Merge pull request #1337 from brendandburns/Sarsate-pd-support

Taking over PD support from sarsate

cluster/gce/config-default.sh

@@ -28,6 +28,6 @@ MASTER_TAG="${INSTANCE_PREFIX}-master"
 MINION_TAG="${INSTANCE_PREFIX}-minion"
 MINION_NAMES=($(eval echo ${INSTANCE_PREFIX}-minion-{1..${NUM_MINIONS}}))
 MINION_IP_RANGES=($(eval echo "10.244.{1..${NUM_MINIONS}}.0/24"))
-MINION_SCOPES=""
+MINION_SCOPES="compute-rw"
 # Increase the sleep interval value if concerned about API rate limits. 3, in seconds, is the default.
 POLL_SLEEP_INTERVAL=3

pkg/api/types.go

@@ -92,6 +92,9 @@ type VolumeSource struct {
 	HostDir *HostDir `yaml:"hostDir" json:"hostDir"`
 	// EmptyDir represents a temporary directory that shares a pod's lifetime.
 	EmptyDir *EmptyDir `yaml:"emptyDir" json:"emptyDir"`
+	// GCEPersistentDisk represents a GCE Disk resource that is attached to a
+	// kubelet's host machine and then exposed to the pod.
+	GCEPersistentDisk *GCEPersistentDisk `yaml:"persistentDisk" json:"persistentDisk"`
 }
 
 // HostDir represents bare host directory volume.
@@ -111,7 +114,28 @@ const (
 	ProtocolUDP Protocol = "UDP"
 )
 
-// Port represents a network port in a single container.
+// GCEPersistent Disk resource.
+// A GCE PD must exist and be formatted before mounting to a container.
+// The disk must also be in the same GCE project and zone as the kubelet.
+// A GCE PD can only be mounted as read/write once.
+type GCEPersistentDisk struct {
+	// Unique name of the PD resource. Used to identify the disk in GCE
+	PDName string `yaml:"pdName" json:"pdName"`
+	// Required: Filesystem type to mount.
+	// Must be a filesystem type supported by the host operating system.
+	// Ex. "ext4", "xfs", "ntfs"
+	// TODO: how do we prevent errors in the filesystem from compromising the machine
+	FSType string `yaml:"fsType,omitempty" json:"fsType,omitempty"`
+	// Optional: Partition on the disk to mount.
+	// If omitted, kubelet will attempt to mount the device name.
+	// Ex. For /dev/sda1, this field is "1", for /dev/sda, this field is 0 or empty.
+	Partition int `yaml:"partition,omitempty" json:"partition,omitempty"`
+	// Optional: Defaults to false (read/write). ReadOnly here will force
+	// the ReadOnly setting in VolumeMounts.
+	ReadOnly bool `yaml:"readOnly,omitempty" json:"readOnly,omitempty"`
+}
+
+// Port represents a network port in a single container
 type Port struct {
 	// Optional: If specified, this must be a DNS_LABEL.  Each named port
 	// in a pod must have a unique name.

pkg/api/v1beta1/types.go

@@ -90,6 +90,9 @@ type VolumeSource struct {
 	HostDir *HostDir `yaml:"hostDir" json:"hostDir"`
 	// EmptyDir represents a temporary directory that shares a pod's lifetime.
 	EmptyDir *EmptyDir `yaml:"emptyDir" json:"emptyDir"`
+	// GCEPersistentDisk represents a GCE Disk resource that is attached to a
+	// kubelet's host machine and then exposed to the pod.
+	GCEPersistentDisk *GCEPersistentDisk `yaml:"persistentDisk" json:"persistentDisk"`
 }
 
 // HostDir represents bare host directory volume.
@@ -109,7 +112,28 @@ const (
 	ProtocolUDP Protocol = "UDP"
 )
 
