code: func (s *APIServer) upsertAuthServer(auth ClientI, w http.ResponseWriter, r *http.Request, p httprouter.Params, version string) (interface{}, error) {
  	return s.upsertServer(auth, teleport.RoleAuth, w, r, p, version)
  }
docs: // upsertAuthServer is called by remote Auth servers when they ping back into the auth service