The offering, called Cloud Foundry, is open in other ways as well. Developers can use it in conjunction with any public or private cloud environment, even those that don't use VMware's technology. They can also choose from among a variety of application infrastructure services.
Until now, PaaS providers have been inclined to tie users to their platform of choice and sometimes to a specific cloud service. "But we knew that would evolve, because people want app portability," said George Hamilton, an analyst at Yankee Group. "Enterprises want the flexibility of developing applications and being able to port to different environments. It's how they're used to developing when they buy on-premise software."
Because Cloud Foundry is open, it could make it easier for enterprises to shift applications from an internal environment to a public cloud, for example, or between different public clouds. "You can now evaluate a public cloud company not based on their infrastructure but on what are their other service attributes," he said.
VMware is offering access to Cloud Foundry in several ways.
The VMware Operated Developer Service, available now in beta, is designed for developers to test new services and operational optimization.
Sometime this quarter, VMware plans to release the Cloud Foundry Micro Cloud, a downloadable instance of Cloud Foundry contained within a virtual machine. Developers can use the Micro Cloud on their desktops to develop and test their applications.
VMware also plans to offer a commercial version of Cloud Foundry for enterprises that want to offer PaaS capabilities within private clouds.
VMware has already released the code behind Cloud Foundry as an open-source project under the Apache 2 license. That means developers can modify the software for their own needs, VMware said.
In addition to Spring for Java, Ruby on Rails and Sinatra for Ruby, Cloud Foundry also supports other JVM-based frameworks, including Grails. VMware said it plans to enable additional programming frameworks as well.
For application services, Cloud Foundry will initially support the MongoDB, MySQL and Redis databases, with planned support for VMware vFabric services.
Cloud Foundry's openness may be attractive to some users, but it doesn't necessarily pose a fatal threat to other PaaS vendors, such as Microsoft, Hamilton said. Microsoft's Azure supports the .Net programming environment.
"The pure PaaS services like Azure take a bit more burden off the developer," he said. "But you lose a little flexibility to not have to worry about system administration." Some developers may decide to give up some flexibility to get the additional support offered by Azure or other PaaS offerings.
Its success earning such credibility will come down to community and developer marketing, he said. For example, Amazon Web Services, which is relatively open, and Google have good relationships with developers, he said. But Microsoft has had to work very hard to convince developers that it's not "some kind of 'evil empire' when it comes to locking in developers to Azure," Cote said.
Because VMware hasn't outlined pricing details yet, Cote sounded a bit skeptical about whether Cloud Foundry will be truly open. PaaS providers typically lock users into some component so the vendor can earn revenue from each installation. It appears that VMware is trying to build a very large environment with hopes of earning revenue only from specific types of uses.
"I hope that's what they're doing at least: The bad thing would be for their business folks to worry about monetizing every single Cloud Foundry instance," he said.