Image pulling via pullthrough and proxy not working in Red Hat OpenShift Container Platform

Issue

• Pulling images with pullthrough and proxy set on docker-registry does not work for images coming from https://registry.access.redhat.com. Proxy has been set according https://docs.openshift.com/container-platform/3.3/install_config/http_proxies.html but it still does not work. The following error is found in the docker-registry logs:

172.27.8.1 - - [20/Mar/2017:09:12:08 +0000] "GET /v2/is-test/dotnetcore-11-rhel7/blobs/sha256:8b8ef94d2f8348489a2b540d89b191c6a06b820e3853082c002a8f41eb79b3d1 HTTP/1.1" 500 18 "" "docker/1.10.3 go/go1.6.2 git-commit/429be27-unsupported kernel/3.10.0-514.6.1.el7.x86_64 os/linux arch/amd64"