adding nova as there is a nova element that need to be fixed also. because nova was observing the network-vif-plugged event form the dhcp agent we were not filtinging our wait condition on live migrate to only wait for backend that had plugtime events.
so once this is fixed by rodolfos patch it actully breaks live migration because we are waiting for an event that will never come until https://review.opendev.org/c/openstack/nova/+/602432 is merged. for backporting reasons i am working in a seperate trivial patch to only wait for backends that send plugtime event. that patch will be backported first allowing rodolfos patch to be backported before https://review.opendev.org/c/openstack/nova/+/602432 i have 1 unit test left to update in the plug time patch and then ill push it and reference this bug. ** Also affects: nova Importance: Undecided Status: New ** Changed in: nova Status: New => Triaged ** Changed in: nova Importance: Undecided => High ** Changed in: nova Assignee: (unassigned) => sean mooney (sean-k-mooney) -- You received this bug notification because you are a member of Yahoo! Engineering Team, which is subscribed to OpenStack Compute (nova). https://bugs.launchpad.net/bugs/1901707 Title: race condition on port binding vs instance being resumed for live- migrations Status in neutron: In Progress Status in OpenStack Compute (nova): Triaged Bug description: This is a separation from the discussion in this bug https://bugs.launchpad.net/neutron/+bug/1815989 There comment https://bugs.launchpad.net/neutron/+bug/1815989/comments/52 goes through in detail the flow on a Train deployment using neutron 15.1.0 (controller) and 15.3.0 (compute) and nova 20.4.0 There is a race condition where nova live-migration will wait for neutron to send the network-vif-plugged event but when nova receives that event the live migration is faster than the OVS l2 agent can bind the port on the destination compute node. This causes the RARP frames sent out to update the switches ARP tables to fail causing the instance to be completely unaccessible after a live migration unless these RARP frames are sent again or traffic is initiated egress from the instance. See Sean's comments after for the view from the Nova side. The correct behavior should be that the port is ready for use when nova get's the external event, but maybe that is not possible from the neutron side, again see comments in the other bug. To manage notifications about this bug go to: https://bugs.launchpad.net/neutron/+bug/1901707/+subscriptions -- Mailing list: https://launchpad.net/~yahoo-eng-team Post to : [email protected] Unsubscribe : https://launchpad.net/~yahoo-eng-team More help : https://help.launchpad.net/ListHelp
