What is Docker (and Containerization)?

Imagine you’re moving to a new house. You could just throw all your stuff into the moving truck loose—but chances are, things will get lost, broken, or mixed up. Instead, you pack everything neatly into boxes. Each box holds the things it needs, and when you arrive, you just place the boxes where they belong and unpack them.

That’s pretty much what Docker does for software. Instead of installing apps directly on your computer (where they might clash with each other or need different setups), Docker “packs” each app and all the stuff it needs—like libraries, settings, and tools—into its own little box, called a container.

These containers are:

1. Portable – You can run them almost anywhere (your laptop, a server, the cloud).
2. Consistent – They work the same no matter where you move them.
3. Isolated – Each one is separate, so if one breaks, it doesn’t mess with the others.

So, in plain terms: Docker makes it easy to run apps without worrying about “it works on my machine” problems.