Docker Compose - Intermediate

Real-world Docker Compose configuration for multi-service applications.

Full Application Example

services:
  nginx:
    image: nginx:alpine
    ports:
      - "80:80"
      - "443:443"
    volumes:
      - ./nginx/nginx.conf:/etc/nginx/nginx.conf:ro
      - ./nginx/certs:/etc/nginx/certs:ro
    depends_on:
      backend:
        condition: service_healthy
    networks:
      - frontend
    restart: unless-stopped

  backend:
    build:
      context: ./backend
      dockerfile: Dockerfile
      args:
        - NODE_ENV=production
    env_file:
      - .env
    environment:
      - DATABASE_URL=postgres://user:pass@db:5432/myapp
      - REDIS_URL=redis://redis:6379
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:3000/health"]
      interval: 30s
      timeout: 10s
      retries: 3
      start_period: 40s
    depends_on:
      db:
        condition: service_healthy
      redis:
        condition: service_started
    networks:
      - frontend
      - backend
    restart: unless-stopped

  db:
    image: postgres:16-alpine
    environment:
      POSTGRES_USER: user
      POSTGRES_PASSWORD: pass
      POSTGRES_DB: myapp
    volumes:
      - postgres_data:/var/lib/postgresql/data
      - ./init.sql:/docker-entrypoint-initdb.d/init.sql
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U user -d myapp"]
      interval: 10s
      timeout: 5s
      retries: 5
    networks:
      - backend
    restart: unless-stopped

  redis:
    image: redis:7-alpine
    command: redis-server --appendonly yes --maxmemory 256mb
    volumes:
      - redis_data:/data
    networks:
      - backend
    restart: unless-stopped

networks:
  frontend:
    driver: bridge
  backend:
    driver: bridge
    internal: true

volumes:
  postgres_data:
  redis_data:

Network Isolation

networks:
  frontend:
    driver: bridge
  backend:
    driver: bridge
    internal: true

• frontend: accessible by nginx and backend
• backend: accessible by db, redis and backend only, no external access

Healthcheck Configuration

healthcheck:
  test: ["CMD", "curl", "-f", "http://localhost:3000/health"]
  interval: 30s
  timeout: 10s
  retries: 3
  start_period: 40s

Environment Management

# .env file
DATABASE_URL=postgres://user:pass@db:5432/myapp
REDIS_URL=redis://redis:6379
JWT_SECRET=my-secret-key

services:
  backend:
    env_file:
      - .env
      - .env.local
    environment:
      - NODE_ENV=production

Useful Compose Commands

docker compose up -d --build backend
docker compose logs -f backend db
docker compose ps
docker compose exec db psql -U user -d myapp
docker compose down -v --remove-orphans
docker compose up -d db redis