Drupal

Aegir is a hosting system for managing rapid, automated provisioning and ongoing maintenance (upgrades, cloning, destroying) of Drupal sites. Aegir itself is made of Drupal - it consists of a Drupal frontend 'control panel' and a ‘backend’, which makes extensive use of Drush.

Here Miguel Jacq explains:

1) The basics of using Aegir 

2) How to upgrade your site(s)