Update VerifyDevicePath logic to run udevadm --trigger to fix scenarios where disk is not found or is wrong device

Author: davidz627

Dockerfile

@@ -20,11 +20,15 @@ ADD . .
 ARG TAG
 RUN CGO_ENABLED=0 GOOS=linux go build -a -ldflags '-X main.vendorVersion='"${TAG:-latest}"' -extldflags "-static"' -o bin/gce-pd-csi-driver ./cmd/
 
+# MAD HACKS: Build a version first so we can take the scsi_id bin and put it somewhere else in our real build
+FROM gcr.io/google-containers/debian-base-amd64:v2.0.0 as base
+RUN clean-install udev
+
 # Start from Google Debian base
 FROM gcr.io/google-containers/debian-base-amd64:v2.0.0
 COPY --from=builder /go/src/sigs.k8s.io/gcp-compute-persistent-disk-csi-driver/bin/gce-pd-csi-driver /gce-pd-csi-driver
-
 # Install necessary dependencies
 RUN clean-install util-linux e2fsprogs mount ca-certificates udev xfsprogs
+COPY --from=base /lib/udev/scsi_id /lib/udev_containerized/scsi_id
 
 ENTRYPOINT ["/gce-pd-csi-driver"]

cmd/main.go

@@ -28,10 +28,6 @@ import (
 	mountmanager "sigs.k8s.io/gcp-compute-persistent-disk-csi-driver/pkg/mount-manager"
 )
 
-func init() {
-	flag.Set("logtostderr", "true")
-}
-
 var (
 	endpoint          = flag.String("endpoint", "unix:/tmp/csi.sock", "CSI endpoint")
 	gceConfigFilePath = flag.String("cloud-config", "", "Path to GCE cloud provider config")
@@ -49,6 +45,7 @@ func init() {
 	// Use V(5) for GCE Cloud Provider Call informational logging
 	// Use V(6) for extra repeated/polling information
 	klog.InitFlags(flag.CommandLine)
+	flag.Set("logtostderr", "true")
 }
 
 func main() {

pkg/gce-pd-csi-driver/node.go

@@ -528,7 +528,7 @@ func (ns *GCENodeServer) getDevicePath(volumeID string, partition string) (strin
 	}
 
 	devicePaths := ns.DeviceUtils.GetDiskByIdPaths(deviceName, partition)
-	devicePath, err := ns.DeviceUtils.VerifyDevicePath(devicePaths)
+	devicePath, err := ns.DeviceUtils.VerifyDevicePath(devicePaths, volumeKey.Name)
 
 	if err != nil {
 		return "", fmt.Errorf("error verifying GCE PD (%q) is attached: %v", volumeKey.Name, err)

pkg/mount-manager/device-utils.go

@@ -20,10 +20,13 @@ import (
 	"os/exec"
 	"path"
 	"path/filepath"
+	"regexp"
 	"strings"
+	"time"
 
-	"k8s.io/apimachinery/pkg/util/sets"
+	"k8s.io/apimachinery/pkg/util/wait"
 	"k8s.io/klog"
+	pathutils "k8s.io/utils/path"
 )
 
 const (
@@ -46,6 +49,14 @@ const (
 	// 'fsck' found errors but exited without correcting them
 	fsckErrorsUncorrected = 4
 	defaultMountCommand   = "mount"
+	// scsi_id output should be in the form of:
+	// 0Google PersistentDisk <disk name>
+	scsiPattern = `^0Google\s+PersistentDisk\s+([\S]+)\s*$`
+)
+
+var (
+	// regex to parse scsi_id output and extract the serial
+	scsiRegex = regexp.MustCompile(scsiPattern)
 )
 
 // DeviceUtils are a collection of methods that act on the devices attached
@@ -57,7 +68,7 @@ type DeviceUtils interface {
 
