One more approach to get working SIP in kubernetes. We can utilize `Ingress` to routes SIP traffic inside Kubernetes. Routing and load balancing may be implemented using: 1. transport protocol; 2. To(From) URI domain part; 3. To(From) URI user part.
As `Ingress` may be used stateless Kamailio with `carrier_route` and `registrar` modules. Here is description how to implement clustered IP in cloud providers and how to implement load balancing. [Link](http://arthurchiao.art/blog/k8s-l4lb/)