What's the difference between these two forms:

Question

ENTRYPOINT ["cmd", "param0", "param1"]
CMD ["param0"]

ENTRYPOINT cmd param0 param1
CMD param0

Answer 1

The first form is also referred as "Exec form" and the second one is referred as "Shell form".

The second one (Shell form) wraps the commands in /bin/sh -c hence creates a shell process for it.

While using either Exec form or Shell form might be fine, it's the mixing that can lead to unexpected results.

Consider:

ENTRYPOINT ["ls"]
CMD /tmp

That would results in running ls /bin/sh -c /tmp

Answer