Google lets developers try building applications with on-premise version of App Engine

Google (s goog) is looking to help more companies develop applications in the Google App Engine way — except on companies’ own servers, not on Google gear.

Toward that end, Google has been working with Red Hat (s rhat) to produce an open-source project called the Test-Compatibility Kit, Google software engineer Ludovic Champenois noted in a Thursday in a blog post. The kit lets developers get multiple Google App Engine services, such as the datastore and task queues, and it all runs atop JBoss application servers.

The program could have a mix of effects on Google. The company surely is eager to encourage developers to understand what’s possible by tapping into its vast cloud-computing resources, but allowing them to stay in their own walled IT gardens could work against the idea of public-cloud adoption.

If developers currently running their applications on site like how the program works when they play around with it, down the line, it could lead to new business for Google. Such a scenario is more likely to play out if traffic to a consumer-facing site spikes and scalability issues arise when an application is being served up from an on-premise data center. That’s when Google’s scale might well become appealing, and developers would port their existing applications onto App Engine’s external infrastructure. Think of it this way: Once an application prone to spikes in traffic goes to the cloud, it might never go back.

But there is a possibility that some developers running applications on Google servers will take the Test-Compatibility Kit and try running those applications on premise — sort of like the old pre-cloud days. And that might end up taking business away from App Engine.

It should be said, though, that a few customers ditching the public App Engine and moving onto the on-premise model might not make much of a difference for Google. App Engine has gained lots of popularity among developers since springing onto the scene in 2008.

In any case, the move comes alongside other efforts to make it possible to launch a PaaS on premise.

AppScale — a company that lets companies take applications running on Google App Engine and bring versions of them on premise, and that plans to add support for other public PaaSes — pitched itself to investors at the LaunchPad competition at our Structure conference in San Francisco on Thursday.

And another instance of PaaS becoming available on premise, a version of Red Hat’s (s rhat) OpenShift service, also came up in conversation at Structure: PayPal has been using it to build applications with its own servers, said Ryan Granard, the company’s vice president of platform engineering.