[FROG] layer-2 vxlan discovery w/ EVPN question

[Henry Snow]

I have a bare metal hosting provider that provides me with layer-3
networking to every server. For some applications, I require a layer-2
network spanning the servers. This network is for the applications running
on the server OS, not via VM or container tennants.

I've been following this blog post:
https://vincent.bernat.im/en/blog/2017-vxlan-bgp-evpn, using frr 3.1dev
from git master from several nights ago. I believe I have the route
reflector + vteps configured with respect to bgpd as described, but no
routes are advertised. I do see bgp neighbors as expected.

When I run 'show evpn mac vni 100', I do not see any mac addresses. My
suspicion is that it is because I'm not using a bridge, but assigning an IP
address directly to the vxlan interface. Looking at the source code (my C
is very rusty), it looks like it enumerates all the VNIs, finds the bridges
they're slaved to, then enumerates the interfaces on the bridge. I'm
looking at this:
https://github.com/FRRouting/frr/blob/8eac4812601f069f14fc7950e10904c2ae0ae774/zebra/zebra_vxlan.c#L2668

Is there a way to configure my interfaces without a bridge (or is this a
bad approach)? If a bridge and additional slaved interface is required, any
suggestions on how to configure the bridge with no additional tenants on
the servers?

Additional Thoughts:
- using static unicast discovery, vxlan membership across servers works
- adding a bridge interface and slaving the vxlan interface + a dummy
interface, assigning an ip to the dummy did not seem to work
- tried kernel 4.4 from elrepo, (tends to work better from previous docker
overlay network experiences)

Config:
compiled from commit c1240044fbf081bb7407b1449d3954e4b63fec9f on CentOS
7.4, with --enable-cumulus

Route Reflector:
10.40.1.131/31

bgpd.conf:
router bgp 65000
 bgp router-id 10.40.1.131
 bgp cluster-id 10.40.1.131
 bgp log-neighbor-changes
 no bgp default ipv4-unicast
 coalesce-time 1000
 neighbor fabric peer-group
 neighbor fabric remote-as 65000
 neighbor fabric update-source 10.40.1.131
 neighbor fabric capability extended-nexthop
 bgp listen range 10.40.1.128/25 peer-group fabric
 !
 address-family l2vpn evpn
  neighbor fabric activate
  neighbor fabric route-reflector-client
 exit-address-family
!


layer-2 member server example:
10.40.1.129/31

bgpd.conf:
router bgp 65000
 bgp router-id 10.40.1.129
 no bgp default ipv4-unicast
 coalesce-time 1000
 neighbor fabric peer-group
 neighbor fabric remote-as 65000
 neighbor fabric capability extended-nexthop
 neighbor 10.40.1.131 peer-group fabric
 !
 address-family l2vpn evpn
  neighbor fabric activate
  advertise-all-vni
 exit-address-family
!

vxlan configured with:
# ip link vxlan100 type vxlan id 100 local 10.40.1.129 port 4789 nolearning
# ip link set up dev vxlan100
# ip addr add 172.31.254.2/24 dev vxlan100

Thanks for any suggestions (or course corrections, as this is new to me)!



-- 
Henry Snow | Director, Site Reliability Engineering
eXelate, a Nielsen company <http://exelate.com/>
E: henry.snow at nielsen.com | M: 347.366.2700
675 6th Ave, 3rd Floor, New York, NY 10010
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