makitzo

makitzo is a remote-host Swiss army knife and has been battle-tested in an environment with ~150 nodes.

Feature list:

Ruby configuration DSL
host migrations
key/value store for centralised storage of per-host config data, with pluggable backends
"helper" system for defining remote commands in Ruby code
run any command on a subset of defined hosts via SSH
compare output of commands across multiple hosts

Installation:

$ gem install makitzo