Hoping to get a good answer via Cunningham's law here: the way I currently do it is to create a shared GID on the host, add the docker user to that same number

Hoping to get a good answer via Cunningham's law here: the way I currently do it is to create a shared GID on the host, add the docker user to that same number GID (via build args), and chmod it appropriately. chmod -R 2775 on folder to be shared seems to do the trick. This is probably wrong and lazy. I think the rigorous approach is to use namespaces https://www.jujens.eu/posts/en/2017/Jul/02/docker-userns-remap/ https://www.jujens.eu/posts/en/2017/Jul/02/docker-userns-rem...