-// Port represents a network port in a single container.
+// GCEPersistent Disk resource.
+// A GCE PD must exist before mounting to a container. The disk must
+// also be in the same GCE project and zone as the kubelet.
+// A GCE PD can only be mounted as read/write once.
+type GCEPersistentDisk struct {
+	// Unique name of the PD resource. Used to identify the disk in GCE
+	PDName string `yaml:"pdName" json:"pdName"`
+	// Required: Filesystem type to mount.
+	// Must be a filesystem type supported by the host operating system.
+	// Ex. "ext4", "xfs", "ntfs"
+	// TODO: how do we prevent errors in the filesystem from compromising the machine
+	FSType string `yaml:"fsType,omitempty" json:"fsType,omitempty"`
+	// Optional: Partition on the disk to mount.
+	// If omitted, kubelet will attempt to mount the device name.
+	// Ex. For /dev/sda1, this field is "1", for /dev/sda, this field 0 or empty.
+	Partition int `yaml:"partition,omitempty" json:"partition,omitempty"`
+	// Optional: Defaults to false (read/write). ReadOnly here will force
+	// the ReadOnly setting in VolumeMounts.
+	ReadOnly bool `yaml:"readOnly,omitempty" json:"readOnly,omitempty"`
+}
+
+// Port represents a network port in a single container
 type Port struct {
 	// Optional: If specified, this must be a DNS_LABEL.  Each named port
 	// in a pod must have a unique name.

pkg/api/v1beta2/types.go

@@ -90,6 +90,9 @@ type VolumeSource struct {
 	HostDir *HostDir `yaml:"hostDir" json:"hostDir"`
 	// EmptyDir represents a temporary directory that shares a pod's lifetime.
 	EmptyDir *EmptyDir `yaml:"emptyDir" json:"emptyDir"`
+	// A persistent disk that is mounted to the
+	// kubelet's host machine and then exposed to the pod.
+	GCEPersistentDisk *GCEPersistentDisk `yaml:"persistentDisk" json:"persistentDisk"`
 }
 
 // HostDir represents bare host directory volume.
@@ -124,6 +127,27 @@ type Port struct {
 	HostIP string `yaml:"hostIP,omitempty" json:"hostIP,omitempty"`
 }
 
+// GCEPersistent Disk resource.
+// A GCE PD must exist before mounting to a container. The disk must
+// also be in the same GCE project and zone as the kubelet.
+// A GCE PD can only be mounted as read/write once.
+type GCEPersistentDisk struct {
+	// Unique name of the PD resource. Used to identify the disk in GCE
+	PDName string `yaml:"pdName" json:"pdName"`
+	// Required: Filesystem type to mount.
+	// Must be a filesystem type supported by the host operating system.
+	// Ex. "ext4", "xfs", "ntfs"
+	// TODO: how do we prevent errors in the filesystem from compromising the machine
+	FSType string `yaml:"fsType,omitempty" json:"fsType,omitempty"`
+	// Optional: Partition on the disk to mount.
+	// If omitted, kubelet will attempt to mount the device name.
+	// Ex. For /dev/sda1, this field is "1", for /dev/sda, this field 0 or empty.
+	Partition int `yaml:"partition,omitempty" json:"partition,omitempty"`
+	// Optional: Defaults to false (read/write). ReadOnly here will force
+	// the ReadOnly setting in VolumeMounts.
+	ReadOnly bool `yaml:"readOnly,omitempty" json:"readOnly,omitempty"`
+}
+
 // VolumeMount describes a mounting of a Volume within a container.
 type VolumeMount struct {
 	// Required: This must match the Name of a Volume [above].

pkg/api/v1beta3/types.go

@@ -175,6 +175,9 @@ type VolumeSource struct {
 	HostDir *HostDir `json:"hostDir" yaml:"hostDir"`
 	// EmptyDir represents a temporary directory that shares a pod's lifetime.
 	EmptyDir *EmptyDir `json:"emptyDir" yaml:"emptyDir"`
+	// GCEPersistentDisk represents a GCE Disk resource that is attached to a
+	// kubelet's host machine and then exposed to the pod.
+	GCEPersistentDisk *GCEPersistentDisk `yaml:"persistentDisk" json:"persistentDisk"`
 }
 
 // HostDir represents bare host directory volume.
@@ -194,6 +197,27 @@ const (
 	ProtocolUDP Protocol = "UDP"
 )
 
