GKE + Istio to access Google APIS

external-svc.yaml

#########################################################################################################################
# External Services Istio
#########################################################################################################################
apiVersion: networking.istio.io/v1alpha3
kind: ServiceEntry
metadata:
  name: external-svc-https
spec:
  hosts:
  - www.googleapis.com #bigquery
  - pubsub.googleapis.com #pubsub
  - 136.237.338.439 #postgresql Obviously use yours
  - 10.10.10.10 #Internal Postgresql
  location: MESH_EXTERNAL
  ports:
  - number: 443
    name: https
    protocol: HTTPS
  - number: 80
    name: http
    protocol: HTTP
  resolution: DNS

If you have a GKE cluster on GCP and want to access the google APIs or any resource outside the cluster you need to have a service entry in the egress proxy.

You need to add your the hosts you want to connect that are outside the GKE cluster to the hosts list, in this case I had to add Bigquery (www.googleapis.com), PubSub (pubsub.googleapis.com) and CloudSQL/PostgreSQL.

This affects to GKE managed istio version and if you install it by hand on GKE.

this link you can find the reference: https://istio.io/docs/tasks/traffic-management/egress/

If you want to use this is the command:
kubectl apply -f external-svc.yaml