Hello Nova developers, Cinder is working on a feature that will allow it to compress volumes uploaded to Glance [0,1]. We are proposing a new container_format for Glance named 'compressed' [2]. The idea is that a consumer of a 'compressed' image would read the file to determine the kind of compression and take appropriate action (either successfully decompress to find a payload that matches the image's disk_format, or fail with 'unsupported container_format'). Our preliminary testing with a raw image with container_format == compressed, disk_format == raw is that Nova boots a VM from the image but the VM appears to be unusable. Nova seems taking it as a real RAW image as disk_format indicates. So we want to open a discussion about handling this. Thanks! [0] cinder spec patch https://review.opendev.org/#/c/652275/ [1] cinder code implementation https://review.opendev.org/#/c/668825 [2] glance spec patch https://review.opendev.org/#/c/670454/