Windows Azure provides a locked-down environment for websites hosted in IIS (web roles) and application services (worker roles). While this hardening significantly eases administration, it also limits the ability to perform certain tasks, such as installing software or writing to the registry. Another problem is that any changes to an instance are lost whenever the instance is reimaged or moved to a different server.
The Windows Azure SDK v1.3 release provided two solutions to this problem. The simple solution allows for the creation of startup tasks, which are script files or executable programs that are invoked each time an instance is started. Startup tasks allow a temporary escape from the restrictions of the locked-down web role and worker role while retaining the benefits of these roles. The more complex solution is the creation of a new role type, VM Role, which allows an appropriately configured Guest OS image to be uploaded to a hosted...