Add conformance tests for headless DNS

Verify type A and SRV records are returned from DNS.

Verify individual pods are accessible through
"hostname.clusterid.svc.ns.svc.clusterset.local" for a StatefulSet
service.

Related to #69

Signed-off-by: Tom Pantelis <[email protected]>

Author: tpantelis

conformance/clusterip_service_dns.go

@@ -58,7 +58,7 @@ var _ = Describe("", Label(OptionalLabel, DNSLabel, ClusterIPLabel), func() {
 			By(fmt.Sprintf("Found ServiceImport on cluster %q with clusterset IP %q", client.name, clusterSetIP))
 			By(fmt.Sprintf("Executing command %q on cluster %q", strings.Join(command, " "), client.name))
 
-			t.awaitCmdOutputContains(&client, command, clusterSetIP, 1, reportNonConformant(""))
+			t.awaitCmdOutputMatches(&client, command, clusterSetIP, 1, reportNonConformant(""))
 		}
 	})
 
@@ -104,7 +104,7 @@ var _ = Describe("", Label(OptionalLabel, DNSLabel, ClusterIPLabel), func() {
 
 		By(fmt.Sprintf("Executing command %q on cluster %q", strings.Join(command, " "), clients[0].name))
 
-		t.awaitCmdOutputContains(&clients[0], command, resolvedIP, 1, reportNonConformant(""))
+		t.awaitCmdOutputMatches(&clients[0], command, resolvedIP, 1, reportNonConformant(""))
 	})
 })
 
@@ -135,6 +135,10 @@ type srvRecord struct {
 	domainName string
 }
 
+func (s srvRecord) String() string {
+	return fmt.Sprintf("port:%d, domainName:%q", s.port, s.domainName)
+}
+
 func parseSRVRecords(str string) []srvRecord {
 	var recs []srvRecord
 

conformance/conformance_suite.go

@@ -30,6 +30,8 @@ import (
 
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
+	"github.com/onsi/gomega/types"
+	appsv1 "k8s.io/api/apps/v1"
 	corev1 "k8s.io/api/core/v1"
 	discoveryv1 "k8s.io/api/discovery/v1"
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
@@ -143,9 +145,10 @@ func setupClients() error {
 }
 
 type testDriver struct {
-	namespace    string
-	helloService *corev1.Service
-	requestPod   *corev1.Pod
+	namespace       string
+	helloService    *corev1.Service
+	helloDeployment *appsv1.Deployment
+	requestPod      *corev1.Pod
 }
 
 func newTestDriver() *testDriver {
@@ -154,6 +157,7 @@ func newTestDriver() *testDriver {
 	BeforeEach(func() {
 		t.namespace = fmt.Sprintf("mcs-conformance-%v", rand.Uint32())
 		t.helloService = newHelloService()
+		t.helloDeployment = newHelloDeployment()
 		t.requestPod = newRequestPod()
 	})
 
@@ -202,9 +206,12 @@ func (t *testDriver) deleteServiceExport(c *clusterClients) {
 }
 
 func (t *testDriver) deployHelloService(c *clusterClients, service *corev1.Service) {
-	_, err := c.k8s.AppsV1().Deployments(t.namespace).Create(ctx, newHelloDeployment(), metav1.CreateOptions{})
-	Expect(err).ToNot(HaveOccurred())
-	_, err = c.k8s.CoreV1().Services(t.namespace).Create(ctx, service, metav1.CreateOptions{})
+	if t.helloDeployment != nil {
+		_, err := c.k8s.AppsV1().Deployments(t.namespace).Create(ctx, t.helloDeployment, metav1.CreateOptions{})
+		Expect(err).ToNot(HaveOccurred())
+	}
+
+	_, err := c.k8s.CoreV1().Services(t.namespace).Create(ctx, service, metav1.CreateOptions{})
 	Expect(err).ToNot(HaveOccurred())
 }
 
@@ -293,10 +300,19 @@ func (t *testDriver) execCmdOnRequestPod(c *clusterClients, command []string) st
 	return string(stdout)
 }
 
-func (t *testDriver) awaitCmdOutputContains(c *clusterClients, command []string, expectedString string, nIter int, msg func() string) {
+func (t *testDriver) awaitCmdOutputMatches(c *clusterClients, command []string, expected any, nIter int, msg func() string) {
+	var matcher types.GomegaMatcher
+
+	switch v := expected.(type) {
+	case string:
+		matcher = ContainSubstring(v)
+	case types.GomegaMatcher:
+		matcher = v
+	}
+
 	Eventually(func(g Gomega) {
 		output := t.execCmdOnRequestPod(c, command)
-		g.Expect(output).To(ContainSubstring(expectedString), "Command output")
+		g.Expect(output).To(matcher, "Command output")
 	}).Within(time.Duration(20*int64(nIter))*time.Second).ProbeEvery(time.Second).MustPassRepeatedly(nIter).Should(Succeed(), msg)
 }
 

conformance/connectivity.go

@@ -64,7 +64,7 @@ var _ = Describe("", func() {
 				for _, client := range clients {
 					By(fmt.Sprintf("Executing command %q on cluster %q", strings.Join(command, " "), client.name))
 
-					t.awaitCmdOutputContains(&client, command, "pod ip", 1, reportNonConformant(""))
+					t.awaitCmdOutputMatches(&client, command, "pod ip", 1, reportNonConformant(""))
 				}
 			})
 		})
@@ -111,7 +111,7 @@ var _ = Describe("", func() {
 			for _, client := range clients {
 				By(fmt.Sprintf("Executing command %q on cluster %q", strings.Join(command, " "), client.name))
 
