Docker Compose

Real applications consist of multiple services — a web server, an API, a database, a cache, a message queue. Managing these with individual docker run commands is tedious and error-prone. Docker Compose lets you define and manage multi-container applications in a single YAML file.

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What Is Docker Compose?

Docker Compose is a tool for defining and running multi-container Docker applications. You describe your entire application stack in a docker-compose.yml (or compose.yaml) file, then use a single command to create and start everything.

# Start all services defined in docker-compose.yml
docker compose up -d

# Stop all services
docker compose down

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Basic Structure

# docker-compose.yml
services:
  web:
    image: nginx:alpine
    ports:
      - "8080:80"
    depends_on:
      - api

  api:
    build: ./api
    ports:
      - "3000:3000"
    environment:
      - DATABASE_URL=postgres://user:pass@db:5432/mydb
    depends_on:
      - db

  db:
    image: postgres:16
    environment:
      POSTGRES_USER: user
      POSTGRES_PASSWORD: pass
      POSTGRES_DB: mydb
    volumes:
      - db-data:/var/lib/postgresql/data

volumes:
  db-data:

Top-Level Keys