[Openstack] Quantum L3: Incorrect GRE Tunnel ID

Justin Brown justin.brown at fandingo.org
Fri Aug 9 16:35:43 UTC 2013


Hello,

I'm working my way through setting up Quantum, and I've come to a
roadblock with my L3 configuration.

I'm using Openvswitch with GRE tunnels.

I have created a private network with subnet 10.1.1.0/24 that routes
to external network with subnet 192.168.27.0/24. I spawn an instance,
and assign it IP 10.1.1.2 (dhcp is not working yet).
The L3 router has assigned itself 10.1.1.1 and 192.168.27.10 in a Linux netns.

Now I try to ping from the instance to 10.1.1.1, but I don't get any
reply. If I run tcpdump on the hypervisor interface, I see arp
requests but no reply. The traffic is properly encapsulated in GRE
tunnel 0x1:

11:22:38.055555 IP 192.168.26.21 > 192.168.26.105: GREv0, key=0x1,
length 54: ARP, Request who-has 10.1.1.1 tell 10.1.1.2, length 28


Now if I try the reverse, ping from the L3 agent (ip netns exec $NS
ping 10.1.1.2), I see the same problem: arp requests but no reply.
Looking at tcpdump from the hypervisor interface, I see the GRE
traffic, but the tunnel id (key) is 0x0:

11:23:20.055930 IP 192.168.26.105 > 192.168.26.21: GREv0, key=0x0,
length 50: ARP, Request who-has 10.1.1.2 tell 10.1.1.1, length 28

The problem is that Quantum isn't configuring the router to use tunnel 0x1.

Does anyone know how to get Quantum L3 agent to properly set the
tunnel id / open flow rules?

Thanks,
Justin




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