Fallback service?

Hi,

In a kubernetes context i'd like to have an ingress route fallback to a service only if the default service has no backend avaiable or if the backend pool is empty.

apiVersion: traefik.containo.us/v1alpha1
kind: IngressRoute
metadata:
  name: go-lev-tls
  namespace: default
spec:
  entryPoints:
  - https
  routes:
  - kind: Rule
    match: Host(`go-lev.company.com`)
    services:
    - name: go-lev
      passHostHeader: true
      port: 80
  tls:
    secretName: company-com-tls
---
apiVersion: traefik.containo.us/v1alpha1
kind: IngressRoute
metadata:
  name: go-lev-maintenance-tls
  namespace: default
spec:
  entryPoints:
  - https
  routes:
  - kind: Rule
    match: Host(`go-lev.company.com`)
    priority: 2
    services:
    - name: maintenance
      namespace: maintenance
      passHostHeader: true
      port: 80
  tls:
    secretName: company-com-tls

This work in the case there is no pod thus no endpoint for the service go-lev but it does not work if there are go-lev pods but in unready state.

Hey,

can you elaborte a bit more? Is that potentially linked to https://github.com/containous/traefik/issues/1007 ?