I have 2 services that are very similar. I have seen that it is a common practice to give a variable name to one service configuration and use it and extend it in your specific services’ configurations.

services:
  backend: &backend
    build:
      context: .
      dockerfile: ./docker/app/DockerFile
    volumes:
      - .:/var/www/apps

  app:
    <<: *backend
    ports:
      - 127.0.0.1:3000:3000
    depends_on:
      - db
      - dashboard_db
      - redis
      - sidekiq

  sidekiq:
    <<: *backend
    depends_on:
      - redis
    command: bundle exec sidekiq

The problem is that when I execute docker compose up the service backend is also up and running, but in my case, I only want the specific services (app and sidekiq) to be up.

Am I using the &variable syntax properly?