I confirm the issue I reported in comment #7 has been fixed.
After installing openvswitch-common, openvswitch-switch, python-openvswitch 2.9.2-0ubuntu0.18.04.2 the neutron-openvswitch-agent continued working and after restarting neutron-openvswitch-agent network traffic between running instances was working again.
Restarting the neutron nodes also worked, neutron-ovs-cleanup.log did not complain about the missing compat module anymore.
(leaving formal verification to the openstack team, as mentioned in the bug description)
I confirm the issue I reported in comment #7 has been fixed. 18.04.2 the neutron- openvswitch- agent continued working and after restarting neutron- openvswitch- agent network traffic between running instances was working again. ovs-cleanup. log did not complain about the missing compat module anymore.
After installing openvswitch-common, openvswitch-switch, python-openvswitch 2.9.2-0ubuntu0.
Restarting the neutron nodes also worked, neutron-
(leaving formal verification to the openstack team, as mentioned in the bug description)