Given that I am going to be talking with the Eucalyptus guys in a week I figured it was a pretty opportune time to sit down and really think about private clouds. Much to the chagrin of some people, I firmly believe that private clouds are still clouds. In my mind the real question is where do private clouds fit in the cloud ecosystem?
Lets get one thing straight, private clouds are transitional. What I mean by this is that private clouds are not going to be here forever, they are instead filling in a very important gap in the current cloud landscape. While a large number of servers could be moved into the cloud today, there are still quite a few use cases which don't allow for such rapid change.
To illustrate one such example, lets say you head IT for some Fortune 500 mega-corporation. After a few months of waiting your purchase order for X racks of servers (finally) goes through. You estimated that with the servers you have ordered you should have sufficient capacity for the next year. Shortly thereafter you reassess the opportunities provided by the cloud and deem it fit for use by your company. So enthusiastic about the change you even decide to join Lew Moorman and Marc Benioff on stage at some cloud event to chant "No more servers!" and pledge never to buy another one. However, upon returning to the reality of work you recall that in addition to the servers you currently have running in your data center, the new racks you just ordered are going to provide you sufficient capacity for the next year. Assuming a 3-5 year lifespan of the average server you are looking at at least two years before you can move a majority of your servers into the cloud. Enter the private cloud. You already have the resources, there is no reason for them to sit around and gather dust. Make your own private cloud with the existing resources and expand out into the public cloud in as necessary. Once the servers in your data center have run their course, toss them and move to the cloud.
The other big elephant in the room with regards to moving to the public cloud is compliance. These days it seems like every big industry has its own compliance and regulatory constraints that must be met. Whether it's PCI for credit card processing or HIPAA in the health fields, almost none of the big cloud vendors have met the requirements for becoming compliant. In fact, its not even clear that they are trying. Unfortunately, regulation is not something that can be skirted around, it is a big time show stopper. This means that companies in industries which have regulatory requirements are going to be in a holding pattern around the public cloud for the foreseeable future. What's the next best thing? That's right, private cloud.
While private clouds are transitional, they will be around until the aforementioned issues are addressed. For some this may be on the order or months or a year, but for others it will probably be much longer. The regulatory issue in particular is not an overnight fix, I think it is going to be a big parachute that prevents the cloud from running at full sprint for the year. So while the cloud is transitional, that transition period is looking like its going to be a long one.