None of the in-tree nova virt drivers support attaching SR-IOV ports to a running instance, you can only create a server with an SR-IOV port. I have a patch proposed [1] to make this an explicit failure rather than the user getting an obscure 500 KeyError failure. Supporting this would be a feature change [2]. However, the out of tree powervm driver apparently supports attaching SR-IOV ports to running servers, so I'm sending this email to make any other out of tree virt drivers aware of the change to make it explicitly fail in case they also support his functionality downstream. [1] https://review.openstack.org/#/c/591898/ [2] https://blueprints.launchpad.net/nova/+spec/sriov-interface-attach-detach -- Thanks, Matt