Add e2e session affinity timeout test

The service session affinity allows to set the maximum session
sticky timeout.
This commit adds e2e tests to check that the session is sticky
before the timeout and is not after.

Author: aojea

test/e2e/network/service.go

@@ -2369,6 +2369,13 @@ var _ = SIGDescribe("Services", func() {
 		execAffinityTestForNonLBService(f, cs, svc)
 	})
 
+	// [LinuxOnly]: Windows does not support session affinity.
+	ginkgo.It("should have session affinity timeout work for service with type clusterIP [LinuxOnly]", func() {
+		svc := getServeHostnameService("affinity-clusterip-timeout")
+		svc.Spec.Type = v1.ServiceTypeClusterIP
+		execAffinityTestForSessionAffinityTimeout(f, cs, svc)
+	})
+
 	// [LinuxOnly]: Windows does not support session affinity.
 	ginkgo.It("should be able to switch session affinity for service with type clusterIP [LinuxOnly]", func() {
 		svc := getServeHostnameService("affinity-clusterip-transition")
@@ -2383,6 +2390,13 @@ var _ = SIGDescribe("Services", func() {
 		execAffinityTestForNonLBService(f, cs, svc)
 	})
 
+	// [LinuxOnly]: Windows does not support session affinity.
+	ginkgo.It("should have session affinity timeout work for NodePort service [LinuxOnly]", func() {
+		svc := getServeHostnameService("affinity-nodeport-timeout")
+		svc.Spec.Type = v1.ServiceTypeNodePort
+		execAffinityTestForSessionAffinityTimeout(f, cs, svc)
+	})
+
 	// [LinuxOnly]: Windows does not support session affinity.
 	ginkgo.It("should be able to switch session affinity for NodePort service [LinuxOnly]", func() {
 		svc := getServeHostnameService("affinity-nodeport-transition")
@@ -3042,6 +3056,69 @@ func execSourceipTest(pausePod v1.Pod, serviceAddress string) (string, string) {
 	return pausePod.Status.PodIP, host
 }
 
+// execAffinityTestForSessionAffinityTimeout is a helper function that wrap the logic of
+// affinity test for non-load-balancer services. Session afinity will be
+// enabled when the service is created and a short timeout will be configured so
+// session affinity must change after the timeout expirese.
+func execAffinityTestForSessionAffinityTimeout(f *framework.Framework, cs clientset.Interface, svc *v1.Service) {
+	ns := f.Namespace.Name
+	numPods, servicePort, serviceName := 3, defaultServeHostnameServicePort, svc.ObjectMeta.Name
+	ginkgo.By("creating service in namespace " + ns)
+	serviceType := svc.Spec.Type
+	// set an affinity timeout equal to the number of connection requests
+	svcSessionAffinityTimeout := int32(AffinityConfirmCount)
+	svc.Spec.SessionAffinity = v1.ServiceAffinityClientIP
+	svc.Spec.SessionAffinityConfig = &v1.SessionAffinityConfig{
+		ClientIP: &v1.ClientIPConfig{TimeoutSeconds: &svcSessionAffinityTimeout},
+	}
+	_, _, err := StartServeHostnameService(cs, svc, ns, numPods)
+	framework.ExpectNoError(err, "failed to create replication controller with service in the namespace: %s", ns)
+	defer func() {
+		StopServeHostnameService(cs, ns, serviceName)
+	}()
+	jig := e2eservice.NewTestJig(cs, ns, serviceName)
+	svc, err = jig.Client.CoreV1().Services(ns).Get(context.TODO(), serviceName, metav1.GetOptions{})
+	framework.ExpectNoError(err, "failed to fetch service: %s in namespace: %s", serviceName, ns)
+	var svcIP string
+	if serviceType == v1.ServiceTypeNodePort {
+		nodes, err := e2enode.GetReadySchedulableNodes(cs)
+		framework.ExpectNoError(err)
+		addrs := e2enode.CollectAddresses(nodes, v1.NodeInternalIP)
+		gomega.Expect(len(addrs)).To(gomega.BeNumerically(">", 0), "ginkgo.Failed to get Node internal IP")
+		svcIP = addrs[0]
+		servicePort = int(svc.Spec.Ports[0].NodePort)
+	} else {
+		svcIP = svc.Spec.ClusterIP
+	}
+
+	execPod := e2epod.CreateExecPodOrFail(cs, ns, "execpod-affinity", nil)
+	defer func() {
+		framework.Logf("Cleaning up the exec pod")
+		err := cs.CoreV1().Pods(ns).Delete(context.TODO(), execPod.Name, nil)
+		framework.ExpectNoError(err, "failed to delete pod: %s in namespace: %s", execPod.Name, ns)
+	}()
+	err = jig.CheckServiceReachability(svc, execPod)
+	framework.ExpectNoError(err)
+
+	// the service should be sticky until the timeout expires
+	framework.ExpectEqual(checkAffinity(execPod, svcIP, servicePort, true), true)
+	// but it should return different hostnames after the timeout expires
+	// try several times to avoid the probability that we hit the same pod twice
+	hosts := sets.NewString()
+	cmd := fmt.Sprintf(`curl -q -s --connect-timeout 2 http://%s/`, net.JoinHostPort(svcIP, strconv.Itoa(servicePort)))
+	for i := 0; i < 10; i++ {
+		hostname, err := framework.RunHostCmd(execPod.Namespace, execPod.Name, cmd)
+		if err == nil {
+			hosts.Insert(hostname)
+			if hosts.Len() > 1 {
+				return
+			}
+			time.Sleep(time.Duration(svcSessionAffinityTimeout) * time.Second)
+		}
+	}
+	framework.Fail("Session is sticky after reaching the timeout")
+}
+
 func execAffinityTestForNonLBServiceWithTransition(f *framework.Framework, cs clientset.Interface, svc *v1.Service) {
 	execAffinityTestForNonLBServiceWithOptionalTransition(f, cs, svc, true)
 }