Health check problem with setting up GKE with istio-gateway - google-cloud-platform

Question

Goal
I'm trying to setup a
Cloud LB -> GKE [istio-gateway -> my-service]
This was working before, however, I have to recreate the cluster 2 days ago and run into this problem. Maybe some version change?
This is my ingress manifest file
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: "my-dev-ingress"
namespace: "istio-system"
annotations:
kubernetes.io/ingress.global-static-ip-name: "my-dev-gclb-ip"
ingress.gcp.kubernetes.io/pre-shared-cert: "my-dev-cluster-cert-05"
kubernetes.io/ingress.allow-http: "false"
spec:
backend:
serviceName: "istio-ingressgateway"
servicePort: 80
Problem
The health check issue by the Cloud LB failed. The backend service created by the Ingress create a /:80 default health check.
What I have tried
1) I tried to set the health check generated by the gke ingress to point to the istio-gateway StatusPort port 15020 in the Backend config console. Then the health check passed for a bit until the backend config revert itself to use the original /:80 healthcheck that it created. I even tried to delete the healthcheck that it created and it just create another one.
2) I also tried using the istio-virtual service to route the healthcheck to 15020 port as shown here with out much success.
3) I also tried just route everything in the virtual-service the healthcheck port
hosts:
- "*"
gateways:
- my-web-gateway
http:
- match:
- method:
exact: GET
uri:
exact: /
route:
- destination:
host: istio-ingress.gke-system.svc.cluster.local
port:
number: 15020
4) Most of the search result I found say that setting readinessProbe in the deployment should tell the ingress to set the proper health check. However, all of my service are under the istio-gateway and I can't really do the same.
I'm very lost right now and will really appreciate it if anyone could point me to the right direction. Thanks

Answer 1

i got it working with gke 1.20.4-gke.2200 and istio 1.9.2, the documentation for this is non existent or i have not found anything, you have to add an annotation to istio-ingressgateway service to use a backend-config when using "istioctl install -f values.yaml" command
apiVersion: install.istio.io/v1alpha1
kind: IstioOperator
spec:
components:
ingressGateways:
- name: istio-ingressgateway
enabled: true
k8s:
serviceAnnotations:
cloud.google.com/backend-config: '{"default": "istio-ingressgateway-config"}'
then you have to create the backend-config with the correct healthcheck port
apiVersion: cloud.google.com/v1
kind: BackendConfig
metadata:
name: istio-ingressgateway-config
namespace: istio-system
spec:
healthCheck:
checkIntervalSec: 30
port: 15021
type: HTTP
requestPath: /healthz/ready
with this the ingress should automatically change the configuration for the load balancer health check pointing to istio port 80
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: web
namespace: istio-system
annotations:
kubernetes.io/ingress.global-static-ip-name: web
networking.gke.io/managed-certificates: "web"
spec:
rules:
- host: test.example.com
http:
paths:
- path: "/*"
pathType: Prefix
backend:
service:
name: istio-ingressgateway
port:
number: 80
apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
name: direct-web
namespace: istio-system
spec:
hosts:
- test.example.com
gateways:
- web
http:
- match:
- uri:
prefix: "/"
route:
- destination:
port:
number: 8080 #internal service port
host: "internal-service.service-namespace.svc.cluster.local"
apiVersion: networking.istio.io/v1beta1
kind: Gateway
metadata:
name: web
namespace: istio-system
spec:
selector:
istio: ingressgateway
servers:
- port:
number: 80
name: http
protocol: HTTP
hosts:
- test.example.com
you could also set hosts to "*" in the virtualservice and gateway