On Tue, 2021-01-05 at 22:27 +0800, 付志华 wrote:

hello，     I encountered some problems in deploying the smart network interface card（SmartNIC）where Nova-compute is not together with OVS. For example, OVS is deployed on the SmartNIC and Nova-compute is on the Host(Compute Node), how does Nova plug the virtual interface of VM to OVS bridge?     Does the latest version of openstack support this?

no it does not. there are ways that you coudl attepmt to make this work namely you could change [os_vif_ovs]/ovsdb_connection https://github.com/openstack/os-vif/blob/master/vif_plug_ovs/ovs.py#L59-L64 so that os-vif could talk to ovs on the smart nic but that would not work for cases where libvirt plugggs the interface.

even in case where os-vif pluggs the interface qemu/libvirt will create the vm tap device on the host not on the smart nic so ovs will not be able to see it to manage it.

running ovs on a smart nic instead of the host cpu would require other chagne as well so this is a non tirival change. there were some propoals to allow the neutron l2 agent to mange remote ovs instance but that was not accepted.

as it stands without a lot of work there is no easy way to deploy openstack in that topology and at this point in the cycle im not sure its something that could be completed this cycle even if we wanted too. its certenly somethign that can be discussed buti would suggest that any work to enable this should proably take place in X at the earliest.

Thanks.