Add e2e test for configurable pod resolv.conf

test/e2e/network/dns.go

@@ -17,255 +17,22 @@ limitations under the License.
 package network
 
 import (
-	"context"
 	"fmt"
 	"strings"
 	"time"
 
-	. "github.com/onsi/ginkgo"
-	. "github.com/onsi/gomega"
 	"k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	"k8s.io/apimachinery/pkg/util/uuid"
 	"k8s.io/apimachinery/pkg/util/wait"
-	clientset "k8s.io/client-go/kubernetes"
-	"k8s.io/kubernetes/pkg/api/testapi"
 	"k8s.io/kubernetes/test/e2e/framework"
-	imageutils "k8s.io/kubernetes/test/utils/image"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
 )
 
 const dnsTestPodHostName = "dns-querier-1"
 const dnsTestServiceName = "dns-test-service"
 
-func createDNSPod(namespace, wheezyProbeCmd, jessieProbeCmd string) *v1.Pod {
-	dnsPod := &v1.Pod{
-		TypeMeta: metav1.TypeMeta{
-			Kind:       "Pod",
-			APIVersion: testapi.Groups[v1.GroupName].GroupVersion().String(),
-		},
-		ObjectMeta: metav1.ObjectMeta{
-			Name:      "dns-test-" + string(uuid.NewUUID()),
-			Namespace: namespace,
-		},
-		Spec: v1.PodSpec{
-			Volumes: []v1.Volume{
-				{
-					Name: "results",
-					VolumeSource: v1.VolumeSource{
-						EmptyDir: &v1.EmptyDirVolumeSource{},
-					},
-				},
-			},
-			Containers: []v1.Container{
-				// TODO: Consider scraping logs instead of running a webserver.
-				{
-					Name:  "webserver",
-					Image: imageutils.GetE2EImage(imageutils.TestWebserver),
-					Ports: []v1.ContainerPort{
-						{
-							Name:          "http",
-							ContainerPort: 80,
-						},
-					},
-					VolumeMounts: []v1.VolumeMount{
-						{
-							Name:      "results",
-							MountPath: "/results",
-						},
-					},
-				},
-				{
-					Name:    "querier",
-					Image:   imageutils.GetE2EImage(imageutils.Dnsutils),
-					Command: []string{"sh", "-c", wheezyProbeCmd},
-					VolumeMounts: []v1.VolumeMount{
-						{
-							Name:      "results",
-							MountPath: "/results",
-						},
-					},
-				},
-				{
-					Name:    "jessie-querier",
-					Image:   imageutils.GetE2EImage(imageutils.JessieDnsutils),
-					Command: []string{"sh", "-c", jessieProbeCmd},
-					VolumeMounts: []v1.VolumeMount{
-						{
-							Name:      "results",
-							MountPath: "/results",
-						},
-					},
-				},
-			},
-		},
-	}
-
-	dnsPod.Spec.Hostname = dnsTestPodHostName
-	dnsPod.Spec.Subdomain = dnsTestServiceName
-
-	return dnsPod
-}
-
-func createProbeCommand(namesToResolve []string, hostEntries []string, ptrLookupIP string, fileNamePrefix, namespace string) (string, []string) {
-	fileNames := make([]string, 0, len(namesToResolve)*2)
-	probeCmd := "for i in `seq 1 600`; do "
-	for _, name := range namesToResolve {
-		// Resolve by TCP and UDP DNS.  Use $$(...) because $(...) is
-		// expanded by kubernetes (though this won't expand so should
-		// remain a literal, safe > sorry).
-		lookup := "A"
-		if strings.HasPrefix(name, "_") {
-			lookup = "SRV"
-		}
-		fileName := fmt.Sprintf("%s_udp@%s", fileNamePrefix, name)
-		fileNames = append(fileNames, fileName)
-		probeCmd += fmt.Sprintf(`test -n "$$(dig +notcp +noall +answer +search %s %s)" && echo OK > /results/%s;`, name, lookup, fileName)
-		fileName = fmt.Sprintf("%s_tcp@%s", fileNamePrefix, name)
-		fileNames = append(fileNames, fileName)
-		probeCmd += fmt.Sprintf(`test -n "$$(dig +tcp +noall +answer +search %s %s)" && echo OK > /results/%s;`, name, lookup, fileName)
-	}
-
-	for _, name := range hostEntries {
-		fileName := fmt.Sprintf("%s_hosts@%s", fileNamePrefix, name)
-		fileNames = append(fileNames, fileName)
-		probeCmd += fmt.Sprintf(`test -n "$$(getent hosts %s)" && echo OK > /results/%s;`, name, fileName)
-	}
-
-	podARecByUDPFileName := fmt.Sprintf("%s_udp@PodARecord", fileNamePrefix)
-	podARecByTCPFileName := fmt.Sprintf("%s_tcp@PodARecord", fileNamePrefix)
-	probeCmd += fmt.Sprintf(`podARec=$$(hostname -i| awk -F. '{print $$1"-"$$2"-"$$3"-"$$4".%s.pod.cluster.local"}');`, namespace)
-	probeCmd += fmt.Sprintf(`test -n "$$(dig +notcp +noall +answer +search $${podARec} A)" && echo OK > /results/%s;`, podARecByUDPFileName)
-	probeCmd += fmt.Sprintf(`test -n "$$(dig +tcp +noall +answer +search $${podARec} A)" && echo OK > /results/%s;`, podARecByTCPFileName)
-	fileNames = append(fileNames, podARecByUDPFileName)
-	fileNames = append(fileNames, podARecByTCPFileName)
-
-	if len(ptrLookupIP) > 0 {
-		ptrLookup := fmt.Sprintf("%s.in-addr.arpa.", strings.Join(reverseArray(strings.Split(ptrLookupIP, ".")), "."))
-		ptrRecByUDPFileName := fmt.Sprintf("%s_udp@PTR", ptrLookupIP)
-		ptrRecByTCPFileName := fmt.Sprintf("%s_tcp@PTR", ptrLookupIP)
