Comment 2 for bug 1166110

Responding here since that's what ijw-ubuntu requested.

Why do you want to do this? So to take the case of the controlplane and dataplane on the same network, you can just create two networks in quantum that both have the same interface as the output interface. So on the hyperwiser you have just eth0 that goes into the ovs-integration bridge that then the ovs flows take the 2 separate networks, and outputs them on the same physical network.

The argument against is really one of simplicity, the end user (the one spinning up instances) should not have to care about the underlying infrastructure, that is the responsibility of the cloud operator, ie the burden of setup is on the cloud operator to configure their hyperwisers and ovs/quantum appropriately to support the network configurations required by the images they support.

Nova currently does not support multiple interfaces on the same network. Its all up to the driver on how to interpret the network model, and explicitly disallowed by drivers that use the legacy format, so really this is a feature request that should be a blueprint not a bug, the discussion of the merits should probably move there.