SwarmKit by Docker: a toolkit to orchestrate distributed systems at any scale

Obviously it is very early in the data center orchestration and scheduling world, but it looks like this is filling in many of the gaps that exist today. Excited to dig into a bit more. I'm setting up a test cluster right now to give it a spin. I spent all day today working with Docker for OSX and an super impressed with some of the new docker-compose functionality.

I like how easy service-defined networking is getting. (Side note: I'm still working through an issue where Docker on OSX won't bind to a gateway address of a bridge network. My YAML works on Ubuntu, but not on OSX. I'm starting to think it's a beta bug, but I haven't given up yet.)

If SwarmKit can make progress in delivering an easy to run, but still very powerful scheduler and orchestration platform, I think it might be a big platform.

It's not clear from the README how this fits in with the rest of the Docker ecosystem. How does this relate to Docker Swarm? Would I use this to create apps that are directly manipulated by Docker Swarm, or does it just provide primitives that Docker Swarm uses that other apps may find useful, but that don't depend on Docker at all?