-		probeCmd += fmt.Sprintf(`test -n "$$(dig +notcp +noall +answer +search %s PTR)" && echo OK > /results/%s;`, ptrLookup, ptrRecByUDPFileName)
-		probeCmd += fmt.Sprintf(`test -n "$$(dig +tcp +noall +answer +search %s PTR)" && echo OK > /results/%s;`, ptrLookup, ptrRecByTCPFileName)
-		fileNames = append(fileNames, ptrRecByUDPFileName)
-		fileNames = append(fileNames, ptrRecByTCPFileName)
-	}
-
-	probeCmd += "sleep 1; done"
-	return probeCmd, fileNames
-}
-
-// createTargetedProbeCommand returns a command line that performs a DNS lookup for a specific record type
-func createTargetedProbeCommand(nameToResolve string, lookup string, fileNamePrefix string) (string, string) {
-	fileName := fmt.Sprintf("%s_udp@%s", fileNamePrefix, nameToResolve)
-	probeCmd := fmt.Sprintf("dig +short +tries=12 +norecurse %s %s > /results/%s", nameToResolve, lookup, fileName)
-	return probeCmd, fileName
-}
-
-func assertFilesExist(fileNames []string, fileDir string, pod *v1.Pod, client clientset.Interface) {
-	assertFilesContain(fileNames, fileDir, pod, client, false, "")
-}
-
-func assertFilesContain(fileNames []string, fileDir string, pod *v1.Pod, client clientset.Interface, check bool, expected string) {
-	var failed []string
-
-	framework.ExpectNoError(wait.Poll(time.Second*10, time.Second*600, func() (bool, error) {
-		failed = []string{}
-
-		ctx, cancel := context.WithTimeout(context.Background(), framework.SingleCallTimeout)
-		defer cancel()
-
-		for _, fileName := range fileNames {
-			contents, err := client.CoreV1().RESTClient().Get().
-				Context(ctx).
-				Namespace(pod.Namespace).
-				Resource("pods").
-				SubResource("proxy").
-				Name(pod.Name).
-				Suffix(fileDir, fileName).
-				Do().Raw()
-
-			if err != nil {
-				if ctx.Err() != nil {
-					framework.Failf("Unable to read %s from pod %s: %v", fileName, pod.Name, err)
-				} else {
-					framework.Logf("Unable to read %s from pod %s: %v", fileName, pod.Name, err)
-				}
-				failed = append(failed, fileName)
-			} else if check && strings.TrimSpace(string(contents)) != expected {
-				framework.Logf("File %s from pod %s contains '%s' instead of '%s'", fileName, pod.Name, string(contents), expected)
-				failed = append(failed, fileName)
-			}
-		}
-		if len(failed) == 0 {
-			return true, nil
-		}
-		framework.Logf("Lookups using %s failed for: %v\n", pod.Name, failed)
-		return false, nil
-	}))
-	Expect(len(failed)).To(Equal(0))
-}
-
-func validateDNSResults(f *framework.Framework, pod *v1.Pod, fileNames []string) {
-	By("submitting the pod to kubernetes")
-	podClient := f.ClientSet.CoreV1().Pods(f.Namespace.Name)
-	defer func() {
-		By("deleting the pod")
-		defer GinkgoRecover()
-		podClient.Delete(pod.Name, metav1.NewDeleteOptions(0))
-	}()
-	if _, err := podClient.Create(pod); err != nil {
-		framework.Failf("Failed to create %s pod: %v", pod.Name, err)
-	}
-
-	framework.ExpectNoError(f.WaitForPodRunning(pod.Name))
-
-	By("retrieving the pod")
-	pod, err := podClient.Get(pod.Name, metav1.GetOptions{})
-	if err != nil {
-		framework.Failf("Failed to get pod %s: %v", pod.Name, err)
-	}
-	// Try to find results for each expected name.
-	By("looking for the results for each expected name from probers")
-	assertFilesExist(fileNames, "results", pod, f.ClientSet)
-
-	// TODO: probe from the host, too.
-
-	framework.Logf("DNS probes using %s succeeded\n", pod.Name)
-}
-
-func validateTargetedProbeOutput(f *framework.Framework, pod *v1.Pod, fileNames []string, value string) {
-	By("submitting the pod to kubernetes")
-	podClient := f.ClientSet.CoreV1().Pods(f.Namespace.Name)
-	defer func() {
-		By("deleting the pod")
-		defer GinkgoRecover()
-		podClient.Delete(pod.Name, metav1.NewDeleteOptions(0))
-	}()
-	if _, err := podClient.Create(pod); err != nil {
-		framework.Failf("Failed to create %s pod: %v", pod.Name, err)
-	}
-
-	framework.ExpectNoError(f.WaitForPodRunning(pod.Name))
-
-	By("retrieving the pod")
-	pod, err := podClient.Get(pod.Name, metav1.GetOptions{})
-	if err != nil {
-		framework.Failf("Failed to get pod %s: %v", pod.Name, err)
-	}
-	// Try to find the expected value for each expected name.
-	By("looking for the results for each expected name from probers")
-	assertFilesContain(fileNames, "results", pod, f.ClientSet, true, value)
-
-	framework.Logf("DNS probes using %s succeeded\n", pod.Name)
-}
-
-func reverseArray(arr []string) []string {
-	for i := 0; i < len(arr)/2; i++ {
-		j := len(arr) - i - 1
-		arr[i], arr[j] = arr[j], arr[i]
-	}
-	return arr
-}
-
 var _ = SIGDescribe("DNS", func() {
 	f := framework.NewDefaultFramework("dns")
 
