e2e_node: add a test to verify kubelet fails to create pod if userns isn't supported

and the pod requests a user namespace

Signed-off-by: Peter Hunt <[email protected]>

Author: haircommander

test/e2e_node/user_namespaces_test.go

@@ -0,0 +1,89 @@
+//go:build linux
+// +build linux
+
+/*
+Copyright 2024 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 e2enode
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/onsi/gomega"
+	v1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	kubefeatures "k8s.io/kubernetes/pkg/features"
+	kubeletconfig "k8s.io/kubernetes/pkg/kubelet/apis/config"
+	"k8s.io/kubernetes/test/e2e/feature"
+	"k8s.io/kubernetes/test/e2e/framework"
+	e2epod "k8s.io/kubernetes/test/e2e/framework/pod"
+	e2eskipper "k8s.io/kubernetes/test/e2e/framework/skipper"
+	imageutils "k8s.io/kubernetes/test/utils/image"
+	admissionapi "k8s.io/pod-security-admission/api"
+)
+
+var _ = SIGDescribe("UserNamespaces", "[LinuxOnly]", feature.UserNamespacesSupport, framework.WithSerial(), func() {
+	f := framework.NewDefaultFramework("user-namespace-off-test")
+	f.NamespacePodSecurityLevel = admissionapi.LevelPrivileged
+	f.Context("when UserNamespacesSupport=false in the kubelet", func() {
+		// Turn off UserNamespacesSupport for this test
+		// TODO: once the UserNamespacesSupport feature is removed, this test should be removed too
+		tempSetCurrentKubeletConfig(f, func(ctx context.Context, initialConfig *kubeletconfig.KubeletConfiguration) {
+			if initialConfig.FeatureGates == nil {
+				initialConfig.FeatureGates = make(map[string]bool)
+			}
+			initialConfig.FeatureGates[string(kubefeatures.UserNamespacesSupport)] = false
+		})
+		f.It("will fail to create a hostUsers=false pod", func(ctx context.Context) {
+			if on, ok := serviceFeatureGates[string(kubefeatures.UserNamespacesSupport)]; !ok || !on {
+				e2eskipper.Skipf("services do not have user namespaces on")
+			}
+			falseVar := false
+			podClient := e2epod.NewPodClient(f)
+			pod, err := podClient.PodInterface.Create(ctx, &v1.Pod{
+				ObjectMeta: metav1.ObjectMeta{Name: "userns-pod"},
+				Spec: v1.PodSpec{
+					Containers: []v1.Container{
+						{
+							Name:    "test-container-1",
+							Image:   imageutils.GetE2EImage(imageutils.BusyBox),
+							Command: []string{"/bin/sleep"},
+							Args:    []string{"10000"},
+						},
+					},
+					HostUsers: &falseVar,
+				},
+			}, metav1.CreateOptions{})
+			framework.ExpectNoError(err)
+
+			// Pod should stay in pending
+			// Events would be a better way to tell this, as we could actually read the event,
+			// but history proves events aren't reliable enough to base a test on.
+			gomega.Consistently(ctx, func() error {
+				p, err := f.ClientSet.CoreV1().Pods(f.Namespace.Name).Get(ctx, pod.Name, metav1.GetOptions{})
+				if err != nil {
+					return err
+				}
+				if p.Status.Phase != v1.PodPending {
+					return fmt.Errorf("Pod phase isn't pending")
+				}
+				return nil
+			}, 30*time.Second, 5*time.Second).ShouldNot(gomega.HaveOccurred())
+		})
+	})
+})