My recent post on how sick I am of people being confused by the basic concept of cloud computing quickly brought out the comments on “what cloud is” and “what cloud is not.” And the truth is, it’s a little messy, there’s not a clear definition, especially across “the three aaSes“. So now let’s have a post for the advanced students. Chip in with your thoughts!
Here’s my Grand Unified Theory of Cloud Computing. Rather than being a legalistic definition that will always be wrong for some instances of cloud, it attempts to convey the history and related concepts that inform the cloud.
The Grand Unified Theory of Cloud Computing
( ISP -> colo -> MSP ) + virtualization + HPC + (AJAX + SOAP -> REST APIs) = IaaS
(( web site -> web app -> ASP ) + virtualization + fast ubiquitous Internet + [ RIA browsers & mobile ] = SaaS
( IDEs & 4GLs ) + ( EAI -> SOA ) + SaaS + IaaS = PaaS
[ IaaS | PaaS | SaaS ] + [ devops | open source | noSQL ] = cloud
* Note, I don’t agree with all those Wikipedia definitions, they are only linked to clue in people unsure about a given term
Sure, that’s where the cloud comes from, but “what is the cloud?” Well, here’s my thoughts, the Seven Pillars of Cloud Computing. Having more of these makes something “more cloudy” and having fewer makes something “less cloudy.” Arguments over whether some specific offering “is cloud” or not, however, is for people without sufficiently challenging jobs.
The Seven Pillars of Cloud Computing
“The Cloud” may be characterized as:
- An outsourced managed service
- providing hosted computing or functionality
- delivered over the Internet
- offering extreme scalability
- by using dynamically provisioned, multitenant, virtualized systems, storage, and applications
- controlled via REST APIs
- and billed in a utility manner.
You can remove one or more of these pillars to form most of the things people sell you as “private cloud,” for example, losing specific cloud benefits in exchange for other concerns.
Now there’s also the new vs old argument. There’s the technohipsters that say “Cloud is nothing new, I was doing that back in the ’90’s.” And some of that is true, but only in the most uninteresting way. The old and the new have, via alchemy, begun to help users realize benefits beyond what they did before.
Benefits of Cloud – What and How
Not New:
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Pretty New:
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Resulting Benefits:
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Okay, Clouderati – what do you think?
the agile admin 
LoL, nice exhaustive definition, I preferred you’re first “Mystifying Cloud Computer” post last week.
It reminds me of the old “What is Web 2.0” days.
I think the whole idea of “Cloud” was that it was undefined and shapeless.
Clouds are unique and don’t always look the same. Even if 2 people on the ground are looking up.
I fear that the marketing department has already irrevocably co-opted the term. I’m starting to steer away from it as much as possible, either citing the specific “aaS” I am talking about, or going with the generic term “utility computing” instead. My hope is that gets more to the root benefits of the concept without dragging in all the hazy and debatable aspects.
As far as a device for clarifying the term, I like your seven pillars concept, but I think it’s probably too late. Introducing “the cloud” into actual business conversations these days just serves to unfocus them. The punditocracy probably needs a convenient handle, but talking with clients, I would rather break out and discuss the relevant pillars and services on their own merits since, as you point out, not all will apply in every instance.