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介绍

使多个 Redis 实例共同工作，实现数据的水平扩展。通过将数据分片到多个节点上，Redis 集群能够在不牺牲性能的前提下扩展存储容量和处理能力，从而支持更高并发的请求。Redis 集群不仅支持数据分片，还提供了自动故障转移和高可用性功能。

这些主节点会相互的ping来达到自动故障转移

特点

• 集群中有多个master，每个master保存不同数据
• 每个master都可以有多个slave节点
• master之间通过ping监测彼此健康状态 就不用哨兵了

部署文件

version: "3.2"services:r1:image: rediscontainer_name: r1network_mode: "host"entrypoint: ["redis-server", "--port", "7001", "--cluster-enabled", "yes", "--cluster-config-file", "node.conf", "--requirepass", "mypassword","--masterauth", "yourpassword"]r2:image: rediscontainer_name: r2network_mode: "host"entrypoint: ["redis-server", "--port", "7002", "--cluster-enabled", "yes", "--cluster-config-file", "node.conf", "--requirepass", "mypassword","--masterauth", "yourpassword"]r3:image: rediscontainer_name: r3network_mode: "host"entrypoint: ["redis-server", "--port", "7003", "--cluster-enabled", "yes", "--cluster-config-file", "node.conf", "--requirepass", "mypassword","--masterauth", "yourpassword"]r4:image: rediscontainer_name: r4network_mode: "host"entrypoint: ["redis-server", "--port", "7004", "--cluster-enabled", "yes", "--cluster-config-file", "node.conf", "--requirepass", "mypassword","--masterauth", "yourpassword"]r5:image: rediscontainer_name: r5network_mode: "host"entrypoint: ["redis-server", "--port", "7005", "--cluster-enabled", "yes", "--cluster-config-file", "node.conf", "--requirepass", "mypassword","--masterauth", "yourpassword"]r6:image: rediscontainer_name: r6network_mode: "host"entrypoint: ["redis-server", "--port", "7006", "--cluster-enabled", "yes", "--cluster-config-file", "node.conf", "--requirepass", "mypassword","--masterauth", "yourpassword"]

部署

 docker-compose up -d

集群连接

 进入任意节点容器
docker exec -it r1 bash

连接
将各个节点进行连接

• redis-cli --cluster：代表集群操作命令
• create：代表是创建集群
• –cluster-replicas 1 ：指定集群中每个master的副本个数为1
  • 此时节点总数 ÷ (replicas + 1) 得到的就是master的数量n。因此节点列表中的前n个节点就是master，其它节点都是slave节点，随机分配到不同master

redis-cli --cluster create --cluster-replicas 1 \
13.116.247.215:7001 13.116.247.215:7002 13.116.247.215:7003 \
13.116.247.215:7004 13.116.247.215:7005 13.116.247.215:7006 \
-a mypassword

查看集群状态

redis-cli -p 7001 -a mypassword cluster nodes

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散片插槽

创建成功后 每一个主节点都会分配哈希散片插槽，Redis数据不是与节点绑定，而是与插槽slot绑定。当我们读写数据时，Redis基于CRC16算法对key做hash运算，得到的结果与16384取余，就计算出了这个key的slot值。然后到slot所在的Redis节点执行读写操作。