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dockerdocker-composedocker-swarmalpine-linux

Redis cluster with docker swarm using docker compose


I'm just learning docker and all of its goodness like swarm and compose. My intention is to create a Redis cluster in docker swarm.

Here is my compose file -

version: '3'

services:
  redis:
    image: redis:alpine
    command: ["redis-server","--appendonly yes","--cluster-enabled yes","--cluster-node-timeout 60000","--cluster-require-full-coverage no"]
    deploy:
      replicas: 5
      restart_policy:
        condition: on-failure
    ports:
      - 6379:6379
      - 16379:16379

networks:
  host:
    external: true

If I add the network: - host then none of the containers start, if I remove it then the containers start but when I try to connect it throws an error like CLUSTERDOWN Hash slot not served.

Specs -

Windows 10

Docker Swarm Nodes -
2 Virtual Box VMs running Alpine Linux 3.7.0 with two networks

VirtualBox VM Network - 
eth0 - NAT
eth1 - VirtualBox Host-only network

Docker running inside the above VMs - 
17.12.1-ce

Solution

  • For anyone struggling with this unfortunately this can't be done via docker-compose.yml yet. Refer to this issue Start Redis cluster #79. The only way to do this is by getting the IP address and ports of all the nodes that are running Redis and then running this command in any of the swarm nodes.

    # Gives you all the command help
    docker run --rm -it thesobercoder/redis-trib 
    
    # This creates all master nodes
    docker run --rm -it thesobercoder/redis-trib create 172.17.8.101:7000 172.17.8.102:7000 172.17.8.103:7000 
    
    # This creates slaves nodes. Note that this requires at least six nodes running master
    docker run --rm -it thesobercoder/redis-trib create --replicas 1 172.17.8.101:7000 172.17.8.102:7000 172.17.8.103:7000 172.17.8.104:7000 172.17.8.105:7000 172.17.8.106:7000