Comment 2 for bug 1912450

This needs quite a complex environment to reproduce so let me have a few questions first.

It seems to me you have an ovs dvr environment with securitygroup.firewall_driver=iptables_hybrid and you're running version 17.0.0 (victoria). Is that all correct? If anything is different in your environment please let us know.

How often does the error occur with and without the sleep?

Do you have an traffic broken by the stale flows? The stale flows listed above are all specific to a dst_mac so I guess those cannot break any other traffic.

One suggestion, which may or may not be related to the problem. Since we have the 'openvswitch' firewall driver there's hardly any reason to use the older and less performant 'iptables_hybrid' driver. But the hybrid driver adds some extra complexity. Even independently of this bug it may be worth to switch to the 'openvswitch' firewall driver. Can you reproduce the bug with the other driver?

Also it seems to me we may have had an earlier bug in which the error was not the same, but the error conditions were just like here:
https://bugs.launchpad.net/neutron/+bug/1737892