[Aegir][aegir] is a very clever hosting system for [Drupal][drupal] that sites and provisions them on various servers and does lots of clever things. One of the clever things that it has had for a while is a task queuing system. You can ask Aegir to lots of different things all in one go, and Aegir will queue them up and run them at its own pace. This provides a really good separation from the front-end Aegir website and the back-end Aegir scripts.
We've been using Aegir in production for just under a year, and one thing that has bugged me...