Celery workers unable to connect to redis on docker instances

Question

I have a dockerized setup running a Django app within which I use Celery tasks. Celery uses Redis as the broker.

Versioning:

• Docker ve

Answer 1

You may need to add the link and depends_on sections to your docker compose file, and then reference the containers by their hostname.

Updated docker-compose.yml:

version: '2.1'
services:
    db:
        image: postgres
    memcached:
        image: memcached
    redis:
        image: redis
        ports:
          - '6379:6379'
    backend-base:
        build:
            context: .
            dockerfile: backend/Dockerfile-base
        image: "/backend:base"
    backend:
        build:
            context: .
            dockerfile: backend/Dockerfile
        image: "/backend:${ENV:-local}"
        command: ./wait-for-it.sh db:5432 -- gunicorn backend.wsgi:application -b 0.0.0.0:8000 -k gevent -w 3
        ports:
            - 8000
        links:
            - db
            - redis
            - memcached
        depends_on:
            - db
            - redis
            - memcached
    celery:
        image: "/backend:${ENV:-local}"
        command: ./wait-for-it.sh db:5432 -- celery worker -E -B --loglevel=INFO --concurrency=1
        environment:
            C_FORCE_ROOT: "yes"
        links:
            - db
            - redis
            - memcached
        depends_on:
            - db
            - redis
            - memcached
    frontend-base:
        build:
            context: .
            dockerfile: frontend/Dockerfile-base
            args:
                NPM_REGISTRY: http://.view.build
                PACKAGE_INSTALLER: yarn
        image: "/frontend:base"
        links:
            - db
            - redis
            - memcached
        depends_on:
            - db
            - redis
            - memcached
    frontend:
        build:
            context: .
            dockerfile: frontend/Dockerfile
        image: "/frontend:${ENV:-local}"
        command: 'bash -c ''gulp'''
        working_dir: /app/user
        environment:
            PORT: 3000
        links:
            - db
            - redis
            - memcached
        depends_on:
            - db
            - redis
            - memcached

Then configure the urls to redis, postgres, memcached, etc. with:

• redis://redis:6379/0
• postgres://user:pass@db:5432/database