I think it was likely caused by the cache trying to compare the tag with Docker Hub: https://docs.docker.com/docker-hub/image-library/mirror/#wha...

> "When a pull is attempted with a tag, the Registry checks the remote to ensure if it has the latest version of the requested content. Otherwise, it fetches and caches the latest content."

So if the authentication service is down, it might also affect the caching service.

Even cloud vendors can’t get distributed systems design right.

I’m able to pull by the digest, even images that are now missing a tag.

In our ci setting up the docker buildx driver to use the artifact registry pull through cache involves (apparently) an auth transaction to dockerhub which fails out