🚀 Docker Compose Introduction¶

1. Overview¶

• Welcome to the Docker Compose Hands-on Labs!
• This introductory lab will guide you through the fundamentals of Docker Compose, its key features, and benefits.
• This lab is designed for beginners and those new to Docker Compose.

What is Docker Compose?¶

Docker Compose is a powerful tool for defining and running multi-container Docker applications. Instead of managing containers individually with complex docker run commands, Docker Compose lets you:

• Define your entire application stack in a single docker-compose.yml file
• Configure services, networks, and volumes declaratively using YAML
• Start, stop, and manage all containers with simple commands
• Share your application configuration easily across teams
• Ensure consistency across development, testing, and production environments

Why Docker Compose?¶

2. Key Features & Benefits¶

3. Prerequisites¶

• Before starting this lab, ensure you have:

• Basic Docker Knowledge: Understanding of containers, images, and basic Docker commands

• Docker Installed: Docker Engine or Docker Desktop installed on your system
• Command Line Familiarity: Comfortable using terminal/command prompt
• Text Editor: Any text editor for editing YAML files (VS Code, Vim, Nano, etc.)

4. Installation¶

# Update package index
sudo apt-get update

# Install Docker Compose
sudo apt-get install docker-compose-plugin

# Alternative for older systems
sudo apt-get install docker-compose

# Download the latest version
sudo curl -L "https://github.com/docker/compose/releases/latest/download/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose

# Make it executable
sudo chmod +x /usr/local/bin/docker-compose

# Create symbolic link (optional, for docker-compose command)
sudo ln -s /usr/local/bin/docker-compose /usr/bin/docker-compose

# Install using Python pip
pip install docker-compose

# Install Docker Compose using Homebrew
brew install docker-compose

# Check the installation
brew info docker-compose

{
  "cliPluginsExtraDirs": ["/opt/homebrew/lib/docker/cli-plugins"]
}

4.1 Verify Installation¶

• After installation, verify Docker Compose is working:

# Modern Docker Compose (V2) - Recommended
docker compose version

# Output example:
# Docker Compose version v2.36.0

# Legacy Docker Compose (V1) - Still supported
docker-compose --version

# Output example:
# docker-compose version 1.29.2, build 5becea4c

Test with a simple command:

# Check available commands
docker compose --help

5. Common Commands Reference¶

• Here’s a comprehensive reference of Docker Compose commands you’ll use regularly:

5.1 Core Commands¶

5.2 Build & Image Management¶

5.3 Monitoring & Debugging¶

5.4 Service Management¶

5.5 Configuration & Validation¶

5.6 Advanced Operations¶

5.7 Examples¶

# Start fresh - remove everything and rebuild
docker compose down -v && docker compose up --build

# View logs from specific service
docker compose logs -f service_name

# Execute interactive shell in running container
docker compose exec service_name /bin/bash
docker compose exec service_name sh

# Run database migrations
docker compose exec app python manage.py migrate

# Check resource usage
docker compose stats

# View differences in configuration
docker compose config --resolve-image-digests

6. Your First Steps¶

• Now that you have Docker Compose installed, let’s understand the basic workflow:

6.1 Project Directory¶

• Create a new directory for your Docker Compose project and navigate into it:

  # Create and navigate to your project directory
  mkdir my-first-compose
  cd my-first-compose
  

6.2 docker-compose.yml¶

• This is the heart of Docker Compose. Here’s a simple example:
• Save this content in a file named docker-compose.yml inside your project directory.

  version: "3.8"
  services:
    web:
      image: nginx:latest
      ports:
        - "8080:80"
  

6.3 Start Your Application¶

• Start your services using the following command:

  # Start the services
  docker compose up
  

6.4 View Running Services¶

• Verify everything is running smoothly:

  # In another terminal, check status
  docker compose ps
  
  # View logs
  docker compose logs
  
  # Access the application
  # Open browser: http://localhost:8080
  

6.5 Clean Up¶

• Stop Your Application

  # Stop and remove containers
  docker compose down
  

🎉 Congratulations! You’ve just run your first Docker Compose application!

7. What will we cover?¶

• Throughout this Docker Compose labs series, you’ll master:

📚 Fundamentals¶

• Creating and structuring docker-compose.yml files
• Defining services, networks, and volumes
• Understanding YAML syntax and best practices

🏗️ Service Configuration¶

• Building custom images
• Setting environment variables
• Configuring health checks
• Managing dependencies between services

🌐 Networking¶

• Default bridge networks
• Custom network creation
• Service discovery and DNS
• Network isolation patterns

💾 Data Management¶

• Named volumes vs bind mounts
• Persisting data across container restarts
• Sharing data between services

🚀 Advanced Features¶

• Multi-stage builds
• Scaling services
• Using profiles for different environments
• Docker Compose Watch for development
• Converting to Kubernetes (Helm)

🔧 Production Readiness¶

• Environment-specific configurations
• Security best practices
• Monitoring and logging
• CI/CD integration

🛠️ Fragments¶

• Reusable configuration snippets
• Using extends and YAML anchors
• Modularizing large Compose files
• Managing complex applications
• Debugging and troubleshooting tips
• Performance optimization strategies
• Real-world case studies and examples

8. Next Steps¶

Before moving to the next lab, ensure you can:¶

• Execute docker compose version successfully
• Understand what Docker Compose does
• Know the basic commands (up, down, ps, logs)
• Have a text editor ready for YAML files