Tutorial

Docker Compose Advanced: Multi-Container Applications

Master Docker Compose for complex multi-container applications with advanced configuration, networking, and orchestration.

TechDevDex Team

12/14/2024

25 min

#Docker#Docker Compose#Multi-container#Orchestration

Docker Compose Advanced: Multi-Container Applications

Docker Compose is a powerful tool for defining and running multi-container Docker applications. This advanced guide covers complex scenarios, networking, and production-ready configurations.

Advanced Docker Compose Features

Environment Variables

Use environment variables for configuration:

          
yaml

version: '3.8'

services:
  web:
    build: .
    environment:
      - NODE_ENV=${NODE_ENV:-development}
      - DATABASE_URL=${DATABASE_URL}
      - REDIS_URL=${REDIS_URL}
    env_file:
      - .env
      - .env.local

Volume Management

Advanced volume configurations:

          
yaml

version: '3.8'

services:
  web:
    image: nginx
    volumes:
      - ./nginx.conf:/etc/nginx/nginx.conf:ro
      - static_files:/var/www/static
      - logs:/var/log/nginx

  database:
    image: postgres:13
    volumes:
      - postgres_data:/var/lib/postgresql/data
      - ./init.sql:/docker-entrypoint-initdb.d/init.sql

volumes:
  postgres_data:
    driver: local
  static_files:
    driver: local
  logs:
    driver: local

Networking

Custom network configurations:

          
yaml

version: '3.8'

services:
  web:
    build: .
    networks:
      - frontend
      - backend

  api:
    build: ./api
    networks:
      - backend
      - database

  db:
    image: postgres:13
    networks:
      - database

networks:
  frontend:
    driver: bridge
  backend:
    driver: bridge
  database:
    driver: bridge

Production-Ready Configurations

Health Checks

Implement health checks for reliability:

          
yaml

version: '3.8'

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

  database:
    image: postgres:13
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U postgres"]
      interval: 30s
      timeout: 10s
      retries: 3

Resource Limits

Set resource constraints:

          
yaml

version: '3.8'

services:
  web:
    build: .
    deploy:
      resources:
        limits:
          cpus: '0.5'
          memory: 512M
        reservations:
          cpus: '0.25'
          memory: 256M

  database:
    image: postgres:13
    deploy:
      resources:
        limits:
          cpus: '1.0'
          memory: 1G
        reservations:
          cpus: '0.5'
          memory: 512M

Restart Policies

Configure restart behavior:

          
yaml

version: '3.8'

services:
  web:
    build: .
    restart: unless-stopped

  database:
    image: postgres:13
    restart: on-failure:3

  cache:
    image: redis:6
    restart: always

Complex Application Examples

Full-Stack Application

          
yaml

version: '3.8'

services:
  frontend:
    build: ./frontend
    ports:
      - "3000:3000"
    environment:
      - REACT_APP_API_URL=http://backend:5000
    depends_on:
      - backend

  backend:
    build: ./backend
    ports:
      - "5000:5000"
    environment:
      - DATABASE_URL=postgresql://user:password@database:5432/myapp
      - REDIS_URL=redis://cache:6379
    depends_on:
      - database
      - cache

  database:
    image: postgres:13
    environment:
      POSTGRES_DB: myapp
      POSTGRES_USER: user
      POSTGRES_PASSWORD: password
    volumes:
      - postgres_data:/var/lib/postgresql/data

  cache:
    image: redis:6
    volumes:
      - redis_data:/data

  nginx:
    image: nginx:alpine
    ports:
      - "80:80"
    volumes:
      - ./nginx.conf:/etc/nginx/nginx.conf
    depends_on:
      - frontend
      - backend

volumes:
  postgres_data:
  redis_data:

Microservices Architecture

          
yaml

version: '3.8'

services:
  api-gateway:
    build: ./api-gateway
    ports:
      - "8080:8080"
    environment:
      - USER_SERVICE_URL=http://user-service:3001
      - ORDER_SERVICE_URL=http://order-service:3002
      - PRODUCT_SERVICE_URL=http://product-service:3003

  user-service:
    build: ./user-service
    environment:
      - DATABASE_URL=postgresql://user:password@user-db:5432/users
    depends_on:
      - user-db

  order-service:
    build: ./order-service
    environment:
      - DATABASE_URL=postgresql://user:password@order-db:5432/orders
    depends_on:
      - order-db

  product-service:
    build: ./product-service
    environment:
      - DATABASE_URL=postgresql://user:password@product-db:5432/products
    depends_on:
      - product-db

  user-db:
    image: postgres:13
    environment:
      POSTGRES_DB: users
      POSTGRES_USER: user
      POSTGRES_PASSWORD: password
    volumes:
      - user_data:/var/lib/postgresql/data

  order-db:
    image: postgres:13
    environment:
      POSTGRES_DB: orders
      POSTGRES_USER: user
      POSTGRES_PASSWORD: password
    volumes:
      - order_data:/var/lib/postgresql/data

  product-db:
    image: postgres:13
    environment:
      POSTGRES_DB: products
      POSTGRES_USER: user
      POSTGRES_PASSWORD: password
    volumes:
      - product_data:/var/lib/postgresql/data

volumes:
  user_data:
  order_data:
  product_data:

