use trivial resizer if only node expansion supported

cmd/csi-resizer/main.go

@@ -80,7 +80,7 @@ func main() {
 
 	informerFactory := informers.NewSharedInformerFactory(kubeClient, *resyncPeriod)
 
-	csiResizer, err := resizer.NewCSIResizer(*csiAddress, *csiTimeout, kubeClient, informerFactory)
+	csiResizer, err := resizer.NewResizer(*csiAddress, *csiTimeout, kubeClient, informerFactory)
 	if err != nil {
 		klog.Fatal(err.Error())
 	}

pkg/csi/client.go

@@ -41,6 +41,10 @@ type Client interface {
 	// in ControllerGetCapabilities() gRPC call.
 	SupportsControllerResize(ctx context.Context) (bool, error)
 
+	// SupportsNodeResize returns whether the CSI driver reports EXPAND_VOLUME
+	// in NodeGetCapabilities() gRPC call.
+	SupportsNodeResize(ctx context.Context) (bool, error)
+
 	// Expand expands the volume to a new size at least as big as requestBytes.
 	// It returns the new size and whether the volume need expand operation on the node.
 	Expand(ctx context.Context, volumeID string, requestBytes int64, secrets map[string]string) (int64, bool, error)
@@ -60,12 +64,14 @@ func New(address string, timeout time.Duration) (Client, error) {
 
 	return &client{
 		conn:       conn,
+		nodeClient: csi.NewNodeClient(conn),
 		ctrlClient: csi.NewControllerClient(conn),
 	}, nil
 }
 
 type client struct {
 	conn       *grpc.ClientConn
+	nodeClient csi.NodeClient
 	ctrlClient csi.ControllerClient
 }
 
@@ -89,6 +95,26 @@ func (c *client) SupportsControllerResize(ctx context.Context) (bool, error) {
 	return caps[csi.ControllerServiceCapability_RPC_EXPAND_VOLUME], nil
 }
 
+func (c *client) SupportsNodeResize(ctx context.Context) (bool, error) {
+	rsp, err := c.nodeClient.NodeGetCapabilities(ctx, &csi.NodeGetCapabilitiesRequest{})
+	if err != nil {
+		return false, fmt.Errorf("error getting node capabilities: %v", err)
+	}
+	for _, capacity := range rsp.GetCapabilities() {
+		if capacity == nil {
+			continue
+		}
+		rpc := capacity.GetRpc()
+		if rpc == nil {
+			continue
+		}
+		if rpc.GetType() == csi.NodeServiceCapability_RPC_EXPAND_VOLUME {
+			return true, nil
+		}
+	}
+	return false, nil
+}
+
 func (c *client) Expand(
 	ctx context.Context,
 	volumeID string,

pkg/resizer/csi_resizer.go

@@ -41,8 +41,8 @@ const (
 	resizerSecretNamespaceKey = "csi.storage.k8s.io/resizer-secret-namespace"
 )
 
-// NewCSIResizer creates a new resizer responsible for resizing CSI volumes.
-func NewCSIResizer(
+// NewResizer creates a new resizer responsible for resizing CSI volumes.
+func NewResizer(
 	address string, timeout time.Duration,
 	k8sClient kubernetes.Interface, informerFactory informers.SharedInformerFactory) (Resizer, error) {
 	csiClient, err := csi.New(address, timeout)
@@ -55,22 +55,30 @@ func NewCSIResizer(
 		return nil, fmt.Errorf("get driver name failed: %v", err)
 	}
 
-	supports, err := supportsPluginControllerService(csiClient, timeout)
+	supportControllerService, err := supportsPluginControllerService(csiClient, timeout)
 	if err != nil {
 		return nil, fmt.Errorf("failed to check if plugin supports controller service: %v", err)
 	}
 
-	if !supports {
+	if !supportControllerService {
 		return nil, errors.New("CSI driver does not support controller service")
 	}
 
-	supports, err = supportsControllerResize(csiClient, timeout)
+	supportControllerResize, err := supportsControllerResize(csiClient, timeout)
 	if err != nil {
 		return nil, fmt.Errorf("failed to check if plugin supports controller resize: %v", err)
 	}
 
-	if !supports {
-		return nil, fmt.Errorf("CSI driver does not support controller resize")
+	if !supportControllerResize {
+		supportsNodeResize, err := supportsNodeResize(csiClient, timeout)
+		if err != nil {
+			return nil, fmt.Errorf("failed to check if plugin supports node resize: %v", err)
+		}
+		if supportsNodeResize {
+			klog.Info("The CSI driver supports node resize only, using trivial resizer to handle resize requests")
+			return newTrivialResizer(driverName), nil
+		}
+		return nil, fmt.Errorf("CSI driver neither supports controller resize nor node resize")
 	}
 
 	return &csiResizer{
@@ -166,6 +174,12 @@ func supportsControllerResize(client csi.Client, timeout time.Duration) (bool, e
 	return client.SupportsControllerResize(ctx)
 }
 
+func supportsNodeResize(client csi.Client, timeout time.Duration) (bool, error) {
+	ctx, cancel := timeoutCtx(timeout)
+	defer cancel()
+	return client.SupportsNodeResize(ctx)
+}
+
 func timeoutCtx(timeout time.Duration) (context.Context, context.CancelFunc) {
 	return context.WithTimeout(context.Background(), timeout)
 }

pkg/resizer/trivial_resizer.go

@@ -21,23 +21,23 @@ import (
 	"k8s.io/apimachinery/pkg/api/resource"
 )
 
-const exampleResizerName = "csi/example-resizer"
-
 // newTrivialResizer returns a trivial resizer which will mark all pvs' resize process as finished.
-func newTrivialResizer() Resizer {
-	return &trivialResizer{}
+func newTrivialResizer(name string) Resizer {
+	return &trivialResizer{name: name}
 }
 
-type trivialResizer struct{}
+type trivialResizer struct {
+	name string
+}
 
 func (r *trivialResizer) Name() string {
-	return exampleResizerName
+	return r.name
 }
 
 func (r *trivialResizer) CanSupport(pv *v1.PersistentVolume) bool {
 	return true
 }
 
 func (r *trivialResizer) Resize(pv *v1.PersistentVolume, requestSize resource.Quantity) (newSize resource.Quantity, fsResizeRequired bool, err error) {
-	return requestSize, false, nil
+	return requestSize, true, nil
 }