The VM launched from a controller node on a compute host fails to get an IP address.

Issue

• After installing OpenStack through packstack, we have launched a VM on the compute host through the controller host. We have expected to see the IP address getting assigned to the VM launched on the compute host; However the VM did not get any IP. The problem seems to be that the dhcp discover messages are not reaching the tunnel bridge (br-tun) of the compute host it self.