Though I think the term is generally useless as either an analytical tool or category of computing that large entities can and should use in planning strategy, I’m not quite ready to give up on the idea that “the cloud” does have at least some worthwhile content. And after three days at the Cloud Expo, I’d like to suggest a simple signature of cloudiness that seems to fit everything I’ve seen with the sole exception of Oracle’s “cloud” offerings. Here’s my idea: it’s “cloud” at the platform and infrastructure layers if users can provision their own resources via some automated system.

Viewing cloud through the lens of user-driven provisioning sheds light on two themes that I’ve seen come up again and again in multiple presentations at the Cloud Expo: 1) cloud adoption is currently easiest for and happening most rapidly in the small business (SMB) segment, and 2) while the enterprise is still in the exploratory phase with cloud, cloud computing will ultimately transform the IT department into a collection of devops teams that create and maintain a collection of “apps” and services, and it will transform the enterprise user experience into something very much like the app- and service-centric experience that consumers and SMBs now get from the web and from their smartphones.

SMBs: ahead in the cloud

It almost goes without saying that the main reason that SMBs can go cloud more quickly than the enterprise is the former’s either total lack of legacy systems or minimal investment in such systems. SMBs just don’t have a lot of baggage preventing them from moving to Google Apps, or Salesforce.com, or any of the other myriad cloud services on offer.

It’s also drastically cheaper for SMBs to move to rental and utility models for compute resources, rather than owning their own. As Rackspace CTO John Engates put it in a conversation with Wired.com on Tuesday, it’s ridiculous that a doctor’s office would have a server closet and a bunch of shrink-wrapped software licenses to manage. By throwing out the server closet and moving their entire operation to cloud-based SaaS, SMBs can save a bundle.

Aside from lowering costs, the main thing that cloud does for SMBs is it empowers them to select and provision their own tech resources without the need for hand-holding or intervention by trained professionals. Any doctor can add seats to a Google Apps account, but the same can’t be said for adding new Windows and Exchange accounts on a LAN workgroup or domain. This user-initiated, user-managed provisioning is pretty much the primary appeal of the cloud—it’s where the other benefits like lower costs flow from.

Control and appification

A number of presenters commented on the natural fit between cloud and SMB, and the focus of much of what I’ve seen at the Expo is around how to make the cloud equally as compelling for enterprise users. The challenge that cloud faces in the enterprise is that the enterprise needs something that the SMB segment does not: control. Thus the answer to the question of how to make the cloud enterprise-friendly seems mostly to involve transferring control and ownership back to centralized IT. In this regard, there’s a spectrum of options that offer varying degrees of control.

Private cloud: This is where IT owns and runs the whole thing. The cloud is brought up in the corporation’s datacenter—the hardware and site are either owned or leased—and is run by IT.

Managed cloud: In this scenario, a datacenter provider leases either floor space and/or hardware, and the provider does some amount of maintenance. With Rackspace’s managed cloud offering, for instance, Rackspace does everything for you, from leasing you the servers to running the cloud.

Hybrid cloud: There’s probably more hype around this than anything else at the moment. With a hybrid cloud config, the corporation uses either a managed or private cloud, and then bursts workloads onto a public cloud during peak usage. According to the presenters here, most enterprise customers are seriously interested in this option.

All of these options are aimed at building something that works like “the cloud,” but that’s behind the corporate firewall and under the purview of IT. But if it’s behind a corporate firewall and controlled by central IT, in what respect does it work like the cloud? In almost every case, the answer is going to be that it’s “cloudy” in that users can provision their own IT resources directly from the cloud, without having to deal with a human.

In a non-cloud private datacenter, for instance, users who want to bring up new VMs might have to submit a request to IT and get it approved. A cloudy way to do this is to automate the entire process and provide a portal—an internal “web app”, if you will—where departments or individual users can bring up, monitor, manage, and shut down their own VMs.

This “there’s an app for that” approach can be applied to almost anything, because the fundamental design rule at work here is to decompose everything people do with their computers into small, self-contained services and then push the ability to select and manage those services down to the lowest possible level of the corporate hierarchy. What you end up with is an IT department filled with teams that maintain these apps and services, and a user base that interacts with the apps and services themselves when they want to do something new, and not so much with the IT department.

The key enabler for this appification of IT will be the increasing level of automation of the maintenance phase of the software lifecycle that the cloud enables. Sysadmin roles are increasingly being replaced in the cloud by automated systems run by one or two people—Facebook’s FBAR is an example of this trend. When this automation process is complete for private clouds, then IT’s support and maintenance functions are reduced to a handful of people who tend the systems that tend the cloud. (And the provisioning function is, as I described above, taken over by the users themselves.)

Ultimately, there can be no “adoption” of cloud by enterprise IT. Instead, the cloud will effectively replace corporate IT as means by which users select and provision technologies that let them do new things and do existing things in new ways. There will still be a corporate IT budget, of course, but it’ll be spent on a combination of cloud technology and on app and service developers who push out new features in response to both user requests and the cloud’s evolving maintenance/administration needs.