Until today, cloud infrastructure company Joyent had raised a total of $120 million in a number of funding rounds, with its 2012 $85 million Series D round being the latest and largest. There aren’t all that many companies that go past the Series D stage, but cloud platform provider Joyent today announced that it has raised an additional $15 million from existing investors Intel Capital, Orascom TMT Investments, El Dorado Ventures, EPIC Ventures, LGI Ventures and others.

Joyent plans to use this money to capitalize on the current trends around Docker and container-based infrastructure (of the software kind, not the shipping one). Joyent has been running a platform based on containers for more than 10 years now, but it really wasn’t until Docker emerged as a cloud infrastructure darling in the last year or so that people really took notice of this technology.

“Our customers are rapidly adopting Docker to create application containers, and they are seeking to use this new technology on Joyent’s proven infrastructure containers,” said Scott Hammond, CEO of Joyent, in a canned statement today. “We believe that this specific combination of application containers and infrastructure containers will completely disrupt the data center and transform how business applications are built and delivered.

As Joyent CEO Scott Hammond told me in an email interview earlier this week, he believes that “the market is finally ready to pay attention to the benefits of containers.” He also stressed, however, that the company isn’t focusing on containers to compete with Docker. “Rather, we want to leverage our experience to make Joyent to be the best place to run Docker containers.”

Joyent uses an operating system virtualization layer called SmartOS (a combination of OpenSolaris and Linux’s KVM virtualization technology) that runs Docker containers on bare metal, which, according to Hammond, makes it “the best run-time environment for their application containers and we are delivering the functions that data center operators need to run these containers securely at bare metal speed with enterprise grade networking, and the workload density that OS virtualization delivers.”

Joyent plans to continue to run its public cloud platform as its core business, but in addition, it will also now build new products and service for developers and ops teams who need to manage containers on bare metal. While Hammond didn’t want to give away too many details on the company’s forthcoming products, he did note that Joyent is “developing products and services that will support and integrate with Docker.”

So why did the company go out and look for more funding now? “To me, it’s all about speed,” Hammond told me. “We’re at the beginning of a high speed technology shift.” While it took VMWare many years to go from developer test environments to mass adoption, today’s technologies get to mass adoption much faster. “We raised this round to speed up development so we can be one of the drivers in this next wave of disruptive technology.”