How to use Docker Compose for multi-service apps

Real applications have several parts: a web server, a database, maybe a cache. Docker Compose describes them all in one file and starts them together.

1. The compose.yaml file

services:
  web:
    image: nginx
    ports:
      - "80:80"
  db:
    image: mysql:8
    environment:
      MYSQL_ROOT_PASSWORD: password
    volumes:
      - db_data:/var/lib/mysql

volumes:
  db_data:

2. Start everything

docker compose up -d

3. Useful commands

docker compose ps        # service status
docker compose logs -f   # live logs
docker compose down      # stop and remove containers

Why Compose

• All configuration in one file, easy to version in git.
• Services reach each other by name (web can access "db").
• Volumes keep data even if you recreate containers, see Docker volumes.

For a full app with a proxy and HTTPS, see How to deploy an app with Docker Compose.