Like it or not, the private cloud is hot. It was the talk of VMworld 2010 -- in fact, it was nearly the only topic of conversation. But it's increasingly clear that many enterprises, while intrigued by the concept, aren't at all sure about the benefits. Making sense of where the private cloud fits into the IT landscape isn't as straightforward as many would have us to believe.
First off, it's important to step back and take a good look at what a "private cloud" actually is. As I've explored in some of my more critical posts about the cloud in general, much of what makes up the cloud isn't new at all. The same is largely true of private clouds. In many ways, the private cloud is a relabeling of what many large enterprises have already been doing -- yet there is a difference.
The private cloud unites virtual and sometimes physical server management behind a framework of management software that implements automated self-service resource provisioning and chargeback. These features are not new in any sense -- though they have tended to be limited to high-end implementations, due to the complexity of configuring them in heterogeneous environments.
So here's how the private cloud is different: It's built to mimic the functionality of a public, multitenant cloud rather than simply automating a collection of privately managed server resources. This difference is subtle, yet very important.
Stand-alone provisioning and chargeback implementations, as they are implemented with certain high-end systems today, increase IT efficiency and more accurately reflect the cost of IT services. Those same services delivered as part of a private cloud shift the IT organization into the role of a cloud service provider -- creating an even greater degree of abstraction between resource consumers and the actual server, storage, and networking resources.
Personally, I think that's great. The more separation there is between the applications that run the business and the infrastructure that powers them, the better. Too often I've seen the perceived needs of a single application drive outlandish infrastructure investments that would have been far better spent elsewhere. By stuffing everything into an externally opaque cloud and charging back on a per-usage basis, such lopsided investments and others like it can be neatly avoided -- allowing IT to invest in infrastructure based on need.