Juju, for those of you who haven't had the pleasure of meeting it, is a DevOps like Puppet and Chef. It works on a higher level though to make setting up and maintaining cloud services even easier.
These DevOps programs are there to get rid of the busy work of setting up and managing standard servers and their relationships on the cloud. This is why Jorge Castro, a Canonical developer relations executive, says that Juju's main idea is to get rid of "metawork."
According to Canonical and Microsoft, "With Juju support on Windows Azure you can now deploy over 100 services (Juju Charms) onto your Windows Azure Ubuntu instances. With service relations and scaling built into Juju, automating your cloud infrastructure has never been easier. To keep the user experience optimal Juju leverages Simple Stream cloud data to automatically know which Windows Azure cloud image is the freshest for a given release and region so you don’t have to worry about image IDs and keeping up with the latest published images."
This isn't just hype. I've used Juju myself, albeit on OpenStack instead of Azure, to manage cloud services and I found it to work remarkably well. Perhaps what's even more important is that Juju charms can significantly save system administrators time on the grunt work of setting up such common Web-based applications as the Drupal content management system, the Tomcat Java server, and WordPress.