file and redirect the public url to k8 dns url?

Yes! that would work, Nice!
You can add it into the extra_docker_shell_script it will be executed in any pod the clearml-glue will spin (obviously this needs to be configured on the pod running the clearml k8s glue)
https://github.com/allegroai/clearml-agent/blob/ba2db4e727b90e595df2b13f458d9580659bf12e/docs/clearml.conf#L152