How do you measure the number of companies that have adopted OpenStack for cloud computing? One metric is the popularity of OpenStack training courses, which surged in 2015, according to data out this week from Mirantis.

Mirantis launched OpenStack training in 2012. In the past year, it said, its program expanded to include two new courses, fifteen additional locations and 5,000 students -- a figure that doubles the number who have completed Mirantis's training since it began three years ago, according to the company.

Mirantis executives are pitching this news as a sign of OpenStack's growing importance in enterprise production environments.

"Training is often a leading indicator to a technology’s impact. In 2015 OpenStack advanced beyond early adopters, and we saw an uptick in individuals and businesses scrambling to develop OpenStack skills," said Mirantis Head of OpenStack Training Services, Lee Xie. "Students choose Mirantis Training because our courses cover vanilla OpenStack, equipping them with true technical understanding of what it's like to deploy and operate OpenStack in the real world."

Strictly speaking, an uptick in OpenStack training doesn't necessarily mean organizations are adopting the open source cloud computing platform at a higher rate. It could just mean more engineers are interested in learning OpenStack, whether or not employers are deploying it.

Still, it's a perfectly logical and likely possibility that more demand for training means higher OpenStack adoption -- especially because Mirantis's training is designed to be vendor-agnostic, making it a decent measure of the popularity of OpenStack overall, not just a specific distribution.