I have a Portainer Agent deployed on a Kubernetes cluster with the default manifests you are providing and according to the instructions displayed on the Portainer ...
2021-02-18 21:12:08 level=info msg="RESTful API listening at: 127.0.0.1:9090" 2021-02-18 21:12:08 level=info msg="HTTP proxy listening at: :7890" 2021-02-18 21:12:08 level=info msg="SOCKS proxy ...