Docker

Introduction

Docker is a platform for containerization that packages applications and their dependencies into portable, lightweight containers. It revolutionizes how we deploy and manage applications across different environments.

Key Benefits

Installation Guide

Essential Commands

Docker Compose

Docker Compose simplifies multi-container application deployment using declarative YAML configuration.

Basic Configuration

services:
  web:
    image: nginx:alpine
    ports:
      - "8080:80"
    volumes:
      - ./html:/usr/share/nginx/html
    depends_on:
      - database
    environment:
      - NODE_ENV=production
  
  database:
    image: postgres:15-alpine
    environment:
      POSTGRES_DB: myapp
      POSTGRES_USER: user
      POSTGRES_PASSWORD: password
    volumes:
      - db_data:/var/lib/postgresql/data
    ports:
      - "5432:5432"

volumes:
  db_data:
    driver: local

networks:
  default:
    driver: bridge

Essential Commands

Advanced Patterns

Quick Start Example

Let's deploy a simple web application to see Docker in action:

# 1. Pull the nginx image
docker pull nginx:alpine

# 2. Run nginx container with port mapping
docker run -d -p 8080:80 --name my-nginx nginx:alpine

# 3. Check if it's running
docker ps

# 4. Visit http://localhost:8080 in your browser

# 5. View logs
docker logs my-nginx

# 6. Stop and remove
docker stop my-nginx
docker rm my-nginx

Best Practices

Common Patterns

services:
  web:
    image: php:8.1-apache
    ports:
      - "80:80"
    volumes:
      - ./src:/var/www/html
    depends_on:
      - database
  
  database:
    image: mysql:8.0
    environment:
      MYSQL_ROOT_PASSWORD: rootpass
      MYSQL_DATABASE: myapp

services:
  app:
    build: .
    ports:
      - "3000:3000"
    environment:
      - REDIS_URL=redis://redis:6379
    depends_on:
      - redis
  
  redis:
    image: redis:7-alpine
    ports:
      - "6379:6379"

Troubleshooting

Learning Path

Phase 1: Foundations (Week 1-2)

• ✅ Installation & Setup - Get Docker running on your system
• ✅ Basic Commands - Learn essential Docker CLI commands
• ✅ Images & Containers - Understand the core concepts
• 🎯 Practice: Deploy nginx, postgres, and redis containers

Phase 2: Development (Week 3-4)

• 📝 Dockerfiles - Create custom images for your applications
• 🔧 Docker Compose - Multi-container application orchestration
• 💾 Volumes & Networks - Data persistence and container communication
• 🎯 Practice: Containerize a full-stack application

Phase 3: Production (Week 5-6)

• 🔒 Security - Container security best practices
• ⚡ Optimization - Image size and performance optimization
• 📊 Monitoring - Logging and health checks
• 🎯 Practice: Deploy production-ready applications

Phase 4: Advanced (Week 7-8)

• 🏗️ Multi-stage Builds - Optimize build processes
• 🌐 Registry Management - Private registries and image distribution
• 🔄 CI/CD Integration - Automated building and deployment
• 🎯 Practice: Set up automated deployment pipelines

Next Steps

Ready to advance your containerization skills?