The shift to scale out architectures and an app-centric culture has turned out well for Docker and its lightweight open-source “container” technology designed for developers to quickly move code to the cloud.

That’s evident in today’s news that the company has raised $15 million in a Series B round led by Greylock Partners, with minority participation from Insight Venture Partners and existing investors Benchmark Capital and Trinity Ventures. Also participating is Yahoo! Co-Founder Jerry Yang, who has participated in previous rounds.

Docker will use the funding to push toward the general availability of the Docker environment, develop commercial services that pair with the open-source technology and build a team to support the growing community.

The technology path is similar to the one VMware followed in its early days when IT managed their corporate-owned infrastructure. These were state-of-the-art data centers that had to be optimized to run enterprise software. For these IT managers, VMware became a critical part of the equation so multiple virtual machines could run on its hypervisor and server environment. VMware is lauded for the excellent job it did in managing its technology so the end-user was not impacted and the IT manager could manage the infrastructure effectively.

The similarity to VMware in its early days and the excitement that Docker has generated made it an attractive investment, said Jerry Chen, a general partner at Greylock who joined the venture capital firm in August. It is Chen’s first investment since joining Greylock.

“One of the things we learned at VMware is be as frictionless as possible,” Chen said in a phone interview today. “Docker has that ability as well.”

Docker also can be scaled from scratch. It can grow to multiple apps or be used on public or private servers, Chen said. And it can be scaled out in seconds, moved anywhere and all done without having to re-configure all over again.

“Docker is the right tech to fit the rapid updates,” Chen said.

Docker faces the challenge of making its technology easy-to-use with features that make it effective for a developer or a DevOps professional. For this new DevOps pro, Docker has to consider the management and orchestration of apps that are continuously updated using the Docker environment. For example, Docker will develop both public and private registries for developers to store their containers. It also plans to build management and orchestration tools that are needed as people and their organizations manage more and more Docker containers.

And then there is the community, which continues to grow at scale. Docker is now one of the world’s fastest-growing, open-source efforts. There have been more than 9,000 stars given to Docker on GitHub as well as more than 1,320 forks. To manage that growing community will take investment that the company will need to manage with product development.

It’s that community that helped Docker gain acceptance with Red Hat, which is integrating it into OpenShift, its PaaS environment. It has also been adopted by Google Compute Engine. eBay, Yandex and a host of other companies are using Docker in production environments.

Docker’s Background

Docker is the result of a pivot led by Solomon Hykes, who originally launched the company as DotCloud in 2009.

Originally designed as a platform as a service (PaaS), Docker showed promise for its flexible capabilities in providing developers with a service that supported multiple programming languages. But the competition from companies like Heroku and VMware’s Cloud Foundry made for a challenging market, further exacerbated by the lack of a widespread market acceptance for the benefits that PaaS providers offered.

But developers did need a way to move their code to cloud services in a lightweight way without the tax of heavy virtual machines that were difficult to move and required a degree of manual integration. The problem stemmed from the virtualization technology itself, which sits below the operating system. It virtualizes the server, not the app. And because of that, the operating system has to move in order to run the app wherever it might be transported. Once delivered, it has to be booted up and configured to run with the database and the rest of the stack that it depends on.

With Docker, the container sits on top of the operating system. The only thing that moves is the code. The developer does not have to boot and config. Instead, the container syncs with the cloud service.

Hykes launched the open-source effort last spring and the acceptance has been almost unprecedented.

“I have never seen a technology take off as quickly as Docker and get the type of broad-based adoption that it is getting,” said Dan Scholnick of Trinity Ventures in a phone interview last week. “If you look at the absolute numbers — the number of Docker containers downloaded, the number of docker containers created — they are off the charts. What is more interesting, the adoption is not just coming from startup or certain types of companies. The adoption is across companies of all sizes and industry verticals. It is a combination of high-growth and broad-based adoption that is really amazing.”

There really are no equivalents to Docker. There are alternatives to it but as a Linux container it is the most widely used in the market. Its deepest competition will stem from VMware and virtualization providers that market to developers. And that’s not it. Cloud Foundry has its own form of a Linux container, which raises a question about how Docker fulfills its promise as a technology platform. The container is one part of the puzzle. It’s the foundation, but there are tool developers who can seize the opportunity to develop technologies that compete with Docker while also participating in its ecosystem.