Allow 39 atached EBS devices.

pkg/cloudprovider/providers/aws/aws.go

@@ -80,6 +80,11 @@ const MaxReadThenCreateRetries = 30
 // need hardcoded defaults.
 const DefaultVolumeType = "gp2"
 
+// Amazon recommends having no more that 40 volumes attached to an instance,
+// and at least one of those is for the system root volume.
+// See http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/volume_limits.html#linux-specific-volume-limits
+const DefaultMaxEBSVolumes = 39
+
 // Used to call aws_credentials.Init() just once
 var once sync.Once
 
@@ -902,10 +907,17 @@ type mountDevice string
 // TODO: Also return number of mounts allowed?
 func (self *awsInstanceType) getEBSMountDevices() []mountDevice {
 	// See: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/block-device-mapping-concepts.html
+	// We will generate "ba", "bb", "bc"..."bz", "ca", ..., up to DefaultMaxEBSVolumes
 	devices := []mountDevice{}
-	for c := 'f'; c <= 'p'; c++ {
-		devices = append(devices, mountDevice(fmt.Sprintf("%c", c)))
+	count := 0
+	for first := 'b'; count < DefaultMaxEBSVolumes; first++ {
+		for second := 'a'; count < DefaultMaxEBSVolumes && second <= 'z'; second++ {
+			device := mountDevice(fmt.Sprintf("%c%c", first, second))
+			devices = append(devices, device)
+			count++
+		}
 	}
+
 	return devices
 }
 
@@ -1014,7 +1026,7 @@ func (self *awsInstance) getMountDevice(volumeID string, assign bool) (assigned
 		if strings.HasPrefix(name, "/dev/xvd") {
 			name = name[8:]
 		}
-		if len(name) != 1 {
+		if len(name) < 1 || len(name) > 2 {
 			glog.Warningf("Unexpected EBS DeviceName: %q", aws.StringValue(blockDevice.DeviceName))
 		}
 		deviceMappings[mountDevice(name)] = aws.StringValue(blockDevice.Ebs.VolumeId)
@@ -1051,7 +1063,7 @@ func (self *awsInstance) getMountDevice(volumeID string, assign bool) (assigned
 
 	if chosen == "" {
 		glog.Warningf("Could not assign a mount device (all in use?).  mappings=%v, valid=%v", deviceMappings, valid)
-		return "", false, nil
+		return "", false, fmt.Errorf("Too many EBS volumes attached to node %s.", self.nodeName)
 	}
 
 	self.attaching[chosen] = volumeID

pkg/volume/aws_ebs/aws_util.go

@@ -170,6 +170,8 @@ func (util *AWSDiskUtil) CreateVolume(c *awsElasticBlockStoreProvisioner) (strin
 // Attaches the specified persistent disk device to node, verifies that it is attached, and retries if it fails.
 func attachDiskAndVerify(b *awsElasticBlockStoreBuilder, xvdBeforeSet sets.String) (string, error) {
 	var awsCloud *aws.AWSCloud
+	var attachError error
+
 	for numRetries := 0; numRetries < maxRetries; numRetries++ {
 		var err error
 		if awsCloud == nil {
@@ -186,9 +188,10 @@ func attachDiskAndVerify(b *awsElasticBlockStoreBuilder, xvdBeforeSet sets.Strin
 			glog.Warningf("Retrying attach for EBS Disk %q (retry count=%v).", b.volumeID, numRetries)
 		}
 
-		devicePath, err := awsCloud.AttachDisk(b.volumeID, "", b.readOnly)
-		if err != nil {
-			glog.Errorf("Error attaching PD %q: %v", b.volumeID, err)
+		var devicePath string
+		devicePath, attachError = awsCloud.AttachDisk(b.volumeID, "", b.readOnly)
+		if attachError != nil {
+			glog.Errorf("Error attaching PD %q: %v", b.volumeID, attachError)
 			time.Sleep(errorSleepDuration)
 			continue
 		}
@@ -212,6 +215,9 @@ func attachDiskAndVerify(b *awsElasticBlockStoreBuilder, xvdBeforeSet sets.Strin
 		}
 	}
 
+	if attachError != nil {
+		return "", fmt.Errorf("Could not attach EBS Disk %q: %v", b.volumeID, attachError)
+	}
 	return "", fmt.Errorf("Could not attach EBS Disk %q. Timeout waiting for mount paths to be created.", b.volumeID)
 }
 

plugin/pkg/scheduler/algorithmprovider/defaults/defaults.go

@@ -21,6 +21,7 @@ import (
 	"os"
 	"strconv"
 
+	"k8s.io/kubernetes/pkg/cloudprovider/providers/aws"
 	"k8s.io/kubernetes/pkg/util/sets"
 	"k8s.io/kubernetes/plugin/pkg/scheduler"
 	"k8s.io/kubernetes/plugin/pkg/scheduler/algorithm"
@@ -31,10 +32,6 @@ import (
 	"github.com/golang/glog"
 )
 
-// Amazon recommends having no more that 40 volumes attached to an instance,
-// and at least one of those is for the system root volume.
-const DefaultMaxEBSVolumes = 39
-
 // GCE instances can have up to 16 PD volumes attached.
 const DefaultMaxGCEPDVolumes = 16
 
@@ -117,7 +114,7 @@ func defaultPredicates() sets.String {
 			"MaxEBSVolumeCount",
 			func(args factory.PluginFactoryArgs) algorithm.FitPredicate {
 				// TODO: allow for generically parameterized scheduler predicates, because this is a bit ugly
-				maxVols := getMaxVols(DefaultMaxEBSVolumes)
+				maxVols := getMaxVols(aws.DefaultMaxEBSVolumes)
 				return predicates.NewMaxPDVolumeCountPredicate(predicates.EBSVolumeFilter, maxVols, args.PVInfo, args.PVCInfo)
 			},
 		),