Public cloud computing is about capacity and scale on-demand, private cloud computing however, is not.


Legos. Nearly every child has them, and nearly every parent knows that giving a child a Lego “set” is going to end the same way: the set will be put together according to instructions exactly once (usually by the parent) and then the blocks will be incorporated into the large collection of other Lego sets to become part of something completely different.

This is a process we actually encourage as parents – the ability to envision and end-result and to execute on that vision by using the tools at hand to realize it. A child “sees” an end-product, a “thing” they wish to build and they have no problem with using pieces from disparate “sets” to build it. We might call that creativity, innovation, and ingenuity. We are proud when our children identify a problem – how do I build this thing – and are able to formulate a plan to solve it.

So why is it when we grow up and start talking about cloud computing that we suddenly abhor those same characteristics in IT?


That’s really what’s happening right now within our industry. Cloud computing providers and public-only pundits have a set of instructions that define how the building blocks of cloud computing (compute, network, and storage resources) should be put together to form an end-product. But IT, like our innovative and creative children, has a different vision; they see those building blocks as capable of serving other purposes within the data center. They are the means to an end, a tool, a foundation. 

Judith Hurwitz recently explored the topic of private clouds in “What’s a private cloud anyway?” and laid out some key principles of cloud computing:

blockquote There are some key principles of the cloud that I think are worth recounting:

1. A cloud is designed to optimize and manage workloads for efficiency. Therefore repeatable and consistent workloads are most appropriate for the cloud.

2. A cloud is intended to implement automation and virtualization so that users can add and subtract services and capacity based on demand.

3. A cloud environment needs to be economically viable.

Why aren’t traditional data centers private clouds?  What if a data center adds some self-service and  virtualization? Is that enough?  Probably not. 

-- “What’s a private cloud anyway?”, Judith Hurwitz’s twitterbird Cloud-Centric Weblog

What’s common to these “key principles” is that they assume an intent that may or may not be applicable to the enterprise. Judith lays this out in key principle number two and makes the assumption that “cloud” is all about auto-scaling services. Herein lies the disconnect between public and private cloud computing. While public cloud computing focuses on providing resources as a utility, private cloud computing is more about efficiency in resource distribution and processes.

The resource model, the virtualization and integrated infrastructure supporting the rapid provisioning and migration of workloads around an environment are the building blocks upon which a cloud computing model is built. The intended use and purpose to which the end-product is ultimately put is different. Public cloud puts those resources to work generating revenue by offering them up cheaply affordably to other folks while private cloud puts those resources to work generating efficiency and time savings for enterprise IT staff.


What is happening is that the focus of cloud computing is evolving; it’s moving from “what is it” to “what does it do”.

And it is the latter that is much more important in the big scheme of things than the former. Public cloud provides resources-on-demand, primarily compute or storage resources on demand. Private cloud provides flexibility and efficiency and process automation. Public cloud resources may be incorporated into a private cloud as part of the flexibility and efficiency goals, but it is not a requirement. The intent behind a private cloud is in fact not capacity on demand, but more efficient usage and management of resources. 

The focus of cloud is changing from what it is to what it does and the intention behind cloud computing implementations is highly variable and dependent on the implementers. Private cloud computing is implemented for different reasons than public cloud computing. Private cloud implementations are not focused on economy of scale or cheap resources, they are focused on efficiency and processes.

Private cloud implementers are not trying to be Amazon or Google or They’re trying to be a more efficient, leaner version of themselves – IT as a Service. They’ve taken the building blocks – the resources – and are putting them together in a way that makes it possible for them to achieve their goals, not the goals of public  cloud computing. If that efficiency sometimes requires the use of external, public cloud computing resources then that’s where the two meet and are often considered “hybrid” cloud computing.

image The difference between what a cloud “is” and what it “does” is an important distinction especially for those who want to “sell” a cloud solution. Enterprises aren’t trying to build a public cloud environment, so trying to sell the benefits of a solution based on its ability to mimic a public cloud in a private data center is almost certainly a poor strategy. Similarly, trying to “sell” public cloud computing as the answer to all IT’s problems when you haven’t ascertained what it is the enterprise is trying to do with cloud computing is also going to fail. Rather we should take a lesson from our own experiences outside IT with our children and stop trying to force IT into a mold based on some set of instructions someone else put together and listen to what it is they are trying to do.

The intention of a private cloud computing implementation is not the same as that of a public cloud computing implementation. Which ultimately means that “success” or “failure” of such implementations will be measured by a completely different set of sticks.


We’ll debate private cloud and dig into the obstacles (and solutions to them) enterprises are experiencing in moving forward with private cloud computing in the Private Cloud Track at CloudConnect 2011. Hope to see you there!

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