Update:
A test with "skopeo inspect" ran successfully - "docker pull" not. So
I followed
https://stackoverflow.com/questions/23111631/cannot-download-docker-image...
Docker pull works now, but the deploy script still fails with the same error.
Also tried to add
environment:
http_proxy:
http://PROXY-IP:8080
in
/usr/share/ansible/openshift-ansible/playbooks/openshift-checks/private/install.yml
made no difference...