fix hard-coded cluster.local domain (#10306)

Co-authored-by: soloio-bulldozer[bot] <48420018+soloio-bulldozer[bot]@users.noreply.github.com>
Co-authored-by: Sam Heilbron <[email protected]>

changelog/v1.18.0-beta34/cluster-domain.yaml

@@ -0,0 +1,6 @@
+changelog:
+  - type: FIX
+    issueLink: https://github.com/solo-io/gloo/issues/10268
+    resolvesIssue: false
+    description: >-
+      Fix issue where Gloo Gateway did not respect the cluster domain for the xds host address.

pkg/utils/kubeutils/dns.go

@@ -1,18 +1,12 @@
 package kubeutils
 
 import (
-	"fmt"
-
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-)
-
-const (
-	// ClusterInternalDomainName is the internal domain for a Kubernetes Cluster
-	ClusterInternalDomainName = "cluster.local"
+	"knative.dev/pkg/network"
 )
 
 // ServiceFQDN returns the FQDN for the Service, assuming it is being accessed from within the Cluster
 // https://kubernetes.io/docs/concepts/services-networking/dns-pod-service/#services
 func ServiceFQDN(serviceMeta metav1.ObjectMeta) string {
-	return fmt.Sprintf("%s.%s.svc.%s", serviceMeta.GetName(), serviceMeta.GetNamespace(), ClusterInternalDomainName)
+	return network.GetServiceHostname(serviceMeta.Name, serviceMeta.Namespace)
 }

projects/gateway2/utils/upstream.go

@@ -1,18 +1,15 @@
 package utils
 
 import (
-	"fmt"
-
 	v1 "github.com/solo-io/gloo/projects/gloo/pkg/api/v1"
+	"knative.dev/pkg/network"
 )
 
 func GetHostnameForUpstream(us *v1.Upstream) string {
 	// get the upstream name and namespace
-	// TODO: suppport other suffixes that are not cluster.local
-
 	switch uptype := us.GetUpstreamType().(type) {
 	case *v1.Upstream_Kube:
-		return fmt.Sprintf("%s.%s.svc.cluster.local", uptype.Kube.GetServiceName(), uptype.Kube.GetServiceNamespace())
+		return network.GetServiceHostname(uptype.Kube.GetServiceName(), uptype.Kube.GetServiceNamespace())
 	case *v1.Upstream_Static:
 		hosts := uptype.Static.GetHosts()
 		if len(hosts) == 0 {

projects/gloo/pkg/plugins/kubernetes/plugin.go

@@ -11,6 +11,7 @@ import (
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/labels"
 	"k8s.io/client-go/kubernetes"
+	"knative.dev/pkg/network"
 
 	"github.com/solo-io/go-utils/contextutils"
 	corecache "github.com/solo-io/solo-kit/pkg/api/v1/clients/kube/cache"
@@ -54,9 +55,10 @@ func (p *plugin) Resolve(u *v1.Upstream) (*url.URL, error) {
 	if !ok {
 		return nil, nil
 	}
-	return url.Parse(fmt.Sprintf("tcp://%v.%v.svc.cluster.local:%v",
+	return url.Parse(fmt.Sprintf("tcp://%v.%v.svc.%s:%v",
 		kubeSpec.Kube.GetServiceName(),
 		kubeSpec.Kube.GetServiceNamespace(),
+		network.GetClusterDomainName(),
 		kubeSpec.Kube.GetServicePort(),
 	))
 }