redis集群

news2025/1/17 13:54:54

Redis集群在保证主从加哨兵的基本功能之外，还能够提升Redis存储数据的能力。

一致性hash环

k1-->crc(16)===? 0-16384

redis集群的ping-pang机制：一个主机向另一个主机ping，另一个pang回来，说明连接成功，通过这样的方式判断redis是否宕机，如果ping了没有pang回来，不一定是它坏了，也有可能是你坏了。

redis主机宕机后，从机可以上位

集群默认分配16384个hash槽，如果有三个主节点，则每个阶段对应0-5000，5000-10000，1000-15000

有四个主节点，对应你 0-4000 4000-8000 8000-12000 12000-16000

存取数据是对key进行crc16算法，对16384取余，余数在那个范围里就在那个redis里面存。

Redis集群选举原理

集群配置

新建 /usr/local/docker/redis/cluster 目录目录下新建 conf 目录 conf目录下新建redis1-6.conf文件

下图是文件的内容

# redis.conf
# 指定redis的端口号
port 7001
# 开启Redis集群
cluster-enabled yes
# 集群信息的文件
cluster-config-file nodes-7001.conf
# 集群的对外ip地址
cluster-announce-ip 192.168.59.12
# 集群的对外port
cluster-announce-port 7001
# 集群的总线端口
cluster-announce-bus-port 17001

redis1-6.conf的ip地址都一样，是宿主主机地址，但是总线端口，对外port，集群信息文件，port改为对应的123456.

docker-compose.yml文件如下:

# docker-compose.yml
version: "3.1"
services:
  redis1:
    image: daocloud.io/library/redis:5.0.7
    restart: always
    container_name: redis1
    environment:
      - TZ=Asia/Shanghai
    ports:
      - 7001:7001
      - 17001:17001
    volumes:
      - ./conf/redis1.conf:/usr/local/redis/redis.conf
    command: ["redis-server","/usr/local/redis/redis.conf"]
  redis2:
    image: daocloud.io/library/redis:5.0.7
    restart: always
    container_name: redis2
    environment:
      - TZ=Asia/Shanghai
    ports:
      - 7002:7002
      - 17002:17002
    volumes:
      - ./conf/redis2.conf:/usr/local/redis/redis.conf
    command: ["redis-server","/usr/local/redis/redis.conf"]  
  redis3:
    image: daocloud.io/library/redis:5.0.7
    restart: always
    container_name: redis3
    environment:
      - TZ=Asia/Shanghai
    ports:
      - 7003:7003
      - 17003:17003
    volumes:
      - ./conf/redis3.conf:/usr/local/redis/redis.conf
    command: ["redis-server","/usr/local/redis/redis.conf"]  
  redis4:
    image: daocloud.io/library/redis:5.0.7
    restart: always
    container_name: redis4
    environment:
      - TZ=Asia/Shanghai
    ports:
      - 7004:7004
      - 17004:17004
    volumes:
      - ./conf/redis4.conf:/usr/local/redis/redis.conf
    command: ["redis-server","/usr/local/redis/redis.conf"]  
  redis5:
    image: daocloud.io/library/redis:5.0.7
    restart: always
    container_name: redis5
    environment:
      - TZ=Asia/Shanghai
    ports:
      - 7005:7005
      - 17005:17005
    volumes:
      - ./conf/redis5.conf:/usr/local/redis/redis.conf
    command: ["redis-server","/usr/local/redis/redis.conf"]  
  redis6:
    image: daocloud.io/library/redis:5.0.7
    restart: always
    container_name: redis6
    environment:
      - TZ=Asia/Shanghai
    ports:
      - 7006:7006
      - 17006:17006
    volumes:
      - ./conf/redis6.conf:/usr/local/redis/redis.conf
    command: ["redis-server","/usr/local/redis/redis.conf"]

docker-compose up -d 运行

启动了6个Redis的节点。

随便跳转到一个容器内部，使用redis-cli管理集群

在容器内部输入一下命令，6台reids对应的ip加端口

redis-cli --cluster create 192.168.59.12:7001  192.168.59.12:7002  192.168.59.12:7003  192.168.59.12:7004  192.168.59.12:7005  192.168.59.12:7006 --cluster-replicas 1

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