[ovn] Dose L3 router ha support sync conntrack states

[Liu Xie]

We all know the current implementation of L3 router HA based on Ml2/OVN[1][2], but I haven't found the process for conntrack state synchronization. How is router gateway failover/failback ensured for stateful NAT?

Does OVN currently not support state synchronization for DVR's external gateway? If so, do we have any plans for this?

[1]https://docs.openstack.org/neutron/latest/admin/ovn/routing.html
[2]https://www.ovn.org/support/dist-docs/ovn-architecture.7.html

[Jakub Libosvar (libosvar)]

I think this was discussed at the last PTG to revive the conntrackd tool: https://etherpad.opendev.org/p/apr2024-ptg-neutron

Perhaps this is a duplicate of https://bugs.launchpad.net/neutron/+bug/1365438

[Liu Xie (liushy)]

@libosvar, thanks!
I would like to know how to handle it in the OVN scenario, and do we have any relevant discussions and plans.

[Ihar Hrachyshka (ihar-hrachyshka)]

I am not aware of any plans to support it in OVN; but I think a better venue for this would be to ask OVN project how to handle it. We know this can be done with ml2/ovs with conntrackd. I am not sure if this would apply to ml2/ovn.

[Liu Xie (liushy)]

Yeah, I had sent an email to ask the OVN core team.

[Ihar Hrachyshka (ihar-hrachyshka)]

For reference, the email sent to OVN team is: https://mail.openvswitch.org/pipermail/ovs-discuss/2024-June/053170.html