We will explore the process of Dockerizing Python applications. Dockerization involves packaging an application into a Docker container, which contains all dependencies and configurations.

The logic of the Dockerfile lies in executing these instructions sequentially.

Compare a Docker Container to Building a Hotel

Choosing a base material (FROM): When building a hotel, the first step is choosing the base material, like bricks or concrete. In Docker, this is akin to selecting a base image, for example, python:3.9-slim, which already contains all the necessary components to run Python programs.

Copying ingredients (COPY): Assembling a hotel involves moving all the necessary items into its premises, like furniture, bedding, and more. In Docker, this is copying all the required program files into the container's internal space.

Indicating actions upon startup (CMD): When the hotel is ready for use, typically, instructions are given to the staff about what to do upon opening the hotel, such as turning on lights in the lobby or starting to welcome guests. In Docker, this is specifying which command should be executed when the container is started, for example, python app.py, to run the main program file.

In the next chapter, we'll build and launch this container.