BARCELONA, Spain - Docker provides an optimized set of tools that enables application virtualization but what about storage? While Docker includes storage APIs, it is companies like ClusterHQ and its open source Flocker project that are helping to lead the way to provide storage capabilities that plug into Docker.
"With native Docker, the moment the container writes a single bit to a data volume, because the data volume is allocated from outside of container, that container becomes stuck on that machine," Luke Marsden, founder and CTO of ClusterHQ explained.
With Flocker, ClusterHQ has built in the capability using the Docker volume plugin API to have an external data volume follow a container as it moves around across hosts. What ClusterHQ is now doing is expanding its offerings with two news tools: volume hub and dvol.
"The volume hub is a service that allows you to take a Flocker instance and then plug it into the hub and get a visualization of what is going on inside your storage cluster," Marsden said.
Inside the volume hub an organization will be able to see which containers are using which storage specific storage volumes. From a licensing perspective, the backend piece that runs the volume hub is a closed source project, though it works fully with the open source Flocker technology. Marden said that ClusterHQ doesn't yet have a commercial model around volume hub for pricing quite yet as the service is just now being announced. That said, ClusterHQ does provide commercial support for those that need help deploying Flocker in production.
The other new effort from ClusterHQ is a technology called dvol which is intended to help enable developers to run storage, with snapshot capabilities that can capture the state of an application as it is being developed. Marsden said that the name dvol either stands for developer volume or it stand for the docker voluminous plugin.
"Dvol brings git-like functionality to Docker storage volumes," Marsden said.
Git has become the default concurrent distributed version control system used for the majority of open source project in recent years. Git has multiple concepts, including that of branches where multiple versions and concurrent development occurs. With Dvol, developer can make branches of their data as well as their code.
"So if a developer is working on an application and has a problem, the developer can just save the problem state in a branch and then come back to it later for analysis," Marsden explained.
Looking forward, dvol will work together with the volume hub, enabling a developer to push and pull snapshots. Marsden also expects that dvol will make development go faster, since developers can snapshot the data storage before running a test, enabling a quick reset after a test.
Sean Michael Kerner is a senior editor at Datamation and InternetNews.com. Follow him on Twitter @TechJournalist
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