Docker Hub Pull Limits Start Today

From 2 November 2020, Docker Hub applies pull rate limits:

Who	Limit per 6 hours
Anonymous	100 pulls per IP address
Free account, logged in	200 pulls
Pro or Team	Unlimited

Many servers or CI runners behind one NAT address share the anonymous quota, so builds may start failing with toomanyrequests.

docker login                      # authenticated pulls get the higher limit
TOKEN=$(curl -s "https://auth.docker.io/token?service=registry.docker.io&scope=repository:ratelimitpreview/test:pull" | jq -r .token)
curl -sI -H "Authorization: Bearer $TOKEN" https://registry-1.docker.io/v2/ratelimitpreview/test/manifests/latest | grep -i ratelimit

Ways to cope: log in from CI, pin versions so unchanged layers are cached, run a pull-through cache (the registry:2 image supports this), or copy the base images you depend on into Amazon ECR and pull from there.