Virtualization vs. cloud: Let's get this straight

Reports of clouds abound, but true clouds are hard to come by. Turns out, many don't know what separates virtualization vs. cloud. We're here to help.

Over the past few years, we've seen a slow but steady climb in the number of organizations saying they're using or considering a private cloud. But this year, our Readers' Choice Survey showed a bigger jump in the number of companies saying they plan to deploy a private cloud -- 15.5%, up 7.3% over last year. A more surprising trend comes from a recent Forrester Research Inc. study showing that this jump may have more to do with terminology than with tangible changes. The report showed that 70% of infrastructures that admins dubbed private clouds weren't private clouds at all.

Let's Get This Straight logoWhere's the disconnect here? Are admins simply confused about all the nuances of a private cloud? Or has the terminology changed, opening the door for a more liberal application of the "cloud" label? Does it even matter what we call it? The question of what constitutes virtualization vs. cloud can be confusing, so let's get this straight.

Virtualization vs. cloud: A marketing problem?

Virtualization and cloud computing are often confused, but there are important differences that make the distinction more than just a matter of terminology. While server virtualization is the widespread industry standard, it's worth defining what a virtual data center is so we can see how it differs from a private cloud. At the most basic level, virtualization abstracts workloads from hardware. Taken further, this abstraction allows for the pooling of storage, network and compute resources that can be dynamically allocated on-demand. But a pool of centrally managed resources and automated provisioning does not make a cloud.

It's not surprising that many IT pros have trouble understanding exactly what a cloud is and whether they need one, given the generous use of the word "cloud" in today's market. In many cases, vendors eager to capitalize on the cloud craze simply rebrand existing products with the word "cloud," a practice called cloud washing. In recent years, analysts have accused major vendors, like Hewlett-Packard and Oracle Corp., of deceptive marketing practices because their cloud-labeled products don't actually create a true cloud.

What is a private cloud?

Virtualization is the foundation for a cloud, but virtualization alone (even an infrastructure that is 100% virtualized) does not make a cloud. And that's an official definition; industry experts and organizations like the National Institute of Standards and Technology have defined the term "cloud computing."

To summarize, the NIST says cloud computing is a model for enabling on-demand network access to a shared pool of resources that can be rapidly provisioned with minimal effort or interaction. In order to be called a cloud, under this definition, your infrastructure must have five essential characteristics.

  1. On-demand service
  2. Broad network access
  3. Resource pooling
  4. Rapid elasticity
  5. Measured service, or pay-per-use model

If it's missing any one of these characteristics, simply calling your virtual infrastructure a private cloud does not make it so. If for example, your end-users cannot provision a new virtual machine without the assistance of IT staff, you're missing the automated on-demand service a cloud should offer. If you cannot easily monitor, control and report resource usage, your infrastructure is missing an essential piece of the cloud model.

Some experts may define a cloud differently, but nearly all agree it is more than a shared pool of resources. IT must provide some sort of automated provisioning, the flexibility to grow on demand and a way to track and charge for resource usage.

Do you need a private cloud?

So now that we have an idea of exactly what a private cloud is, how do you approach the virtualization vs. cloud comparison to decide if you need a private cloud?

In addition to the misperception about what a private cloud is, there's also confusion over the advantages a private cloud can offer. Private clouds are not all about cost savings. The real benefits come from self-service, resource tracking and the flexibility to meet changing resource demands -- all of which may or may not bring about cost savings.

The decision about whether you need a private cloud should be based on whether the automation and flexibility will improve service and whether that improved service comes with a justifiable price. Start with a virtualization vs. cloud cost-benefit analysis that considers the added cost of maintaining the necessary automation and the software that dynamically manages resources.

Deploying a private cloud simply because the powers that be have heard the cloud buzz is not a good reason. If your infrastructure is effectively serving your end users but is missing one of the essential points needed to call it a cloud, who cares? Maybe you don't need a private cloud after all. Then again, we won't tell if you need to start calling your infrastructure a private cloud to get your boss off your back.

Dig Deeper on Cloud computing architecture