moby: Inconsistencies between --entrypoint/--command for run, service create, service update

docker run uses --entrypoint to override the entrypoint of an image

docker service create currently doesn’t support setting entrypoint docker service update supports overriding the image entrypoint with the --command flag

We should make these consistent. I believe after this (https://github.com/docker/swarmkit/pull/1092) swarmkit change the service.Command acts the same way as container.Entrypoint.

I think we should probably be using --entrypoint for both docker service create and docker service update despite the API using a different name for it.

cc @tiborvass @stevvooe @aluzzardi @aanand

About this issue

Original URL
State: closed
Created 8 years ago
Comments: 23 (18 by maintainers)

Most upvoted comments

@dnephin Could you please stop confusing Cmd and Command? They are not the same thing. Cmd is added to an Entrypoint upon execution, similar Args in other systems. Command replaces Entrypoint.

I understand this is less intuitive to non-docker users, but I don’t see us fixing that here.

This is our only chance to fix this.

As a user, it makes much more sense to think “Oh, I just want to run a command” than “I want to run a command. O, whats an entrypoint? Do I need to override that? How does that work? O, okay, to run a command, I need to override entrypoint, whatever that is”.

We can literally have this both ways, as entrypoint and command are now equivalent from a container perspective. And it is even better: we now have language to differentiate between an image’s entrypoint and running a command in a container that bypasses the image’s entrypoint.

stevvooe on Jul 5, 2016