OCP Security Question

Hi. I'm trying to nail down what the relationship is between the image's containerfile user and group settings and the runAs and other security in OCP. Specifically, we are mounting a NAS volume in OpenShift, and I'm trying to figure out what we should set in the runAs, containerfile user/group, etc., to get integrate the needed Linux user/group of the NAS drive.

I hope that makes sense. Thanks.