[neutron] Status on BGP support when using OVN in Neutron

Thomas Goirand zigo at debian.org
Wed Dec 9 09:50:04 UTC 2020

On 12/8/20 4:12 PM, Tim Sæterøy wrote:
> Hi,
> I'm trying to explore BGP support when using OVN in Neutron, but
> haven't been able to find much info on the topic. According to [1]
> committed in march 2020, OVN seems to lack similar functionality as is
> seen in ML2/OVS, but there's no further references:
>> Currently ML2/OVS supports making a tenant subnet routable via BGP,
>> and can announce host routes for both floating and fixed IP
>> addresses.
> I've tried searching for 'bgp' on Neutrons launchpad for issues tagged
> with 'ovn', in the 'ovn-org/ovn' repo or on docs.ovn.org, but I'm
> getting blanks.
> Does anyone happen to know where OVN stands on this, and especially in
> the context of Neutron? Or perhaps able to point me in the right
> direction where I can find out more? Thanks.
> [1]: https://docs.openstack.org/neutron/victoria/ovn/gaps.html
> --
> Tim


As much as I know, there's no upstream (ie: OpenStack without downstream
modification) for BGP-to-the-host support, appart from the
non-mainstream callico driver, which I haven't tested.

However, I have been able to do a kind of "bgp-to-the-rack" where the L2
networking is limited to segments on a single rack. This can be done
adding this patch to Neutron:


As you can see, I did a few iteration of this patch, but now, I've been
told to add more db tests, which I don't have the skills for. I asked
for more help from the Neutron team, but so far, everyone seems busy.
However, I did test this, and it works kind of well. :)

If you wish to help to get this patch going in, please do! :)

Note that this doesn't use OVN. I have no idea if it would work with OVN
or not (I never did such a setup, only used plain OVS).

Now, this doesn't replace a full BGP-to-the-host setup, but hopefully,
the Neutron team will be able to have this done "soon" (whatever that
means), as interest for it is growing.


Thomas Goirand (zigo)

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