Deconstructing Virtualization and the Cloud

It’s been nearly two years since the term "cloud computing" leaked into the IT lexicon and still many leading experts in the field are struggling to come up with a definition.

That has to be a testament to either the cloud’s broad impact on all manner of enterprise functions or the fact that it is a nebulous term signifying everything, or nothing at all.

Either way, the hunt is still on for an exact, or at least a satisfactory, definition of what the cloud is and what it isn’t.

If there is any consensus, though, it is that cloud computing and virtualization are not one and the same. This fact has to be restated every once in a while following repeated attempts to conflate the two — either by ignorance or design. Tech consultant Rajan Chandras, for one, took on the subject following reports of Dell’s recent purchase of 3PAR in which the two terms were used interchangeably. His take is that while virtualization is largely a simulation of traditional hardware functions within a software environment, cloud computing is a repositioning of standard applications as Internet-based services. The two are interconnected, for sure, but they are not the same.

The 451 Group’s Dan Kusnetzky carried the ball even further, noting that virtualization is all about abstracting computing function into logical environments for the sake of increased flexibility, scalability and performance, but cloud computing is the delivery mechanism on which resources can be dispersed over a wide area and to numerous consumers. In this view, virtualization greatly simplifies cloud computing but is not an essential component.

Part of the problem, according to David Linthicum, CTO of services distribution firm Bick Group, is that the cloud is so widely defined already that it can mean almost anything you want it to be. So while the cloud does indeed encompass virtualization, it also incorporates a good deal of multitenancy, auto-provisioning and a host of other concepts. Unfortunately, as more and more virtual products and services are tailored to the cloud, expect to see more confusion regarding the two, not less.

At the risk of muddying the waters even further, I’d like to take my own stab as clarifying this argument, not by focusing on what the cloud and virtualization are, but what they aren’t. True, virtualization lets you decouple operating systems, applications and other resources from rigid hardware constraints, but it doesn’t let you deliver those resources to a wide audience much beyond your data center walls.

The cloud, on the other hand, does enable the kind of mass distribution of resources by repackaging them as services. But it can only do so on the kind of scale that makes it worthwhile by using an underlying virtual environment.

In that sense then, the confusion shouldn’t be so much between virtualization and the cloud, but between the cloud and the various XaaS platforms out there. Specifically, I’d like to know where something like a Platform-as-a-Service (PaaS) ends and where the cloud begins, and whether or not either service represents the most efficient and effective use of IT resources.