Graduate SeccompDefault feature to beta

As outlined in the KEP, we now graduate the Kubelet feature to beta
which means that it is enabled by default. The corresponding Kubelet
flag still defaults to `false`, but we now have the chance to e2e test
the feature by using a new serial test case.

KEP: https://github.com/kubernetes/enhancements/issues/2413

Signed-off-by: Sascha Grunert <sgrunert@redhat.com>

pkg/features/kube_features.go

@@ -981,7 +981,7 @@ var defaultKubernetesFeatureGates = map[featuregate.Feature]featuregate.FeatureS
 
 	RotateKubeletServerCertificate: {Default: true, PreRelease: featuregate.Beta},
 
-	SeccompDefault: {Default: false, PreRelease: featuregate.Alpha},
+	SeccompDefault: {Default: true, PreRelease: featuregate.Beta},
 
 	ServiceIPStaticSubrange: {Default: false, PreRelease: featuregate.Beta},
 

test/e2e_node/seccompdefault_test.go

@@ -0,0 +1,71 @@
+//go:build linux
+// +build linux
+
+/*
+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 e2enode
+
+import (
+	"github.com/onsi/ginkgo"
+
+	v1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/util/uuid"
+	kubeletconfig "k8s.io/kubernetes/pkg/kubelet/apis/config"
+	"k8s.io/kubernetes/test/e2e/framework"
+	admissionapi "k8s.io/pod-security-admission/api"
+)
+
+// Serial because the test updates kubelet configuration.
+var _ = SIGDescribe("SeccompDefault [Serial] [Feature:SeccompDefault] [LinuxOnly]", func() {
+	f := framework.NewDefaultFramework("seccompdefault-test")
+	f.NamespacePodSecurityEnforceLevel = admissionapi.LevelPrivileged
+
+	ginkgo.Context("with SeccompDefault enabled", func() {
+		tempSetCurrentKubeletConfig(f, func(cfg *kubeletconfig.KubeletConfiguration) {
+			cfg.SeccompDefault = true
+		})
+
+		newPod := func(securityContext *v1.SecurityContext) *v1.Pod {
+			name := "seccompdefault-test-" + string(uuid.NewUUID())
+			return &v1.Pod{
+				ObjectMeta: metav1.ObjectMeta{Name: name},
+				Spec: v1.PodSpec{
+					RestartPolicy: v1.RestartPolicyNever,
+					Containers: []v1.Container{
+						{
+							Name:            name,
+							Image:           busyboxImage,
+							Command:         []string{"grep", "Seccomp:", "/proc/self/status"},
+							SecurityContext: securityContext,
+						},
+					},
+				},
+			}
+		}
+
+		ginkgo.It("should use the default seccomp profile when unspecified", func() {
+			pod := newPod(nil)
+			f.TestContainerOutput("SeccompDefault", pod, 0, []string{"2"})
+		})
+
+		ginkgo.It("should use unconfined when specified", func() {
+			pod := newPod(&v1.SecurityContext{SeccompProfile: &v1.SeccompProfile{Type: v1.SeccompProfileTypeUnconfined}})
+			f.TestContainerOutput("SeccompDefault-unconfined", pod, 0, []string{"0"})
+		})
+	})
+})