0.1:7004@17004 slave 62c2ac721e402a27f017be49589bc06532548cdd 0 1609827918000 4 connected8dd6f8799e364e86e3df2acbbc42885482e5f526 127.0.0.1:7007@17007 master - 0 1609827917000 0 connected4359ede424a92c7f249fb6524c6cc3f6dc46fb60 127.0.0.1:7001@17001 myself,slave 357221f17c5f5bf11d0551506fbff245ed0c047b 0 1609827918000 1 connected
分配hash槽位给7007：
命令：$redis-cli --cluster reshard 127.0.0.1:7002 // 7002是随机选的一个master
[OK] All 16384 slots covered.How many slots do you want to move (from 1 to 16384)? 2000 // 这里设置7007所须要的 槽位数量What is the receiving node ID? 8dd6f8799e364e86e3df2acbbc42885482e5f526 // 7007对应的idPlease enter all the source node IDs. Type 'all' to use all the nodes as source nodes for the hash slots. Type 'done' once you entered all the source nodes IDs.Source node #1: all // 类型选择的是每个master平均分配的方式。
检查分结果：
$ redis-cli -c -h 127.0.0.1 -p 7001 cluster nodes357221f17c5f5bf11d0551506fbff245ed0c047b 127.0.0.1:7005@17005 master - 0 1609828313000 7 connected 666-546062c2ac721e402a27f017be49589bc06532548cdd 127.0.0.1:7003@17003 master - 0 1609828315610 3 connected 11589-163832ecce47670970e13a034a37dd425154d298dc480 127.0.0.1:7006@17006 slave 2c779d5cc0b786af908d1c76dd3d4968e15796b3 0 1609828314000 6 connected2c779d5cc0b786af908d1c76dd3d4968e15796b3 127.0.0.1:7002@17002 master - 0 1609828314596 2 connected 6128-109222b51a786e6f204c292dc349b45aa8b515637382c 127.0.0.1:7004@17004 slave 62c2ac721e402a27f017be49589bc06532548cdd 0 1609828313000 4 connected8dd6f8799e364e86e3df2acbbc42885482e5f526 127.0.0.1:7007@17007 master - 0 1609828314000 8 connected 0-665 5461-6127 10923-115884359ede424a92c7f249fb6524c6cc3f6dc46fb60 127.0.0.1:7001@17001 myself,slave 357221f17c5f5bf11d0551506fbff245ed0c047b 0 1609828312000 1 connected
分析：发现每个master都分配了一部分槽位给7007，以下：0-665 5461-6127 10923-11588
3) 7008加入到集群中，并把他变为salve
添加7008到集群： redis-cli --cluster add-node 127.0.0.1:7008 127.0.0.1:7002
[OK] All nodes agree about slots configuration.> Check for open slots...> Check slots coverage...[OK] All 16384 slots covered.> Send CLUSTER MEET to node 127.0.0.1:7008 to make it join the cluster.[OK] New node added correctly.$ redis-cli -c -h 127.0.0.1 -p 7001 cluster nodes558579e037a19ecc2fc541c121df379bba9ab853 127.0.0.1:7008@17008 master - 0 1609828830000 0 connected357221f17c5f5bf11d0551506fbff245ed0c047b 127.0.0.1:7005@17005 master - 0 1609828831852 7 connected 666-546062c2ac721e402a27f017be49589bc06532548cdd 127.0.0.1:7003@17003 master - 0 1609828828000 3 connected 11589-163832ecce47670970e13a034a37dd425154d298dc480 127.0.0.1:7006@17006 slave 2c779d5cc0b786af908d1c76dd3d4968e15796b3 0 1609828830000 6 connected2c779d5cc0b786af908d1c76dd3d4968e15796b3 127.0.0.1:7002@17002 master - 0 1609828829000 2 connected 6128-109222b51a786e6f204c292dc349b45aa8b515637382c 127.0.0.1:7004@17004 slave 62c2ac721e402a27f017be49589bc06532548cdd 0 1609828830000 4 connected8dd6f8799e364e86e3df2acbbc42885482e5f526 127.0.0.1:7007@17007 master - 0 1609828830843 8 connected 0-665 5461-6127 10923-115884359ede424a92c7f249fb6524c6cc3f6dc46fb60 127.0.0.1:7001@17001 myself,slave 357221f17c5f5bf11d0551506fbff245ed0c047b 0 1609828828000 1 connected
