We have an issue with live-migration if operators update OVS from a version that does not support dpdkvhostuserclient to a version that is supporting it.
Basically from OVS2.6 to OVS2.7 or upper. The problem is that, for libvirt driver all the instances created that use vhu interfaces in server mode (OVS2.6) wont be able to live-migrate anymore. That because Neutron to select which vhu mode to use is looking at OVS capabilities [0]. Meaning that During the live-migration port details are going to be updated but Nova and in particular libvirt driver does not update guests domain XML to refer the changes. - We can fix Neutron by making it consider to always use the same vhu mode if the ports already exist. - We can enhance Nova and in particular libvirt driver to update guests domain XML during live-migration. The benefit is that the instances are going to be updated for free to use vhu in client mode which is totally better but it's probably not so trivial to implement. - We can avoid fixing it meaning that operators will have to update their instances to use vhu mode client that by a way like snapshot/rebuild. Then live-migration will be possible. [0] https://git.openstack.org/cgit/openstack/neutron/tree/neutron/plugins/ml2/drivers/openvswitch/mech_driver/mech_openvswitch.py#n94 __________________________________________________________________________ OpenStack Development Mailing List (not for usage questions) Unsubscribe: [email protected]?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
