Cannot create service error="getting backend addresses: service port not found"

Traefik Traefik v3 (latest)
1

Hi all,

I was really pleased to see that traefik aims to provide such a smooth migration for users of ingress-nginx. It mostly just works by following the official guide, which is already pretty cool.

I have some service that does not seem to get properly proxied though. The services are configured more or less like this:

---
kind: Service
apiVersion: v1
metadata:
  name: google-storage-buckets
spec:
  type: ExternalName
  externalName: storage.googleapis.com
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: external-proxy
  labels:
    app.kubernetes.io/component: http-server
  annotations:
    nginx.ingress.kubernetes.io/backend-protocol: "HTTPS"
    nginx.ingress.kubernetes.io/upstream-vhost: "storage.googleapis.com"
    nginx.ingress.kubernetes.io/rewrite-target: /internal-prefix/$1
    nginx.ingress.kubernetes.io/use-regex: "true"
spec:
  ingressClassName: nginx
  rules:
  - host: somewhere.example.com
    http:
      paths:
      - path: /(.+)
        pathType: ImplementationSpecific
        backend:
          service:
            name: google-storage-buckets
            port:
              number: 443
---

This is essentially the configuration remmondended in this GitHub issue.
I repeatedly see the following line in kubectl -n traefik logs deployment/traefik | grep ingress:

2026-02-24T15:27:58Z ERR Cannot create service error="getting backend addresses: service port not found" ingress=content-api-gcs-private namespace=some-namespace providerName=kubernetesingressnginx serviceName=external-proxy servicePort=&ServiceBackendPort{Name:,Number:443,}

I tried to find anything about that error in the traefik source code, but couldn't. I checked and all the annotations seem to be supported.

Any idea what might be going on there?

Thanks!

2

I found this fixture in the repository which at first glance looked quite similar to the snippet above:

However you can see that the ExternalName service isn't actually referenced by any ingress. Is this intentional?

3

This is a Traefik user-to-user community forum.

If you think this is a bug, you can submit it to the devs at Traefik Github.