Overview of Windows Azure

Windows azure is Microsoft's cloud platform. It includes Windows Azure operating system that serves as the Platform-as-a-Service (PAAS) and Infrastructure-as-a Service (IAAS). In order to understand AAS lets take an example-

1. To deploy or use software we first need servers, firewalls, switches etc.
2. Once server is setup then we need an OS then application server or database.
3. Then we have to install the actual application.

So we need some infrastructure, then platform and software. Windows Azure provides platform and infrastructure by providing a scalable and cost-effective computing, storage and networking resources on demand.

Windows Azure has three main components in azure: Compute, Storage and Fabric.

1) Windows Azure Compute:

Windows azure provides hosting environment for managed code. It provides computation service through roles. Windows azure supports 3 types of roles:

• Web roles used for web application programming and supported by IIS7
• Worker roles used for background processing of web roles.
• Virtual Machine (VM) roles used for migrating windows server applications to Windows azure in an easy way.

Within a subscription one can have zero or more hosted service. Each hosted service can have deployment- either production or staging. And each deployment can have one or more roles of any types. Each role can have multiple instances.

2) Windows Azure Storage:

Windows azure provides storage in cloud. It provides 4 types of storage services:

• Queues for messaging between web roles and worker roles.
• Tables for storing structural data.
• BLOBs (Binary Large Objects) to store text, files or large data.
• Windows Azure Drives (VHD) to mount a page blob. These can be uploaded and downloaded via blobs.

3) Windows Azure AppFabric:

AppFabric provides infrastructure services for developing, deploying and managing Windows azure application. It provides 5 services:

• Service bus It provides secure connectivity between distributed and disconnected applications in cloud.
• Access control It grants access control to application and services based on the identity user. So the authorization decisions are pulled out from application into a set of rules that can transform incoming security claims into claims that applications understand.
• Caching It provides caching for high speed access, scaling, and high availability of data to application. It is available for developer preview only.
• Integration It provides integration between windows azure application and other SAAS. It will be available by CTP 2011.
• Composite App It provides a hosting environment for WCF web services and workflows. It will be available by CTP 2011.