[dev][nova][glance][cinder] introducing 'compressed' image container_format
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/
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.
It looks like [3] has been introduced to fail the instance creation, which seems like a legit first step.
So we want to open a discussion about handling this.
Is there a sense of what it would take for nova to support compressed images? We're past spec freeze, but if the impact is small...
efried
participants (2)
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Eric Fried
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Ma, Zheng