Description of problem:
In order to test spine/leaf OSP-Director implementation, tripleo-quickstart will need to support DHCP relay between bridges on the virt-host.
tripleo-quickstart can configure bridge interfaces and IP addresses on the libvirt bridge in order to forward IP traffic between virtual interfaces on the overcloud VMs. However, it does not include any support for configuring DHCP relay between those networks.
tripleo-quickstart will have to support configuring DHCP relay in order to more fully emulate a real network (where DHCP relay can be configured on the routers or switches).
This RFE is explained in more detail upstream:
will work this from the upstream bug.