@@ -295,7 +62,7 @@ var _ = SIGDescribe("DNS", func() {
 
 		// Run a pod which probes DNS and exposes the results by HTTP.
 		By("creating a pod to probe DNS")
-		pod := createDNSPod(f.Namespace.Name, wheezyProbeCmd, jessieProbeCmd)
+		pod := createDNSPod(f.Namespace.Name, wheezyProbeCmd, jessieProbeCmd, dnsTestPodHostName, dnsTestServiceName)
 		validateDNSResults(f, pod, append(wheezyFileNames, jessieFileNames...))
 	})
 
@@ -345,7 +112,7 @@ var _ = SIGDescribe("DNS", func() {
 
 		// Run a pod which probes DNS and exposes the results by HTTP.
 		By("creating a pod to probe DNS")
-		pod := createDNSPod(f.Namespace.Name, wheezyProbeCmd, jessieProbeCmd)
+		pod := createDNSPod(f.Namespace.Name, wheezyProbeCmd, jessieProbeCmd, dnsTestPodHostName, dnsTestServiceName)
 		pod.ObjectMeta.Labels = testServiceSelector
 
 		validateDNSResults(f, pod, append(wheezyFileNames, jessieFileNames...))
@@ -378,7 +145,7 @@ var _ = SIGDescribe("DNS", func() {
 
