Docker, CoreOS, Others Form Vendor-Agnostic Linux Container Project

A potential war for control of the future direction of Linux containers appears to have been averted following an agreement between Docker and most of the leading players driving the development of containers to create a standard that will enable images to be shared across multiple container formats.

Vendors backing the new Open Container Project standard, to be overseen by the Linux Foundation, include Amazon Web Services, CoreOS, Docker, Google, Microsoft, HP, IBM, Intel, Red Hat, and VMware, among others. Investment banking giant Goldman Sachs announced its support for the initiative as well.

Announced today at DockerCon conference in San Francisco, the letter of intent signed by all the major parties represents a major advance in the sense that OCP isolates end users from potential battles between vendors over whether Docker or Rocket containers created by CoreOS are the best way forward, CoreOS CEO Alex Polvi said.

Specifically, OCP has pledged to not be bound by higher-level constructs such as a particular client or orchestration stack, and not be tightly associated with any particular commercial vendor or project and be portable across a wide variety of operating systems, hardware, CPU architectures and clouds.

The OCP image format will be backwards compatible with the Docker image format and appc, the CoreOS-created format. OCP will also make an effort to harmonize multiple Linux container projects that already exist. For example, the backers of a Docker libcontainer project will become the lead maintainers for the OCP, joined by two prominent maintainers of the appc project, which CoreOS recently spun off as an independent entity.

“Users will be able to share images across container formats without having to worry about getting locked into a specific vendor,” Polvi said. “This is a win-win for everybody.”

Scott Johnston, senior vice president of product for Docker, said this approach will enable the industry to innovate in a way that doesn’t wind up tearing the IT house asunder.

“It’s really about fostering a community,” Johnston said. “There’s no need to fragment the industry.”

However, CoreOS will continue to make its case that Rocket containers are more secure and easier to compose inside of multiple management frameworks than Docker containers, Polvi said.

OCP at is core incorporates both draft specifications and existing Docker code around an image format and container runtime along with concepts that CoreOS put forward in an Application Container spec that CoreOS created to define how to build containerized applications when it first launched Rocket.

Within three months, the parties aim to complete the process of creating the projet, migrating code, and publishing a draft specification, building on technology donated by Docker.

Polvi said that in the case of OCP, Docker deserves credit for exercising a considerable amount of leadership. For Docker’s part, Johnson credits CoreOS for coming up with the Application Container spec concept.

In the meantime, Polvi said he personally wished more end-user IT organizations like Goldman would join OCP to help balance out what for the moment is a vendor-heavy standardization effort.