Comment 3 for bug 1639566

This has some up before, there are basically three different modes of burning IPs for SNAT.

Single IP per router: Current model used by Neutron.

Single IP per compute node: This seems to be what you are implying in this request, but it's completely incompatible with the current L3 API because there is nothing that makes any sense to put in the external gateway field for a router.

Single IP per (router,compute node) pair. This is much more feasible because IPs are still scoped to the router (which is also important for tenant traffic attribution) so it can modeled as multiple fixed IPs per gateway if we want.

I would only be in favor of the option to burn an IP per (router,compute node) pair. The single IP per compute node doesn't fit the API.