 		// Run a pod which probes DNS and exposes the results by HTTP.
 		By("creating a pod to probe DNS")
-		pod1 := createDNSPod(f.Namespace.Name, wheezyProbeCmd, jessieProbeCmd)
+		pod1 := createDNSPod(f.Namespace.Name, wheezyProbeCmd, jessieProbeCmd, dnsTestPodHostName, dnsTestServiceName)
 		pod1.ObjectMeta.Labels = testServiceSelector
 		pod1.Spec.Hostname = podHostname
 		pod1.Spec.Subdomain = serviceName
@@ -407,7 +174,7 @@ var _ = SIGDescribe("DNS", func() {
 
 		// Run a pod which probes DNS and exposes the results by HTTP.
 		By("creating a pod to probe DNS")
-		pod1 := createDNSPod(f.Namespace.Name, wheezyProbeCmd, jessieProbeCmd)
+		pod1 := createDNSPod(f.Namespace.Name, wheezyProbeCmd, jessieProbeCmd, dnsTestPodHostName, dnsTestServiceName)
 
 		validateTargetedProbeOutput(f, pod1, []string{wheezyFileName, jessieFileName}, "foo.example.com.")
 
@@ -424,7 +191,7 @@ var _ = SIGDescribe("DNS", func() {
 
 		// Run a pod which probes DNS and exposes the results by HTTP.
 		By("creating a second pod to probe DNS")
-		pod2 := createDNSPod(f.Namespace.Name, wheezyProbeCmd, jessieProbeCmd)
+		pod2 := createDNSPod(f.Namespace.Name, wheezyProbeCmd, jessieProbeCmd, dnsTestPodHostName, dnsTestServiceName)
 
 		validateTargetedProbeOutput(f, pod2, []string{wheezyFileName, jessieFileName}, "bar.example.com.")
 
@@ -444,11 +211,111 @@ var _ = SIGDescribe("DNS", func() {
 
 		// Run a pod which probes DNS and exposes the results by HTTP.
 		By("creating a third pod to probe DNS")
-		pod3 := createDNSPod(f.Namespace.Name, wheezyProbeCmd, jessieProbeCmd)
+		pod3 := createDNSPod(f.Namespace.Name, wheezyProbeCmd, jessieProbeCmd, dnsTestPodHostName, dnsTestServiceName)
 
 		svc, err := f.ClientSet.CoreV1().Services(f.Namespace.Name).Get(externalNameService.Name, metav1.GetOptions{})
 		Expect(err).NotTo(HaveOccurred())
 
