openstack team mailing list archive

[Salvatore Orlando <sorlando@xxxxxxxxxx>]

Hi Joe,

are you using the OVS plugin with GRE overlays?
In that case your problem might be the fact that the plugin pushes a OVS
flow entry which applies the 'local' vlan tag only to packet directed to
the VM's mac [1]

To me, this does not look like a bug; it's probably intended behaviour, as
it kind of implements mac spoofing prevention. In the future we might also
expect stricter anti-spoof checking; on the other side a change
for administratively enabling promiscuos mode might be welcome - this
should allow you to do nested OVS.

Salvatore

[1]
https://github.com/openstack/quantum/blob/master/quantum/plugins/openvswitch/agent/ovs_quantum_agent.py#L448



On 30 April 2013 22:08, Joe Topjian <joe.topjian@xxxxxxxxx> wrote:

> Hello,
>
> I have OpenStack (Grizzly) up and running with Quantum. I'm using the Open
> vSwitch plugin, per-tenant routing, and network namespaces. As far as I'm
> aware, this is all set up correctly as instances that I create are able to
> retrieve an IP address via DHCP, reach the metadata server, and reach the
> outside internet.
>
> The issue that I'm running into is that when I install Open vSwitch on the
> instance itself, I'm unable to create working bridges. For example:
>
> ovs-vsctl add-br br-eth0
> ovs-vsctl add-port br-eth0 eth0
> (swap IPs from eth0 to br-eth0, kill dhcp, etc etc)
>
> Traffic isn't flowing properly, though.
>
> If I run a continuous ping and run tcpdump on both the instance and the
> tap interface on the controller, I see arp requests going out of the
> instance, being received on the tap interface, the tap interface sending a
> reply, but the reply never reaching the instance.
>
> However, I have found that if I create a bridge with the same MAC as the
> interface that I'm adding to the bridge, traffic flows correctly:
>
> ovs-vsctl set bridge br-eth0 other-config:hwaddr=aa:bb:cc:00:11:22
>
> My best guess is that there's something (L2) blocking the flow of traffic,
> but I'm not exactly sure where to start looking. I think it's safe to
> assume that Open vSwitch on the OpenStack servers is doing the blocking but
> I think it's Quantum that's implementing the blocking since if I use Open
> vSwitch with nova-network, this problem doesn't happen.
>
> Does anyone have any pointers? Or even a fix?
>
> Thanks,
> Joe
>
> --
> Joe Topjian
> Systems Administrator
> Cybera Inc.
>
> www.cybera.ca
>
> Cybera is a not-for-profit organization that works to spur and support
> innovation, for the economic benefit of Alberta, through the use
> of cyberinfrastructure.
>
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