Greetings! Disclaimer: It is super rare for me to go look at glance back ends. From an Ironic point of view, the recommendation is geared so you can use TempURL access and that URL can just be provided through to the deployment agent so it can directly download the image contents from the object storage backend. Be that Swift, or ultimately Ceph operating with the Swift compatibility enabled. If that is not desirable, Ironic can cache the image locally on the conductor and still allow the nodes being deployed to stream the image out from the conductor instead. It really depends on the size of images you're dealing with and how much you're doing in terms of rapid deployments. Consult the [agent] section option image_download_source in ironic.conf[0]. That being said, if the glance image can be downloaded by a more recent glance v2 client, then in all likelihood it is just more a terminology/confusion issue. Hope that helps! -Julia [0]: https://docs.openstack.org/ironic/latest/configuration/sample-config.html On Fri, Jan 5, 2024 at 9:12 AM Michael Sherman <shermanm@uchicago.edu> wrote:
Hey!
We’re looking into deploying a cloud with a mix of VM and baremetal hosts (nova-compute vs ironic), and discovered some tension between the recommendations for glance for each case. At scale, ironic seems to recommend usage of the swift backend to remove the conductor as a bottleneck when streaming disk images, but for KVM usage, the RBD backend allows for faster launches by cloning the source image.
Any thoughts on these or any other tradeoffs, or some recommended configurations?
Thanks!
-Mike
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Michael Sherman
Infrastructure Lead – Chameleon
Computer Science, University of Chicago
MCS, Argonne National Lab