The role of open source firms has been to consolidate a set of rapidly occurring changes in a class of commercial software, frequently adding their own updates to the code and then commoditizing them in the marketplace. The Apache Web server did that. The JBoss Application Server under Marc Fleury's team of developers did it.

But in cloud software, the opposite is happening. There are no leading commercial products, but there are four open source projects. The commercial products are not advertising the capabilities of a new class of software; the open source projects are. And while one, and only one, open source project tends to gain the upper hand in each new category, there are three contenders in the cloud space, with none of them having a clear advantage.

It was thus an unusual situation when leaders of the three projects appeared on a panel together Thursday at the GigaOm Structure 2012 event in San Francisco. They were: Chris Kemp, the self-assured, 34-year-old former CTO at NASA, a founder of the OpenStack project, and CEO of Nebula, an OpenStack company; Sameer Dholakia, the tough and poised general manager of the Citrix cloud unit that acquired Cloud.com and converted its product into the CloudStack Project at the Apache Software Foundation; and Marten Mickos, sagacious CEO of Eucalyptus Systems, with deep experience in managing open source code as a business.

The stage had been set with heightened tension between the three as Citrix announced in April that CloudStack would become an Apache project. Citrix had been a contributor to the OpenStack project. But Dholakia explained in an interview that Citrix bought Cloud.com "because we needed to be in the market sooner than OpenStack would allow to compete with VMware."

Among OpenStack supporters, Kemp in particular responded with bitterness to Citrix's establishing another and competing open source project. Citrix's earlier support for OpenStack had been a front and it never intended to stick with the project to see it bear fruit, he supposedly said in comments cited by Eric Knorr at InfoWorld. Dholakia says that isn't so. Citrix was a major contributor to OpenStack and remains a contributor to this day.

[Want to learn more about how OpenStack is distinguished from competing projects and products? See OpenStack Is Not A Proprietary Cloud, Kemp Argues. ]

Meanwhile, during the OpenStack Summit in May, Mickos didn't hesitate to spread the news that NASA, a co-founder of OpenStack with Rackspace, had left the project a month earlier. Asked about that development, Rackspace president Lew Moorman said NASA's contributions had dwindled over the past year and NASA was clearly not able to maintain its role as an early originator of code. The Nova compute module in OpenStack came from NASA, but two of the personalities driving NASA contributions, Joshua McKenty and Kemp himself, left the federal agency to found OpenStack companies, Piston and Nebula. Meanwhile, new IT administrators shifted the focus back into federal IT cost cutting. NASA leaving was "not news," Moorman said in an interview at Structure.

Moorman spoke more bluntly at Structure about what he saw as the shortcomings of Mickos' firm's strategy. Both Eucalyptus and CloudStack are striving for Amazon compatibility in their services' APIs. Going down that road is a dead end for an open source project, he charged. "An API is nothing more than a bridge, a protocol, an interface to the underlying technology. Everything behind the API is invisible to you. You can't replicate the full service," he said. That means the open source project is "fused to the cloud provider" and must follow the lead of a dominant company, as opposed to inventing and leading on its own.

With these preliminaries, the stage was set for pyrotechnics as the advocates of OpenStack, CloudStack, and Eucalyptus sat down to debate Thursday. The question put to them: "The cloud industry has grown up, and after six years Amazon is still on top. Do the open source efforts have a chance?" got things off to a fast start.

OpenStack is about to move from Rackspace stewardship to its own foundation, modeled on Linux, Apache, and Mozilla. Its open principles have "allowed a broad set of the IT community to get behind it. As more companies fund it and more products get built, you will see that community continue to grow," said Kemp, playing OpenStack's card of having attracted 180 member companies.