Docker: When to Use ENTRYPOINT vs CMD

Understand ENTRYPOINT vs CMD in Docker with simple code examples

CMD

Provides default arguments or commands for the container.

Use Case:

It can be overridden by passing a command when you run the container.

If no command is provided at runtime, Docker will use the CMD instruction.

Use it when you want a default behavior but allow users to override it.

CMD ["nginx", "-g", "daemon off;"]

• Default: Runs nginx -g "daemon off;".

Override:

docker run my-image bash

• Runs bash, ignoring nginx.
  
  
  

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ENTRYPOINT

Specifies the main, fixed command that will always run in the container.