From Fedora Project Wiki
Task for volunteers
Complexity: approx. 20h
Contact person: Honza Horak <hhorak AT redhat.com>
Description: There is already rpmdiff package that shows changes between two RPMs. Something similar would be great for Docker images.
The tool docker-image-diff img1 img2 will return differences in content and also in metadata.
The content in Docker image is either coming from RPMs or is added above RPM content. It must be possible to see only changes in particular content (metadata, RPM content, non-RPM content).
Some randomly-picked library that can be used for displaying JSON-diff of metadata: http://json-delta.readthedocs.org/en/latest/