Totally agree with this and that's one of the core tenants of our API design. We should probably be more clear about how docker fits with pfs. Our APIs are all designed as RESTful services to allow for composability, however we want to take a batteries included but removable approach. In our case Docker is a battery. We want it to be there so that users have a really easy primitive to implement M.R jobs with. But we recognize it might not be for every user so we also want to allow people to put anything they want there. I think the easiest way would be just letting people pass an arbitrary endpoint to be used in an M/R job.
> Additionally, you seem to be leaning on CoreOS at the moment. That seems a dangerous dependency considering the CoreOS/Docker relationship. I'm hopeful that both of these companies commitment to a batteries included but removable approach will make leveraging both ecosystems a realistic option. I agree that it would be a pain to have to pick one.