 		validateTargetedProbeOutput(f, pod3, []string{wheezyFileName, jessieFileName}, svc.Spec.ClusterIP)
 	})
+
+	It("should support configurable pod resolv.conf", func() {
+		By("Preparing a test DNS service with injected DNS names...")
+		testInjectedIP := "1.1.1.1"
+		testDNSNameShort := "notexistname"
+		testSearchPath := "resolv.conf.local"
+		testDNSNameFull := fmt.Sprintf("%s.%s", testDNSNameShort, testSearchPath)
+
+		testServerPod := generateDNSServerPod(map[string]string{
+			testDNSNameFull: testInjectedIP,
+		})
+		testServerPod, err := f.ClientSet.CoreV1().Pods(f.Namespace.Name).Create(testServerPod)
+		Expect(err).NotTo(HaveOccurred(), "failed to create pod %s", testServerPod.Name)
+		framework.Logf("Created pod %v", testServerPod)
+		defer func() {
+			framework.Logf("Deleting pod %s...", testServerPod.Name)
+			if err := f.ClientSet.CoreV1().Pods(f.Namespace.Name).Delete(testServerPod.Name, metav1.NewDeleteOptions(0)); err != nil {
+				framework.Failf("Failed to delete pod %s: %v", testServerPod.Name, err)
+			}
+		}()
+		Expect(f.WaitForPodRunning(testServerPod.Name)).NotTo(HaveOccurred(), "failed to wait for pod %s to be running", testServerPod.Name)
+
+		// Retrieve server pod IP.
+		testServerPod, err = f.ClientSet.CoreV1().Pods(f.Namespace.Name).Get(testServerPod.Name, metav1.GetOptions{})
+		Expect(err).NotTo(HaveOccurred(), "failed to get pod %v", testServerPod.Name)
+		testServerIP := testServerPod.Status.PodIP
+		framework.Logf("testServerIP is %s", testServerIP)
+
+		By("Creating a pod with dnsPolicy=None and customized dnsConfig...")
+		testUtilsPod := generateDNSUtilsPod()
+		testUtilsPod.Spec.DNSPolicy = v1.DNSNone
+		testNdotsValue := "2"
+		testUtilsPod.Spec.DNSConfig = &v1.PodDNSConfig{
+			Nameservers: []string{testServerIP},
+			Searches:    []string{testSearchPath},
+			Options: []v1.PodDNSConfigOption{
+				{
+					Name:  "ndots",
+					Value: &testNdotsValue,
+				},
+			},
+		}
+		testUtilsPod, err = f.ClientSet.CoreV1().Pods(f.Namespace.Name).Create(testUtilsPod)
+		Expect(err).NotTo(HaveOccurred(), "failed to create pod %s", testUtilsPod.Name)
+		framework.Logf("Created pod %v", testUtilsPod)
+		defer func() {
+			framework.Logf("Deleting pod %s...", testUtilsPod.Name)
+			if err := f.ClientSet.CoreV1().Pods(f.Namespace.Name).Delete(testUtilsPod.Name, metav1.NewDeleteOptions(0)); err != nil {
+				framework.Failf("Failed to delete pod %s: %v", testUtilsPod.Name, err)
+			}
+		}()
+		Expect(f.WaitForPodRunning(testUtilsPod.Name)).NotTo(HaveOccurred(), "failed to wait for pod %s to be running", testUtilsPod.Name)
+
+		By("Verifying customized DNS option is configured on pod...")
+		// TODO: Figure out a better way other than checking the actual resolv,conf file.
+		cmd := []string{"cat", "/etc/resolv.conf"}
+		stdout, stderr, err := f.ExecWithOptions(framework.ExecOptions{
+			Command:       cmd,
+			Namespace:     f.Namespace.Name,
+			PodName:       testUtilsPod.Name,
+			ContainerName: "util",
+			CaptureStdout: true,
+			CaptureStderr: true,
+		})
+		Expect(err).NotTo(HaveOccurred(), "failed to examine resolv,conf file on pod, stdout: %v, stderr: %v, err: %v", stdout, stderr, err)
+		if !strings.Contains(stdout, "ndots:2") {
+			framework.Failf("customized DNS options not found in resolv.conf, got: %s", stdout)
+		}
+
+		By("Verifying customized name server and search path are working...")
+		// Do dig on not-exist-dns-name and see if the injected DNS record is returned.
+		// This verifies both:
+		// - Custom search path is appended.
+		// - DNS query is sent to the specified server.
+		cmd = []string{"/usr/bin/dig", "+short", "+search", testDNSNameShort}
+		digFunc := func() (bool, error) {
+			stdout, stderr, err := f.ExecWithOptions(framework.ExecOptions{
+				Command:       cmd,
+				Namespace:     f.Namespace.Name,
+				PodName:       testUtilsPod.Name,
+				ContainerName: "util",
+				CaptureStdout: true,
+				CaptureStderr: true,
+			})
+			if err != nil {
+				framework.Logf("Failed to execute dig command, stdout:%v, stderr: %v, err: %v", stdout, stderr, err)
+				return false, nil
+			}
+			res := strings.Split(stdout, "\n")
+			if len(res) != 1 || res[0] != testInjectedIP {
+				framework.Logf("Expect command `%v` to return %s, got: %v", cmd, testInjectedIP, res)
+				return false, nil
+			}
+			return true, nil
+		}
+		err = wait.PollImmediate(5*time.Second, 3*time.Minute, digFunc)
+		Expect(err).NotTo(HaveOccurred(), "failed to verify customized name server and search path")
+
+		// TODO: Add more test cases for other DNSPolicies.
+	})
 })

test/e2e/network/dns_common.go

@@ -17,6 +17,7 @@ limitations under the License.
 package network
 
 import (
+	"context"
 	"fmt"
 	"strings"
 	"time"
@@ -27,8 +28,10 @@ import (
 	"k8s.io/apimachinery/pkg/fields"
 	"k8s.io/apimachinery/pkg/labels"
 	"k8s.io/apimachinery/pkg/util/intstr"
+	"k8s.io/apimachinery/pkg/util/uuid"
 	"k8s.io/apimachinery/pkg/util/wait"
 	clientset "k8s.io/client-go/kubernetes"
+	"k8s.io/kubernetes/pkg/api/testapi"
 	"k8s.io/kubernetes/test/e2e/framework"
 	imageutils "k8s.io/kubernetes/test/utils/image"
 