-				t.awaitCmdOutputContains(&client, command, servicePodIP, 10, reportNonConformant(""))
+				t.awaitCmdOutputMatches(&client, command, servicePodIP, 10, reportNonConformant(""))
 			}
 		})
 	})

conformance/endpoint_slice.go

@@ -17,7 +17,6 @@ limitations under the License.
 package conformance
 
 import (
-	"context"
 	"fmt"
 	"time"
 
@@ -26,7 +25,6 @@ import (
 	discoveryv1 "k8s.io/api/discovery/v1"
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	"k8s.io/apimachinery/pkg/util/wait"
 	"sigs.k8s.io/mcs-api/pkg/apis/v1alpha1"
 )
 
@@ -47,24 +45,19 @@ var _ = Describe("", Label(OptionalLabel, EndpointSliceLabel), func() {
 		endpointSlices := make([]*discoveryv1.EndpointSlice, len(clients))
 
 		for i, client := range clients {
-			eps := t.awaitMCSEndpointSlice(&client)
-			Expect(eps).ToNot(BeNil(), reportNonConformant(fmt.Sprintf(
+			eps := t.awaitMCSEndpointSlice(&client, discoveryv1.AddressTypeIPv4, nil, reportNonConformant(fmt.Sprintf(
 				"an MCS EndpointSlice was not found on cluster %q. An MCS EndpointSlice is identified by the presence "+
-					"of at least one of the required MCS labels, whose names are prefixed with \"multicluster.kubernetes.io\". "+
+					"of the required MCS labels (%q and %q). "+
 					"If the MCS implementation does not use MCS EndpointSlices, you can specify a Ginkgo label filter using "+
 					"the %q label where appropriate to skip this test.",
-				client.name, EndpointSliceLabel)))
+				client.name, v1alpha1.LabelServiceName, v1alpha1.LabelSourceCluster, EndpointSliceLabel)))
 
 			endpointSlices[i] = eps
 
 			Expect(eps.Labels).To(HaveKeyWithValue(v1alpha1.LabelServiceName, t.helloService.Name),
 				reportNonConformant(fmt.Sprintf("the MCS EndpointSlice %q does not contain the %q label referencing the service name",
 					eps.Name, v1alpha1.LabelServiceName)))
 
-			Expect(eps.Labels).To(HaveKey(v1alpha1.LabelSourceCluster),
-				reportNonConformant(fmt.Sprintf("the MCS EndpointSlice %q does not contain the %q label",
-					eps.Name, v1alpha1.LabelSourceCluster)))
-
 			Expect(eps.Labels).To(HaveKey(discoveryv1.LabelManagedBy),
 				reportNonConformant(fmt.Sprintf("the MCS EndpointSlice %q does not contain the %q label",
 					eps.Name, discoveryv1.LabelManagedBy)))
@@ -90,32 +83,38 @@ var _ = Describe("", Label(OptionalLabel, EndpointSliceLabel), func() {
 	})
 })
 
-func (t *testDriver) awaitMCSEndpointSlice(c *clusterClients) *discoveryv1.EndpointSlice {
+func (t *testDriver) awaitMCSEndpointSlice(c *clusterClients, addressType discoveryv1.AddressType,
+	verify func(Gomega, *discoveryv1.EndpointSlice), desc ...any) *discoveryv1.EndpointSlice {
 	var endpointSlice *discoveryv1.EndpointSlice
 
 	hasLabel := func(eps *discoveryv1.EndpointSlice, label string) bool {
 		_, exists := eps.Labels[label]
 		return exists
 	}
 
-	_ = wait.PollUntilContextTimeout(ctx, 100*time.Millisecond,
-		20*time.Second, true, func(ctx context.Context) (bool, error) {
-			defer GinkgoRecover()
+	Eventually(func(g Gomega) {
+		list, err := c.k8s.DiscoveryV1().EndpointSlices(t.namespace).List(ctx, metav1.ListOptions{})
+		g.Expect(err).ToNot(HaveOccurred(), "Error retrieving EndpointSlices")
+
+		endpointSlice = nil
 
-			list, err := c.k8s.DiscoveryV1().EndpointSlices(t.namespace).List(ctx, metav1.ListOptions{})
-			Expect(err).ToNot(HaveOccurred(), "Error retrieving EndpointSlices")
+		for i := range list.Items {
+			eps := &list.Items[i]
 
-			for i := range list.Items {
-				eps := &list.Items[i]
+			if hasLabel(eps, v1alpha1.LabelServiceName) && hasLabel(eps, v1alpha1.LabelSourceCluster) && eps.AddressType == addressType {
+				endpointSlice = eps
 
-				if hasLabel(eps, v1alpha1.LabelServiceName) || hasLabel(eps, v1alpha1.LabelSourceCluster) {
-					endpointSlice = eps
-					return true, nil
+				if verify != nil {
+					verify(g, endpointSlice)
 				}
 			}
+		}
+
+		g.Expect(endpointSlice).ToNot(BeNil(), desc...)
 
-			return false, nil
-		})
+		// The final run succeeded so cancel any prior non-conformance reported.
+		cancelNonConformanceReport()
+	}).Within(20 * time.Second).ProbeEvery(100 * time.Millisecond).Should(Succeed())
 
 	return endpointSlice
 }