That's a fair point. In this case I was especially interested in running multiple instances of the same application on a CoreOS mini-cluster, demonstrating flee

That's a fair point. In this case I was especially interested in running multiple instances of the same application on a CoreOS mini-cluster, demonstrating fleet's capabilities of scaling/distributing the containers over the cluster. However, in a real life application I think I would still keep the containers as "single-process" as possible; in our case that would mean: a single Rails application or a group of Resque workers. It would make the containers quick to boot and would increase security by sandboxing all the separate parts of a system in their own containers. I do think this is up to personal preferences, though :-).