What is the Difference Between IaaS and PaaS?

If infrastructure as a service is a way to provide virtual machines, servers, storage and other infrastructure services via the cloud, what is platform as a service (PaaS)? There has long been confusion between the two — and for good reason.

Both offer computing via the cloud, but at different layers. The difference is this: The PaaS model provides both a computing platform, consisting of application building blocks such as databases and file sharing, along with applications that run on the platform, while IaaS provides the infrastructure building blocks only — storage, hardware and networking components.

Clearly, PaaS and IaaS are closely related, because applications, platforms and infrastructure can’t work without each other. This has led some to speculate that the two eventually will become one layer of service. In the past year, Microsoft added an IaaS platform on top of its Azure PaaS platform, while Amazon added PaaS functions to its IaaS platform.

And just recently, HP announced plans to launch a cloud service that will combine PaaS, IaaS and SaaS (software as a service). It will offer both structured and unstructured databases, along with data analytics as a service. It will also offer tools to help developers use software languages such as Ruby, Java and PHP, as well as ways for users to provision and manage workloads remotely.

Combining two layers (or even three) of cloud services is a trend that may grow over time. By adopting some cloud infrastructure earlier rather than later, organizations will be better prepared to move more service to the cloud — in whatever form they happen to take.

Downnload our whitepaper on Infrastructure as a Service for more information.