☁️ Free practice test question from: Container Orchestration (KCNA)

ENTRYPOINT: This instruction configures a container that will run as an executable. It defines the main command that will always be executed when the container starts. It's designed to make the container behave like a single executable.

CMD: This instruction provides default arguments for the ENTRYPOINT command or specifies a command by itself if ENTRYPOINT is not used. It can be overridden by providing arguments to docker run.

> Running docker run <image> will execute echo "Hello, World!".

> Running docker run <image> "Goodbye!" will execute echo "Goodbye!".

ENTRYPOINT allows you to turn a container into a self-contained executable. This is particularly useful for command-line tools or applications that perform a specific task.  

Imagine you have a container that runs a web server.

• ENTRYPOINT could be the web server's executable (e.g., /usr/sbin/nginx).

• CMD could be the default configuration file to use (e.g., ["-c", "/etc/nginx/default.conf"]).

This way, the web server always starts, but users can provide a different configuration file if needed by overriding the CMD.