Docker Compose is a tool for defining and running multi-container Docker applications using YAML files to configure application services.

What is Docker Compose?

Docker Compose allows defining a complete application with multiple containers in a single file, facilitating the development and deployment of complex applications.

docker-compose.yml File

Basic Configuration

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version: '3.8'
services:
  web:
    build: .
    ports:
      - "5000:5000"
    environment:
      - FLASK_ENV=development
    depends_on:
      - db
  
  db:
    image: postgres:13
    environment:
      - POSTGRES_DB=myapp
      - POSTGRES_USER=user
      - POSTGRES_PASSWORD=password
    volumes:
      - postgres_data:/var/lib/postgresql/data

volumes:
  postgres_data:

Complex Services

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version: '3.8'
services:
  nginx:
    image: nginx:alpine
    ports:
      - "80:80"
      - "443:443"
    volumes:
      - ./nginx.conf:/etc/nginx/nginx.conf
      - ./ssl:/etc/nginx/ssl
    depends_on:
      - web
      - api
  
  web:
    build: ./web
    environment:
      - NODE_ENV=production
    volumes:
      - ./web:/app
  
  api:
    build: ./api
    environment:
      - DATABASE_URL=postgresql://user:pass@db:5432/myapp
    depends_on:
      - db
  
  db:
    image: postgres:13
    environment:
      - POSTGRES_DB=myapp
      - POSTGRES_USER=user
      - POSTGRES_PASSWORD=password
    volumes:
      - postgres_data:/var/lib/postgresql/data
  
  redis:
    image: redis:alpine
    volumes:
      - redis_data:/data

volumes:
  postgres_data:
  redis_data:

Main Commands

Service Management

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# Start services
docker-compose up

# Start in background
docker-compose up -d

# Stop services
docker-compose down

# View logs
docker-compose logs

# Execute command in service
docker-compose exec web bash

Development

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# Rebuild services
docker-compose build

# Scale services
docker-compose up --scale web=3

# Environment variables
docker-compose --env-file .env up

References