Restricting Container Registries

When working in a multi-user development environment restrictions are required to prevent users operating at a permission level higher than they should have in containers. Most exploits (running as root, etc) can be prevented by limiting users to sanctioned containers. How to isolate users to only working in approved containers is a hurdle though.

This question and this question have several answers that touch on the general idea and various solution methods.

In Docker

This question talks about a hacky method of using the hosts file to just blacklist the host names because there is not native method in mainline Docker. OP talks about --block-registry which is only in the RH fork of Docker 1.10 not mainline.

In Podman

Using native config files this can be accomplished easily. See: Podman registry configurations