Apply the hosts-etc-hosts-update.yaml manifest to set up a daemonset that attepts to edit /etc/hosts on current and future nodes.
The init container adds the knative.registry.svc.cluster.local hostname if it's not already present, pointing to the IP of the knative service.
There might be node types for which this edit isn't allowed or doesn't work. To see status use kubectl -n kube-system logs -l app=registry-etc-hosts-update -c update which should print out a getent hosts command for first time runs and the IP given by kubectl -n registry get service knative -o jsonpath='{.spec.clusterIP}' on subsequent runs.