You know, I am in the same situation. I suspect one day, the Kubernetes team will embed something like multus into the K8S ecosystem like they did with cadvisor. Although, I doubt it will be multus since it’s heavily an Intel sponsored project. Until then, multus is a great choice.
I have mixed opinions regarding single homed containers. While it does reduce application configuration and allows containers to be easily portable – it does neglect the part of the software industry which deals with large networking requirements. It’s easy to refactor software applications to deal with one network, but not so easy with networking and telecommunications as your “service”.
Even then, if you applied a CQRS-type approach to your NFVs, you still need multiple segmented networks even with single homed container threads. I am surprised Weave has not implemented multi-homed solutions for K8S yet.