There seems to be no end in sight to the uncertainty and debate over what, exactly, constitutes an open source cloud. What’s far more clear, however, is that the concept is rapidly gaining ground.

It’s hardly any wonder. Cost, customizability, transparency and collaborative development are all among the benefits frequently associated with the open cloud, as is innovation.

That, presumably, goes a long way toward explaining why Linux is by far the dominant platform in cloud computing, as the Linux Foundation’s latest Enterprise End User Report recently found. In fact, nearly 76 percent of cloud-enabled organizations use Linux servers for the cloud, the report concluded, while 74 percent plan to maintain or increase their use of Linux for future cloud initiatives.

Need more convincing? Here are just a few additional pieces of evidence from the past few weeks that suggest the open cloud is on the rise.

1. IBM Jumps In

“IBM To Make Its Cloud Services and Software Open Source-based” was the title of the press release from the PC giant in early March, and it contained plenty of endorsement for the open cloud.

“History has shown that open source and standards are hugely beneficial to end customers and are a major catalyst for innovation,” said Robert LeBlanc, IBM senior vice president of software, in a statement. “Just as standards and open source revolutionized the Web and Linux, they will also have a tremendous impact on cloud computing.”

As a first step toward its new, open goals, the company unveiled a private cloud offering based on OpenStack that “significantly speeds and simplifies managing an enterprise-grade cloud,” it said.

Security is another benefit observers see included here.

Either way, the move is particularly big news given that competing “Big Three” server vendors HP and Dell have already pledged OpenStack support themselves, as a recent Data Center Knowledge article pointed out.

2. Oracle Buys Nimbula

Speaking of industry giants, it was just a week or so later last month that Oracle announced it was buying Nimbula, a provider of private cloud infrastructure management software. 

Last fall, Nimbula joined the OpenStack community and announced that it would collaborate on the OpenStack codebase as well as incorporate OpenStack services in future releases of its flagship Nimbula Director product.

“OpenStack has gathered strong industry momentum,” said Reza Malekzadeh, VP of marketing and sales at Nimbula. “Our customers appreciate the advanced functionality, scale and security model we provide, but have been asking us about a standardized core. We are excited to now be in a position to work with the OpenStack community to deliver a range of extended infrastructure and platform services around an industry-standard effort.”

3. BMW Shows Its Hand

Also in mid-March, the Open Data Center Alliance (ODCA) announced the release of a new white paper detailing auto maker BMW’s multiple phases of cloud implementation, from internal cloud delivery to full integration of public cloud services, using ODCA requirements. Entitled, “Open Data Center Alliance: Private Cloud Strategy at BMW,” the publication is designed to help other enterprise IT managers making their way to the cloud and help providers identify requirements for enterprise-ready cloud service delivery. A video featuring highlights is also available on the ODCA website.

4. Rackspace Launches a School

Of all the possible signals that a technology is becoming ubiquitous, the launching of a school dedicated to training professionals in its use is pretty darn indicative.

That, in fact, is just what Rackspace did later in March with its launch of the Open Cloud Academy.

“Organizations are struggling to hire talent with the cloud computing skills necessary for the new world of IT,” the company explained in a blog post. “We hope to change that.

“This week Rackspace opened the doors to the Open Cloud Academy, an educational program designed to arm students with affordable IT certifications, specifically around open cloud technologies,” it added. “We want to offer an innovative, hands-on learning experience that helps jumpstart careers in open cloud technologies, including but not limited to sharpening Linux expertise, cyber and network security and software development.”

5. Riak CS Opens Up

Then, too, there was Basho’s announcement last month that it was open-sourcing its Riak CS (Cloud Storage) software under the Apache 2 license, nearly a year after the product’s initial release. 

“Over the past year we’ve had an opportunity to learn more from our customers,” Shanley Kane, a product manager at Basho, recently told Wired.

Developers also tend to be more attracted to open source technologies than proprietary ones, the company reportedly said, adding that going open source is expected to increase the product’s traction as well as ease integrations.

6. IBM Opens a Lab

Finally, offering a nice complement to Rackspace’s IT-focused open cloud school, IBM on Monday announced that it is planning to open a lab in New York City designed to help financial services firms adopt open-source virtualization technologies.

Following the company’s launch late last year of a similar center in Beijing, the KVM Center of Excellence “will help clients, software engineers and business partners to quickly leverage open-source virtualization to build cloud-computing platforms,” it says.

“Wall Street is at the forefront of the adoption of Linux, and financial clients are now leading the way on adopting KVM in order to build a flexible computing infrastructure to meet business demands,” said Jean Staten, director of cross-Linux strategy at IBM, in a statement. “As the industry evolves to meet new demands from customers and regulators, these enterprises will need expertise on how to build open standards-based clouds.”