From add46523526f4b342b1d0ad9f472b6ff8fb9eda6 Mon Sep 17 00:00:00 2001
From: Gunju Kim <gjkim042@gmail.com>
Date: Sun, 27 Mar 2022 13:45:01 +0900
Subject: [PATCH] Promote ExpandedDNSConfig feature to the beta stage

This adds an e2e test for the feature and promotes ExpandedDNSConfig
feature to the beta stage.
---
 pkg/features/kube_features.go |  3 ++-
 test/e2e/network/dns.go       | 44 +++++++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/pkg/features/kube_features.go b/pkg/features/kube_features.go
index c689295be6e..80681b6e201 100644
--- a/pkg/features/kube_features.go
+++ b/pkg/features/kube_features.go
@@ -308,6 +308,7 @@ const (
 	// owner: @gjkim42
 	// kep: https://kep.k8s.io/2595
 	// alpha: v1.22
+	// beta: v1.26
 	//
 	// Enables apiserver and kubelet to allow up to 32 DNSSearchPaths and up to 2048 DNSSearchListChars.
 	ExpandedDNSConfig featuregate.Feature = "ExpandedDNSConfig"
@@ -877,7 +878,7 @@ var defaultKubernetesFeatureGates = map[featuregate.Feature]featuregate.FeatureS
 
 	ExpandPersistentVolumes: {Default: true, PreRelease: featuregate.GA}, // remove in 1.26
 
-	ExpandedDNSConfig: {Default: false, PreRelease: featuregate.Alpha},
+	ExpandedDNSConfig: {Default: true, PreRelease: featuregate.Beta},
 
 	ExperimentalHostUserNamespaceDefaultingGate: {Default: false, PreRelease: featuregate.Beta},
 
diff --git a/test/e2e/network/dns.go b/test/e2e/network/dns.go
index f3788a49a1c..d60fb2e6427 100644
--- a/test/e2e/network/dns.go
+++ b/test/e2e/network/dns.go
@@ -569,6 +569,50 @@ var _ = common.SIGDescribe("DNS", func() {
 		// TODO: Add more test cases for other DNSPolicies.
 	})
 
+	ginkgo.It("should work with the pod containing more than 6 DNS search paths and longer than 256 search list characters", func() {
+		ginkgo.By("Getting the kube-dns IP")
+		svc, err := f.ClientSet.CoreV1().Services("kube-system").Get(context.TODO(), "kube-dns", metav1.GetOptions{})
+		framework.ExpectNoError(err, "Failed to get kube-dns service")
+		kubednsIP := svc.Spec.ClusterIP
+
+		// All the names we need to be able to resolve.
+		namesToResolve := []string{
+			"kubernetes.default",
+			"kubernetes.default.svc",
+		}
+		hostFQDN := fmt.Sprintf("%s.%s.%s.svc.%s", dnsTestPodHostName, dnsTestServiceName, f.Namespace.Name, framework.TestContext.ClusterDNSDomain)
+		hostEntries := []string{hostFQDN, dnsTestPodHostName}
+		// TODO: Validate both IPv4 and IPv6 families for dual-stack
+		wheezyProbeCmd, wheezyFileNames := createProbeCommand(namesToResolve, hostEntries, "", "wheezy", f.Namespace.Name, framework.TestContext.ClusterDNSDomain, framework.TestContext.ClusterIsIPv6())
+		jessieProbeCmd, jessieFileNames := createProbeCommand(namesToResolve, hostEntries, "", "jessie", f.Namespace.Name, framework.TestContext.ClusterDNSDomain, framework.TestContext.ClusterIsIPv6())
+		ginkgo.By("Running these commands on wheezy: " + wheezyProbeCmd + "\n")
+		ginkgo.By("Running these commands on jessie: " + jessieProbeCmd + "\n")
+
+		ginkgo.By("Creating a pod with expanded DNS configuration to probe DNS")
+		testNdotsValue := "5"
+		testSearchPaths := []string{
+			fmt.Sprintf("%038d.k8s.io", 1),
+			fmt.Sprintf("%038d.k8s.io", 2),
+			fmt.Sprintf("%038d.k8s.io", 3),
+			fmt.Sprintf("%038d.k8s.io", 4),
+			fmt.Sprintf("%038d.k8s.io", 5),
+			fmt.Sprintf("%038d.k8s.io", 6), // 260 characters
+		}
+		pod := createDNSPod(f.Namespace.Name, wheezyProbeCmd, jessieProbeCmd, dnsTestPodHostName, dnsTestServiceName)
+		pod.Spec.DNSPolicy = v1.DNSClusterFirst
+		pod.Spec.DNSConfig = &v1.PodDNSConfig{
+			Nameservers: []string{kubednsIP},
+			Searches:    testSearchPaths,
+			Options: []v1.PodDNSConfigOption{
+				{
+					Name:  "ndots",
+					Value: &testNdotsValue,
+				},
+			},
+		}
+		validateDNSResults(f, pod, append(wheezyFileNames, jessieFileNames...))
+	})
+
 })
 
 var _ = common.SIGDescribe("DNS HostNetwork", func() {