Bypass the remap CRD version plugin when v1beta1 CRD is not supported

When velero is running on clusters that don't support v1beta1 CRD, the
plugin will not try to backup v1beta1 CRD.
The plugin should be kept for backward compatibility.  It will be
removed when velero drop the support for k8s v1.21

Signed-off-by: Daniel Jiang <jiangd@vmware.com>

changelogs/unreleased/4686-reasonerjt

@@ -0,0 +1 @@
+Bypass the remap CRD version plugin when v1beta1 CRD is not supported

pkg/backup/remap_crd_version_action.go

@@ -30,6 +30,8 @@ import (
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime"
 
+	velerodiscovery "github.com/vmware-tanzu/velero/pkg/discovery"
+
 	v1 "github.com/vmware-tanzu/velero/pkg/apis/velero/v1"
 	"github.com/vmware-tanzu/velero/pkg/plugin/velero"
 )
@@ -37,13 +39,14 @@ import (
 // RemapCRDVersionAction inspects CustomResourceDefinition and decides if it is a v1
 // CRD that needs to be backed up as v1beta1.
 type RemapCRDVersionAction struct {
-	logger        logrus.FieldLogger
-	betaCRDClient apiextv1beta1client.CustomResourceDefinitionInterface
+	logger          logrus.FieldLogger
+	betaCRDClient   apiextv1beta1client.CustomResourceDefinitionInterface
+	discoveryHelper velerodiscovery.Helper
 }
 
 // NewRemapCRDVersionAction instantiates a new RemapCRDVersionAction plugin.
-func NewRemapCRDVersionAction(logger logrus.FieldLogger, betaCRDClient apiextv1beta1client.CustomResourceDefinitionInterface) *RemapCRDVersionAction {
-	return &RemapCRDVersionAction{logger: logger, betaCRDClient: betaCRDClient}
+func NewRemapCRDVersionAction(logger logrus.FieldLogger, betaCRDClient apiextv1beta1client.CustomResourceDefinitionInterface, discoveryHelper velerodiscovery.Helper) *RemapCRDVersionAction {
+	return &RemapCRDVersionAction{logger: logger, betaCRDClient: betaCRDClient, discoveryHelper: discoveryHelper}
 }
 
 // AppliesTo selects the resources the plugin should run against. In this case, CustomResourceDefinitions.
@@ -68,7 +71,26 @@ func (a *RemapCRDVersionAction) Execute(item runtime.Unstructured, backup *v1.Ba
 		return item, nil, nil
 	}
 
-	// We've got a v1 CRD, so proceed.
+	// This plugin will exit if the CRD was installed via v1beta1 but the cluster does not support v1beta1 CRD
+	supportv1b1 := false
+CheckVersion:
+	for _, g := range a.discoveryHelper.APIGroups() {
+		if g.Name == apiextv1.GroupName {
+			for _, v := range g.Versions {
+				if v.Version == apiextv1beta1.SchemeGroupVersion.Version {
+					supportv1b1 = true
+					break CheckVersion
+				}
+			}
+
+		}
+	}
+	if !supportv1b1 {
+		a.logger.Info("Exiting RemapCRDVersionAction, the cluster does not support v1beta1 CRD")
+		return item, nil, nil
+	}
+
+	// We've got a v1 CRD and the cluster supports v1beta1 CRD, so proceed.
 	var crd apiextv1.CustomResourceDefinition
 
 	// Do not use runtime.DefaultUnstructuredConverter.FromUnstructured here because it has a bug when converting integers/whole

pkg/backup/remap_crd_version_action_test.go

@@ -32,6 +32,8 @@ import (
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime"
 
