Understanding Dockerfile: A Beginner’s Guide to Building Docker Images

What is a Dockerfile?
A Dockerfile is a plain text file that contains instructions to build a Docker image. It automates the image creation process.

Why is Dockerfile Important?
A Dockerfile is important because it helps you automate the process of creating Docker images.
Instead of manually installing software and setting things up inside a container every time, you can write instructions once in a Dockerfile — and Docker will follow those steps automatically to build your image.

It makes your setup:
Repeatable – You get the same setup every time, no matter where you run it
Easy to Share – You can give your Dockerfile to others, and they’ll get the same result
Track Changes – You can save your Dockerfile in Git and see what changed over time
Saves Time – No need to set things up manually again and again
Fewer Mistakes – Everything is automated, so less chance of human error

Basic Syntax of a Dockerfile:

FROM ubuntu
RUN apt update
CMD ["echo", "Hello from Dockerfile"]

Basic Dockerfile Instructions