 	// VerifyDevicePath returns the first of the list of device paths that
 	// exists on the machine, or an empty string if none exists
-	VerifyDevicePath(devicePaths []string) (string, error)
+	VerifyDevicePath(devicePaths []string, diskName string) (string, error)
 }
 
 type deviceUtils struct {
@@ -85,74 +96,163 @@ func (m *deviceUtils) GetDiskByIdPaths(deviceName string, partition string) []st
 	return devicePaths
 }
 
-// Returns the first path that exists, or empty string if none exist.
-func (m *deviceUtils) VerifyDevicePath(devicePaths []string) (string, error) {
-	sdBefore, err := filepath.Glob(diskSDPattern)
-	if err != nil {
-		// Seeing this error means that the diskSDPattern is malformed.
-		klog.Errorf("Error filepath.Glob(\"%s\"): %v\r\n", diskSDPattern, err)
+func existingDevicePath(devicePaths []string) (string, error) {
+	for _, devicePath := range devicePaths {
+		if pathExists, err := pathExists(devicePath); err != nil {
+			return "", fmt.Errorf("error checking if path exists: %v", err)
+		} else if pathExists {
+			return devicePath, nil
+		}
 	}
-	sdBeforeSet := sets.NewString(sdBefore...)
-	// TODO(#69): Verify udevadm works as intended in driver
-	if err := udevadmChangeToNewDrives(sdBeforeSet); err != nil {
-		// udevadm errors should not block disk detachment, log and continue
-		klog.Errorf("udevadmChangeToNewDrives failed with: %v", err)
+	return "", nil
+}
+
+// getScsiSerial assumes that /lib/udev/scsi_id exists and will error if it
+// doesnt. It is the callers responsibility to verify the existence of this
+// tool. Calls scsi_id on the given devicePath to get the serial number reported
+// by that device.
+func getScsiSerial(devicePath string) (string, error) {
+	out, err := exec.Command(
+		"/lib/udev_containerized/scsi_id",
+		"--page=0x83",
+		"--whitelisted",
+		fmt.Sprintf("--device=%v", devicePath)).CombinedOutput()
+	if err != nil {
+		return "", fmt.Errorf("scsi_id failed for device %q with output %s: %v", devicePath, string(out), err)
 	}
 
-	for _, path := range devicePaths {
-		if pathExists, err := pathExists(path); err != nil {
-			return "", fmt.Errorf("Error checking if path exists: %v", err)
-		} else if pathExists {
-			return path, nil
-		}
+	return parseScsiSerial(string(out))
+}
+
+// Parse the output returned by scsi_id and extract the serial number
+func parseScsiSerial(output string) (string, error) {
+	substrings := scsiRegex.FindStringSubmatch(output)
+	if substrings == nil {
+		return "", fmt.Errorf("scsi_id output cannot be parsed: %q", output)
 	}
 
-	return "", nil
+	return substrings[1], nil
 }
 
-// Triggers the application of udev rules by calling "udevadm trigger
-// --action=change" for newly created "/dev/sd*" drives (exist only in
-// after set). This is workaround for Issue #7972. Once the underlying
-// issue has been resolved, this may be removed.
-func udevadmChangeToNewDrives(sdBeforeSet sets.String) error {
-	sdAfter, err := filepath.Glob(diskSDPattern)
+// VerifyDevicePath returns the first devicePath that maps to a real disk in the
+// candidate devicePaths or an empty string if none is found. If
+// /lib/udev_containerized/scsi_id exists it will attempt to fix any issues
+// caused by missing paths or mismatched devices by running a udevadm --trigger.
+func (m *deviceUtils) VerifyDevicePath(devicePaths []string, diskName string) (string, error) {
+	var devicePath string
+	var err error
+	const (
+		pollInterval = 500 * time.Millisecond
+		pollTimeout  = 3 * time.Second
+	)
+
+	scsiIDPath := "/lib/udev_containerized/scsi_id"
+	exists, err := pathutils.Exists(pathutils.CheckFollowSymlink, scsiIDPath)
 	if err != nil {
-		return fmt.Errorf("Error filepath.Glob(\"%s\"): %v\r\n", diskSDPattern, err)
+		return "", fmt.Errorf("failed to check scsi_id existence: %v", err)
+	}
+	if !exists {
+		// No SCSI ID tool, the driver should be containerized with the tool so
+		// maybe something is wrong with the build process
+		return "", fmt.Errorf("could not find scsi_id tool at %s, unable to verify device paths", scsiIDPath)
 	}
 
