Redis Cluster Docker Compose

Question

I'm struggling to create a Docker Compose to create a Redis Cluster. I saw that there is a Redis Cluster image from Bitnami, I tried but it my Spring Boot App cannot connect to it due to the below error:

I tried another approach is to create 2 Redis instances master-slave and I can connect to it. Now I'm trying to create 6 Redis Instances and later create a Redis Cluster with 3 master and 3 slaves with the following command:

redis-cli --cluster create 127.0.0.1:6380 127.0.0.1:6381 \
127.0.0.1:6382 127.0.0.1:6383 127.0.0.1:6384 127.0.0.1:6385 --cluster-replicas 1

But when I executed the command it said that

Could not connect to Redis at 127.0.0.1:6380: Connection refused

Below is my current Docker-compose.yaml:

version: '3.8'
services:
  redis-node-0:
    image: redis:latest
    container_name: redis-0
    ports:
      - "6380:6379"
    command: ["redis-server","--appendonly yes","--cluster-enabled yes","--cluster-node-timeout 5000"]
    volumes:
      - redis-cluster_data-0:/redis/data

  redis-node-1:
    image: redis:latest
    container_name: redis-1
    ports:
      - "6381:6379"
    command: ["redis-server","--appendonly yes","--cluster-enabled yes","--cluster-node-timeout 5000"]  
    volumes:
      - redis-cluster_data-1:/redis/data

  redis-node-2:
    image: redis:latest
    container_name: redis-2
    ports:
      - "6382:6379"
    command: ["redis-server","--appendonly yes","--cluster-enabled yes","--cluster-node-timeout 5000"]
    volumes:
      - redis-cluster_data-2:/redis/data

  redis-node-3:
    image: redis:latest
    container_name: redis-3
    ports:
      - "6383:6379"
    command: ["redis-server","--appendonly yes","--cluster-enabled yes","--cluster-node-timeout 5000"]
    volumes:
      - redis-cluster_data-3:/redis/data

  redis-node-4:
    image: redis:latest
    container_name: redis-4
    ports:
      - "6384:6379"
    command: ["redis-server","--appendonly yes","--cluster-enabled yes","--cluster-node-timeout 5000"]
    volumes:
      - redis-cluster_data-4:/redis/data

  redis-node-5:
    image: redis:latest
    container_name: redis-5
    ports:
      - "6385:6379"
    command: ["redis-server","--appendonly yes","--cluster-enabled yes","--cluster-node-timeout 5000"]
    volumes:
      - redis-cluster_data-5:/redis/data


networks: 
  default:
    name: overlay
volumes:
  redis-cluster_data-0:
    driver: local
  redis-cluster_data-1:
    driver: local
  redis-cluster_data-2:
    driver: local
  redis-cluster_data-3:
    driver: local
  redis-cluster_data-4:
    driver: local
  redis-cluster_data-5:
    driver: local

I'm totally new to Both Docker and Redis, I'm learning so any help would be really appreciated. Thanks in advance.

Answer 1

The way to do this is not obvious, because Redis Cluster doesn't easily work with Docker bridge networking. The simplest way to setup a single-node cluster is to cheat and bind it to 127.0.0.1:

version: '3.8'

services:
  redis-single-node-cluster:
    image: docker.io/bitnami/redis-cluster:7.0
    environment:
      - 'ALLOW_EMPTY_PASSWORD=yes'
      - 'REDIS_CLUSTER_REPLICAS=0'
      - 'REDIS_NODES=127.0.0.1 127.0.0.1 127.0.0.1'
      - 'REDIS_CLUSTER_CREATOR=yes'
      - 'REDIS_CLUSTER_DYNAMIC_IPS=no'
      - 'REDIS_CLUSTER_ANNOUNCE_IP=127.0.0.1'
    ports:
      - '6379:6379'

You can then connect to it with this Spring Boot config:

spring:
  redis:
    cluster:
      nodes: [localhost:6379]
    ssl: false

If you want to setup multiple nodes, you'll have to create a custom network and assign static IPs. You'll probably also have to set network_mode: host.

Answer 2

I faced the same problem, many thanks to Michael Böckling for the answer, but for me it was not the final solution, besides that I made some changes, maybe it will be useful for someone

version: '3.8'

services:
  app:
    ...
    environment:
      - REDIS_URL=redis://:@redis-cluster:6379/0
    depends_on:
      redis-cluster:
        condition: service_started


  redis-cluster:
    image: docker.io/bitnami/redis-cluster:7.0
    environment:
      - 'ALLOW_EMPTY_PASSWORD=yes'
      - 'REDIS_CLUSTER_REPLICAS=0'
      - 'REDIS_NODES=redis-cluster redis-cluster redis-cluster'
      - 'REDIS_CLUSTER_CREATOR=yes'
      - 'REDIS_CLUSTER_DYNAMIC_IPS=no'
      - 'REDIS_CLUSTER_ANNOUNCE_IP=redis-cluster'
    ports:
      - '6379:6379'