[L3][L2 pop] Is it necessary to enforce enabling the option arp_responder and l2_population?

[LIU Yulong]

Recently I played the ovs-agent with bagpipe_bgpvpn. It has some mechanism which will install the same flows to br-tun by using BGP. But now arp_responder and l2_population are enforced, after this patch https://review.opendev.org/c/openstack/neutron/+/669938.

[Brian Haley (brian-haley)]

Hi Liu,

If there is a problem with what I did in that change to better support DVR maybe we can find a way to configure around it? Maybe list the details so we know what's broken.

Thanks

[LIU Yulong (dragon889)]

I created a revert for the patch [1] mentioned in the bug description.
As the commit meassage says, all those changes are now not necessary anymore. Because the final approach [2] will not be accepted in current implementation way.

@Brian, the problem is if neutron uses ``bagpipe_bgpvpn`` to populate the L2 entry (IP+mac+ vxlan vni). The arp responder flows and tunnel direct flows will be covered by that mechanism. But after patch 669938, ovs-agent will not be allowed to do that. Since if you enable DVR, the "arp_responder" and "l2_population" are enforced.

[1] https://review.opendev.org/c/openstack/neutron/+/778820
[2] https://review.opendev.org/c/openstack/neutron/+/601336

[Brian Haley (brian-haley)]

Oh, I missed it was a follow-up to the other reverts.

[OpenStack Infra (hudson-openstack)]

Change abandoned by "liuyulong <email address hidden>" on branch: master
Review: https://review.opendev.org/c/openstack/neutron/+/782345
Reason: Restore if someday we want this.