It often takes real money to move virtualization technology forward, which is why open-source virtualization vendor Docker is now raising new funds.

Docker announced today that it has raised $15 million in a new Series B round of funding led by Greylock Partners, with participation from Trinity Ventures, Benchmark and Insight Ventures. Total funding to date from Docker now stands at $26 million.

Docker as a company was originally known as dot Cloud. It changed its name in 2013 to reflect a shift in strategy and to capitalize on the brand recognition of its open-source Docker container virtualization software efforts. Instead of using a virtual machine hypervisor to virtualize applications and the supporting operating system, Docker is a container technology. The container approach leverages the existing host system's operating system and virtualizes the application delivery, making for a potentially more efficient approach.

As to why Docker is raising new funds now, CEO Ben Golub told eWEEK that it's not because his company was running out of operating funds. Prior to the Series B funding being raised, Docker still had a substantial portion of its Series A funding left, he said.

"For most of 2013, we operated very conservatively, with a low burn rate," Golub said. "However, it has become clear to us that Docker is becoming very significant, very quickly."

Docker has already gained adoption and has seen interest from large enterprises to run their container technology in production. Among those that see the promise of Docker is Linux vendor Red Hat, which will be including the technology in its Red Hat Enterprise Linux 7 platform in 2014.

Golub noted that there has also been a high degree of interest from the venture community, and as such it makes sense to pursue the market opportunity that Docker represents with new funding.

The new funding will be funneled into continued investment in the Docker technology as it continues to develop and mature. Docker is not yet at the all-important 1.0 release, which is a key goal for Golub. The release of a production-ready Docker 1.0 will add support for additional platforms and enable additional isolation, storage, networking and orchestration capabilities.

Growing the community platform for Docker is another key goal. Golub said that for the Docker ecosystem to work well, there is a need to expand the platforms that make it easy to find, publish and use containers.

"We are investing in the infrastructure around our public registry, improving the ability to integrate Dockerfiles with source code systems like GitHub, and adding a host of services like developer IDs, timestamping and digital signatures to allow anyone to confidently assess the origin and provenance of public containers," Golub said.

Commercial Efforts

So far, Docker as a company has not yet made any money directly from its Docker container technology, though that is likely to change soon.

"While Docker itself will always remain free and open source, we are busy gearing up for the launch of both hosted services around Docker and commercial support for Docker," Golub said.

Part of the commercial gearing up includes hiring James Turnbull, former vice president of Technical Operations and Support at Puppet Labs, to build out Docker's support organization. Docker also hired Roger Egan, former vice president of North American Channels/SMB at Red Hat, to build out the Docker's sales organization and partner network.

"As they scale out their teams, and as the engineering team builds out our hosted services, we hope to make it even easier for enterprises to deploy Docker in production, and for partners to build compelling businesses around Docker," Golub said.

With the new funding in hand, the challenge for Docker is to execute and deliver on the opportunity in front of it.

"We think we have the ability to deliver a technology and ecosystem that can help fundamentally transform how code is built, run, scaled and deployed," Golub said.

Sean Michael Kerner is a senior editor at eWEEK and InternetNews.com. Follow him on Twitter @TechJournalist.