I work at Nextdoor.com as the Systems Architect... We've just published a new blog entry on our Engineering Blog (http://engblog.nextdoor.com/) discussing how we use ZooKeeper and Puppet to dynamically configure our environments as they change in the cloud. We've written a few tools to help us do this, and we've now published them openly so that others can leverage them as well.
Please check out the blog post here: http://engblog.nextdoor.com/post/34583564058/zookeepers-puppet-masters-and-clouds --Matt Nextdoor.com Sr. Systems Architect
