Support for multiple gateways in Neutron subnets

[Shraddha Pandhe]

Currently, the subnets in Neutron only support one gateway. For provider networks in large data centers, quite often, the architecture is such a way that multiple gateways are configured for the subnets. These multiple gateways are typically spread across backplanes so that the production traffic can be load-balanced between backplanes.

This is just my use case for supporting multiple gateways, but other folks might have more use cases as well.

I want to open up a discussion on this topic and figure out the best way to handle this. Should this be done in a same way as dns-nameserver, with a separate table with two columns: gateway_ip, subnet_id.

[Kyle Mestery (mestery)]

Ignoring the implementation details, the use case appears valid to me. I'd like other network operators to comment on how common having different gateways is here.

[yong sheng gong (gongysh)]

make sense to me

[Kevin Benton (kevinbenton)]

For now I don't think we are going to go forward with this because it's a very invasive change and there isn't a really strong demand for it. Let's revisit this if necessary after the routed networks and other model changes happen during mitaka that are designed to help with large operator use cases like this.