@@ -229,13 +232,12 @@ func (t *dnsTestCommon) deleteUtilPod() {
 	}
 }
 
-func (t *dnsTestCommon) createDNSServer(aRecords map[string]string) {
+func generateDNSServerPod(aRecords map[string]string) *v1.Pod {
-	t.dnsServerPod = &v1.Pod{
+	pod := &v1.Pod{
 		TypeMeta: metav1.TypeMeta{
 			Kind: "Pod",
 		},
 		ObjectMeta: metav1.ObjectMeta{
-			Namespace:    t.f.Namespace.Name,
 			GenerateName: "e2e-dns-configmap-dns-server-",
 		},
 		Spec: v1.PodSpec{
@@ -257,10 +259,15 @@ func (t *dnsTestCommon) createDNSServer(aRecords map[string]string) {
 	}
 
 	for name, ip := range aRecords {
-		t.dnsServerPod.Spec.Containers[0].Command = append(
+		pod.Spec.Containers[0].Command = append(
-			t.dnsServerPod.Spec.Containers[0].Command,
+			pod.Spec.Containers[0].Command,
 			fmt.Sprintf("-A/%v/%v", name, ip))
 	}
+	return pod
+}
+
+func (t *dnsTestCommon) createDNSServer(aRecords map[string]string) {
+	t.dnsServerPod = generateDNSServerPod(aRecords)
 