-	for _, sd := range sdAfter {
-		if !sdBeforeSet.Has(sd) {
-			return udevadmChangeToDrive(sd)
+	err = wait.Poll(pollInterval, pollTimeout, func() (bool, error) {
+		var innerErr error
+
+		devicePath, innerErr = existingDevicePath(devicePaths)
+		if innerErr != nil {
+			return false, fmt.Errorf("failed to check for existing device path: %v", innerErr)
+		}
+
+		if len(devicePath) == 0 {
+			// Couldn't find the path so we need to find a /dev/sdx with the SCSI
+			// serial that matches diskName. Then we run udevadm trigger on that
+			// device to get the device to show up in /dev/by-id/
+			innerErr := udevadmTriggerForDiskIfExists(diskName)
+			if innerErr != nil {
+				return false, fmt.Errorf("failed to trigger udevadm fix for disk %s: %v", diskName, innerErr)
+			}
+			// Go to next retry loop to get the deviceName again after
+			// potentially fixing it with the udev command
+			return false, nil
+		}
+
+		// If there exists a devicePath we make sure disk at /dev/sdx matches the
+		// expected disk at devicePath by matching SCSI Serial to the disk name
+		devSDX, innerErr := filepath.EvalSymlinks(devicePath)
+		if innerErr != nil {
+			return false, fmt.Errorf("filepath.EvalSymlinks(%q) failed with %v", devicePath, innerErr)
+		}
+		// Check to make sure device path maps to the correct disk
+		if strings.Contains(devSDX, diskSDPath) {
+			scsiSerial, innerErr := getScsiSerial(devSDX)
+			if innerErr != nil {
+				return false, fmt.Errorf("couldn't get SCSI serial number for disk %s: %v", diskName, innerErr)
+			}
+			// SUCCESS! devicePath points to a /dev/sdx that has a SCSI serial
+			// equivilant to our disk name
+			if scsiSerial == diskName {
+				return true, nil
+			}
 		}
+		// The devicePath is not mapped to the correct disk
+		innerErr = udevadmTriggerForDiskIfExists(diskName)
+		if innerErr != nil {
+			return false, fmt.Errorf("failed to trigger udevadm fix for disk %s: %v", diskName, innerErr)
+		}
+		// Go to next retry loop to get the deviceName again after
+		// potentially fixing it with the udev command
+		return false, nil
+	})
+
+	if err != nil {
+		return "", fmt.Errorf("failed to find and re-link disk %s with udevadm after retrying for %v: %v", diskName, pollTimeout, err)
 	}
 
