Module Overview

What You’ll Learn

• Explain what a container is, and what problem it solves that “it works on my machine” doesn’t
• Write a Dockerfile for a Node.js application, including a multi-stage build
• Run a multi-container application locally with Docker Compose

💡 Why this matters: “Works on my machine” has never been good enough for a real deployment, a container packages an application together with everything it needs to run, so it behaves identically on a laptop, a teammate’s machine, and a production server.

What’s Covered

• What a container actually is, and how it differs from a virtual machine.
• Writing a Dockerfile, base images, layers, and a multi-stage build that keeps a production image small.
• Docker Compose, running an application together with a database or cache locally, with one command.
• Image size and build caching, why both matter for a real deployment pipeline.

Hands-On

By the end of this module, you’ll have a Dockerfile that packages a Node.js API into a small, production-ready image, and a Compose file that runs it alongside a database locally.

Next module: automating testing and building with a CI/CD pipeline, so every change is verified before it ships.