Check whether the action is a CSI action and whether CSI feature is

enabled, before executing the action.

The DeleteItemAction is not checked, because the DIA doesn't have a
method to get the action's plugin name.
This should be OK, because the CSI will check whether the VS and VSC
have a backup name annotation. If the VS and VSC is not handled by
the CSI plugin, then they don't have the annotation.

Signed-off-by: Xun Jiang <jxun@vmware.com>

pkg/cmd/server/server.go

@@ -73,6 +73,7 @@ import (
 	"github.com/vmware-tanzu/velero/pkg/persistence"
 	"github.com/vmware-tanzu/velero/pkg/plugin/clientmgmt"
 	"github.com/vmware-tanzu/velero/pkg/plugin/clientmgmt/process"
+	"github.com/vmware-tanzu/velero/pkg/plugin/framework/common"
 	"github.com/vmware-tanzu/velero/pkg/podexec"
 	"github.com/vmware-tanzu/velero/pkg/podvolume"
 	"github.com/vmware-tanzu/velero/pkg/repository"
@@ -309,6 +310,13 @@ func newServer(f client.Factory, config serverConfig, logger *logrus.Logger) (*s
 		return nil, err
 	}
 
+	if !features.IsEnabled(velerov1api.CSIFeatureFlag) {
+		_, err = pluginRegistry.Get(common.PluginKindBackupItemActionV2, "velero.io/csi-pvc-backupper")
+		if err == nil {
+			logger.Warn("CSI plugins are registered, but the EnableCSI feature is not enabled.")
+		}
+	}
+
 	// cancelFunc is not deferred here because if it was, then ctx would immediately
 	// be canceled once this function exited, making it useless to any informers using later.
 	// That, in turn, causes the velero server to halt when the first informer tries to use it.