-	return nil
+	return devicePath, nil
 }
 
-// Calls "udevadm trigger --action=change" on the specified drive.
-// drivePath must be the block device path to trigger on, in the format "/dev/sd*", or a symlink to it.
-// This is workaround for Issue #7972. Once the underlying issue has been resolved, this may be removed.
-func udevadmChangeToDrive(drivePath string) error {
-	klog.V(4).Infof("udevadmChangeToDrive: drive=%q", drivePath)
-
-	// Evaluate symlink, if any
-	drive, err := filepath.EvalSymlinks(drivePath)
+func udevadmTriggerForDiskIfExists(diskName string) error {
+	sds, err := filepath.Glob(diskSDPattern)
 	if err != nil {
-		return fmt.Errorf("udevadmChangeToDrive: filepath.EvalSymlinks(%q) failed with %v.", drivePath, err)
+		return fmt.Errorf("failed to filepath.Glob(\"%s\"): %v", diskSDPattern, err)
 	}
-	// Check to make sure input is "/dev/sd*"
-	if !strings.Contains(drive, diskSDPath) {
-		return fmt.Errorf("udevadmChangeToDrive: expected input in the form \"%s\" but drive is %q.", diskSDPattern, drive)
+	for _, devSDX := range sds {
+		scsiSerial, err := getScsiSerial(devSDX)
+		if err != nil {
+			return fmt.Errorf("failed to get SCSI Serial num for %s: %v", devSDX, err)
+		}
+		if scsiSerial == diskName {
+			// Found the disk that we're looking for so run a trigger on it
+			// to resolve its /dev/by-id/ path
+			klog.Warningf("udevadm --trigger running to fix disk at path %s which has SCSI ID %s", devSDX, scsiSerial)
+			err := udevadmChangeToDrive(devSDX)
+			if err != nil {
+				return fmt.Errorf("failed to fix disk at path %s which has SCSI ID %s: %v", devSDX, scsiSerial, err)
+			}
+			return nil
+		}
 	}
+	return fmt.Errorf("udevadm --trigger requested to fix disk %s but no such disk was found in %v", diskName, sds)
+}
 
+// Calls "udevadm trigger --action=change" on the specified drive. drivePath
+// must be the block device path to trigger on, in the format "/dev/sd*", or a
+// symlink to it. This is workaround for Issue #7972. Once the underlying issue
+// has been resolved, this may be removed.
+// udevadm takes a little bit to work its magic in the background so any callers
+// should not expect the trigger to complete instantly and may need to poll for
+// the change
+func udevadmChangeToDrive(devSDX string) error {
 	// Call "udevadm trigger --action=change --property-match=DEVNAME=/dev/sd..."
-	_, err = exec.Command(
+	out, err := exec.Command(
 		"udevadm",
 		"trigger",
 		"--action=change",
-		fmt.Sprintf("--property-match=DEVNAME=%s", drive)).CombinedOutput()
+		fmt.Sprintf("--property-match=DEVNAME=%s", devSDX)).CombinedOutput()
 	if err != nil {
-		return fmt.Errorf("udevadmChangeToDrive: udevadm trigger failed for drive %q with %v.", drive, err)
+		return fmt.Errorf("udevadmChangeToDrive: udevadm trigger failed for drive %q with output %s: %v.", devSDX, string(out), err)
 	}
 	return nil
 }

pkg/mount-manager/fake-device-utils.go

@@ -30,7 +30,7 @@ func (m *fakeDeviceUtils) GetDiskByIdPaths(pdName string, partition string) []st
 }
 
 // Returns the first path that exists, or empty string if none exist.
-func (m *fakeDeviceUtils) VerifyDevicePath(devicePaths []string) (string, error) {
+func (m *fakeDeviceUtils) VerifyDevicePath(devicePaths []string, diskName string) (string, error) {
 	// Return any random device path to use as mount source
 	return "/dev/disk/fake-path", nil
 }

test/e2e/tests/setup_e2e_test.go

@@ -89,6 +89,16 @@ var _ = BeforeSuite(func() {
 				klog.Fatalf("Failed to setup instance %v: %v", nodeID, err)
 			}
 
+			err = testutils.MkdirAll(i, "/lib/udev_containerized")
+			if err != nil {
+				klog.Fatalf("Could not make scsi_id containerized directory: %v", err)
+			}
+
+			err = testutils.CopyFile(i, "/lib/udev/scsi_id", "/lib/udev_containerized/scsi_id")
+			if err != nil {
+				klog.Fatalf("could not copy scsi_id to containerized directory: %v", err)
+			}
+
 			klog.Infof("Creating new driver and client for node %s\n", i.GetName())
 			// Create new driver and client
 			testContext, err := testutils.GCEClientAndDriverSetup(i)