+// GCEPersistent Disk resource.
+// A GCE PD must exist and be formatted before mounting to a container.
+// The disk must also be in the same GCE project and zone as the kubelet.
+// A GCE PD can only be mounted as read/write once.
+type GCEPersistentDisk struct {
+	// Unique name of the PD resource. Used to identify the disk in GCE
+	PDName string `yaml:"pdName" json:"pdName"`
+	// Required: Filesystem type to mount.
+	// Must be a filesystem type supported by the host operating system.
+	// Ex. "ext4", "xfs", "ntfs"
+	// TODO: how do we prevent errors in the filesystem from compromising the machine
+	FSType string `yaml:"fsType,omitempty" json:"fsType,omitempty"`
+	// Optional: Partition on the disk to mount.
+	// If omitted, kubelet will attempt to mount the device name.
+	// Ex. For /dev/sda1, this field is "1", for /dev/sda, this field is 0 or empty.
+	Partition int `yaml:"partition,omitempty" json:"partition,omitempty"`
+	// Optional: Defaults to false (read/write). ReadOnly here will force
+	// the ReadOnly setting in VolumeMounts.
+	ReadOnly bool `yaml:"readOnly,omitempty" json:"readOnly,omitempty"`
+}
+
 // Port represents a network port in a single container.
 type Port struct {
 	// Optional: If specified, this must be a DNS_LABEL.  Each named port

pkg/api/validation/validation.go

@@ -64,6 +64,10 @@ func validateSource(source *api.VolumeSource) errs.ErrorList {
 		numVolumes++
 		//EmptyDirs have nothing to validate
 	}
+	if source.GCEPersistentDisk != nil {
+		numVolumes++
+		allErrs = append(allErrs, validateGCEPersistentDisk(source.GCEPersistentDisk)...)
+	}
 	if numVolumes != 1 {
 		allErrs = append(allErrs, errs.NewFieldInvalid("", source))
 	}
@@ -80,6 +84,20 @@ func validateHostDir(hostDir *api.HostDir) errs.ErrorList {
 
 var supportedPortProtocols = util.NewStringSet(string(api.ProtocolTCP), string(api.ProtocolUDP))
 
+func validateGCEPersistentDisk(PD *api.GCEPersistentDisk) errs.ErrorList {
+	allErrs := errs.ErrorList{}
+	if PD.PDName == "" {
+		allErrs = append(allErrs, errs.NewFieldInvalid("PD.PDName", PD.PDName))
+	}
+	if PD.FSType == "" {
+		allErrs = append(allErrs, errs.NewFieldInvalid("PD.FSType", PD.FSType))
+	}
+	if PD.Partition < 0 || PD.Partition > 255 {
+		allErrs = append(allErrs, errs.NewFieldInvalid("PD.Partition", PD.Partition))
+	}
+	return allErrs
+}
+
 func validatePorts(ports []api.Port) errs.ErrorList {
 	allErrs := errs.ErrorList{}
 
@@ -373,5 +391,17 @@ func ValidateReplicationControllerState(state *api.ReplicationControllerState) e
 		allErrs = append(allErrs, errs.NewFieldInvalid("replicas", state.Replicas))
 	}
 	allErrs = append(allErrs, ValidateManifest(&state.PodTemplate.DesiredState.Manifest).Prefix("podTemplate.desiredState.manifest")...)
+	allErrs = append(allErrs, ValidateReadOnlyPersistentDisks(state.PodTemplate.DesiredState.Manifest.Volumes).Prefix("podTemplate.desiredState.manifest")...)
+	return allErrs
+}
+func ValidateReadOnlyPersistentDisks(volumes []api.Volume) errs.ErrorList {
+	allErrs := errs.ErrorList{}
+	for _, vol := range volumes {
+		if vol.Source.GCEPersistentDisk != nil {
+			if vol.Source.GCEPersistentDisk.ReadOnly == false {
+				allErrs = append(allErrs, errs.NewFieldInvalid("GCEPersistentDisk.ReadOnly", false))
+			}
+		}
+	}
 	return allErrs
 }

