Sebastiaan van Stijn
aa91af81c6
Docker Engine v20.10 and up includes optimizations to verify if images in the local image cache need updating before pulling, preventing the Docker Engine from making unnecessary API requests. These optimizations require the container image registry to conform to the Open Container Initiative Distribution Specification (https://github.com/opencontainers/distribution-spec). While most registries conform to the specification, we encountered some registries to be non-compliant, resulting in `docker pull` to fail. As a temporary solution, Docker Engine v20.10 includes a fallback mechanism to allow `docker pull` to be functional when using a non-compliant registry. A warning message is printed in this situation: WARNING Failed to pull manifest by the resolved digest. This registry does not appear to conform to the distribution registry specification; falling back to pull by tag. This fallback is DEPRECATED, and will be removed in a future release. The fallback is added to allow users to either migrate their images to a compliant registry, or for these registries to become compliant. Note that this fallback only addresses failures on `docker pull`. Other commands, such as `docker stack deploy`, or pulling images with `containerd` will continue to fail. Given that other functionality is still broken with these registries, we consider this fallback a _temporary_ solution, and will remove the fallback in an upcoming major release. Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
The non-reference docs have been moved!
The documentation for Docker Engine has been merged into the general documentation repo.
See the README for instructions on contributing to and building the documentation.
If you'd like to edit the current published version of the Engine docs, do it in the master branch here: https://github.com/docker/docker.github.io/tree/master/engine
If you need to document the functionality of an upcoming Engine release,
use the vnext-engine branch:
https://github.com/docker/docker.github.io/tree/vnext-engine/engine
The reference docs have been left in docker/docker (this repo), which remains the place to edit them.
The docs in the general repo are open-source and we appreciate your feedback and pull requests!