test connectivity for terminating pods

Test 2 scenarios:

- pod can connect to a terminating pods
- terminating pod can connect to other pods

Change-Id: Ia5dc4e7370cc055df452bf7cbaddd9901b4d229d

test/e2e/network/pod_lifecycle.go

@@ -0,0 +1,101 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package network
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"strconv"
+	"time"
+
+	"github.com/onsi/ginkgo/v2"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	clientset "k8s.io/client-go/kubernetes"
+	"k8s.io/kubernetes/test/e2e/framework"
+	e2epod "k8s.io/kubernetes/test/e2e/framework/pod"
+	"k8s.io/kubernetes/test/e2e/network/common"
+	admissionapi "k8s.io/pod-security-admission/api"
+)
+
+var _ = common.SIGDescribe("Connectivity Pod Lifecycle", func() {
+
+	fr := framework.NewDefaultFramework("podlifecycle")
+	fr.NamespacePodSecurityEnforceLevel = admissionapi.LevelPrivileged
+
+	var (
+		cs        clientset.Interface
+		ns        string
+		podClient *e2epod.PodClient
+	)
+	ginkgo.BeforeEach(func(ctx context.Context) {
+		cs = fr.ClientSet
+		ns = fr.Namespace.Name
+		podClient = e2epod.NewPodClient(fr)
+	})
+
+	ginkgo.It("should be able to connect from a Pod to a terminating Pod", func(ctx context.Context) {
+		ginkgo.By("Creating 1 webserver pod able to serve traffic during the grace period of 300 seconds")
+		gracePeriod := int64(100)
+		webserverPod := e2epod.NewAgnhostPod(ns, "webserver-pod", nil, nil, nil, "netexec", "--http-port=80", fmt.Sprintf("--delay-shutdown=%d", gracePeriod))
+		webserverPod.Spec.TerminationGracePeriodSeconds = &gracePeriod
+		webserverPod = podClient.CreateSync(ctx, webserverPod)
+
+		ginkgo.By("Creating 1 client pod that will try to connect to the webserver")
+		pausePod := e2epod.NewAgnhostPod(ns, "pause-pod-1", nil, nil, nil)
+		pausePod = podClient.CreateSync(ctx, pausePod)
+
+		ginkgo.By("Try to connect to the webserver")
+		// Wait until we are able to connect to the Pod
+		podIPAddress := net.JoinHostPort(webserverPod.Status.PodIP, strconv.Itoa(80))
+		execHostnameTest(*pausePod, podIPAddress, webserverPod.Name)
+
+		// webserver should continue to serve traffic after delete
+		// since will be gracefully terminating
+		err := cs.CoreV1().Pods(ns).Delete(ctx, webserverPod.Name, metav1.DeleteOptions{})
+		framework.ExpectNoError(err, "error deleting webserver pod")
+		// wait some time to ensure the test hit the pod during the terminating phase
+		time.Sleep(15 * time.Second)
+		execHostnameTest(*pausePod, podIPAddress, webserverPod.Name)
+	})
+
+	ginkgo.It("should be able to connect to other Pod from a terminating Pod", func(ctx context.Context) {
+		ginkgo.By("Creating 1 webserver pod able to serve traffic during the grace period of 300 seconds")
+		gracePeriod := int64(100)
+		webserverPod := e2epod.NewAgnhostPod(ns, "webserver-pod", nil, nil, nil, "netexec", "--http-port=80", fmt.Sprintf("--delay-shutdown=%d", gracePeriod))
+		webserverPod = podClient.CreateSync(ctx, webserverPod)
+
+		ginkgo.By("Creating 1 client pod that will try to connect to the webservers")
+		pausePod := e2epod.NewAgnhostPod(ns, "pause-pod-1", nil, nil, nil, "netexec", "--http-port=80", fmt.Sprintf("--delay-shutdown=%d", gracePeriod))
+		pausePod.Spec.TerminationGracePeriodSeconds = &gracePeriod
+		pausePod = podClient.CreateSync(ctx, pausePod)
+
+		ginkgo.By("Try to connect to the webserver")
+		// Wait until we are able to connect to the Pod
+		podIPAddress := net.JoinHostPort(webserverPod.Status.PodIP, strconv.Itoa(80))
+		execHostnameTest(*pausePod, podIPAddress, webserverPod.Name)
+
+		// pod client should continue to connect to the webserver after delete
+		// since will be gracefully terminating
+		err := cs.CoreV1().Pods(ns).Delete(ctx, pausePod.Name, metav1.DeleteOptions{})
+		framework.ExpectNoError(err, "error deleting client pod")
+		// wait some time to ensure the test hit the pod during the terminating
+		time.Sleep(15 * time.Second)
+		execHostnameTest(*pausePod, podIPAddress, webserverPod.Name)
+	})
+
+})