pkg/api/validation/validation_test.go

@@ -40,12 +40,13 @@ func TestValidateVolumes(t *testing.T) {
 		{Name: "123", Source: &api.VolumeSource{HostDir: &api.HostDir{"/mnt/path2"}}},
 		{Name: "abc-123", Source: &api.VolumeSource{HostDir: &api.HostDir{"/mnt/path3"}}},
 		{Name: "empty", Source: &api.VolumeSource{EmptyDir: &api.EmptyDir{}}},
+		{Name: "gcepd", Source: &api.VolumeSource{GCEPersistentDisk: &api.GCEPersistentDisk{"my-PD", "ext4", 1, false}}},
 	}
 	names, errs := validateVolumes(successCase)
 	if len(errs) != 0 {
 		t.Errorf("expected success: %v", errs)
 	}
-	if len(names) != 4 || !names.HasAll("abc", "123", "abc-123", "empty") {
+	if len(names) != 5 || !names.HasAll("abc", "123", "abc-123", "empty", "gcepd") {
 		t.Errorf("wrong names result: %v", names)
 	}
 
@@ -552,7 +553,14 @@ func TestValidateReplicationController(t *testing.T) {
 		},
 		Labels: validSelector,
 	}
-
+	invalidVolumePodTemplate := api.PodTemplate{
+		DesiredState: api.PodState{
+			Manifest: api.ContainerManifest{
+				Version: "v1beta1",
+				Volumes: []api.Volume{{Name: "gcepd", Source: &api.VolumeSource{GCEPersistentDisk: &api.GCEPersistentDisk{"my-PD", "ext4", 1, false}}}},
+			},
+		},
+	}
 	successCases := []api.ReplicationController{
 		{
 			TypeMeta: api.TypeMeta{ID: "abc", Namespace: api.NamespaceDefault},
@@ -609,6 +617,13 @@ func TestValidateReplicationController(t *testing.T) {
 				ReplicaSelector: validSelector,
 			},
 		},
+		"read-write presistent disk": {
+			TypeMeta: api.TypeMeta{ID: "abc"},
+			DesiredState: api.ReplicationControllerState{
+				ReplicaSelector: validSelector,
+				PodTemplate:     invalidVolumePodTemplate,
+			},
+		},
 		"negative_replicas": {
 			TypeMeta: api.TypeMeta{ID: "abc", Namespace: api.NamespaceDefault},
 			DesiredState: api.ReplicationControllerState{
@@ -628,6 +643,7 @@ func TestValidateReplicationController(t *testing.T) {
 				field != "id" &&
 				field != "namespace" &&
 				field != "desiredState.replicaSelector" &&
+				field != "GCEPersistentDisk.ReadOnly" &&
 				field != "desiredState.replicas" {
 				t.Errorf("%s: missing prefix for: %v", k, errs[i])
 			}

pkg/cloudprovider/gce/gce.go

@@ -23,6 +23,7 @@ import (
 	"net"
 	"net/http"
 	"os/exec"
+	"path"
 	"strconv"
 	"strings"
 	"time"
@@ -41,43 +42,71 @@ type GCECloud struct {
 	service    *compute.Service
 	projectID  string
 	zone       string
-	instanceRE string
+	instanceID string
 }
 
 func init() {
 	cloudprovider.RegisterCloudProvider("gce", func(config io.Reader) (cloudprovider.Interface, error) { return newGCECloud() })
 }
 
-func getProjectAndZone() (string, string, error) {
+func getMetadata(url string) (string, error) {
 	client := http.Client{}
-	url := "http://metadata/computeMetadata/v1/instance/zone"
 	req, err := http.NewRequest("GET", url, nil)
 	if err != nil {
-		return "", "", err
+		return "", err
 	}
 	req.Header.Add("X-Google-Metadata-Request", "True")
 	res, err := client.Do(req)
 	if err != nil {
-		return "", "", err
+		return "", err
 	}
 	defer res.Body.Close()
 	data, err := ioutil.ReadAll(res.Body)
+	if err != nil {
+		return "", err
+	}
+	return string(data), nil
+}
+
+func getProjectAndZone() (string, string, error) {
+	url := "http://metadata/computeMetadata/v1/instance/zone"
+	result, err := getMetadata(url)
 	if err != nil {
 		return "", "", err
 	}
-	parts := strings.Split(string(data), "/")
+	parts := strings.Split(result, "/")
 	if len(parts) != 4 {
-		return "", "", fmt.Errorf("Unexpected response: %s", string(data))
+		return "", "", fmt.Errorf("Unexpected response: %s", result)
 	}
 	return parts[1], parts[3], nil
 }
 
