test/e2e/apimachinery: add e2e test for APIServerIdentity, validating behavior when restarting kube-apiserver

Signed-off-by: Andrew Sy Kim <andrewsy@google.com>

test/e2e/apimachinery/apiserver_identity.go

@@ -0,0 +1,169 @@
+/*
+Copyright 2022 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 apimachinery
+
+import (
+	"context"
+	"crypto/sha256"
+	"encoding/base32"
+	"errors"
+	"fmt"
+	"net"
+	"strings"
+	"time"
+
+	"github.com/onsi/ginkgo/v2"
+	v1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/util/wait"
+	"k8s.io/kubernetes/test/e2e/framework"
+	e2enode "k8s.io/kubernetes/test/e2e/framework/node"
+	e2eskipper "k8s.io/kubernetes/test/e2e/framework/skipper"
+	e2essh "k8s.io/kubernetes/test/e2e/framework/ssh"
+	admissionapi "k8s.io/pod-security-admission/api"
+)
+
+func getControlPlaneHostname(node *v1.Node) (string, error) {
+	nodeAddresses := e2enode.GetAddresses(node, v1.NodeExternalIP)
+	if len(nodeAddresses) == 0 {
+		return "", errors.New("no valid addresses to use for SSH")
+	}
+
+	controlPlaneAddress := nodeAddresses[0]
+
+	host := controlPlaneAddress + ":" + e2essh.SSHPort
+	result, err := e2essh.SSH("hostname", host, framework.TestContext.Provider)
+	if err != nil {
+		return "", err
+	}
+
+	if result.Code != 0 {
+		return "", fmt.Errorf("encountered non-zero exit code when running hostname command: %d", result.Code)
+	}
+
+	return strings.TrimSpace(result.Stdout), nil
+}
+
+// restartAPIServer attempts to restart the kube-apiserver on a node
+func restartAPIServer(node *v1.Node) error {
+	nodeAddresses := e2enode.GetAddresses(node, v1.NodeExternalIP)
+	if len(nodeAddresses) == 0 {
+		return errors.New("no valid addresses to use for SSH")
+	}
+
+	controlPlaneAddress := nodeAddresses[0]
+	cmd := "pidof kube-apiserver | xargs sudo kill"
+	framework.Logf("Restarting kube-apiserver via ssh, running: %v", cmd)
+	result, err := e2essh.SSH(cmd, net.JoinHostPort(controlPlaneAddress, e2essh.SSHPort), framework.TestContext.Provider)
+	if err != nil || result.Code != 0 {
+		e2essh.LogResult(result)
+		return fmt.Errorf("couldn't restart kube-apiserver: %v", err)
+	}
+	return nil
+}
+
+// This test requires that --feature-gates=APIServerIdentity=true be set on the apiserver
+var _ = SIGDescribe("kube-apiserver identity [Feature:APIServerIdentity]", func() {
+	f := framework.NewDefaultFramework("kube-apiserver-identity")
+	f.NamespacePodSecurityEnforceLevel = admissionapi.LevelPrivileged
+
+	ginkgo.It("kube-apiserver identity should persist after restart [Disruptive]", func() {
+		e2eskipper.SkipUnlessProviderIs("gce")
+
+		client := f.ClientSet
+
+		var controlPlaneNodes []v1.Node
+		nodes, err := client.CoreV1().Nodes().List(context.TODO(), metav1.ListOptions{})
+		framework.ExpectNoError(err)
+
+		for _, node := range nodes.Items {
+			if _, ok := node.Labels["node-role.kubernetes.io/control-plane"]; ok {
+				controlPlaneNodes = append(controlPlaneNodes, node)
+				continue
+			}
+
+			if _, ok := node.Labels["node-role.kubernetes.io/master"]; ok {
+				controlPlaneNodes = append(controlPlaneNodes, node)
+				continue
+			}
+
+			for _, taint := range node.Spec.Taints {
+				if taint.Key == "node-role.kubernetes.io/master" {
+					controlPlaneNodes = append(controlPlaneNodes, node)
+					break
+				}
+
+				if taint.Key == "node-role.kubernetes.io/control-plane" {
+					controlPlaneNodes = append(controlPlaneNodes, node)
+					break
+				}
+			}
+		}
+
+		leases, err := client.CoordinationV1().Leases(metav1.NamespaceSystem).List(context.TODO(), metav1.ListOptions{
+			LabelSelector: "k8s.io/component=kube-apiserver",
+		})
+		framework.ExpectNoError(err)
+		framework.ExpectEqual(len(leases.Items), len(controlPlaneNodes), "unexpected number of leases")
+
+		for _, node := range controlPlaneNodes {
+			hostname, err := getControlPlaneHostname(&node)
+			framework.ExpectNoError(err)
+
+			hash := sha256.Sum256([]byte(hostname))
+			leaseName := "kube-apiserver-" + strings.ToLower(base32.StdEncoding.WithPadding(base32.NoPadding).EncodeToString(hash[:16]))
+
+			lease, err := client.CoordinationV1().Leases(metav1.NamespaceSystem).Get(context.TODO(), leaseName, metav1.GetOptions{})
+			framework.ExpectNoError(err)
+			oldHolderIdentity := lease.Spec.HolderIdentity
+			lastRenewedTime := lease.Spec.RenewTime
+
+			err = restartAPIServer(&node)
+			framework.ExpectNoError(err)
+
+			err = wait.PollImmediate(time.Second, wait.ForeverTestTimeout, func() (bool, error) {
+				lease, err = client.CoordinationV1().Leases(metav1.NamespaceSystem).Get(context.TODO(), leaseName, metav1.GetOptions{})
+				if err != nil {
+					return false, nil
+				}
+
+				// expect only the holder identity to change after a restart
+				newHolderIdentity := lease.Spec.HolderIdentity
+				if newHolderIdentity == oldHolderIdentity {
+					return false, nil
+				}
+
+				// wait for at least one lease heart beat after the holder identity changes
+				if !lease.Spec.RenewTime.After(lastRenewedTime.Time) {
+					return false, nil
+				}
+
+				return true, nil
+
+			})
+			framework.ExpectNoError(err, "holder identity did not change after a restart")
+		}
+
+		// As long as the hostname of kube-apiserver is unchanged, a restart should not result in new Lease objects.
+		// Check that the number of lease objects remains the same after restarting kube-apiserver.
+		leases, err = client.CoordinationV1().Leases(metav1.NamespaceSystem).List(context.TODO(), metav1.ListOptions{
+			LabelSelector: "k8s.io/component=kube-apiserver",
+		})
+		framework.ExpectNoError(err)
+		framework.ExpectEqual(len(leases.Items), len(controlPlaneNodes), "unexpected number of leases")
+	})
+})