At the enterprise level, the interest in private clouds still exceeds serious interest in public clouds. Gartner and others predict that private cloud investments in the enterprise will exceed public cloud through 2012. In my conversations with people, there appears to be some confusion as to just what is a private cloud, where you might find them, and how they can be used.
My definition of what distinguishes a private cloud from a public cloud is very simple — tenancy at the host level. If more than one organization is sharing the physical infrastructure, it’s Public. If it’s just you on the box – it’s Private. It’s not about where it runs, because some of my smarter cloud colleagues in the industry believe that the hottest deployment model for private clouds this year will be external — in someone else’s data center. That means that “most” private cloud deployments in 2010 could very well NOT be inside the corporate firewall.
Digging into the reasons, this makes a lot of sense. If your developers want a dev/test cloud, they have three options: use a public cloud, build a private internal cloud, or get a third party to stand up a private cloud (dedicated infrastructure) in their data center. Many organizations are not ready to use public clouds yet due to concerns over security, control, governance or other reasons. The next place the developers may turn is to their internal, totally overworked and under funded, IT infrastructure group. We know how that conversation is likely to go…
So, if you need an internal cloud, but don’t have time to wait a few quarters for your cloud to arrive, what do you do? You put it in someone else’s data center. This is the basis for Rackspace’s private cloud offering. Unisys can do this too, particularly for customers who need an extra level of security and customization (such as physical and virtual servers, etc.).