Skip attach for non-attachable CSI volumes

pkg/volume/csi/csi_attacher.go

@@ -70,6 +70,16 @@ func (c *csiAttacher) Attach(spec *volume.Spec, nodeName types.NodeName) (string
 		return "", err
 	}
 
+	skip, err := c.plugin.skipAttach(csiSource.Driver)
+	if err != nil {
+		glog.Error(log("attacher.Attach failed to find if driver is attachable: %v", err))
+		return "", err
+	}
+	if skip {
+		glog.V(4).Infof(log("skipping attach for driver %s", csiSource.Driver))
+		return "", nil
+	}
+
 	node := string(nodeName)
 	pvName := spec.PersistentVolume.GetName()
 	attachID := getAttachmentName(csiSource.VolumeHandle, csiSource.Driver, node)
@@ -120,6 +130,16 @@ func (c *csiAttacher) WaitForAttach(spec *volume.Spec, attachID string, pod *v1.
 		return "", err
 	}
 
+	skip, err := c.plugin.skipAttach(source.Driver)
+	if err != nil {
+		glog.Error(log("attacher.Attach failed to find if driver is attachable: %v", err))
+		return "", err
+	}
+	if skip {
+		glog.V(4).Infof(log("Driver is not attachable, skip waiting for attach"))
+		return "", nil
+	}
+
 	return c.waitForVolumeAttachment(source.VolumeHandle, attachID, timeout)
 }
 
@@ -221,11 +241,22 @@ func (c *csiAttacher) VolumesAreAttached(specs []*volume.Spec, nodeName types.No
 			glog.Error(log("attacher.VolumesAreAttached failed: %v", err))
 			continue
 		}
+		skip, err := c.plugin.skipAttach(source.Driver)
+		if err != nil {
+			glog.Error(log("Failed to check CSIDriver for %s: %s", source.Driver, err))
+		} else {
+			if skip {
+				// This volume is not attachable, pretend it's attached
+				attached[spec] = true
+				continue
+			}
+		}
 
 		attachID := getAttachmentName(source.VolumeHandle, source.Driver, string(nodeName))
 		glog.V(4).Info(log("probing attachment status for VolumeAttachment %v", attachID))
 		attach, err := c.k8s.StorageV1beta1().VolumeAttachments().Get(attachID, meta.GetOptions{})
 		if err != nil {
+			attached[spec] = false
 			glog.Error(log("attacher.VolumesAreAttached failed for attach.ID=%v: %v", attachID, err))
 			continue
 		}
@@ -325,19 +356,7 @@ func (c *csiAttacher) MountDevice(spec *volume.Spec, devicePath string, deviceMo
 
 	// Start MountDevice
 	nodeName := string(c.plugin.host.GetNodeName())
-	attachID := getAttachmentName(csiSource.VolumeHandle, csiSource.Driver, nodeName)
-
-	// search for attachment by VolumeAttachment.Spec.Source.PersistentVolumeName
-	attachment, err := c.k8s.StorageV1beta1().VolumeAttachments().Get(attachID, meta.GetOptions{})
-	if err != nil {
-		return err // This err already has enough context ("VolumeAttachment xyz not found")
-	}
-
-	if attachment == nil {
-		err = errors.New("no existing VolumeAttachment found")
-		return err
-	}
-	publishVolumeInfo := attachment.Status.AttachmentMetadata
+	publishVolumeInfo, err := c.plugin.getPublishVolumeInfo(c.k8s, csiSource.VolumeHandle, csiSource.Driver, nodeName)
 
 	nodeStageSecrets := map[string]string{}
 	if csiSource.NodeStageSecretRef != nil {

pkg/volume/csi/csi_mounter.go

@@ -18,7 +18,6 @@ package csi
 
 import (
 	"context"
-	"errors"
 	"fmt"
 	"os"
 	"path"
@@ -26,7 +25,6 @@ import (
 	"github.com/golang/glog"
 
 	api "k8s.io/api/core/v1"
-	meta "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/client-go/kubernetes"
 	kstrings "k8s.io/kubernetes/pkg/util/strings"
@@ -113,9 +111,6 @@ func (c *csiMountMgr) SetUpAt(dir string, fsGroup *int64) error {
 	}
 
 	csi := c.csiClient
-	nodeName := string(c.plugin.host.GetNodeName())
-	attachID := getAttachmentName(csiSource.VolumeHandle, csiSource.Driver, nodeName)
-
 	ctx, cancel := context.WithTimeout(context.Background(), csiTimeout)
 	defer cancel()
 