+func getInstanceID() (string, error) {
+	url := "http://metadata/computeMetadata/v1/instance/hostname"
+	result, err := getMetadata(url)
+	if err != nil {
+		return "", err
+	}
+	parts := strings.Split(result, ".")
+	if len(parts) == 0 {
+		return "", fmt.Errorf("Unexpected response: %s", result)
+	}
+	return parts[0], nil
+}
+
 // newGCECloud creates a new instance of GCECloud.
 func newGCECloud() (*GCECloud, error) {
 	projectID, zone, err := getProjectAndZone()
 	if err != nil {
 		return nil, err
 	}
+	// TODO: if we want to use this on a machine that doesn't have the http://metadata server
+	// e.g. on a user's machine (not VM) somewhere, we need to have an alternative for
+	// instance id lookup.
+	instanceID, err := getInstanceID()
+	if err != nil {
+		return nil, err
+	}
 	client, err := serviceaccount.NewClient(&serviceaccount.Options{})
 	if err != nil {
 		return nil, err
@@ -87,9 +116,10 @@ func newGCECloud() (*GCECloud, error) {
 		return nil, err
 	}
 	return &GCECloud{
-		service:   svc,
-		projectID: projectID,
-		zone:      zone,
+		service:    svc,
+		projectID:  projectID,
+		zone:       zone,
+		instanceID: instanceID,
 	}, nil
 }
 
@@ -310,6 +340,29 @@ func (gce *GCECloud) GetZone() (cloudprovider.Zone, error) {
 	}, nil
 }
 
+func (gce *GCECloud) AttachDisk(diskName string, readOnly bool) error {
+	disk, err := gce.getDisk(diskName)
+	if err != nil {
+		return err
+	}
+	readWrite := "READ_WRITE"
+	if readOnly {
+		readWrite = "READ_ONLY"
+	}
+	attachedDisk := gce.convertDiskToAttachedDisk(disk, readWrite)
+	_, err = gce.service.Instances.AttachDisk(gce.projectID, gce.zone, gce.instanceID, attachedDisk).Do()
+	return err
+}
+
+func (gce *GCECloud) DetachDisk(devicePath string) error {
+	_, err := gce.service.Instances.DetachDisk(gce.projectID, gce.zone, gce.instanceID, devicePath).Do()
+	return err
+}
+
+func (gce *GCECloud) getDisk(diskName string) (*compute.Disk, error) {
+	return gce.service.Disks.Get(gce.projectID, gce.zone, diskName).Do()
+}
+
 // getGceRegion returns region of the gce zone. Zone names
 // are of the form: ${region-name}-${ix}.
 // For example "us-central1-b" has a region of "us-central1".
@@ -321,3 +374,14 @@ func getGceRegion(zone string) (string, error) {
 	}
 	return zone[:ix], nil
 }
+
+// Converts a Disk resource to an AttachedDisk resource.
+func (gce *GCECloud) convertDiskToAttachedDisk(disk *compute.Disk, readWrite string) *compute.AttachedDisk {
+	return &compute.AttachedDisk{
+		DeviceName: disk.Name,
+		Kind:       disk.Kind,
+		Mode:       readWrite,
+		Source:     "https://" + path.Join("www.googleapis.com/compute/v1/projects/", gce.projectID, "zones", gce.zone, "disks", disk.Name),
+		Type:       "PERSISTENT",
+	}
+}

