The Docker - Rocket discussion is about to get into full swing but in fact the conversation started a long time ago and without getting into a debate on the subjective qualities of each project let’s discuss the facts.
Docker is currently the leader in the Linux container market. With their acquisition of the fig project (now called machine), the implementation of the libcontainer (departing from the true LCX container), swarm for clustering containers. While the registry is open source Docker offers several SaaS solutions from free to enterprise.
CoreOS started as a bare metal OS that was meant to be immutable, much like ChromeOS, consume Docker containers as it’s distributable unit of work. The CoreOS team developed etcd and fleetd to support Docker clusters. Multiple projects like Deis and Kubernetes were implemented and took advantage of the structure of CoreOS. Frankly when you have a heavy host OS & containers then you have many multiples of systems that need maintaining. CoreOS, with it’s tools makes this so much easier. CoreOS also has an enterprise control program for managing the host updates.
As for Docker and Rocket… Docker is clearly encroaching on the CoreOS domain and CoreOS is responding in kind. I suppose if I were an insider I might know more about the exact timing, however, I don’t think it matters much. What is interesting to me is that CoreOS is moving toward a trusted environment. This is of critical importance to me as I’m thinking about the best possible design for implementing an HSM (Host Security Module).
**Not to be confused, projectatomic is also interesting but is just enough far enough along to warrant comparison.
Only time will tell who the winner is going to be. It should be no surprise if we come to find out that Docker’s APIs and libcontainer were premeditated in order to protect their assets in a way that is opposed to the open source from which it was spawned. As for CoreOS I think they are already in the sweet spot. They are likely to be able to support both Rocket and Docker (maybe not at the same time) but until Docker deploys a proper OS or partners with someone else CoreOS will have at least one leg up.