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The blogged wandering of Robert W. Anderson

Cloud Services Continuum

I have found myself talking about cloud services a lot recently.  We have been talking about them here — there is an obvious synergy between what we do at Digipede and cloud services.  And I’ve been talking about them externally too: at the recent CloudCamp, on the Gillmor Gang, and in all sorts of other interesting contexts. 

Note that I refer to cloud services, not to the cloud.  I am not interested in defining cloud as a term, because I don’t think it very useful.  For those of us in the distributed computing space, cloud is the latest buzzword to compete with the word grid in terms of utter ambiguity.  I think the ship has already sailed on this one and I’m not going to try to call it back.

So, everyone is talking about cloud services and much of the conversation centers on understanding them and how they are changing the landscape.  Of course, cloud services are not one thing.  I find it helpful to think about them as parts of a continuum.  This seems useful regardless of the technical level of the people with whom I’m speaking.

imageThe diagram to the right shows this continuum from infrastructure to platform to software.   Brief definitions of these parts are:

  • Infrastructure includes provisioning of hardware or virtual computers on which one generally has control over the OS; therefore allowing the execution of arbitrary software.
  • Platform indicates a higher-level environment for which developers write custom applications.  Generally the developer is accepting some restrictions on the type of software they can write in exchange for built-in application scalability. 
  • Software (as a Service) indicates special-purpose software made available through the Internet.

I have indicated several companies that play at different parts of this stack.  This list is not comprehensive nor does it attempt to represent motion across the stack.

One scenario in which I find myself talking about the continuum is when people equate Amazon EC2 with Google App Engine.  EC2 is a flexible / scalable virtual hosting platform with provisioning APIs.  It allows you to dynamically scale the number of instances of your OS (i.e., Linux).  What you do with those instances is up to you.  Google App Engine operates at a much higher level in the stack.  It is a new software platform with specific APIs.  It requires developers to build for this specific platform.  yes, they are both in the cloud, but they are very different services. 

Another scenario in which the continuum is useful is in thinking about what vendors and new entrants might be up to.  The continuum makes one thing even more clear: many vendors that operate higher in the stack are relying on their own internal lower-level infrastructure or platform.  This begs some questions: which vendors will expose lower-level interfaces?  And of course, which vendors will move up the stack? 

  • SalesForce is already moving down with their PaaS offering. 
  • Any chance Google will expose its infrastructure stack?  I doubt it, but I do expect them to move down a little. 
  • Some of the readers of this blog probably know better than I where Amazon and Microsoft are planning to go.

Yet another way it is useful is in comparing vendors inside of a particular category.  Maybe I’ll write more on that later.

Is the continuum obvious?  Using the definition of obvious from patent law, yes, but I think it a useful paradigm.

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    Jason Etheridge wrote @ July 3rd, 2008 at 6:17 pm

An excellent summation! You’ve certainly boiled it down, so the reality can be appreciated without all the hyperbole.

Regarding Microsoft’s venture into this space, it seems self-evident that they’ll provide a platform that’s analogous to Google App Engine, but based entirely on a cut-down version of the .NET CLR. It would have the advantage of allowing development in any language that can work on the CLR, and will no doubt be fully supported by Visual Studio. They will also be server-side infrastructure specifically to support client-side Silverlight running in the browser; they’ll also be support for integrating with Live Mesh.

I’m curious what they’ll provide for persistence: the ability to provision SQL Server instances? Microsoft has nothing (that I’m aware of) that’s the equivalent of a scalable persistence store such as Google’s BigTable or Amazon’s S3 or SimpleDB.

It’s a great chance for Microsoft to capture a vast amount of mindshare: a facility giving the hordes of MS developers somewhere to host their web apps, with all the .NET goodness they’ve grown accustomed to.

The only real question is whether Microsoft can make this happen soon.

    Robert W. Anderson wrote @ July 3rd, 2008 at 9:37 pm

Thanks, Jason.

There are a lot of ideas floating around about what Microsoft is up to in the cloud platform space. It sounds like all will be revealed in October at the Microsoft PDC. I bet we’ll see services in beta shortly after that.

In terms of persistent data, Microsoft does have a cloud service: SQL Server Data Services. Ryan Dunn did a session on it at CloudCamp. It is more like a database than S3 with “relational” features coming in the future. You can sign up for the beta through the Microsoft Connect site.


    Matias Woloski wrote @ July 15th, 2008 at 7:44 pm

Excelent! I’ve been working on a diagram among the same lines. I like the separation you did between PaaS and IaaS.


[...] posted Cloud Services Continuum a couple of weeks back.  In that post I articulated a simplified view of cloud services and [...]

    Ramesh wrote @ August 1st, 2008 at 10:25 pm

Terrific summary…Hearing about these companies quite often didnt’ make much sense until i looked at this diagram which categorized them neatly..

[...] the current ‘cloud’ market space, although a bit more high level. Robert Anderson had a good post a little while back that distilled some of this, as did Peter Laird via a follow up to [...]

    eko didik widianto wrote @ June 6th, 2010 at 3:40 am

Thank you.
It makes me get more understanding about cloud computing.

    In the Cloud Computing « ห้องลับ wrote @ March 11th, 2012 at 9:24 am

[...] รูปที่ 1 Image from Robert W. Anderson’s blog [...]

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