Docker, the open source company that currently specializes in containerized apps, took a step toward the world beyond containers this week with the acquisition of Unikernel Systems.

As its name implies, Unikernel Systems develops unikernels. Those are minimalist apps that contain only the code needed to run specific functions, rather than all of the libraries and overhead that come with traditional programs. That makes them sort of like Docker containers, which package applications into portable virtual environments that can run without virtualizing an entire operating system.

But unikernels are not just another form of container. They're a very different technology, and by acquiring them, Docker seems to be signaling its intent to expand beyond containers. Unikernels will make it possible for organizations to use the Docker platform to build other types of minimalist, portable apps, not just containers.

Docker made clear that its main interest in acquiring Unikernel Systems was to gain the expertise of the company's developers, who include veterans of the Xen open source hypervisor project. The programmers will continue to contribute to open source unikernel projects as Docker employees, but Docker will now have their brains at its disposal as it works to integrate containers with unikernel technology.

"We are honored to have the Unikernel Systems team, with its incredible pedigree, join the Docker family," said Solomon Hykes, founder and CTO of Docker. "Our shared vision to take transformative technology and make it accessible to a much wider audience has made the union a natural fit and it aligns with one of our core tenets to separate applications from infrastructure constraints. Through the Docker platform, unikernels will be on a ‘continuum’ with Linux and Windows containers, enabling users to create truly hybrid applications across all formats with a uniform workflow."

This is an acquisition that is likely to pay large dividends for Docker, especially as distributed applications and IoT sharply increase the demand for portable apps that consume minimal resources.