Comment 6 for bug 1012144

Good question

Run it on both the compute node and network node

Ah, I see in https://answers.launchpad.net/nova/+question/198681 you already looked at hairpin_mode and it wasn't set for the vlan1XX interfaces

It makes sense to me that hairpin_mode should be enabled on the vlan interfaces too. And, indeed, for the bridge interface in flat networking.

hairpin_mode means that a packet can be forwarded back over the port it arrived from. In the case of nova-network on a remote host, the packet will arrive on the vlan interface, be DNATed and need to be forwarded back over the vlan interface. So, that definitely sounds like we need it enabled.

If you manually do "echo 1 > /sys/class/net/vlan1XX/brport/hairpin_mode" on the network node, does that work?