The interest in private cloud computing continues to change the behavior of cloud providers. Many initially stated they would not sell their technology as on-site software, but they are now changing their tune.Windows Azure Platform Appliance for on-site use was announced last month. This is a bit of a back track from Microsoft, who initially stated that they would not offer Azure as a private cloud offering. However, the requirements of the Microsoft channel partners to actually sell something in a box versus in a cloud, and the interest in private cloud computing was just too tempting for Microsoft not to push out a private cloud version of their technology.
While Amazon Web Services (AWS) is the poster child for cloud computing success, in 2009 they also began offering a Virtual Private Cloud service. This service allows their customers to leverage parts of AWS as if the parts were owned and operated by them. Many other public IaaS providers are following up with a similar offer.
Meanwhile, the debate rages on around the use of the concept and the term "private clouds." Most cloud computing purists reject private clouds as a true cloud because they only focus on sharing within a single enterprise or government agency, and thus are not as effective or efficient as public clouds.
Moreover, many define private cloud differently. Many look at a set of virtualized servers as an instance of private clouds, while most, including me, would not consider that as having all of the characteristics of a true cloud platform. They are missing important things such as multitenancy, use-based accounting, auto-provisioning, and so on.
So, what gives? Clearly cloud computing is having an affect on how we want to consume computing resources going forward. While the initial cloud computing offerings were publically shareable, most enterprises do not yet want to give up the control and security when placing systems on public cloud providers. Thus, when they feel the peer pressure and perhaps the executive pressure to move to the clouds, they opt for the clouds they can hug.
I would not view this as a rejection of public clouds. It is more of an indicator that those moving to the clouds want to do so in baby steps, and private clouds just seem so much less risky than the public options. That said, considering that private clouds are completely under your control, so is the responsibility to create and maintain the security and governance solution, as well as the configuration and maintenance of the local cloud. You want to hug it, you have to take care of it.
I see private clouds as a truly valuable architectural option, but it's not the only option. I suspect that many times private clouds are leveraged when public clouds are a better fit. Thus, this is not a matter of requirements meeting a solution, but that the solution should fit into the comfort zone of those who leverage it, which is a bit illogical to me. However, I also see private clouds as an easy step for most organizations. If this step gets them ultimately and successfully to the clouds, I'm all for it.It's an interesting thing. Everyone loves public cloud computing, but the initial adoption seems to be around private clouds, or, better put, clouds you can hug... Many initially stated they would not sell their technology as on-site software, but they are now changing their tune.