In a largely downbeat year, I couldn't help but delight in Larry Ellison's over-the-top takedown of cloud computing last September. It was classic Larry: In an onstage interview he asks why, exactly, computers attached to networks have suddenly become "the cloud." "What are you talking about?" he yells over and over.
Fair question -- and not just Ellison is asking it. The twelfth most popular InfoWorld article in 2009 was What cloud computing really means, a 900-word definition written by executive editor Galen Gruman and me 20 months ago. It's difficult to recall any trend about which the basic question, "Now, what is it again?" was still being asked more than two years after it emerged. In our 2008 article we offered a simple answer: Subscription-based or pay-per-use services that, in real time over the Internet, extend IT's capabilities.
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While we still stand by that definition, all kinds of issues are mixed up in this fluffy hairball of a trend. David Linthicum has examined many of them this year in his outstanding Cloud Computing blog for InfoWorld. Here, we'll answer five key questions that loomed large on the cloud horizon in 2009.
What defines a cloud service?
In keeping with any trend at the peak of its hype curve, confusion reigns over what is and what is not a cloud service. In our brief 2008 definition, we didn't talk about the definition of a cloud service in detail; we just laid out the main types of services. So based on a growing industry consensus -- and some good work by the analyst firm IDC -- let's try and nail this down:
Self-service: If you can't go to a Web site, set up your account(s), and start provisioning over the Web yourself, then it's not a cloud service. With the self-service approach, epitomized by Amazon EC2, you don't need to spend hours on the phone working out your special configuration. In fact, you can't.
Commodity pricing: Self-service enables cloud service providers to keep costs down. You have an array of pay-per-use (or subscription) options, and if you don't like them, you go somewhere else. If you can negotiate and get some special deal just for you, it's conventional hosting or outsourcing, not a cloud service.
Transparent scalability: If you want more of a service, you go to your service provider's Web site and specify more. Your bill goes up accordingly, but otherwise, you don't have to think about it, whether you're talking about twice the number of VMs or triple the number of seats for a cloud-based development platform.
Shared infrastructure: Cloud services have a one-to-many relationship with their customers. Software-as-a-service providers, for example, deliver their wares in multitenanted fashion, where a single instance of the software runs on the provider's servers and all users log onto that same instance. Infrastructure-as-a-service providers move around customer VMs as needed, so that VMs from multiple customers often run on the same server.