Introduction

The Windows Azure platform is Microsoft’s cloud-based application hosting environment that became commercially available in Feb. 2010. The platform, which now runs more than 20,000 customer applications, comprises a hosted OS, a relational database, and other supporting services that help developers deploy, connect, and secure Internet-based applications, while potentially leveraging other applications hosted on-premises. Azure is primarily a Platform as a Service (PaaS) offering, which could provide scalability, manageability, and geographic distribution advantages while cutting costs over deployments hosted on-premises or elsewhere. However, to fully realize Azure’s potential, planning is important and application code may need to be rewritten.

Platform as a Service Offers New Opportunities

Azure’s approach to hosted computing, with a couple of exceptions, is a PaaS architecture, which could help organizations and ISVs in several ways, especially when they design their applications to take advantage of the architecture. In a PaaS offering, a cloud vendor rents out the use of computer resources and takes responsibility for managing not only the hardware but also the OS and platform software running on the computers; for example, the vendor installs software patches such as those that eliminate security vulnerabilities, as they become available. Customers are responsible for deploying and managing their applications on the computers (such as organizational line-of-business software or services offered by ISVs). PaaS architecture should be compared and contrasted with Infrastructure as a Service (IaaS) architecture.