For Glance to manage encryption key removal for Cinder encrypted volumes uploaded to Glance (bug 1481814), changes are needed in Cinder to supply the correct image metadata.
The basic implementation is https://review.opendev.org/#/c/683228/ There is a related bug that should be fixed before this feature is considered done: https://bugs.launchpad.net/cinder/+bug/1844725 The patch for that bug is https://review.opendev.org/#/c/683235/
Code has merged upstream. Will be included in Train release.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHEA-2020:0283