指定7008的master为7007，命令：
cluster replicate 8dd6f8799e364e86e3df2acbbc42885482e5f526
$ redis-cli -c -h 127.0.0.1 -p 7008 cluster replicate 8dd6f8799e364e86e3df2acbbc42885482e5f526OK cluster nodes558579e037a19ecc2fc541c121df379bba9ab853 127.0.0.1:7008@17008 myself,slave 8dd6f8799e364e86e3df2acbbc42885482e5f526 0 1609829022000 0 connected4359ede424a92c7f249fb6524c6cc3f6dc46fb60 127.0.0.1:7001@17001 slave 357221f17c5f5bf11d0551506fbff245ed0c047b 0 1609829024000 7 connected8dd6f8799e364e86e3df2acbbc42885482e5f526 127.0.0.1:7007@17007 master - 0 1609829023000 8 connected 0-665 5461-6127 10923-11588357221f17c5f5bf11d0551506fbff245ed0c047b 127.0.0.1:7005@17005 master - 0 1609829020000 7 connected 666-546062c2ac721e402a27f017be49589bc06532548cdd 127.0.0.1:7003@17003 master - 0 1609829022956 3 connected 11589-163832b51a786e6f204c292dc349b45aa8b515637382c 127.0.0.1:7004@17004 slave 62c2ac721e402a27f017be49589bc06532548cdd 0 1609829023000 3 connected2c779d5cc0b786af908d1c76dd3d4968e15796b3 127.0.0.1:7002@17002 master - 0 1609829024977 2 connected 6128-109222ecce47670970e13a034a37dd425154d298dc480 127.0.0.1:7006@17006 slave 2c779d5cc0b786af908d1c76dd3d4968e15796b3 0 1609829023966 2 connected
5. 节点下线
$ redis-cli --cluster del-node 127.0.0.1:7008 558579e037a19ecc2fc541c121df379bba9ab853> Removing node 558579e037a19ecc2fc541c121df379bba9ab853 from cluster 127.0.0.1:7008> Sending CLUSTER FORGET messages to the cluster...> SHUTDOWN the node.$ redis-cli -c -h 127.0.0.1 -p 7001 cluster nodes357221f17c5f5bf11d0551506fbff245ed0c047b 127.0.0.1:7005@17005 master - 0 1609829451017 7 connected 666-546062c2ac721e402a27f017be49589bc06532548cdd 127.0.0.1:7003@17003 master - 0 1609829449000 3 connected 11589-163832ecce47670970e13a034a37dd425154d298dc480 127.0.0.1:7006@17006 slave 2c779d5cc0b786af908d1c76dd3d4968e15796b3 0 1609829449000 6 connected2c779d5cc0b786af908d1c76dd3d4968e15796b3 127.0.0.1:7002@17002 master - 0 1609829446000 2 connected 6128-109222b51a786e6f204c292dc349b45aa8b515637382c 127.0.0.1:7004@17004 slave 62c2ac721e402a27f017be49589bc06532548cdd 0 1609829450009 4 connected8dd6f8799e364e86e3df2acbbc42885482e5f526 127.0.0.1:7007@17007 master - 0 1609829448000 8 connected 0-665 5461-6127 10923-115884359ede424a92c7f249fb6524c6cc3f6dc46fb60 127.0.0.1:7001@17001 myself,slave 357221f17c5f5bf11d0551506fbff245ed0c047b 0 1609829447000 1 connected
:7002 //将7007的槽位回收给7005 Performing Cluster Check (using node 127.0.0.1:7007)M: 8dd6f8799e364e86e3df2acbbc42885482e5f526 127.0.0.1:7007 slots:[0-665],[5461-6127],[10923-11588] (1999 slots) masterS: 2b51a786e6f204c292dc349b45aa8b515637382c 127.0.0.1:7004 slots: (0 slots) slave replicates 62c2ac721e402a27f017be49589bc06532548cddM: 62c2ac721e402a27f017be49589bc06532548cdd 127.0.0.1:7003 slots:[11589-16383] (4795 slots) master 1 additional replica(s)S: 2ecce47670970e13a034a37dd425154d298dc480 127.0.0.1:7006 slots: (0 slots) slave replicates 2c779d5cc0b786af908d1c76dd3d4968e15796b3S: 4359ede424a92c7f249fb6524c6cc3f6dc46fb60 127.0.0.1:7001 