What's wrong with using something like ZooKeeper? In my understanding, master election, storage of configuration data and the likes are what it's made for; and you can have multiple ZK servers that still contain one single configuration database.
Interesting, a service registry in Ruby. If you already have redis etc. running on your system, why not. But as I already have the dns servers running — for my specific use case — you cannot beat it, because it means just one line per service in my DNS server configuration to have it available.