@@ -134,20 +129,13 @@ func (c *csiMountMgr) SetUpAt(dir string, fsGroup *int64) error {
 			return err
 		}
 	}
-
 	// search for attachment by VolumeAttachment.Spec.Source.PersistentVolumeName
 	if c.volumeInfo == nil {
-		attachment, err := c.k8s.StorageV1beta1().VolumeAttachments().Get(attachID, meta.GetOptions{})
+		nodeName := string(c.plugin.host.GetNodeName())
+		c.volumeInfo, err = c.plugin.getPublishVolumeInfo(c.k8s, c.volumeID, c.driverName, nodeName)
 		if err != nil {
-			glog.Error(log("mounter.SetupAt failed while getting volume attachment [id=%v]: %v", attachID, err))
 			return err
 		}
-
-		if attachment == nil {
-			glog.Error(log("unable to find VolumeAttachment [id=%s]", attachID))
-			return errors.New("no existing VolumeAttachment found")
-		}
-		c.volumeInfo = attachment.Status.AttachmentMetadata
 	}
 
 	attribs := csiSource.VolumeAttributes

pkg/volume/csi/csi_plugin.go

@@ -29,10 +29,12 @@ import (
 
 	"github.com/golang/glog"
 	api "k8s.io/api/core/v1"
+	apierrs "k8s.io/apimachinery/pkg/api/errors"
 	meta "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/apimachinery/pkg/util/wait"
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
+	clientset "k8s.io/client-go/kubernetes"
 	csiapiinformer "k8s.io/csi-api/pkg/client/informers/externalversions"
 	csiinformer "k8s.io/csi-api/pkg/client/informers/externalversions/csi/v1alpha1"
 	csilister "k8s.io/csi-api/pkg/client/listers/csi/v1alpha1"
@@ -490,3 +492,48 @@ func (p *csiPlugin) ConstructBlockVolumeSpec(podUID types.UID, specVolName, mapP
 
 	return volume.NewSpecFromPersistentVolume(pv, false), nil
 }
+
+func (p *csiPlugin) skipAttach(driver string) (bool, error) {
+	if !utilfeature.DefaultFeatureGate.Enabled(features.CSISkipAttach) {
+		return false, nil
+	}
+	if p.csiDriverLister == nil {
+		return false, errors.New("CSIDriver lister does not exist")
+	}
+	csiDriver, err := p.csiDriverLister.Get(driver)
+	if err != nil {
+		if apierrs.IsNotFound(err) {
+			// Don't skip attach if CSIDriver does not exist
+			return false, nil
+		}
+		return false, err
+	}
+	if csiDriver.Spec.AttachRequired != nil && *csiDriver.Spec.AttachRequired == false {
+		return true, nil
+	}
+	return false, nil
+}
+
+func (p *csiPlugin) getPublishVolumeInfo(client clientset.Interface, handle, driver, nodeName string) (map[string]string, error) {
+	skip, err := p.skipAttach(driver)
+	if err != nil {
+		return nil, err
+	}
+	if skip {
+		return nil, nil
+	}
+
+	attachID := getAttachmentName(handle, driver, nodeName)
+
+	// search for attachment by VolumeAttachment.Spec.Source.PersistentVolumeName
+	attachment, err := client.StorageV1beta1().VolumeAttachments().Get(attachID, meta.GetOptions{})
+	if err != nil {
+		return nil, err // This err already has enough context ("VolumeAttachment xyz not found")
+	}
+
+	if attachment == nil {
+		err = errors.New("no existing VolumeAttachment found")
+		return nil, err
+	}
+	return attachment.Status.AttachmentMetadata, nil
+}