Imagine you’ve opened a restaurant franchise.
For all units to operate identically, you need a standard: the same menu, the same food preparation method, the same equipment, and the same service process.
In Docker, the idea is similar.
You create a standard environment for your application. This standard defines what needs to be installed, which files will be copied, which command will be executed, and how the application should start.
That’s where four important concepts come in:
Dockerfile- image
- container
- configurations
Let’s think of this as a franchise.
Dockerfile: The Franchise Manual
Every franchise needs a manual.
This manual explains how to set up the unit, what tools to use, what processes to follow, and what should happen when everything is ready to operate.
In Docker, this manual is the Dockerfile.
It describes the step-by-step process required to create the application’s environment.
A simple example:
FROM ubuntu:20.04
RUN apt update && apt install -y nginx
CMD ["nginx", "-g", "daemon off;"]