pkg/volume/gce_util.go

@@ -0,0 +1,136 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package volume
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path"
+	"path/filepath"
+	"regexp"
+	"strings"
+	"time"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/cloudprovider"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/cloudprovider/gce"
+)
+
+const partitionRegex = "[a-z][a-z]*(?P<partition>[0-9][0-9]*)?"
+
+var regexMatcher = regexp.MustCompile(partitionRegex)
+
+type GCEDiskUtil struct{}
+
+// Attaches a disk specified by a volume.GCEPersistentDisk to the current kubelet.
+// Mounts the disk to it's global path.
+func (util *GCEDiskUtil) AttachDisk(GCEPD *GCEPersistentDisk) error {
+	gce, err := cloudprovider.GetCloudProvider("gce", nil)
+	if err != nil {
+		return err
+	}
+	flags := uintptr(0)
+	if GCEPD.ReadOnly {
+		flags = MOUNT_MS_RDONLY
+	}
+	if err := gce.(*gce_cloud.GCECloud).AttachDisk(GCEPD.PDName, GCEPD.ReadOnly); err != nil {
+		return err
+	}
+	devicePath := path.Join("/dev/disk/by-id/", "google-"+GCEPD.PDName)
+	if GCEPD.Partition != "" {
+		devicePath = devicePath + "-part" + GCEPD.Partition
+	}
+	//TODO(jonesdl) There should probably be better method than busy-waiting here.
+	numTries := 0
+	for {
+		_, err := os.Stat(devicePath)
+		if err == nil {
+			break
+		}
+		if err != nil && !os.IsNotExist(err) {
+			return err
+		}
+		numTries++
+		if numTries == 10 {
+			return errors.New("Could not attach disk: Timeout after 10s")
+		}
+		time.Sleep(time.Second)
+	}
+	globalPDPath := makeGlobalPDName(GCEPD.RootDir, GCEPD.PDName, GCEPD.ReadOnly)
+	// Only mount the PD globally once.
+	_, err = os.Stat(globalPDPath)
+	if os.IsNotExist(err) {
+		err = os.MkdirAll(globalPDPath, 0750)
+		if err != nil {
+			return err
+		}
+		err = GCEPD.mounter.Mount(devicePath, globalPDPath, GCEPD.FSType, flags, "")
+		if err != nil {
+			os.RemoveAll(globalPDPath)
+			return err
+		}
+	} else if err != nil {
+		return err
+	}
+	return nil
+}
+
+func getDeviceName(devicePath, canonicalDevicePath string) (string, error) {
+	isMatch := regexMatcher.MatchString(path.Base(canonicalDevicePath))
+	if !isMatch {
+		return "", fmt.Errorf("unexpected device: %s", canonicalDevicePath)
+	}
+	if isMatch {
+		result := make(map[string]string)
+		substrings := regexMatcher.FindStringSubmatch(path.Base(canonicalDevicePath))
+		for i, label := range regexMatcher.SubexpNames() {
+			result[label] = substrings[i]
+		}
+		partition := result["partition"]
+		devicePath = strings.TrimSuffix(devicePath, "-part"+partition)
+	}
+	return strings.TrimPrefix(path.Base(devicePath), "google-"), nil
+}
+
+// Unmounts the device and detaches the disk from the kubelet's host machine.
+// Expects a GCE device path symlink. Ex: /dev/disk/by-id/google-mydisk-part1
+func (util *GCEDiskUtil) DetachDisk(GCEPD *GCEPersistentDisk, devicePath string) error {
+	// Follow the symlink to the actual device path.
+	canonicalDevicePath, err := filepath.EvalSymlinks(devicePath)
+	if err != nil {
+		return err
+	}
+	deviceName, err := getDeviceName(devicePath, canonicalDevicePath)
+	if err != nil {
+		return err
+	}
+	globalPDPath := makeGlobalPDName(GCEPD.RootDir, deviceName, GCEPD.ReadOnly)
+	if err := GCEPD.mounter.Unmount(globalPDPath, 0); err != nil {
+		return err
+	}
+	if err := os.RemoveAll(globalPDPath); err != nil {
+		return err
+	}
+	gce, err := cloudprovider.GetCloudProvider("gce", nil)
+	if err != nil {
+		return err
+	}
+	if err := gce.(*gce_cloud.GCECloud).DetachDisk(deviceName); err != nil {
+		return err
+	}
+	return nil
+}

pkg/volume/gce_util_test.go

@@ -0,0 +1,55 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package volume
+
+import (
+	"testing"
+)
+
+func TestGetDeviceName(t *testing.T) {
+	tests := []struct {
+		deviceName    string
+		canonicalName string
+		expectedName  string
+		expectError   bool
+	}{
+		{
+			deviceName:    "/dev/google-sd0-part0",
+			canonicalName: "/dev/google/sd0P1",
+			expectedName:  "sd0",
+		},
+		{
+			canonicalName: "0123456",
+			expectError:   true,
+		},
+	}
+	for _, test := range tests {
+		name, err := getDeviceName(test.deviceName, test.canonicalName)
+		if test.expectError {
+			if err == nil {
+				t.Error("unexpected non-error")
+			}
+			continue
+		}
+		if err != nil {
+			t.Errorf("unexpected error: %v", err)
+		}
+		if name != test.expectedName {
+			t.Errorf("expected: %s, got %s", test.expectedName, name)
+		}
+	}
+}

