The first OpenStack-based cloud operating system came out Wednesday.

The start-up Piston Cloud Computing Inc delivered the thing, which makes sense since Piston's founders were instrumental in OpenStack, which is a framework, not a product. The widgetry is called Piston Enterprise OS or pentOS for short and it will sell for $3,500 a server a year, a price that includes 24/7 telephone support.

Piston co-founder and CEO Joshua McKenty said Piston sold maybe 10 of the things ahead of general availability and the code was destined for big iron $250,000 hardware installations. People apparently just bought it after seeing the demo at Cloud Expo. Nothing is in production yet.

pentOS is cheap compared to VMware, the only alternative. McKenty said it would probably cost $17,000 a server a year using VMware and that's before factoring storage in. If you tried to do it yourself, he said it would probably cost $20,000 a server.

The widgetry is targeted at private enterprise cloud environments. It uses Diablo, the latest cut of OpenStack. It's only good inside a single data center. It'll need the next cut Essex to do cloud hopping and span multiple clouds. Users, however, can cut a single site into 10 zones with each one supporting, say, 200 servers. Such a configuration could support 20,000 VMs, but they'd be small.

Although confined to a single data center, pentOS promises high availability. It is supposed to be focused on security and the easy operation. In that respect it's supposed to install in 10 minutes.

Piston's CloudKey is said to deliver 99.999% automated and hands-free installation of the pentOS software to servers and switches. (It fancies Arista.)

Piston is looking to cultivate the financial market, government and the bio techs, clients with serious regulatory requirements. McKenty says, "As we continue to see security lag in the public cloud environment, it is clear that private cloud is really the only option for organizations dealing with large volumes of regulated data."

The company's Null-Tier Architecture combines storage, compute and networking on every node to deliver massive scalability with what it claims is "unprecedented cost efficiency." It says users can scale a high-availability private cloud, one server at a time.

pentOS is also the first implementation of CloudAudit, an open security standard for cloud and virtualized environments. There will be automatic security updates via a subscription service.

Under pentOS is a custom-built Linux distribution. It will interoperate with any other OpenStack-based public cloud environment, including Rackspace, Dell, Amazon, Internap and AT&T.

Piston was started early last year. McKenty was the technical architect of NASA's Nebula Cloud Computing Platform and the OpenStack compute components. CTO Christopher MacGown was part of OpenStack's Nova-core development team at Rackspace. The start-up has gotten $5 million in funding from Hummer Winblad, True Ventures and Divergent Ventures.

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