Setup:

gke: 1.13.7-gke.8
istio: 1.1.7-gke.0 with ingress and egress gateways
Istio mTLS: Strict

I have 2 namespaces:

• default
• development

What I have:

• Service A deployed to namespace development
• Service A should not be able to have egress traffic outside of cluster, except to whitelisted domains (so should be able to communicate with namespaces default and development and example.com)
• Service A need access to kubernetes.default.svc.cluster.local
• I have egress rule for example.com (working ok)

Without policy I can access kubernetes.default.svc.cluster.local

/app # curl -I kubernetes.default.svc.cluster.local:443
curl: (8) Weird server reply

/app # curl -I example.com
HTTP/1.1 200 OK

Default namespace labeled default-namespace=true

My policy:

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: egress-policy
  namespace: development
spec:
  podSelector: {}
  policyTypes:
    - Egress
  egress:
    - to:
        - namespaceSelector:
            matchLabels:
              kube-system: 'true'
      ports:
        - protocol: UDP
          port: 53
    - to:
        - namespaceSelector:
            matchLabels:
              istio: system
    - to:
        - namespaceSelector:
            matchLabels:
              environment: development
    - to:
        - namespaceSelector:
            matchLabels:
              default-namespace: 'true'

After this policy is applied:

/app # curl -I kubernetes.default.svc.cluster.local:443
curl: (56) Recv failure: Connection reset by peer

/app # curl -I example.com
HTTP/1.1 200 OK

Other service from default namespace are reachable.

How to make kubernetes.default.svc.cluster.local work with istio egress and restrictive egress network policy?

Added:

kubectl get ns --show-labels
NAME           STATUS   AGE    LABELS
default        Active   42d    default-namespace=true,istio-injection=enabled
development    Active   2d2h   environment=development,istio-injection=enabled
istio-system   Active   2d2h   addonmanager.kubernetes.io/mode=Reconcile,istio-injection=disabled,istio=system,k8s-app=istio
kube-public    Active   42d    <none>
kube-system    Active   42d    kube-system=true

Set Istio mTLS (beta) to Permissive did not help