Learning Docker by Building a Three-Tier MERN Application

Source: Dev.to

Why Docker?

• Before Docker, running an application meant:
  • Installing dependencies manually
  • Dealing with environment mismatches
  • Hearing the classic “it works on my machine” problem
• Docker solves this by packaging applications and their dependencies into containers, making them portable, consistent, and repeatable.

What I Built

The application is structured as:

• Frontend: React‑style frontend served via Nginx
• Backend: Node.js + Express API
• Database: MongoDB

Each component runs in its own Docker container, and all services communicate through a shared Docker network.
The entire application can be started using a single command:

docker compose up --build

Docker Concepts I Practiced

1. Docker Images & Containers
2. Dockerfiles
3. Multi‑Stage Docker Builds
4. Docker Networking
5. Docker Volumes
6. Docker Compose

What I Learned

• Docker becomes much clearer when you build something end‑to‑end.
• Multi‑container applications are easier to manage with Docker Compose.
• Volumes are critical for data that should survive container restarts.
• Docker is less about commands and more about reproducible environments.

Why This Project Matters

Repository: