Windows Azure

An enterprise cloud-computing platform. Windows Azure provide tree types of solutions, Virtual Machines, Web Sites and Cloud Services.
Microsoft Azure Introduction

Azure Roles

There are three types of roles in Windows Azure:

Web Role – A service component that is customized for web application programming as supported by Internet Information Services (IIS) 7 and ASP.NET. The web role is intended to serve as the front-end to your cloud service.

Worker Role - A service component that is useful for generalized development, and may perform background processing for a web role. A worker role is frequently used for long-running tasks that are non-interactive, but you can host any type of workload.

VM - Virtual Machine role that has retired
Enable Azure roles for RDP

Azure Start Up Task

The start up task can Register COM components, install a component, or set registry keys. Startup actions are also commonly used for starting long-running processes. Startup tasks are available only for Web and Worker roles; VM roles cannot manage startup tasks.

Azure Role Life Cycle

Manage how each role responds when it is started, running, or stopped.
For more information