Container Good Practice and Common Container Labels


Within Project Atomic a documentation and reasoning for a set of container labels has been worked on since April of 2015 in an open community. Authors from Red Hat include Dan Walsh, Vincent Batts or Daniel Riek.

Today in the course of Container Camp (and on and initiative to define a set of container labels surfaced.

This short article is about why and how to joins these two efforts right before forces get distracted again, and again, and …

Label Schema Org

Label Schema is aiming to “providing a shared and community owned namespace” which in itself is a very good idea. This appears to be the same intention as Project Atomic’s generic labels.

Introducing a new open source project (owning the domain name) and a new organization to drive standardization and common sense seems pointless, as we have an open project which started exactly with this purpose in 2015.

Project Atomic’s Generic Labels

Project Atomic took the initiative to define a common set of labels used with container images, and “Proposals have been made to namespace the label names defined in Docker. But we [Project Atomic] believe there should be some generic toplevel names defined that are not vendor specific, or distribution specific.”

Let’s have one schema to define labels our tools need

Obviously there is a need for a common understanding what certain labels mean, but there is also a need for tool specific labels.

So here is a very simple proposal:

  • Lets use labels without a namespace for general purpose with container image or runtime or distribution agnostic semantics.

  • Lets use namespaced labels for tools, lets define the semantics of labels and let them be owned (by putting them under a certain namespace) by the authors of the tools.

  • Lets join forces and collaborate within the context of the CNCF.