 	var err error
 	t.dnsServerPod, err = t.c.CoreV1().Pods(t.f.Namespace.Name).Create(t.dnsServerPod)
@@ -280,3 +287,252 @@ func (t *dnsTestCommon) deleteDNSServerPod() {
 			t.utilPod.Namespace, t.dnsServerPod.Name, err)
 	}
 }
+
+func createDNSPod(namespace, wheezyProbeCmd, jessieProbeCmd, podHostName, serviceName string) *v1.Pod {
+	dnsPod := &v1.Pod{
+		TypeMeta: metav1.TypeMeta{
+			Kind:       "Pod",
+			APIVersion: testapi.Groups[v1.GroupName].GroupVersion().String(),
+		},
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "dns-test-" + string(uuid.NewUUID()),
+			Namespace: namespace,
+		},
+		Spec: v1.PodSpec{
+			Volumes: []v1.Volume{
+				{
+					Name: "results",
+					VolumeSource: v1.VolumeSource{
+						EmptyDir: &v1.EmptyDirVolumeSource{},
+					},
+				},
+			},
+			Containers: []v1.Container{
+				// TODO: Consider scraping logs instead of running a webserver.
+				{
+					Name:  "webserver",
+					Image: imageutils.GetE2EImage(imageutils.TestWebserver),
+					Ports: []v1.ContainerPort{
+						{
+							Name:          "http",
+							ContainerPort: 80,
+						},
+					},
+					VolumeMounts: []v1.VolumeMount{
+						{
+							Name:      "results",
+							MountPath: "/results",
+						},
+					},
+				},
+				{
+					Name:    "querier",
+					Image:   imageutils.GetE2EImage(imageutils.Dnsutils),
+					Command: []string{"sh", "-c", wheezyProbeCmd},
+					VolumeMounts: []v1.VolumeMount{
+						{
+							Name:      "results",
+							MountPath: "/results",
+						},
+					},
+				},
+				{
+					Name:    "jessie-querier",
+					Image:   imageutils.GetE2EImage(imageutils.JessieDnsutils),
+					Command: []string{"sh", "-c", jessieProbeCmd},
+					VolumeMounts: []v1.VolumeMount{
+						{
+							Name:      "results",
+							MountPath: "/results",
+						},
+					},
+				},
+			},
+		},
+	}
+
+	dnsPod.Spec.Hostname = podHostName
+	dnsPod.Spec.Subdomain = serviceName
+
+	return dnsPod
+}
+
+func createProbeCommand(namesToResolve []string, hostEntries []string, ptrLookupIP string, fileNamePrefix, namespace string) (string, []string) {
+	fileNames := make([]string, 0, len(namesToResolve)*2)
+	probeCmd := "for i in `seq 1 600`; do "
+	for _, name := range namesToResolve {
+		// Resolve by TCP and UDP DNS.  Use $$(...) because $(...) is
+		// expanded by kubernetes (though this won't expand so should
+		// remain a literal, safe > sorry).
+		lookup := "A"
+		if strings.HasPrefix(name, "_") {
+			lookup = "SRV"
+		}
+		fileName := fmt.Sprintf("%s_udp@%s", fileNamePrefix, name)
+		fileNames = append(fileNames, fileName)
+		probeCmd += fmt.Sprintf(`test -n "$$(dig +notcp +noall +answer +search %s %s)" && echo OK > /results/%s;`, name, lookup, fileName)
+		fileName = fmt.Sprintf("%s_tcp@%s", fileNamePrefix, name)
+		fileNames = append(fileNames, fileName)
+		probeCmd += fmt.Sprintf(`test -n "$$(dig +tcp +noall +answer +search %s %s)" && echo OK > /results/%s;`, name, lookup, fileName)
+	}
+
+	for _, name := range hostEntries {
+		fileName := fmt.Sprintf("%s_hosts@%s", fileNamePrefix, name)
+		fileNames = append(fileNames, fileName)
+		probeCmd += fmt.Sprintf(`test -n "$$(getent hosts %s)" && echo OK > /results/%s;`, name, fileName)
+	}
+
+	podARecByUDPFileName := fmt.Sprintf("%s_udp@PodARecord", fileNamePrefix)
+	podARecByTCPFileName := fmt.Sprintf("%s_tcp@PodARecord", fileNamePrefix)
+	probeCmd += fmt.Sprintf(`podARec=$$(hostname -i| awk -F. '{print $$1"-"$$2"-"$$3"-"$$4".%s.pod.cluster.local"}');`, namespace)
+	probeCmd += fmt.Sprintf(`test -n "$$(dig +notcp +noall +answer +search $${podARec} A)" && echo OK > /results/%s;`, podARecByUDPFileName)
+	probeCmd += fmt.Sprintf(`test -n "$$(dig +tcp +noall +answer +search $${podARec} A)" && echo OK > /results/%s;`, podARecByTCPFileName)
+	fileNames = append(fileNames, podARecByUDPFileName)
+	fileNames = append(fileNames, podARecByTCPFileName)
+
+	if len(ptrLookupIP) > 0 {
+		ptrLookup := fmt.Sprintf("%s.in-addr.arpa.", strings.Join(reverseArray(strings.Split(ptrLookupIP, ".")), "."))
+		ptrRecByUDPFileName := fmt.Sprintf("%s_udp@PTR", ptrLookupIP)
+		ptrRecByTCPFileName := fmt.Sprintf("%s_tcp@PTR", ptrLookupIP)
+		probeCmd += fmt.Sprintf(`test -n "$$(dig +notcp +noall +answer +search %s PTR)" && echo OK > /results/%s;`, ptrLookup, ptrRecByUDPFileName)
+		probeCmd += fmt.Sprintf(`test -n "$$(dig +tcp +noall +answer +search %s PTR)" && echo OK > /results/%s;`, ptrLookup, ptrRecByTCPFileName)
+		fileNames = append(fileNames, ptrRecByUDPFileName)
+		fileNames = append(fileNames, ptrRecByTCPFileName)
