Just in case, attach/detach of root volumes is still not possible even in shelve_offlodaded state, despite it was proposed couple of times with following spec [1]

[1] https://specs.openstack.org/openstack/nova-specs/specs/stein/approved/detach...

чт, 6 апр. 2023 г., 18:32 Sean Mooney smooney@redhat.com:

On Thu, 2023-04-06 at 23:21 +0800, kaqiu pi wrote:

...

hello,

I can only attached and dettached volumes for running instances in openstack.

nova allows you to attach volume to instance that are stopped. instance in the shelve offloaded state required micoverion v2.20 and multi attach requires v2.60

https://docs.openstack.org/api-ref/compute/?expanded=attach-a-volume-to-an-i...

for volume attachment to work with virtio blk you need to hanve enough pci slots in teh vm free for the pci hotplug to succeed.

if you are using vritio-scsi via hw_disk_bus=scsi the pci requirement does not apply.

...

I would like to ask the reason for this design. And is there any danger if this restriction is turned on through custom modification in a private scene?

Thank you so much. Yours