Description of problem: DCN 16.1 we introduced ceph at the edge. The DCN doc mentions that a glance image copy must be present on the site's ceph cluster before an instance can be booted on a given site. If the user forgets to copy the image to the site before booting the VM, nova will download the image from glance in central site (raw) and upload it to ceph itself. This is highly inefficient and user is not notified of this process. To prevent this https://bugzilla.redhat.com/show_bug.cgi?id=1886084 adds the nova conf option "never_download_image_if_on_rbd". Tripleo-heat-templates/puppet-nova should expose this nova conf option as a t-h-t parameter. It should be enabled by default (unless explicitly set by the operator) when both glance & nova are rbd backed.
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 (Red Hat OpenStack Platform 16.1.3 bug fix and enhancement 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-2020:5413