Last year was a turbulent one for Docker, the Linux container formatting engine. It ended with a bang as the rival CoreOS Rocket container project launched on the eve of  Docker's European user group meeting, DockerCon, in Amsterdam in December.

CEO Ben Golub said in an interview that he expects a continued debate over the future role of Linux containers, rapid expansion of Docker's container technology platform, and a 10X growth in Docker Inc. revenues. Containers are being adopted for use in deploying composite or distributed applications, where one application is composed of many micro-services and deployed in multiple but linked containers.

One example is Gilt, the clearinghouse for discounted luxury goods, which pre-Docker was built on seven large, monolithic applications. As it reorganized the business, it adopted Docker and broke those applications down into 300 micro-services, said CTO Michael Bryzek during a session at DockerCon in San Francisco last June, captured in this video.

Docker allowed the company to organize around small engineering teams, each with a service for which it was responsible, he explained. Because the services were each running in a Docker container, they could be modified and updated independently, leading to rapid business evolution as 100 code changes were made a day. If one of those changes went awry, it didn't affect the other services, because they are protected from any impact in their own discrete containers. "That application isolation is a really good feature of Docker." The errant code can be deleted and the service rolled back to a version that's known to work.

[Want to learn more about how Docker will encourage the uptake of containers in 2015? See Docker, CoreOS Push Containers To Center Stage.]

"That approach unleashes a lot of productivity and creativity," said Golub. He sees more enterprises moving quickly into containerization of their applications in 2015. Societe Generale and ING, large banking firms in France and the Netherlands, respectively, are also implementers of distributed applications using Docker, along with Gilt, he said.

In some cases, they will stack multiple micro-services on a host, with the containers replacing a virtual machine that used to run a monolithic application. Not every scenario becomes one in which containers replace virtual machines, but in distributed applications they do, he said.

To aid app containerization, in December Docker launched Docker Hub Enterprise, a place where both developers and system administrators can go to find Linux containers that have already been formatted for specific business purposes. Microsoft, IBM and Amazon are key partners in its launch, and IBM is making Docker Hub Enterprise available to customers for use both on-premises and in the cloud. IBM and Microsoft each have middleware needed by applications. By pre-formatting and loading it in a Docker container, developers can install the container in their own data center and invoke the service through a link, speeding their application deployment process.

More information on Docker Hub Enterprise is available in a Docker website blog. It is now available in beta. Within a few months, it will be generally available with fees announced for use of its services. 

Docker Inc. closed out the year by moving out of San Francisco's financial district, where it was renting 5,000 square feet of space, and into the city's South of Market district, heavily populated with technology startups. Docker will lease 15,000 square feet there. Docker expanded from 20 employees in January 2014 to 85 by end of the year. Even so, Golub added, "we'll have a lot of room for growth." He expects employees to double in 2015.

Docker's hiring is mainly in the realm of software engineers. Sixty-five percent of employees are engineers, a percentage that will remain steady in 2015, he said. At the same time, Docker is building its own sales force. Last year it hired Red Hat's Roger Egan, director of North American Channels Alliance, to head up its own sales and channel development. Docker engine sales are made by channel partners, such as Red Hat, Ubuntu, or VMware, who are helping enterprises build up Docker use with their product lines. Fewer than five employees work as a full time, outside sales force; a larger number conduct inside sales and cultivate the channel, said Golub.

He addressed the flap over the creation of another Linux container open source project, Rocket, by acknowledging that CoreOS, the company producing a version of Linux for running container hosts, could do so if it chose. But he was reluctant to say that such a project was really necessary.

The expansion of the Docker project has been unfairly characterized as a bound-together whole, "a binary, monolithic platform," when developers have the option of adopting only the formatting engine, if they choose, Golub said. Docker already supports multiple container image formats, including Lib container, LXC, Solaris Zones, and FreeBSD Jails. It will support a Rocket format, if demand for it materializes, he said.

"I don't know that there's still a remaining need for an alternative container format," he said. "We are open to making Docker better and continuing to address any concerns in the community."

In addition, he cited an increasing number of contributors and code commits within the Docker project itself. At this point, Docker has 730 contributors, and the project's committers pay as much attention to and act as quickly on contributions coming from the outside world as they do Docker's own developers, he claimed.

He was clearly buoyed by the support of major vendors, such as IBM, Intel, Microsoft, and Amazon, as well as a continued high rate of Docker system downloads. In the first six months of 2014, there were three million; by December 2014, there had been 100 million. Any container project that expects to catch up with Docker's momentum will have its work cut out for it, he said.

"There's a huge amount of inbound interest from the largest companies … We're very optimistic about our commercial growth. Revenues are projected to increase close to 1,000%," Golub said.

Docker remains privately held and doesn't disclose its revenues. But Docker has been building a wide developer following that it now is in a position to capitalize on with its products. The Docker formatting engine, the Docker Platform for managing multiple container deployments, and the Docker Hub Enterprise are all likely to bear fruit for the young company in 2015. Golub, despite the Rocket controversy, has sufficient reason to be optimistic.