Docker image metadata can be arbitrarily extended using the LABEL directive in a Dockerfile. This is a great way to annotate an image and enable automation:

  • How to run or install an image
  • Who built an image
  • URLs for documentation or other support information

We’ve been encouraging the docker community to standardize these LABELs in an open source way through the Container Application Generic Labels repository. Recent pull requests added a new vendor directory for software companies (or FOSS projects) to document metadata that is specific to their particular needs.

As a point of reference, Red Hat released their LABEL metadata and image naming policy to the community. This might be a useful reference for other folks building their own metadata.

Have metadata for your project? Just submit a pull request to help create documentation about metadata your tooling or application depends on. Have questions? Ask on the atomic-devel mailing list, or create an issue in the GitHub repository.