Docker Compose: Your First Application in 10 Minutes

Let’s skip the theory and run something real. In about 10 minutes, you’ll have a web application with a database running on your computer.

Step 1: Install Docker Desktop

Docker Desktop includes everything you need, including Docker Compose.

Windows and Mac

Visit docker.com/products/docker-desktop
Download for your operating system
Run the installer
Start Docker Desktop

Wait for the Docker icon in your system tray to show it’s running.

Linux

# Install Docker and Docker Compose
sudo apt-get update
sudo apt-get install docker.io docker-compose-plugin

# Verify installation
docker compose version

Step 2: Verify Installation

Open your terminal:

docker compose version

You should see something like:

Docker Compose version v2.20.0

Step 3: Create a Project Directory

mkdir my-first-app
cd my-first-app

Step 4: Create docker-compose.yml

Create a file named docker-compose.yml with this content:

services:
  web:
    image: nginx:alpine
    ports:
      - "8080:80"
    volumes:
      - ./html:/usr/share/nginx/html

  db:
    image: postgres:15-alpine
    environment:
      POSTGRES_PASSWORD: secret
      POSTGRES_DB: myapp
    volumes:
      - db_data:/var/lib/postgresql/data

volumes:
  db_data:

Step 5: Create a Simple Web Page

Create an html directory with an index file:

mkdir html

Create html/index.html:

<!DOCTYPE html>
<html>
<head>
    <title>My First Docker Compose App</title>
    <style>
        body {
            font-family: Arial, sans-serif;
            max-width: 800px;
            margin: 50px auto;
            padding: 20px;
        }
        h1 { color: #2563eb; }
        .success { color: #16a34a; font-weight: bold; }
    </style>
</head>
<body>
    <h1>It Works!</h1>
    <p class="success">Your Docker Compose application is running successfully.</p>
    <p>This page is served by Nginx, and there's a PostgreSQL database running alongside it.</p>
    <p>Both services started with a single command: <code>docker compose up</code></p>
</body>
</html>

Step 6: Start Everything

From your project directory:

docker compose up

You’ll see Docker downloading images and starting services. When you see lines like:

✔ Container my-first-app-db-1   Started
✔ Container my-first-app-web-1  Started

Your application is running!

Step 7: See It in Action

Open your browser and visit http://localhost:8080

You should see your web page. That’s a real web server running in a container, serving your HTML file.

What Just Happened?

When you ran docker compose up, Docker:

Read your docker-compose.yml file
Downloaded the Nginx and PostgreSQL images
Started both services
Connected them on a private network
Mounted your HTML files into the web server
Made the web server available on port 8080

All of this from one command.

Managing Your Application

Stop the Application

Press Ctrl+C in the terminal where it’s running, or in a new terminal:

docker compose down

Start in Background Mode

docker compose up -d

The -d flag means “detached”—it runs in the background.

View Logs

docker compose logs

Or follow logs in real-time:

docker compose logs -f

Stop and Remove Everything

docker compose down

This stops containers and removes them, but keeps volumes (your database data).

To remove everything including volumes:

docker compose down -v

Understanding the docker-compose.yml File

Let’s break down what you created:

services:          # Define the services (applications) you want to run
  web:            # First service named "web"
    image: nginx:alpine    # Use the Nginx image
    ports:
      - "8080:80"          # Make it accessible on port 8080
    volumes:
      - ./html:/usr/share/nginx/html  # Share your HTML folder

  db:             # Second service named "db"
    image: postgres:15-alpine  # Use PostgreSQL 15
    environment:               # Set environment variables
      POSTGRES_PASSWORD: secret
      POSTGRES_DB: myapp
    volumes:
      - db_data:/var/lib/postgresql/data  # Persist database data

volumes:
  db_data:        # Named volume for database persistence

Try This: Make a Change

Edit html/index.html and change the text
Refresh your browser
See your changes immediately

No restart needed. The volume connection keeps your files in sync.

Common Issues

Port already in use: If you see an error about port 8080, change it in docker-compose.yml:

ports:
  - "8081:80"  # Use 8081 instead

Docker Desktop not running: Make sure you see the Docker icon in your system tray/menu bar.

Permission denied (Linux): You may need to run with sudo or add your user to the docker group.

What You’ve Learned

In less than 10 minutes, you:

Installed Docker Desktop
Created a docker-compose.yml file
Started a multi-service application
Learned basic Docker Compose commands

More importantly, you experienced the core value: describing your entire application in one file and starting it with one command.

What’s Next?

In Part 3, we’ll build something more realistic—a Node.js application that actually connects to the database. You’ll learn how services communicate, how to customize configurations, and how to work with different types of applications.

You’re not just learning a tool. You’re learning a new way to think about running applications.