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 file
port 6379
cluster-enabled yes
cluster-config-file nodes.conf
cluster-node-timeout 5000
appendonly 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

万事俱备，只需运行redis-server ./redis.conf命令即可，当然你需要依次启动八个 redis server

for i in `seq 7000 7007`;
do
	exec redis-server ./${i}/redis.conf &
done

redis-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.conf
port 6379
cluster-enabled yes
cluster-config-file nodes-redis.conf
cluster-node-timeout 5000
appendonly yes
appendfilename "appendonly-redis.aof"

version: "3.7"

networks:
  redis-network:
    name: redis-network
    driver: bridge
    ipam:
      driver: default
      config:
        - subnet: 172.18.0.0/24

services:
  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 6379
set foo bar

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

参考

reids官网 course