Merge pull request #63265 from rajansandeep/dnsconfigtest

Automatic merge from submit-queue (batch tested with PRs 64174, 64187, 64216, 63265, 64223). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Extend dns configmap tests to include CoreDNS

**What this PR does / why we need it**:
This PR extends the DNS configmap e2e tests to include testing the CoreDNS ConfigMap.
The tests now test the equivalent `stubdomain`, `federation` and `upstreamnameserver` configuration of kube-dns for CoreDNS, when CoreDNS is the installed DNS server.

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #62865

**Special notes for your reviewer**:

**Release note**:

```release-note
NONE
```

test/e2e/network/dns_common.go

@@ -55,9 +55,8 @@ type dnsTestCommon struct {
 
 func newDnsTestCommon() dnsTestCommon {
 	return dnsTestCommon{
-		f:    framework.NewDefaultFramework("dns-config-map"),
+		f:  framework.NewDefaultFramework("dns-config-map"),
-		ns:   "kube-system",
+		ns: "kube-system",
-		name: "kube-dns",
 	}
 }
 
@@ -72,6 +71,12 @@ func (t *dnsTestCommon) init() {
 
 	t.dnsPod = &pods.Items[0]
 	framework.Logf("Using DNS pod: %v", t.dnsPod.Name)
+
+	if strings.Contains(t.dnsPod.Name, "coredns") {
+		t.name = "coredns"
+	} else {
+		t.name = "kube-dns"
+	}
 }
 
 func (t *dnsTestCommon) checkDNSRecord(name string, predicate func([]string) bool, timeout time.Duration) {
@@ -102,6 +107,8 @@ func (t *dnsTestCommon) checkDNSRecordFrom(name string, predicate func([]string)
 func (t *dnsTestCommon) runDig(dnsName, target string) []string {
 	cmd := []string{"/usr/bin/dig", "+short"}
 	switch target {
+	case "coredns":
+		cmd = append(cmd, "@"+t.dnsPod.Status.PodIP)
 	case "kube-dns":
 		cmd = append(cmd, "@"+t.dnsPod.Status.PodIP, "-p", "10053")
 	case "dnsmasq":
@@ -161,6 +168,24 @@ func (t *dnsTestCommon) setConfigMap(cm *v1.ConfigMap) {
 	}
 }
 
+func (t *dnsTestCommon) fetchDNSConfigMapData() map[string]string {
+	if t.name == "coredns" {
+		pcm, err := t.c.CoreV1().ConfigMaps(metav1.NamespaceSystem).Get(t.name, metav1.GetOptions{})
+		Expect(err).NotTo(HaveOccurred())
+		return pcm.Data
+	}
+	return nil
+}
+
+func (t *dnsTestCommon) restoreDNSConfigMap(configMapData map[string]string) {
+	if t.name == "coredns" {
+		t.setConfigMap(&v1.ConfigMap{Data: configMapData})
+		t.deleteCoreDNSPods()
+	} else {
+		t.c.CoreV1().ConfigMaps(t.ns).Delete(t.name, nil)
+	}
+}
+
 func (t *dnsTestCommon) deleteConfigMap() {
 	By(fmt.Sprintf("Deleting the ConfigMap (%s:%s)", t.ns, t.name))
 	t.cm = nil
@@ -234,6 +259,21 @@ func (t *dnsTestCommon) deleteUtilPod() {
 	}
 }
 
+// deleteCoreDNSPods manually deletes the CoreDNS pods to apply the changes to the ConfigMap.
+func (t *dnsTestCommon) deleteCoreDNSPods() {
+
+	label := labels.SelectorFromSet(labels.Set(map[string]string{"k8s-app": "kube-dns"}))
+	options := metav1.ListOptions{LabelSelector: label.String()}
+
+	pods, err := t.f.ClientSet.CoreV1().Pods("kube-system").List(options)
+	podClient := t.c.CoreV1().Pods(metav1.NamespaceSystem)
+
+	for _, pod := range pods.Items {
+		err = podClient.Delete(pod.Name, metav1.NewDeleteOptions(0))
+		Expect(err).NotTo(HaveOccurred())
+	}
+}
+
 func generateDNSServerPod(aRecords map[string]string) *v1.Pod {
 	pod := &v1.Pod{
 		TypeMeta: metav1.TypeMeta{

test/e2e/network/dns_configmap.go

@@ -151,6 +151,8 @@ func (t *dnsNameserverTest) run() {
 
 	t.createUtilPod()
 	defer t.deleteUtilPod()
+	originalConfigMapData := t.fetchDNSConfigMapData()
+	defer t.restoreDNSConfigMap(originalConfigMapData)
 
 	t.createDNSServer(map[string]string{
 		"abc.acme.local": "1.1.1.1",
@@ -159,10 +161,28 @@ func (t *dnsNameserverTest) run() {
 	})
 	defer t.deleteDNSServerPod()
 
