Support for external-dns annotations on HTTPRoutes

[Thakurvaibhav]

What would you like to be added:
external-dns annotations are only supported on the Gateway resource. Are there any plans to support these on HTTPRoutes ( and other resources ) as well ?

Why is this needed:
We have a shared gateway with a https listener with a wildcard cert attached to it.
We then create HTTPRoutes with specific hostnames. external-dns is able to look for HTTPRoutes to create hostnames but there is no annotation support such as TTL, additional hostnames etc.

[ivankatliarchuk]

HI @Thakurvaibhav would you be able to share Kubernetes manifests, or anything that could help to understand the request better.

[Thakurvaibhav]

@ivankatliarchuk

Here is a manifest of the shared gateway for various services

apiVersion: gateway.networking.k8s.io/v1
kind: Gateway
metadata:
  name: eg-infra-shared-01
  namespace: envoy-gateway-system
spec:
  gatewayClassName: infra-shared-01
  listeners:
    - allowedRoutes:
        namespaces:
          from: All
      name: http
      port: 80
      protocol: HTTP
    - allowedRoutes:
        namespaces:
          from: All
      hostname: '*.mydomian.io'
      name: https
      port: 443
      protocol: HTTPS
      tls:
        mode: Terminate
        certificateRefs:
        - group: ""
          kind: Secret
          name: mydomain-tls
          namespace: envoy-gateway-system
    - allowedRoutes:
        namespaces:
          from: All
      hostname: mySecureService.mydomain.io
      name: mySecureService-https
      port: 443
      protocol: HTTPS
      tls:
        certificateRefs:
        - group: ""
          kind: Secret
          name: mySecureService-server-tls
          namespace: envoy-gateway-system
        mode: Terminate

As you can see that this gateway has a wildcard host and another defined host which uses mTLS. In addition to the gateway, we have HTTP Routes in various namespaces such as the following:

apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: grafana
  namespace: monitoring
spec:
  parentRefs:
    - name: eg-infra-shared-01
      namespace: envoy-gateway-system
      sectionName: https
  hostnames:
  - grafana.mydomain.io
  rules:
    - backendRefs:
        - name: grafana
          port: 3000
      matches:
        - path:
            type: PathPrefix
            value: /

We would prefer external-dns to consume annotations from both HTTPRoutes object and Gateway objects.

[ivankatliarchuk]

I'm going to add /help we may have someone to be able help with proposing and implementing a solution

[ivankatliarchuk]

/help

[k8s-ci-robot]

@ivankatliarchuk:
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[phuhung273]

I can see we have this test

external-dns/source/gateway_httproute_test.go

Lines 870 to 924 in 6e1651a

	{
	title: "HostnameAnnotation",
	config: Config{},
	namespaces: namespaces("default"),
	gateways: []*v1beta1.Gateway{{
	ObjectMeta: objectMeta("default", "test"),
	Spec: v1.GatewaySpec{
	Listeners: []v1.Listener{{Protocol: v1.HTTPProtocolType}},
	},
	Status: gatewayStatus("1.2.3.4"),
	}},
	routes: []*v1beta1.HTTPRoute{
	{
	ObjectMeta: metav1.ObjectMeta{
	Name: "without-hostame",
	Namespace: "default",
	Annotations: map[string]string{
	hostnameAnnotationKey: "annotation.without-hostname.internal",
	},
	},
	Spec: v1.HTTPRouteSpec{
	CommonRouteSpec: v1.CommonRouteSpec{
	ParentRefs: []v1.ParentReference{
	gwParentRef("default", "test"),
	},
	},
	Hostnames: nil,
	},
	Status: httpRouteStatus(gwParentRef("default", "test")),
	},
	{
	ObjectMeta: metav1.ObjectMeta{
	Name: "with-hostame",
	Namespace: "default",
	Annotations: map[string]string{
	hostnameAnnotationKey: "annotation.with-hostname.internal",
	},
	},
	Spec: v1.HTTPRouteSpec{
	CommonRouteSpec: v1.CommonRouteSpec{
	ParentRefs: []v1.ParentReference{
	gwParentRef("default", "test"),
	},
	},
	Hostnames: hostnames("with-hostname.internal"),
	},
	Status: httpRouteStatus(gwParentRef("default", "test")),
	},
	},
	endpoints: []*endpoint.Endpoint{
	newTestEndpoint("annotation.without-hostname.internal", "A", "1.2.3.4"),
	newTestEndpoint("annotation.with-hostname.internal", "A", "1.2.3.4"),
	newTestEndpoint("with-hostname.internal", "A", "1.2.3.4"),
	},
	},

This means HTTPRoute is supported rite @ivankatliarchuk ? Sorry im new to the project.