PepperMill is the spicy complement to SaltStack. It's a utility to help you remotely manage Salt networks.
Salt is a young but promising new DevOps utility. Much like Chef or Puppet, Salt follows a client-server model that makes it possible to rapidly configure massive numbers of nodes. Unlike Chef, Salt is elegantly simple: at its core, it is a simple python command slinger over ZeroMQ. (Chef, and especially Chef Server, is a monstrosity that no sensible developer should ever wish to adopt.) And unlike Puppet, Salt's declarative configuration "language" is straightforward, expressive, and sane.
This being said, Salt is still a rather young utility. It started out as a simple remote-command execution tool but grew to include Salt States -- the moral equivalent of a Chef cookbook. Basic names and concepts are still up for grabs. (Why it's called "high state" is beyond me. Also: pillars have an absurd name.)
The Salt master/minion model is rather limited:
1. The salt command must be run from the master server... and must be run as root. This is unlike (say) Chef, where the knife command can be used on developer boxes to make configuration changes.
2. There is a very simple fileserver built into salt-master that provides salt state files from the master's local filesystem to interested minions. Salt provides no policy around the management of these state files, or around developer access to them. Again, this is unlike (say) Chef, where the knife command can be used to update cookbooks on the Chef server.
3. Minions must be accepted by the master before they can be administered. While this is a very sane decision, it is problematic in the face of things like AWS auto-scaling, where a third party is responsible for dynamically creating minions.