Development vs Production

Development Configuration

          
yaml

# docker-compose.dev.yml
version: '3.8'

services:
  web:
    build: .
    volumes:
      - .:/app
      - /app/node_modules
    environment:
      - NODE_ENV=development
    ports:
      - "3000:3000"

  database:
    image: postgres:13
    environment:
      POSTGRES_DB: myapp_dev
      POSTGRES_USER: dev
      POSTGRES_PASSWORD: dev
    ports:
      - "5432:5432"

Production Configuration

          
yaml

# docker-compose.prod.yml
version: '3.8'

services:
  web:
    build: .
    environment:
      - NODE_ENV=production
    deploy:
      replicas: 3
      resources:
        limits:
          cpus: '0.5'
          memory: 512M
    restart: unless-stopped

  database:
    image: postgres:13
    environment:
      POSTGRES_DB: myapp_prod
      POSTGRES_USER: prod
      POSTGRES_PASSWORD: ${DB_PASSWORD}
    volumes:
      - postgres_data:/var/lib/postgresql/data
    restart: unless-stopped

Best Practices

1. Use Multiple Compose Files

          
bash

# Development
docker-compose -f docker-compose.yml -f docker-compose.dev.yml up

# Production
docker-compose -f docker-compose.yml -f docker-compose.prod.yml up

2. Environment-Specific Configurations

          
yaml

# docker-compose.override.yml (automatically loaded)
version: '3.8'

services:
  web:
    volumes:
      - .:/app
    environment:
      - DEBUG=true

3. Secrets Management

          
yaml

version: '3.8'

services:
  web:
    build: .
    secrets:
      - db_password
      - api_key

secrets:
  db_password:
    file: ./secrets/db_password.txt
  api_key:
    external: true

Monitoring and Logging

Log Configuration

          
yaml

version: '3.8'

services:
  web:
    build: .
    logging:
      driver: "json-file"
      options:
        max-size: "10m"
        max-file: "3"

  database:
    image: postgres:13
    logging:
      driver: "syslog"
      options:
        syslog-address: "tcp://logs:514"

Health Monitoring

          
yaml

version: '3.8'

services:
  web:
    build: .
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:3000/health"]
      interval: 30s
      timeout: 10s
      retries: 3

  prometheus:
    image: prom/prometheus
    ports:
      - "9090:9090"
    volumes:
      - ./prometheus.yml:/etc/prometheus/prometheus.yml

  grafana:
    image: grafana/grafana
    ports:
      - "3001:3000"
    environment:
      - GF_SECURITY_ADMIN_PASSWORD=admin

Troubleshooting

Common Issues

Port Conflicts

          
bash

# Check what's using the port
lsof -i :3000

# Use different port
docker-compose up -p 3001

Volume Issues

          
bash

# List volumes
docker volume ls

# Remove unused volumes
docker volume prune

Network Issues

          
bash

# List networks
docker network ls

# Inspect network
docker network inspect <network_name>

Debugging Commands

          
bash

# View logs
docker-compose logs -f web

# Execute commands in running container
docker-compose exec web bash

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

# View service status
docker-compose ps

Conclusion

Docker Compose is essential for managing complex multi-container applications. By following these advanced patterns and best practices, you can create robust, scalable, and maintainable containerized applications.

Remember to:

Use environment-specific configurations
Implement proper health checks
Set resource limits
Configure logging and monitoring
Follow security best practices

Happy composing! 🐳

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Stay Updated

Docker Compose Advanced: Multi-Container Applications

Docker Compose Advanced: Multi-Container Applications

Advanced Docker Compose Features

Environment Variables

Volume Management

Networking

Production-Ready Configurations

Health Checks

Resource Limits

Restart Policies

Complex Application Examples

Full-Stack Application

Microservices Architecture

Development vs Production

Development Configuration

Production Configuration

Best Practices

1. Use Multiple Compose Files

2. Environment-Specific Configurations

3. Secrets Management

Monitoring and Logging

Log Configuration

Health Monitoring

Troubleshooting

Common Issues

Debugging Commands

Conclusion