Fix #59601: AWS: Check error code returned from describeVolume

The errors returned by the describeVolume call are not all equal:
if the error is of InvalidVolume.NotFound type it does not necessarily
mean the desired operation cannot be finished successfully.

Fixes #59601

pkg/cloudprovider/providers/aws/aws.go

@@ -1660,6 +1660,20 @@ func newAWSDisk(aws *Cloud, name KubernetesVolumeID) (*awsDisk, error) {
 	return disk, nil
 }
 
+// Helper function for describeVolume callers. Tries to retype given error to AWS error
+// and returns true in case the AWS error is "InvalidVolume.NotFound", false otherwise
+func isAWSErrorVolumeNotFound(err error) bool {
+	if err != nil {
+		if awsError, ok := err.(awserr.Error); ok {
+			// https://docs.aws.amazon.com/AWSEC2/latest/APIReference/errors-overview.html
+			if awsError.Code() == "InvalidVolume.NotFound" {
+				return true
+			}
+		}
+	}
+	return false
+}
+
 // Gets the full information about this volume from the EC2 API
 func (d *awsDisk) describeVolume() (*ec2.Volume, error) {
 	volumeID := d.awsID
@@ -1670,13 +1684,13 @@ func (d *awsDisk) describeVolume() (*ec2.Volume, error) {
 
 	volumes, err := d.ec2.DescribeVolumes(request)
 	if err != nil {
-		return nil, fmt.Errorf("error querying ec2 for volume %q: %q", volumeID, err)
+		return nil, err
 	}
 	if len(volumes) == 0 {
-		return nil, fmt.Errorf("no volumes found for volume %q", volumeID)
+		return nil, fmt.Errorf("no volumes found")
 	}
 	if len(volumes) > 1 {
-		return nil, fmt.Errorf("multiple volumes found for volume %q", volumeID)
+		return nil, fmt.Errorf("multiple volumes found")
 	}
 	return volumes[0], nil
 }
@@ -1780,12 +1794,29 @@ func (d *awsDisk) waitForAttachmentStatus(status string) (*ec2.VolumeAttachment,
 	err := wait.ExponentialBackoff(backoff, func() (bool, error) {
 		info, err := d.describeVolume()
 		if err != nil {
+			// The VolumeNotFound error is special -- we don't need to wait for it to repeat
+			if isAWSErrorVolumeNotFound(err) {
+				if status == "detached" {
+					// The disk doesn't exist, assume it's detached, log warning and stop waiting
+					glog.Warningf("Waiting for volume %q to be detached but the volume does not exist", d.awsID)
+					stateStr := "detached"
+					attachment = &ec2.VolumeAttachment{
+						State: &stateStr,
+					}
+					return true, nil
+				}
+				if status == "attached" {
+					// The disk doesn't exist, complain, give up waiting and report error
+					glog.Warningf("Waiting for volume %q to be attached but the volume does not exist", d.awsID)
+					return false, err
+				}
+			}
 			describeErrorCount++
 			if describeErrorCount > volumeAttachmentStatusConsecutiveErrorLimit {
 				// report the error
 				return false, err
 			} else {
-				glog.Warningf("Ignoring error from describe volume; will retry: %q", err)
+				glog.Warningf("Ignoring error from describe volume for volume %q; will retry: %q", d.awsID, err)
 				return false, nil
 			}
 		} else {
@@ -2013,7 +2044,13 @@ func (c *Cloud) AttachDisk(diskName KubernetesVolumeID, nodeName types.NodeName,
 func (c *Cloud) DetachDisk(diskName KubernetesVolumeID, nodeName types.NodeName) (string, error) {
 	diskInfo, attached, err := c.checkIfAttachedToNode(diskName, nodeName)
 	if err != nil {
-		return "", err
+		if isAWSErrorVolumeNotFound(err) {
+			// Someone deleted the volume being detached; complain, but do nothing else and return success
+			glog.Warningf("DetachDisk %s called for node %s but volume does not exist; assuming the volume is detached", diskName, nodeName)
+			return "", nil
+		} else {
+			return "", err
+		}
 	}
 
 	if !attached && diskInfo.ec2Instance != nil {
@@ -2308,9 +2345,15 @@ func (c *Cloud) GetDiskPath(volumeName KubernetesVolumeID) (string, error) {
 
 // DiskIsAttached implements Volumes.DiskIsAttached
 func (c *Cloud) DiskIsAttached(diskName KubernetesVolumeID, nodeName types.NodeName) (bool, error) {
-	diskInfo, attached, err := c.checkIfAttachedToNode(diskName, nodeName)
-	if diskInfo == nil {
-		return true, err
+	_, attached, err := c.checkIfAttachedToNode(diskName, nodeName)
+	if err != nil {
+		if isAWSErrorVolumeNotFound(err) {
+			// The disk doesn't exist, can't be attached
+			glog.Warningf("DiskIsAttached called for volume %s on node %s but the volume does not exist", diskName, nodeName)
+			return false, nil
+		} else {
+			return true, err
+		}
 	}
 
 	return attached, nil

pkg/cloudprovider/providers/aws/volumes.go

@@ -119,10 +119,9 @@ func (c *Cloud) checkIfAttachedToNode(diskName KubernetesVolumeID, nodeName type
 	info, err := disk.describeVolume()
 
 	if err != nil {
-		describeError := fmt.Errorf("Error describing volume %s with %v", diskName, err)
-		glog.Warning(describeError)
+		glog.Warning("Error describing volume %s with %v", diskName, err)
 		awsDiskInfo.volumeState = "unknown"
-		return awsDiskInfo, false, describeError
+		return awsDiskInfo, false, err
 	}
 
 	awsDiskInfo.volumeState = aws.StringValue(info.State)