+	}
+
+	probeCmd += "sleep 1; done"
+	return probeCmd, fileNames
+}
+
+// createTargetedProbeCommand returns a command line that performs a DNS lookup for a specific record type
+func createTargetedProbeCommand(nameToResolve string, lookup string, fileNamePrefix string) (string, string) {
+	fileName := fmt.Sprintf("%s_udp@%s", fileNamePrefix, nameToResolve)
+	probeCmd := fmt.Sprintf("dig +short +tries=12 +norecurse %s %s > /results/%s", nameToResolve, lookup, fileName)
+	return probeCmd, fileName
+}
+
+func assertFilesExist(fileNames []string, fileDir string, pod *v1.Pod, client clientset.Interface) {
+	assertFilesContain(fileNames, fileDir, pod, client, false, "")
+}
+
+func assertFilesContain(fileNames []string, fileDir string, pod *v1.Pod, client clientset.Interface, check bool, expected string) {
+	var failed []string
+
+	framework.ExpectNoError(wait.Poll(time.Second*10, time.Second*600, func() (bool, error) {
+		failed = []string{}
+
+		ctx, cancel := context.WithTimeout(context.Background(), framework.SingleCallTimeout)
+		defer cancel()
+
+		for _, fileName := range fileNames {
+			contents, err := client.CoreV1().RESTClient().Get().
+				Context(ctx).
+				Namespace(pod.Namespace).
+				Resource("pods").
+				SubResource("proxy").
+				Name(pod.Name).
+				Suffix(fileDir, fileName).
+				Do().Raw()
+
+			if err != nil {
+				if ctx.Err() != nil {
+					framework.Failf("Unable to read %s from pod %s: %v", fileName, pod.Name, err)
+				} else {
+					framework.Logf("Unable to read %s from pod %s: %v", fileName, pod.Name, err)
+				}
+				failed = append(failed, fileName)
+			} else if check && strings.TrimSpace(string(contents)) != expected {
+				framework.Logf("File %s from pod %s contains '%s' instead of '%s'", fileName, pod.Name, string(contents), expected)
+				failed = append(failed, fileName)
+			}
+		}
+		if len(failed) == 0 {
+			return true, nil
+		}
+		framework.Logf("Lookups using %s failed for: %v\n", pod.Name, failed)
+		return false, nil
+	}))
+	Expect(len(failed)).To(Equal(0))
+}
+
+func validateDNSResults(f *framework.Framework, pod *v1.Pod, fileNames []string) {
+	By("submitting the pod to kubernetes")
+	podClient := f.ClientSet.CoreV1().Pods(f.Namespace.Name)
+	defer func() {
+		By("deleting the pod")
+		defer GinkgoRecover()
+		podClient.Delete(pod.Name, metav1.NewDeleteOptions(0))
+	}()
+	if _, err := podClient.Create(pod); err != nil {
+		framework.Failf("Failed to create %s pod: %v", pod.Name, err)
+	}
+
+	framework.ExpectNoError(f.WaitForPodRunning(pod.Name))
+
+	By("retrieving the pod")
+	pod, err := podClient.Get(pod.Name, metav1.GetOptions{})
+	if err != nil {
+		framework.Failf("Failed to get pod %s: %v", pod.Name, err)
+	}
+	// Try to find results for each expected name.
+	By("looking for the results for each expected name from probers")
+	assertFilesExist(fileNames, "results", pod, f.ClientSet)
+
+	// TODO: probe from the host, too.
+
+	framework.Logf("DNS probes using %s succeeded\n", pod.Name)
+}
+
+func validateTargetedProbeOutput(f *framework.Framework, pod *v1.Pod, fileNames []string, value string) {
+	By("submitting the pod to kubernetes")
+	podClient := f.ClientSet.CoreV1().Pods(f.Namespace.Name)
+	defer func() {
+		By("deleting the pod")
+		defer GinkgoRecover()
+		podClient.Delete(pod.Name, metav1.NewDeleteOptions(0))
+	}()
+	if _, err := podClient.Create(pod); err != nil {
+		framework.Failf("Failed to create %s pod: %v", pod.Name, err)
+	}
+
+	framework.ExpectNoError(f.WaitForPodRunning(pod.Name))
+
+	By("retrieving the pod")
+	pod, err := podClient.Get(pod.Name, metav1.GetOptions{})
+	if err != nil {
+		framework.Failf("Failed to get pod %s: %v", pod.Name, err)
+	}
+	// Try to find the expected value for each expected name.
+	By("looking for the results for each expected name from probers")
+	assertFilesContain(fileNames, "results", pod, f.ClientSet, true, value)
+
+	framework.Logf("DNS probes using %s succeeded\n", pod.Name)
+}
+
+func reverseArray(arr []string) []string {
+	for i := 0; i < len(arr)/2; i++ {
+		j := len(arr) - i - 1
+		arr[i], arr[j] = arr[j], arr[i]
+	}
+	return arr
+}
+
+func generateDNSUtilsPod() *v1.Pod {
+	return &v1.Pod{
+		TypeMeta: metav1.TypeMeta{
+			Kind: "Pod",
+		},
+		ObjectMeta: metav1.ObjectMeta{
+			GenerateName: "e2e-dns-utils-",
+		},
+		Spec: v1.PodSpec{
+			Containers: []v1.Container{
+				{
+					Name:    "util",
+					Image:   imageutils.GetE2EImage(imageutils.Dnsutils),
+					Command: []string{"sleep", "10000"},
+				},
+			},
+		},
+	}
+}