Docker极简入门：使用Docker-Compose搭建redis集群

为了构建一个集群，我们首先要让 redis 启用集群模式
一个简单的配置文件如下redis.conf

# redis.conf fileport 6379cluster-enabled yescluster-config-file nodes.confcluster-node-timeout 5000appendonly yes

因为是在单机上演示，所以我们得修改 port 防止冲突
比如我们要创建3主5副的集群，那么这八个 redis 实例启动的时候就应该用不同的端口(7000,7001...7007)，这样能防止冲突。

.├── 7000│   └── redis.conf├── 7001│   └── redis.conf├── 7002│   └── redis.conf├── 7003│   └── redis.conf├── 7004│   └── redis.conf├── 7005│   └── redis.conf├── 7006│   └── redis.conf├── 7007│   └── redis.conf

./7000/redis.conf 中的 port 设置成7000,依此类推./7007/redis.conf中的 port 应该设置成7007

往事俱备，只需运行redis-server ./redis.conf命令即可，当然你需要到依次启动八个 redis server

for i in `seq 7000 7007`;do	exec redis-server ./${i}/redis.conf &doneredis-cli --cluster create\127.0.0.1:7000 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 127.0.0.1:7007\--cluster-replicas 1

这样整个集群就搭建好了，你可以选择运行在 port 7000-7007中的任意一个 servr 登录，然后去执行一些你喜欢的命令验证一下[狗头]

使用Docker-Compose构建集群

现在让我们来明确一下流程，首先我们需要启动八个 redis server 实例，然后运行 redis-cli --cluster create 命令创建集群，这意味着我们需要创建一个 docker network 使得集群成员能够互相通讯

创建一个 network 也很简单

networks:  redis-network:    name: redis-network    ## 使用网桥    driver: bridge    ipam:      driver: default      ## 指定网段，需要注意不能与已有的 docker network 相冲突      config:        - subnet: 172.18.0.0/24

还记得之前命令行是如何启动集群的吗？最后需要运行命令redis-cli --cluster create ，整个集群才算成功创建，那在 yml 文件中该怎么写呢？
我们可以借助 depends_on来告诉 docker 当前的 service 依赖其他的 service
具体的细节请看完整的yml文件

## redis.confport 6379cluster-enabled yescluster-config-file nodes-redis.confcluster-node-timeout 5000appendonly yesappendfilename "appendonly-redis.aof"

version: "3.7"networks:  redis-network:    name: redis-network    driver: bridge    ipam:      driver: default      config:        - subnet: 172.18.0.0/24services:  redis-cluster:    image: redis:6-alpine    command: 'redis-cli --cluster create     172.18.0.11:6379 172.18.0.12:6379 172.18.0.13:6379 172.18.0.14:6379     172.18.0.15:6379 172.18.0.16:6379 172.18.0.17:6379 172.18.0.18:6379    --cluster-yes --cluster-replicas 1'    networks:      - redis-network    depends_on:      - redis1      - redis2      - redis3      - redis4      - redis5      - redis6      - redis7      - redis8  redis1:    image: redis:6-alpine    container_name: redis1    command: redis-server /usr/local/etc/redis/redis.conf    networks:      redis-network:        ipv4_address: 172.18.0.11    expose:      - 6379    volumes:      - $PWD/docker-data/redis1:/data      - $PWD/docker-config/redis.conf:/usr/local/etc/redis/redis.conf  redis2:    image: redis:6-alpine    container_name: redis2    command: redis-server /usr/local/etc/redis/redis.conf    networks:      redis-network:        ipv4_address: 172.18.0.12    expose:      - 6379    volumes:      - $PWD/docker-data/redis2:/data      - $PWD/docker-config/redis.conf:/usr/local/etc/redis/redis.conf  redis3:    image: redis:6-alpine    container_name: redis3    command: redis-server /usr/local/etc/redis/redis.conf    networks:      redis-network:        ipv4_address: 172.18.0.13    expose:      - 6379    volumes:      - $PWD/docker-data/redis3:/data      - $PWD/docker-config/redis.conf:/usr/local/etc/redis/redis.conf  redis4:    image: redis:6-alpine    container_name: redis4    command: redis-server /usr/local/etc/redis/redis.conf    networks:      redis-network:        ipv4_address: 172.18.0.14    expose:      - 6379    volumes:      - $PWD/docker-data/redis4:/data      - $PWD/docker-config/redis.conf:/usr/local/etc/redis/redis.conf        redis5:    image: redis:6-alpine    container_name: redis5    command: redis-server /usr/local/etc/redis/redis.conf    networks:      redis-network:        ipv4_address: 172.18.0.15    expose:      - 6379    volumes:      - $PWD/docker-data/redis5:/data      - $PWD/docker-config/redis.conf:/usr/local/etc/redis/redis.conf        redis6:    image: redis:6-alpine    container_name: redis6    command: redis-server /usr/local/etc/redis/redis.conf    networks:      redis-network:        ipv4_address: 172.18.0.16    expose:      - 6379    volumes:      - $PWD/docker-data/redis6:/data      - $PWD/docker-config/redis.conf:/usr/local/etc/redis/redis.conf              redis7:    image: redis:6-alpine    container_name: redis7    command: redis-server /usr/local/etc/redis/redis.conf    networks:      redis-network:        ipv4_address: 172.18.0.17    expose:      - 6379    volumes:      - $PWD/docker-data/redis7:/data      - $PWD/docker-config/redis.conf:/usr/local/etc/redis/redis.conf        redis8:    image: redis:6-alpine    container_name: redis8    command: redis-server /usr/local/etc/redis/redis.conf    networks:      redis-network:        ipv4_address: 172.18.0.18    expose:      - 6379    volumes:      - $PWD/docker-data/redis8:/data      - $PWD/docker-config/redis.conf:/usr/local/etc/redis/redis.conf

最后不要忘记了最基本的命令

sudo docker-compose up # 在当前命令下运行，启动集群sudo docker-compose down # 关闭集群的同时会将 docker-network也一并删除

如何与集群通信

# 登录任意一个节点执行命令即可，集群会根据key的哈希值，将你的命令重定位sudo docker exec -it redis5 redis-cli -p 6379set foo bar

sudo docker exec -it redis1 redis-cli -p 6379get foo# output bar

参考

reids官网 course