Traefik Forward Authentication in k8s ingress controller
According to the Traefik documentation that feature will be available in version 1.7 of Traefik (currently a release candidate).
Here is a link to the authentication documentation
My guess is that you will need to add the following 2 annotations:
ingress.kubernetes.io/auth-type: forwardingress.kubernetes.io/auth-url: https://example.comand probably also the following annotation with the corresponding header fields your auth service returns as value:
ingress.kubernetes.io/auth-response-headers: X-Auth-User, X-Secret