As a very effective substrate for hosting containers, we at Terminal think a lot about which of the container mechanisms will win over the long term.

My personal opinion is that the winner will be the group that successfully gets Enterprises to change their workload design. I also don't think that Rocket is necessarily a superior format to Docker, but I think they're both dealing with the recognition that any big change in Enterprise behavior represents an opportunity for value capture.

There's a real question as to where any of these abstraction layers fit in if Docker wins (and there's some possibility docker is going to win). If that's the case, coreos doesn't want to look back a few years down the road and wish they'd been working on a container format.

It's 2015. One of the battlegrounds for enterprise dollars is containers. It's going to be a delightful thing to watch.

It's also worth noting that many companies have their own cgroups implementations which are neither docker or rocket based. I rather like the position of dispassionate observer in this war (at Terminal we run all of the containers and also apps without containers).