I don't think you can have multiple entrypoints in one Dockerfile.

Is there a particular reason that you want to run two services in one container? I would not recommend doing that unless you absolutely need to. Two services in one container breaks the single responsibility principle: One container, one service and it anti-pattern. Two containers and they communicate through TCP or other higher protocols are better.

But if you cannot follow the best practice, you can do sth like:

ENTRYPOINT ["/entrypoint.sh"]

then in your entrypoint.sh file, you start jupyter lab and dagit services.