Dockerfile

A Dockerfile is a plain-text recipe Docker reads to build an image — the blueprint a container is created from. It specifies a base operating system, copies in your code, installs dependencies, and defines the command that starts your app, all in a small set of declarative instructions.

• —Writing a Dockerfile is the first practical skill needed to containerise any real project.
• —A well-written Dockerfile keeps image size small and builds fast, which matters at deploy time.
• —Once written, the same Dockerfile reliably reproduces the exact same environment every time.

This is the exact lesson that covers this term in depth — with examples, diagrams, and a hands-on exercise.