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EMC has contributed an open source Apache Mesos container volume driver that supports any network-attached block storage system equipped with a Docker plugin, including storage of EMC competitors.
The EMC container plugin integration for Docker is a joint project of Apache Foundation and EMC code, part of EMC Emerging Technologies Division. It builds on previous EMC container initiatives. The Docker Volume Driver Isolator module exposes native Docker functionality through a command line interface. It is part of the Apache Mesos distribution released in July.
“We’re making it possible for the community to do multi-tiered persistent storage within Docker, which up to now has been a struggle,” said Josh Bernstein, a vice president at EMC code.
Mesos orchestrates deployment of containers on premises or in cloud storage. The Apache Mesos cluster manager presents abstracted data center compute, memory and storage in an aggregated resource pool. Mesos resides in the kernel to isolate resources as applications are shared across a distributed framework.
Mesos lets users create a persistent volume to run a specific task from reserved disk. The volume persists on a node independently of the task’s sandbox and is returned to the orchestration framework when the task is complete. If necessary, new or related tasks launch a container that consumes resources from the previous task. Docker recommends Apache Mesos as an orchestration layer to implement large clusters of storage containers.
EMC’s container module communicates directly with Docker volume plugins, allowing developers to request a persistent volume from any block storage running under Mesos. Mesos then passes the file request to EMC, which searches available storage to identify the volume and deliver it to the destined container host.
“Before this feature, while users could use persistent volumes for running stateful services, there were some limitations. First, the users were not able to easily use non-local storage volumes. Second, data migrations for local persistent volumes had to be manually handled by operators. The newly added Docker volume isolator addresses these limitations,” according to an Apache Software blog posted July 27.
Enterprise adoption of Docker is picking up, although several hurdles remain before containers are as ubiquitous as that of virtual machines. The Apache Mesos integration foreshadows the open source EMC container EMC libStorage project. LibStorage is extensible abstraction and provisioning presented as common package for every heterogeneous storage and container runtime.