There are already private Docker registries out there. My company uses https://quay.io , for example, and Docker has its own private registry. How does Gandalf compare to these existing offerings, besides on price?

Security for Docker images is just as important, and in some cases more important than it is for code assets. What protection does Gandalf offer against unauthorized downloading of images/layers, and tampering with images stored in the repository?

Does Gandalf plan to support features like building images from a Dockerfile, ideally sent via GitHub repo hook? This is a great workflow convenience offered by both Quay and Docker.