When we first heard about cloud computing, public clouds got most of the attention. But as IT managers looked at the security risks of having data outside the corporate firewall, they turned their attention to private clouds, which analysts and various surveys suggest will get more enterprise investment in the next few years.
But private clouds have their share of challenges too. There are management issues and operational processes to figure out. And, of course, an on-premises private cloud needs to be built internally by IT, which takes time, money and a climb up the learning curve. Indeed, the transition from a traditional data center -- even one with some servers virtualized -- to a private cloud architecture is no easy task, especially given that the entire data center won't be cloud-enabled, at least not right away.
(While we generally think of a private cloud as being inside a company's firewall, a private cloud can also be off-premises -- hosted by a third party -- and still remain under the control of the company's IT organization. But this article is only about on-premises private clouds.)
Also, despite the hype you might hear, no single vendor today provides all of the software required to build and manage a real private cloud -- that is, one with server virtualization, storage virtualization, network virtualization, and resource automation and orchestration. Look for vendors to increasingly create their own definitions of private cloud to fit their product sets.
Moreover, you'll have to determine whether your staff has the experience and skills required to support a private-cloud environment, or whether you need to hire someone who has been involved in building private clouds.
Not a Traditional Data Center
Many IT managers equate a private cloud with virtualization. What they describe is usually virtual infrastructure, meaning that "you can treat your servers, storage and networks as a single pool of resources that workloads can request on demand," explains Tony Iams, an analyst at Ideas International Ltd., an IT research firm.
But virtualization and the cloud aren't the same thing; to be considered a cloud, the architecture must be set up to provide resource orchestration and automation on top of the virtualization layer.
Orchestration is the coordinated delivery of many types of resources, such as processors, storage and networks, to provide an integrated provisioning process. It means that resources can be delivered in minutes rather than days or weeks. A single command or request causes a number of actions to occur, possibly in a specific sequence, to coordinate the provisioning request.
The whole point of a private cloud is to allow IT managers to reduce costs and provide so-called agile provisioning rather than just making management of the infrastructure more convenient. A private cloud with virtualization underpinnings turns the technology infrastructure into a pool of resources that can be provisioned on demand with minimal manual labor.