-	t.setConfigMap(&v1.ConfigMap{Data: map[string]string{
+	if t.name == "coredns" {
-		"stubDomains":         fmt.Sprintf(`{"acme.local":["%v"]}`, t.dnsServerPod.Status.PodIP),
+		t.setConfigMap(&v1.ConfigMap{Data: map[string]string{
-		"upstreamNameservers": fmt.Sprintf(`["%v"]`, t.dnsServerPod.Status.PodIP),
+			"Corefile": fmt.Sprintf(`.:53 {
-	}})
+        kubernetes cluster.local in-addr.arpa ip6.arpa {
+           pods insecure
+           upstream
+           fallthrough in-addr.arpa ip6.arpa
+        }
+        proxy . %v
+    }
+     acme.local:53 {
+       proxy . %v
+    }`, t.dnsServerPod.Status.PodIP, t.dnsServerPod.Status.PodIP),
+		}})
+
+		t.deleteCoreDNSPods()
+	} else {
+		t.setConfigMap(&v1.ConfigMap{Data: map[string]string{
+			"stubDomains":         fmt.Sprintf(`{"acme.local":["%v"]}`, t.dnsServerPod.Status.PodIP),
+			"upstreamNameservers": fmt.Sprintf(`["%v"]`, t.dnsServerPod.Status.PodIP),
+		}})
+	}
 
 	t.checkDNSRecordFrom(
 		"abc.acme.local",
@@ -180,7 +200,7 @@ func (t *dnsNameserverTest) run() {
 		"dnsmasq",
 		moreForeverTestTimeout)
 
-	t.c.CoreV1().ConfigMaps(t.ns).Delete(t.name, nil)
+	t.restoreDNSConfigMap(originalConfigMapData)
 	// Wait for the deleted ConfigMap to take effect, otherwise the
 	// configuration can bleed into other tests.
 	t.checkDNSRecordFrom(
@@ -199,6 +219,8 @@ func (t *dnsPtrFwdTest) run() {
 
 	t.createUtilPod()
 	defer t.deleteUtilPod()
+	originalConfigMapData := t.fetchDNSConfigMapData()
+	defer t.restoreDNSConfigMap(originalConfigMapData)
 
 	t.createDNSServerWithPtrRecord()
 	defer t.deleteDNSServerPod()
@@ -210,9 +232,24 @@ func (t *dnsPtrFwdTest) run() {
 		"dnsmasq",
 		moreForeverTestTimeout)
 
-	t.setConfigMap(&v1.ConfigMap{Data: map[string]string{
+	if t.name == "coredns" {
-		"upstreamNameservers": fmt.Sprintf(`["%v"]`, t.dnsServerPod.Status.PodIP),
+		t.setConfigMap(&v1.ConfigMap{Data: map[string]string{
-	}})
+			"Corefile": fmt.Sprintf(`.:53 {
+        kubernetes cluster.local in-addr.arpa ip6.arpa {
+           pods insecure
+           upstream
+           fallthrough in-addr.arpa ip6.arpa
+        }
+        proxy . %v
+    }`, t.dnsServerPod.Status.PodIP),
+		}})
+
+		t.deleteCoreDNSPods()
+	} else {
+		t.setConfigMap(&v1.ConfigMap{Data: map[string]string{
+			"upstreamNameservers": fmt.Sprintf(`["%v"]`, t.dnsServerPod.Status.PodIP),
+		}})
+	}
 
 	t.checkDNSRecordFrom(
 		"123.2.0.192.in-addr.arpa",
@@ -220,7 +257,7 @@ func (t *dnsPtrFwdTest) run() {
 		"dnsmasq",
 		moreForeverTestTimeout)
 
-	t.setConfigMap(&v1.ConfigMap{Data: map[string]string{}})
+	t.restoreDNSConfigMap(originalConfigMapData)
 	t.checkDNSRecordFrom(
 		"123.2.0.192.in-addr.arpa",
 		func(actual []string) bool { return len(actual) == 0 },
@@ -237,6 +274,8 @@ func (t *dnsExternalNameTest) run() {
 
 	t.createUtilPod()
 	defer t.deleteUtilPod()
+	originalConfigMapData := t.fetchDNSConfigMapData()
+	defer t.restoreDNSConfigMap(originalConfigMapData)
 
 	fooHostname := "foo.example.com"
 	t.createDNSServer(map[string]string{
@@ -270,9 +309,24 @@ func (t *dnsExternalNameTest) run() {
 		"dnsmasq",
 		moreForeverTestTimeout)
 
-	t.setConfigMap(&v1.ConfigMap{Data: map[string]string{
+	if t.name == "coredns" {
-		"upstreamNameservers": fmt.Sprintf(`["%v"]`, t.dnsServerPod.Status.PodIP),
+		t.setConfigMap(&v1.ConfigMap{Data: map[string]string{
-	}})
+			"Corefile": fmt.Sprintf(`.:53 {
+        kubernetes cluster.local in-addr.arpa ip6.arpa {
+           pods insecure
+           upstream
+           fallthrough in-addr.arpa ip6.arpa
+        }
+        proxy . %v
+    }`, t.dnsServerPod.Status.PodIP),
+		}})
+
+		t.deleteCoreDNSPods()
+	} else {
+		t.setConfigMap(&v1.ConfigMap{Data: map[string]string{
+			"upstreamNameservers": fmt.Sprintf(`["%v"]`, t.dnsServerPod.Status.PodIP),
+		}})
+	}
 
 	t.checkDNSRecordFrom(
 		fmt.Sprintf("%s.%s.svc.cluster.local", serviceNameLocal, f.Namespace.Name),
@@ -282,7 +336,7 @@ func (t *dnsExternalNameTest) run() {
 		"dnsmasq",
 		moreForeverTestTimeout)
 
-	t.setConfigMap(&v1.ConfigMap{Data: map[string]string{}})
+	t.restoreDNSConfigMap(originalConfigMapData)
 }
 
 var _ = SIGDescribe("DNS configMap nameserver", func() {