True, but they are unviable for most startups.
most of the solutions outlined here are very, very heavy. I'm a 2 man startup and really cannot invest into mesos to deploy a 4 VM cluster.
But the news that Kubernetes is leveraging SaltStack is hopeful.
I don't know about that.
Mesos was already mentioned: http://mesos.apache.org/
There's also Kubernetes which has recently started working on Fedora and CoreOS: https://github.com/GoogleCloudPlatform/kubernetes
And there is CoreOS's fleet system, although this is more low level and would still need orchestration: https://github.com/coreos/fleet