Resource files for gateway on different namespace

gateway-default.yaml

kind: Gateway
apiVersion: gateway.networking.k8s.io/v1alpha2
metadata:
  name: external-http
  namespace: default
spec:
  gatewayClassName: gke-l7-gxlb
  listeners:
  - name: https
    protocol: HTTPS
    port: 443
    allowedRoutes:
      namespaces:
        from: Selector
        selector:
          matchLabels:
            shared-gateway-access: "true"
    tls:
      mode: Terminate
      options:
        networking.gke.io/pre-shared-certs: k8s2-cr-5j7hw88f-g4c3ztkg4vzi81l3-03bb42860f269591

httproute-app.yaml

kind: HTTPRoute
apiVersion: gateway.networking.k8s.io/v1alpha2
metadata:
  name: other-namespace
  namespace: app
spec:
  parentRefs:
  - name: external-http
    namespace: default
  hostnames:
  - "othernamespace.lab-01.k8s.masmovil.com"
  rules:
  - matches:
    - path:
        type: PathPrefix
        value: /
    backendRefs:
    - name: istio-ingressgateway
      namespace: istio-system
      port: 80

referencepolicy-istio-system.yaml

kind: ReferencePolicy
apiVersion: gateway.networking.k8s.io/v1alpha2
metadata:
  name: grant-app-namespace
  namespace: istio-system
spec:
  to: 
  - kind: Service
    group: ""
  from:
  - group: gateway.networking.k8s.io
    kind: HTTPRoute
    namespace: app