pkg/volume/mounter_linux.go

@@ -0,0 +1,86 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package volume
+
+import (
+	"bufio"
+	"io"
+	"os"
+	"regexp"
+	"strings"
+	"syscall"
+)
+
+const MOUNT_MS_BIND = syscall.MS_BIND
+const MOUNT_MS_RDONLY = syscall.MS_RDONLY
+
+type DiskMounter struct{}
+
+// Wraps syscall.Mount()
+func (mounter *DiskMounter) Mount(source string, target string, fstype string, flags uintptr, data string) error {
+	return syscall.Mount(source, target, fstype, flags, data)
+}
+
+// Wraps syscall.Unmount()
+func (mounter *DiskMounter) Unmount(target string, flags int) error {
+	return syscall.Unmount(target, flags)
+}
+
+// Examines /proc/mounts to find the source device of the PD resource and the
+// number of references to that device. Returns both the full device path under
+// the /dev tree and the number of references.
+func (mounter *DiskMounter) RefCount(mount Interface) (string, int, error) {
+	// TODO(jonesdl) This can be split up into two procedures, finding the device path
+	// and finding the number of references. The parsing could also be separated and another
+	// utility could determine if a volume's path is an active mount point.
+	file, err := os.Open("/proc/mounts")
+	if err != nil {
+		return "", -1, err
+	}
+	defer file.Close()
+	scanner := bufio.NewReader(file)
+	refCount := 0
+	var deviceName string
+	// Find the actual device path.
+	for {
+		line, err := scanner.ReadString('\n')
+		if err == io.EOF {
+			break
+		}
+		success, err := regexp.MatchString(mount.GetPath(), line)
+		if err != nil {
+			return "", -1, err
+		}
+		if success {
+			deviceName = strings.Split(line, " ")[0]
+		}
+	}
+	file.Close()
+	file, err = os.Open("/proc/mounts")
+	scanner.Reset(bufio.NewReader(file))
+	// Find the number of references to the device.
+	for {
+		line, err := scanner.ReadString('\n')
+		if err == io.EOF {
+			break
+		}
+		if strings.Split(line, " ")[0] == deviceName {
+			refCount++
+		}
+	}
+	return deviceName, refCount, nil
+}

pkg/volume/mounter_unsupported.go

@@ -0,0 +1,36 @@
+// +build !linux
+
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package volume
+
+const MOUNT_MS_BIND = 0
+const MOUNT_MS_RDONLY = 0
+
+type DiskMounter struct{}
+
+func (mounter *DiskMounter) Mount(source string, target string, fstype string, flags uintptr, data string) error {
+	return nil
+}
+
+func (mounter *DiskMounter) Unmount(target string, flags int) error {
+	return nil
+}
+
+func (mounter *DiskMounter) RefCount(PD Interface) (string, int, error) {
+	return "", 0, nil
+}

pkg/volume/volume.go

@@ -21,6 +21,7 @@ import (
 	"io/ioutil"
 	"os"
 	"path"
+	"strconv"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 	"github.com/golang/glog"
@@ -49,6 +50,22 @@ type Cleaner interface {
 	TearDown() error
 }
 
+type gcePersistentDiskUtil interface {
+	// Attaches the disk to the kubelet's host machine.
+	AttachDisk(PD *GCEPersistentDisk) error
+	// Detaches the disk from the kubelet's host machine.
+	DetachDisk(PD *GCEPersistentDisk, devicePath string) error
+}
+
+// Mounters wrap os/system specific calls to perform mounts.
+type mounter interface {
+	Mount(source string, target string, fstype string, flags uintptr, data string) error
+	Unmount(target string, flags int) error
+	// RefCount returns the device path for the source disk of a volume, and
+	// the number of references to that target disk.
+	RefCount(vol Interface) (string, int, error)
+}
+
 // HostDir volumes represent a bare host directory mount.
 // The directory in Path will be directly exposed to the container.
 type HostDir struct {
@@ -118,11 +135,128 @@ func createHostDir(volume *api.Volume) *HostDir {
 	return &HostDir{volume.Source.HostDir.Path}
 }
 
