Rhel7 atomic docker base image subscription
Seems that the atomic container inherits the subscription from the host, as explained in a comment here: https://access.redhat.com/discussions/3219221
I've tested running microdnf in the container on a RHEL host without subscriptions attached and I get:
(process:5): librhsm-WARNING **: Found 0 entitlement certificates
After registering the host and attaching it a valid subscription, the atomic-rhel container does not return the warning anymore.