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-
- To deploy or use software we first need servers, firewalls, switches etc.
- Once server is setup then we need an OS then application server or database.
- 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.