Mirroring traffic outside the cluster

1

Hi everyone. I want to achieve it the possibility to mirror the traffic from my cluster to the external service that is available over HTTP. So for this, I have a ServiceEntry that point to the external service, and the VirtialService that mirrors the traffic to the ServiceEntry. Here are my configs:

apiVersion: networking.istio.io/v1alpha3
kind: ServiceEntry
metadata:
  name: external-svc-http
spec:
  hosts:
    - external.service.url
  ports:
    - number: 80
      name: http-ext
      protocol: HTTP
  location: MESH_EXTERNAL
  resolution: NONE
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: service-default
spec:
  hosts:
    - service
  http:
    - route:
      - destination:
          host: service
          subset: v1
      mirror:
        host: external.service.url

I also have a simple DestinationRule that creates the subset v1.
However, when I apply these configs my external service still does not get any requests. I can curl the external service from inside the pod using the URL after applying these configs. Any help would be appreciated!

I’ve tried to inspect the traffic using tcpdump:

kubectl exec -it $POD_NAME -c istio-proxy -- sudo tcpdump -A -s 0 host external.service.url

And it does not show any traffic for the given host when I’m requesting my application. However, it does show the traffic when I’m explicitly curl the host from inside the pod.

I can as well see that the endpoint is present in the list of clusters:

> istioctl proxy-config clusters $POD_NAME
SERVICE FQDN                                              PORT      SUBSET         DIRECTION     TYPE
external.service.url                                      80        -              outbound      &{ORIGINAL_DST}