It's been clear for some time now that independent platform as a service providers would have a tough run going forward. Today, CloudBees, one of the earliest public PaaS providers, said it plans to shut down its PaaS at the end of the year.

It's not the end of the road for CloudBees. The company plans to focus now on Jenkins, the popular continuous integration technology that it developed. As proof of the wide support for Jenkins, CloudBees today also announced that Pivotal has integrated CloudBees into its Cloud Foundry internal PaaS offering so that users can easily get started using it. CloudBees also said that it expects annual recurring revenue from its continuous delivery products to quadruple by the end of this year compared to 2013.

There are a couple of reasons life is tough for independent PaaS providers these days. One is that giant infrastructure providers, like Amazon Web Services, Microsoft, and Google, have all begun to offer PaaS-like services.

"That blurs the lines in terms of what an independent PaaS vendor is bringing to the equation," said Steve Harris, senior vice president of products for CloudBees.

But there's another reason that the independants aren't growing as fast as maybe they'd like. "The adoption of PaaS in the enterprise has been, I'd say, mostly oriented around on-premises usage," he said. Rather than using a public PaaS, enterprises are opting to build similar functionality in their internal clouds, he said. "That slowed the adoption of public cloud-based PaaSes," he said.

In the future, independent PaaS providers might have yet another bit of competition to contend with. As more businesses use Docker's container technology as well as infrastructure orchestration technologies like Chef and Puppet, "things start to look like PaaS," he said. Those tools provide a similar kind of functionality as PaaS services, he said.

CloudBees has "hundreds" of users of its PaaS, including those using it in production as well as those who only use it for development, Harris said. CloudBees has been working closely with customers to help them transition to other offerings. The CloudBees PaaS will shut down on Dec. 31.

Customers have already been told about the impending shut down and their plans show that remaining independent PaaS providers should be worried. Harris mentioned that CloudBees customers who liked CloudBees' fully managed services are more apt to go with Heroku while those who already have workloads at AWS and don't mind being a bit more hands on are going with Amazon. He didn't mention that customers have been talking about migrating to the standalones.

There aren't a lot of independent PaaS services left. Engine Yard and Cumulogic are still around. DotCloud is open for business but recently got bought by a German PaaS provider.

CloudBees is in a good position because it has products and community around Jenkins; shutting down its PaaS doesn't mean it's out of business. The Pivotal announcement could also give it a boost.

Pivotal chose to integrate CloudBees' continuous integration tools because Jenkins is the mostly widely used CI tool out there, said Nima Badiey, head of business development for Cloud Foundry at Pivotal. "Jenkins is the de facto tool chain enterprises are used to," he said. Jenkins has over 85,000 active installations in use, according to CloudBees.

Continuous integration and delivery tools like Jenkins help a group of developers manage the process of development so that they can build and test their software quicker and then roll out updates regularly.

Badiey said Pivotal hasn't thought about whether it would integrate with other CI tools in the future. "From our perspective, we want to start with the Cadillac. There are other options in CI, there's a lot of money chasing it from venture funded companies, but just because you're the hot new thing doesn't differentiate you from the fact that Jenkins is very much embedded in the enterprise and very much a tool preferred by the enterprise."