[ovs-discuss] MAC_Binding\" table to have identical values

Thu Oct 21 05:38:32 UTC 2021

Hi Numan,

I tried to reproduce the issue with your way but didn't get the warning
again by restarting the controller of one chassis. Then I reviewed your
last response and seen the warning log.

The mac_binding entry that it tries to create is learned from external as
seen in the last warning log. I have then applied below patch of neutron.

https://opendev.org/openstack/neutron/commit/a278c5ba789c014ec777a75fc9538179d6707202

The patch is making always_learn_from_arp_request to false while creating
the router. This has reduced the SB DB size as well.

On Thu, Oct 21, 2021 at 1:29 AM Numan Siddique <numans at ovn.org> wrote:

> On Mon, Oct 18, 2021 at 7:55 AM Daniel Alvarez Sanchez
> <dalvarez at redhat.com> wrote:
> >
> >
> >
> > On Mon, Oct 18, 2021 at 1:12 PM Ammad Syed <syedammad83 at gmail.com>
> wrote:
> >>
> >> Hi Brendan,
> >>
> >> Not sure but this could be related to the patch below in neutron that
> was recently released.
> >>
> >>
> https://opendev.org/openstack/neutron/commit/f6c35527698119ee6f73a6a3613c9beebb563840
> >
> >
> > Not really, as this commit that you refer to is to reduce the memory
> footprint in the neutron-server process itself. Neutron never inserts
> anything into the MAC_Binding table.
> > However, we landed another patch [0] that will likely minimize this
> issue as it will reduce the MAC_Binding insertions, limiting them only to
> MAC addresses that need to be reached out by the overlay.
> >
> > Thanks!
> > daniel
> >
> > [0] https://review.opendev.org/c/openstack/neutron/+/813610
> >
> >
> >>
> >>
> >> Ammad
> >>
> >> On Mon, Oct 18, 2021 at 3:40 PM Brendan Doyle <brendan.doyle at oracle.com>
> wrote:
> >>>
> >>>
> >>> I too am seeing many entries in the ovn-controller log like these:
> >>>
> >>>
> ovn/ovn-controller.log:2021-10-18T09:50:46.984Z|00164|ovsdb_idl|WARN|transaction
> error: {"details":"Transaction causes multiple rows in \"MAC_Binding\"
> table to have identical values (lr_vcn6727324-ls_vcn6727324_external_ugw
> and \"253.255.80.18\") for index on columns \"logical_port\" and \"ip\".
> First row, with UUID 614509d1-5dfc-4268-94b7-6190c1bd8c58, was inserted by
> this transaction.  Second row, with UUID
> 5b56044f-7e62-4e6b-b559-2bca31ad5ab0, existed in the database before this
> transaction and was not modified by the transaction.","error":"constraint
> violation"}
> >>>
> >>>
> >>> So with my limited understanding of the MAC_Binding table I'm
> wondering are these benign?
> >
> >
> > I think it's benign
> >>>
> >>>
> >>> In that is it that we for what ever reason have decided that we need
> to do an ARP to discover
> >>> a MAC, then ovn-controller tries to add the discovered MAC to the
> MAC_Binding only to find
> >>> that it is already there. In which case the question is why was an ARP
> request sent when
> >>> we already had a MAC binding.
>
> FYI,  ovn-controller also learns from the ARP requests received from
> external which can be
> turned off if desired with the option - always_learn_from_arp_request
> set in the logical router's options
> column.
>
> I don't think ovn-controller will generate an ARP request if its
> already learnt.  Looks to me
> multiple ovn-controller try to learn from an ARP request originated
> from external and ofcourse
> only one will be able to write to the mac_binding entry and others would
> fail.
>
> Thanks
> Numan
>
>
>
> >>>
> >>> For me these are only ever seen on Distributed router Port Gateways.
> >>>
> >>>
> >>> On 12/10/2021 13:06, Ammad Syed wrote:
> >>>
> >>> Hi,
> >>>
> >>> I am using openstack with ml2/ovn. I have two gateway chassis whenever
> I shutdown one chassis and bring it back online, I see below error in
> ovn-controller logs.
> >>>
> >>> Can you please advise the way to fix it ?
> >>>
> >>>
> 2021-10-12T11:49:22.124Z|00511|binding|INFO|cr-lrp-4c882760-15b1-4cf4-b680-53e88880e928:
> Claiming fa:16:3e:55:12:5a 101.53.244.97/24
> >>> 2021-10-12T11:49:22.126Z|00512|binding|INFO|Releasing lport
> cr-lrp-4c882760-15b1-4cf4-b680-53e88880e928 from this chassis.
> >>> 2021-10-12T11:50:32.032Z|00513|ovsdb_idl|WARN|transaction error:
> {"details":"Transaction causes multiple rows in \"MAC_Binding\" table to
> have identical values (lrp-4c882760-15b1-4cf4-b680-53e88880e928 and
> \"fe80::6a4f:64ff:fef7:8c0\") for index on columns \"logical_port\" and
> \"ip\".  First row, with UUID cbc847e6-75e4-4d73-9906-4fef221cad38, was
> inserted by this transaction.  Second row, with UUID
> bcac2e3e-5f32-411a-afcf-3249b85700f4, existed in the database before this
> transaction and was not modified by the transaction.","error":"constraint
> violation"}
> >>>
> >>> Ammad
> >>>
> >>> _______________________________________________
> >>> discuss mailing list
> >>> discuss at openvswitch.org
> >>>
> https://urldefense.com/v3/__https://mail.openvswitch.org/mailman/listinfo/ovs-discuss__;!!ACWV5N9M2RV99hQ!eo4L8XZbywCy0zb_p7-7LEVv9xl6g9V8JEf6oZTAO21scCtNAudRSGcK9mYnI7H-cyA$
> >>>
> >>>
> >>> _______________________________________________
> >>> discuss mailing list
> >>> discuss at openvswitch.org
> >>> https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
> >>
> >>
> >>
> >> --
> >> Regards,
> >>
> >>
> >> Syed Ammad Ali
> >> _______________________________________________
> >> discuss mailing list
> >> discuss at openvswitch.org
> >> https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
> >
> > _______________________________________________
> > discuss mailing list
> > discuss at openvswitch.org
> > https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
>

-- 
Regards,

Syed Ammad Ali
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