Renski says he has no problem with VMware employees contributing code to Quantum, as Dan Wendlandt does. The problem lies in VMware's "gold" status as a sponsor of the organization and its potential board membership. In an email to me, Renski elaborated:

"Through the very nature of business that VMware is engaged in they are simply unable to 'promote OpenStack software' as that would imply cannibalizing their existing business. For instance, they would never unlock ESX hypervisor to allow for some of the same features that are present in KVM (such as live migration) without forcing people to pay for vSphere. Without live migration capabilities, ESX is not relevant for an OpenStack environment. VMware can't promote OpenStack and compete with it at the same time. If you can't promote it, you can't help the foundation on its mission and you can't be a gold sponsor," Renski wrote.

However, some fear that denying VMware gold sponsor status would prompt VMware to pull Nicira expertise from the Quantum project. Renski thinks that risk isn't great, citing Mirantis' investment in three full-time developers, along with investments by HP, IBM, Red Hat and others.

"This is the beauty of open source," he said in his email. "Nobody, including VMware, can derail OpenStack development velocity."

Jonathan Bryce, executive director, noted that the earliest VMware could take a seat on the board is 2014, so there's plenty of time to watch and see if VMware unfairly pushes its own agenda. "Bad behavior tends to get called out pretty quickly in open source projects," he said.

Bryce also emphasized that not only does VMware have virtual networking expertise but there is also value in getting ESX Server to work with OpenStack, through VMware contributions.

Frank Rego, business development manager at Novell's SUSE Linux unit, offered an additional perspective at Cloud Expo in Santa Clara, Calif., Tuesday. He drew an analogy to Microsoft's opposition to Linux, which suddenly turned around and became Microsoft cooperation with SUSE and its current support for running SUSE Linux virtual machines in the Azure cloud.

A dominant vendor, like Microsoft, "wakes up one morning and realizes the whole world isn't going to be Windows. Then it starts cooperating" with the thing it previously opposed. VMware has had such an awakening, he suggested.

I agree. I think it's also true that VMware, while a strong proprietary company, has never expressed vehement opposition to open source code in the manner that Microsoft once did. It has found ways to cooperate with it in the past. Its Cloud Foundry is all open source.

But the main point, I think, is that virtual networking is the key to the expansion of virtualization in general, and VMware's vision for a software-defined data center in particular. VMware has as much interest as anyone in removing obstacles from the virtual net's path, and that's why it joined OpenStack.

From SDN to network overlays, emerging technologies promise to reshape the data center for the age of virtualization. Also in the new, all-digital The Virtual Network issue of Network Computing: Open Compute rethinks server design. (Free registration required.)