slots: (0 slots) slave replicates 357221f17c5f5bf11d0551506fbff245ed0c047bM: 2c779d5cc0b786af908d1c76dd3d4968e15796b3 127.0.0.1:7002 slots:[6128-10922] (4795 slots) master 1 additional replica(s)M: 357221f17c5f5bf11d0551506fbff245ed0c047b 127.0.0.1:7005 slots:[666-5460] (4795 slots) master 1 additional replica(s) All nodes agree about slots configuration. Check for open slots... Check slots coverage... All 16384 slots covered.How many slots do you want to move (from 1 to 16384)? 2000What is the receiving node ID? 357221f17c5f5bf11d0551506fbff245ed0c047bPlease enter all the source node IDs. Type 'all' to use all the nodes as source nodes for the hash slots. Type 'done' once you entered all the source nodes IDs.: 8dd6f8799e364e86e3df2acbbc42885482e5f526Source node #2: done
$ redis-cli -c -h 127.0.0.1 -p 7001 cluster nodes357221f17c5f5bf11d0551506fbff245ed0c047b 127.0.0.1:7005@17005 master - 0 1609830719272 9 connected 0-8578 10923-1236362c2ac721e402a27f017be49589bc06532548cdd 127.0.0.1:7003@17003 master - 0 1609830720283 3 connected 12364-163832ecce47670970e13a034a37dd425154d298dc480 127.0.0.1:7006@17006 slave 2c779d5cc0b786af908d1c76dd3d4968e15796b3 0 1609830721294 6 connected2c779d5cc0b786af908d1c76dd3d4968e15796b3 127.0.0.1:7002@17002 master - 0 1609830717248 2 connected 8579-109222b51a786e6f204c292dc349b45aa8b515637382c 127.0.0.1:7004@17004 slave 62c2ac721e402a27f017be49589bc06532548cdd 0 1609830719000 4 connected8dd6f8799e364e86e3df2acbbc42885482e5f526 127.0.0.1:7007@17007 master - 0 1609830718000 8 connected4359ede424a92c7f249fb6524c6cc3f6dc46fb60 127.0.0.1:7001@17001 myself,slave 357221f17c5f5bf11d0551506fbff245ed0c047b 0 1609830718000 1 connected
$ redis-cli -p 7007 shutdown$ redis-cli -c -h 127.0.0.1 -p 7001 cluster nodes357221f17c5f5bf11d0551506fbff245ed0c047b 127.0.0.1:7005@17005 master - 0 1609830849507 9 connected 0-8578 10923-1236362c2ac721e402a27f017be49589bc06532548cdd 127.0.0.1:7003@17003 master - 0 1609830850515 3 connected 12364-163832ecce47670970e13a034a37dd425154d298dc480 127.0.0.1:7006@17006 slave 2c779d5cc0b786af908d1c76dd3d4968e15796b3 0 1609830850000 6 connected2c779d5cc0b786af908d1c76dd3d4968e15796b3 127.0.0.1:7002@17002 master - 0 1609830846472 2 connected 8579-109222b51a786e6f204c292dc349b45aa8b515637382c 127.0.0.1:7004@17004 slave 62c2ac721e402a27f017be49589bc06532548cdd 0 1609830848000 4 connected8dd6f8799e364e86e3df2acbbc42885482e5f526 127.0.0.1:7007@17007 master - 1609830839496 1609830838387 8 disconnected4359ede424a92c7f249fb6524c6cc3f6dc46fb60 127.0.0.1:7001@17001 myself,slave 357221f17c5f5bf11d0551506fbff245ed0c047b 0 1609830848000 1 connected
参考文档：
redis的几种模式：https://www.cnblogs.com/jing99/p/12651186.htmlclient的几种链接方式：https://blog.csdn.net/comprel/article/details/96716708哨兵模式：https://www.cnblogs.com/yangming1996/p/12677771.htmlredis官方文档：https://godoc.org/gopkg.in/redis.v5redis安装：https://juejin.im/post/6844904002270789645redis-cli命令：https://segmentfault.com/a/1190000022713251redis命令：http://redisdoc.com/string/mset.html
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