Kubernetes out of box not ready for VoIP/ You can look https://github.com/kubernetes/kubernetes/issues/80122
RTP will be fixed if rtpproxy, FreeSwitch or similar daemon will started on `host` network. Do to it reqired own dedicated media daemon image. [Example](https://cloud.docker.com/u/safarov/repository/docker/safarov/freeswitch)
`rtpproxy` image not exist on docker hub. bit may be easyly creeated. Here example how to create own docker images for your needs https://github.com/sergey-safarov/dockerfiles/blob/master/certbot/0.37.1/alp...
One feature that not exist on Kubernes is "static IP" for Kamailio. This may be done by customizing Kubernetes source code. Or by customizing kubernetes nodegroup init script.
I will close ticket, because this not related to kamailio or kamailio packaging.