Docker Entrypoint overridden by k8s command

[Nataliia5722]

Hi Team!

Could you, please, advise? Is there any way to not duplicate the entrypoint that was specified in Dockerfile.

Sample example of Dockerfile:

FROM ubuntu:14.04

ENTRYPOINT ["echo", "Hello"]

Sample workflow:

metadata:
  name: test
  namespace: argo-workflows
spec:
  entrypoint: test
  templates:
    - name: test
      container:
        name: main
        image: <custom_image>
        command:
          - "World"

Getting the error:

Error (exit code 64): failed to find name in PATH: exec: "World": executable file not found in $PATH

Why it's not recognizing the "echo", "Hello" entrypoint from Docker image? What can be done to make it work?

[agilgur5]

I think you've fallen into a common misunderstanding of the Docker vs. k8s terminology. Docker's ENTRYPOINT is equivalent to k8s's command, and Docker's CMD is equivalent to k8s's args.

The terminology is unfortunately pretty confusing so this happens quite often.
To be explicit, that's not an Argo error or specific to Argo, that's just Kubernetes functionality. If you run a plain Pod in Kubernetes with that image and that command, you'll get the same error

So your command: - "World" is actually overriding your ENTRYPOINT ["echo", "Hello"]. If you want to print "Hello World", you probably want to use args and not command:

        args:
          - "World"

[Nataliia5722]

Thanks a lot!
Yes, was setting as args first, but as a command is required, what value should be set to not override the ENTRYPOINT ["echo", "Hello"] ?

[agilgur5]

command shouldn't be required if you have an ENTRYPOINT and are using an up-to-date image manifest (v2).
Are you getting an Emissary error without command? If the docker image inspect command on this doc page can get the entrypoint, then you should have an up-to-date manifest. (v1 is pretty old at this point, so if all your tools are up-to-date, they should create v2 manifests by default)

But to answer the question, you'd set the command to be equivalent to ENTRYPOINT then, i.e.:

        command:
          - echo
          - "Hello"
        args:
          - "World"

You'd still be overriding it, to be clear, just with the same value.