MACVLAN not working on qg interface of qrouter

asked 2017-07-27 10:34:49 -0500

RyanYMT gravatar image

updated 2017-07-27 10:35:47 -0500

I'm setting up openstack(ocata) on CentOS 7.3 on OVH. Everything is working except floating ip. OVH has known limitation for the network. They use MAC mapping for each of the ip for the outgoing traffics.

I followed this guide to setup the br-ex and external router. But floating-ip does not seem to be working. (

Instances can access to internet i use normal snat (without floating-ip). But traffics started to fail once i assign the floating-ip. I did some tcpdump and wireshark to understand where is the traffic broken. Here is a summary.

My qg interface IP of the qrouter is x.x.x.55 and mac address is 02:00:00:e0:4c:8a. My floating-ip is x.x.x.54, and i setup macvlan with address of 02:00:00:0b:d8:e5 (that is the mac address assigned by ovn for this IP).

I cannot ping to internet after floating-ip assigned. tcpdump show that icmp reply packet reached to qg interface, but never pass over to qr interface, hence never reach back to VM. I capture with wireshark to understand a bit more and i found that egress icmp request were sent with primary mac address (e0:4c:8a), but icmp reply came back to floating-ip mac address (0b:d8:e5). This seem to looks like my qg interface of the qrouter is accepting only the packets with primary mac address (e0:4c:8a).

To confirm this, i tried nping. nping to floating ip with mac address of that floating ip, it failed.

nping --icmp --icmp-type 8 x.x.x.54 --dest-mac 02:00:00:0b:d8:e5

Then i tried to nping to floating ip with mac address of primary ip, i got response.

nping --icmp --icmp-type 8 x.x.x.54 --dest-mac 02:00:00:e0:4c:8a

So this appear to me that, even with macvlan, my qg interface is accepting only the packets coming to its primary macaddress.

Here is my macvlan interface.

2f.3@qg-60eaa81a-2f: <broadcast,multicast,up,lower_up> mtu 1450 qdisc noqueue state UNKNOWN qlen 1000 link/ether 02:00:00:0b:d8:e5 brd ff:ff:ff:ff:ff:ff

What could be the problem ? Please advice on this. Thanks.

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