On the other hand, Ansible works well as simply a remote task runner (like Fabric). Salt is the one I have least experience with, but I had a conversation with the creator once and he seemed excited about the orchestration possibilities with Salt. If I understand correctly you can react to events that get triggered either manually or based on a condition on some other server you're managing. So both of these tools make it easy/natural to do something like run a rolling restart of a group of servers.