+	velerodiscovery "github.com/vmware-tanzu/velero/pkg/discovery"
+
 	v1 "github.com/vmware-tanzu/velero/pkg/apis/velero/v1"
 	"github.com/vmware-tanzu/velero/pkg/builder"
 	velerotest "github.com/vmware-tanzu/velero/pkg/test"
@@ -48,8 +50,7 @@ func TestRemapCRDVersionAction(t *testing.T) {
 	c := b.Result()
 	_, err := betaClient.Create(context.TODO(), c, metav1.CreateOptions{})
 	require.NoError(t, err)
-
-	a := NewRemapCRDVersionAction(velerotest.NewLogger(), betaClient)
+	a := NewRemapCRDVersionAction(velerotest.NewLogger(), betaClient, fakeDiscoveryHelper())
 
 	t.Run("Test a v1 CRD without any Schema information", func(t *testing.T) {
 		b := builder.ForV1CustomResourceDefinition("test.velero.io")
@@ -109,6 +110,33 @@ func TestRemapCRDVersionAction(t *testing.T) {
 		require.NoError(t, err)
 		assert.Equal(t, "apiextensions.k8s.io/v1beta1", item.UnstructuredContent()["apiVersion"])
 	})
+
+	t.Run("When the cluster only supports v1 CRD, v1 CRD will be returned even the input has Spec.PreserveUnknownFields set to true (issue 4080)", func(t *testing.T) {
+		a.discoveryHelper = &velerotest.FakeDiscoveryHelper{
+			APIGroupsList: []metav1.APIGroup{
+				{
+					Name: apiextv1.GroupName,
+					Versions: []metav1.GroupVersionForDiscovery{
+						{
+							Version: apiextv1.SchemeGroupVersion.Version,
+						},
+					},
+				},
+			},
+		}
+		b := builder.ForV1CustomResourceDefinition("test.velero.io")
+		b.PreserveUnknownFields(true)
+		c := b.Result()
+		obj, err := runtime.DefaultUnstructuredConverter.ToUnstructured(&c)
+		require.NoError(t, err)
+
+		item, _, err := a.Execute(&unstructured.Unstructured{Object: obj}, backup)
+		require.NoError(t, err)
+		assert.Equal(t, "apiextensions.k8s.io/v1", item.UnstructuredContent()["apiVersion"])
+		// set it back to the default one
+		a.discoveryHelper = fakeDiscoveryHelper()
+	})
+
 }
 
 // TestRemapCRDVersionActionData tests the RemapCRDVersionAction plugin against actual CRD to confirm that the v1beta1 version is returned when the v1 version is passed in to the plugin.
@@ -116,8 +144,7 @@ func TestRemapCRDVersionActionData(t *testing.T) {
 	backup := &v1.Backup{}
 	clientset := apiextfakes.NewSimpleClientset()
 	betaClient := clientset.ApiextensionsV1beta1().CustomResourceDefinitions()
-
-	a := NewRemapCRDVersionAction(velerotest.NewLogger(), betaClient)
+	a := NewRemapCRDVersionAction(velerotest.NewLogger(), betaClient, fakeDiscoveryHelper())
 
 	tests := []struct {
 		crd                     string
@@ -192,3 +219,21 @@ func TestRemapCRDVersionActionData(t *testing.T) {
 	}
 
 }
+
+func fakeDiscoveryHelper() velerodiscovery.Helper {
+	return &velerotest.FakeDiscoveryHelper{
+		APIGroupsList: []metav1.APIGroup{
+			{
+				Name: apiextv1.GroupName,
+				Versions: []metav1.GroupVersionForDiscovery{
+					{
+						Version: apiextv1beta1.SchemeGroupVersion.Version,
+					},
+					{
+						Version: apiextv1.SchemeGroupVersion.Version,
+					},
+				},
+			},
+		},
+	}
+}

pkg/cmd/server/plugin/plugin.go

@@ -110,7 +110,16 @@ func newRemapCRDVersionAction(f client.Factory) veleroplugin.HandlerInitializer
 			return nil, err
 		}
 
-		return backup.NewRemapCRDVersionAction(logger, client.ApiextensionsV1beta1().CustomResourceDefinitions()), nil
+		clientset, err := f.KubeClient()
+		if err != nil {
+			return nil, err
+		}
+		discoveryHelper, err := velerodiscovery.NewHelper(clientset.Discovery(), logger)
+		if err != nil {
+			return nil, err
+		}
+
+		return backup.NewRemapCRDVersionAction(logger, client.ApiextensionsV1beta1().CustomResourceDefinitions(), discoveryHelper), nil
 	}
 }