ClusterHQ, a little-known startup that’s driving development of the open-source Flocker container manager, believes there’s a fortune to be made by whoever can capitalize on the nascent technology. And now, thanks to a new $12 million Series A funding round, it believes that it’s well positioned to do just that.

The startup, which is based in the UK, has already made a substantial impact on the developer scene with its Flocker tool, which makes it simple to move Docker container apps and their data. Docker containers are rapidly growing in popularity among devs, but one of the main challenges is that not all application components can be easily moved from one server to another. In particular, stateful services like databases are a difficult match for the container model, and that’s what Flocker is intended to solve.

The problem with Docker containers is that any data stored within them is automatically lost whenever a container is shut down. But Flocker allows developers to manage those data volumes and make them as portable as the Docker containers themselves. Virtually all of the major databases, message queueing services and key-value stores are supported by Flocker, and it can run on most cloud platforms as well.

Speaking to ZDnet, ClusterHQ CEO Mark Davis said Flocker is invaluable because the vast majority of containerized applications contain not one, but multiple stateful services.

“The way Docker works is these need to be essentially delivered as external services that the container connects to. That external service is outside the domain of Docker and the container system,” Davis said. “It works fine. You can do all sorts of cool stuff with your containers but the benefit of containers, like the ability to think about deploying them super-rapidly and maybe in different places, is not something that is built into Docker today for the stateful parts of services.”

It’s a limitation that rules out numerous possibilities, for example live-migrating a stateful application from one server to another, or one cloud to another, inside a Docker environment. Davis explained that while this kind of task is taken for granted with traditional virtualization, it simply can’t be done with the standard Docker model.

“It allows us to do lots of things operationally inside a datacentre, for high availability reasons, disaster recovery, load balancing, maintenance,” he said. “[But] you can’t do that with containers because the stateful part of the application can’t be moved while the state is maintained.”

ClusterHQ plans to use the fresh funds to beef up the size of its software engineering team and redouble its efforts in the developer community. Besides that, it’s also aiming to increase adoption of Flocker, which means that commericialization is likely to be a next step. In addition, it also wants to build lots of new features into the tool, such as the ability to relocate containers without any downtime.

The new round was led by Accel Partners with participation from Canaan Partners, and brings ClusterHQ’s total amount of funding raised to $15 million.

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