Use pod-network k8s service endpoint for non-cluster-host Typha

pkg/controller/installation/core_controller.go

@@ -1410,13 +1410,14 @@ func (r *ReconcileInstallation) Reconcile(ctx context.Context, request reconcile
 
 	// Build a configuration for rendering calico/typha.
 	typhaCfg := render.TyphaConfiguration{
-		K8sServiceEp:      k8sapi.Endpoint,
-		Installation:      &instance.Spec,
-		TLS:               typhaNodeTLS,
-		MigrateNamespaces: needsNamespaceMigration,
-		ClusterDomain:     r.clusterDomain,
-		NonClusterHost:    nonclusterhost,
-		FelixHealthPort:   *felixConfiguration.Spec.HealthPort,
+		K8sServiceEp:           k8sapi.Endpoint,
+		K8sServiceEpPodNetwork: k8sapi.PodNetworkEndpoint,
+		Installation:           &instance.Spec,
+		TLS:                    typhaNodeTLS,
+		MigrateNamespaces:      needsNamespaceMigration,
+		ClusterDomain:          r.clusterDomain,
+		NonClusterHost:         nonclusterhost,
+		FelixHealthPort:        *felixConfiguration.Spec.HealthPort,
 	}
 	components = append(components, render.Typha(&typhaCfg))
 

pkg/render/typha.go

@@ -69,7 +69,12 @@ var (
 // TyphaConfiguration is the public API used to provide information to the render code to
 // generate Kubernetes objects for installing calico/typha on a cluster.
 type TyphaConfiguration struct {
-	K8sServiceEp      k8sapi.ServiceEndpoint
+	K8sServiceEp k8sapi.ServiceEndpoint
+
+	// K8sServiceEpPodNetwork is used for pod-networked Typha (i.e. the non-cluster-host
+	// deployment), where K8sServiceEp may be unreachable from pods.
+	K8sServiceEpPodNetwork k8sapi.ServiceEndpoint
+
 	Installation      *operatorv1.InstallationSpec
 	TLS               *TyphaNodeTLS
 	MigrateNamespaces bool
@@ -675,6 +680,13 @@ func (c *typhaComponent) typhaEnvVarsNonClusterHost() []corev1.EnvVar {
 	envVars = replaceOrAppendEnvVar(envVars, "TYPHA_CLIENTCN", c.cfg.TLS.NodeNonClusterHostCommonName)
 	envVars = replaceOrAppendEnvVar(envVars, "TYPHA_CLIENTURISAN", c.cfg.TLS.NodeNonClusterHostURISAN)
 
+	// NCH Typha runs pod-networked, so the host-network apiserver endpoint
+	// (e.g. MKE's proxy.local) may not be reachable.
+	if podEp := c.cfg.K8sServiceEpPodNetwork; podEp.Host != "" && podEp.Port != "" {
+		envVars = replaceOrAppendEnvVar(envVars, "KUBERNETES_SERVICE_HOST", podEp.Host)
+		envVars = replaceOrAppendEnvVar(envVars, "KUBERNETES_SERVICE_PORT", podEp.Port)
+	}
+
 	// Tell the health aggregator to listen on all interfaces.
 	envVars = append(envVars, corev1.EnvVar{Name: "TYPHA_HEALTHHOST", Value: "0.0.0.0"})
 	return envVars

pkg/render/typha_test.go

@@ -217,6 +217,27 @@ var _ = Describe("Typha rendering tests", func() {
 		Expect(d.Spec.Template.Spec.Containers[0].ReadinessProbe.ProbeHandler.HTTPGet.Host).To(BeEmpty())
 	})
 
+	It("should override KUBERNETES_SERVICE_HOST/PORT on the non-cluster-host Typha when a pod-network endpoint is configured", func() {
+		cfg.K8sServiceEp = k8sapi.ServiceEndpoint{Host: "proxy.local", Port: "6444"}
+		cfg.K8sServiceEpPodNetwork = k8sapi.ServiceEndpoint{Host: "10.96.0.1", Port: "443"}
+
+		component := render.Typha(&cfg)
+		resources, _ := component.Objects()
+
+		d := rtest.GetResource(resources, "calico-typha-noncluster-host", "calico-system", "apps", "v1", "Deployment").(*appsv1.Deployment)
+		Expect(d.Spec.Template.Spec.Containers[0].Env).To(ContainElements(
+			corev1.EnvVar{Name: "KUBERNETES_SERVICE_HOST", Value: "10.96.0.1"},
+			corev1.EnvVar{Name: "KUBERNETES_SERVICE_PORT", Value: "443"},
+		))
+
+		// The host-networked Typha should still use the host-network endpoint.
+		dMain := rtest.GetResource(resources, "calico-typha", "calico-system", "apps", "v1", "Deployment").(*appsv1.Deployment)
+		Expect(dMain.Spec.Template.Spec.Containers[0].Env).To(ContainElements(
+			corev1.EnvVar{Name: "KUBERNETES_SERVICE_HOST", Value: "proxy.local"},
+			corev1.EnvVar{Name: "KUBERNETES_SERVICE_PORT", Value: "6444"},
+		))
+	})
+
 	It("should use custom client common name when specified for non-cluster host Typha deployment", func() {
 		cfg.TLS.NodeNonClusterHostCommonName = "custom-nch-cn"
 		component := render.Typha(&cfg)