+// GCEPersistentDisk volumes are disk resources provided by Google Compute Engine
+// that are attached to the kubelet's host machine and exposed to the pod.
+type GCEPersistentDisk struct {
+	Name    string
+	PodID   string
+	RootDir string
+	// Unique identifier of the PD, used to find the disk resource in the provider.
+	PDName string
+	// Filesystem type, optional.
+	FSType string
+	// Specifies the partition to mount
+	Partition string
+	// Specifies whether the disk will be attached as ReadOnly.
+	ReadOnly bool
+	// Utility interface that provides API calls to the provider to attach/detach disks.
+	util gcePersistentDiskUtil
+	// Mounter interface that provides system calls to mount the disks.
+	mounter mounter
+}
+
+func (PD *GCEPersistentDisk) GetPath() string {
+	return path.Join(PD.RootDir, PD.PodID, "volumes", "gce-pd", PD.Name)
+}
+
+// Attaches the disk and bind mounts to the volume path.
+func (PD *GCEPersistentDisk) SetUp() error {
+	// TODO: handle failed mounts here.
+	if _, err := os.Stat(PD.GetPath()); !os.IsNotExist(err) {
+		return nil
+	}
+	err := PD.util.AttachDisk(PD)
+	if err != nil {
+		return err
+	}
+	flags := uintptr(0)
+	if PD.ReadOnly {
+		flags = MOUNT_MS_RDONLY
+	}
+	//Perform a bind mount to the full path to allow duplicate mounts of the same PD.
+	if _, err = os.Stat(PD.GetPath()); os.IsNotExist(err) {
+		err = os.MkdirAll(PD.GetPath(), 0750)
+		if err != nil {
+			return err
+		}
+		globalPDPath := makeGlobalPDName(PD.RootDir, PD.PDName, PD.ReadOnly)
+		err = PD.mounter.Mount(globalPDPath, PD.GetPath(), "", MOUNT_MS_BIND|flags, "")
+		if err != nil {
+			os.RemoveAll(PD.GetPath())
+			return err
+		}
+	}
+	return nil
+}
+
+// Unmounts the bind mount, and detaches the disk only if the PD
+// resource was the last reference to that disk on the kubelet.
+func (PD *GCEPersistentDisk) TearDown() error {
+	devicePath, refCount, err := PD.mounter.RefCount(PD)
+	if err != nil {
+		return err
+	}
+	if err := PD.mounter.Unmount(PD.GetPath(), 0); err != nil {
+		return err
+	}
+	refCount--
+	if err := os.RemoveAll(PD.GetPath()); err != nil {
+		return err
+	}
+	if err != nil {
+		return err
+	}
+	// If refCount is 1, then all bind mounts have been removed, and the
+	// remaining reference is the global mount. It is safe to detach.
+	if refCount == 1 {
+		if err := PD.util.DetachDisk(PD, devicePath); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+//TODO(jonesdl) prevent name collisions by using designated pod space as well.
+// Ex. (ROOT_DIR)/pods/...
+func makeGlobalPDName(rootDir, devName string, readOnly bool) string {
+	var mode string
+	if readOnly {
+		mode = "ro"
+	} else {
+		mode = "rw"
+	}
+	return path.Join(rootDir, "global", "pd", mode, devName)
+}
+
 // createEmptyDir interprets API volume as an EmptyDir.
 func createEmptyDir(volume *api.Volume, podID string, rootDir string) *EmptyDir {
 	return &EmptyDir{volume.Name, podID, rootDir}
 }
 
+// Interprets API volume as a PersistentDisk
+func createGCEPersistentDisk(volume *api.Volume, podID string, rootDir string) (*GCEPersistentDisk, error) {
+	PDName := volume.Source.GCEPersistentDisk.PDName
+	FSType := volume.Source.GCEPersistentDisk.FSType
+	partition := strconv.Itoa(volume.Source.GCEPersistentDisk.Partition)
+	if partition == "0" {
+		partition = ""
+	}
+	readOnly := volume.Source.GCEPersistentDisk.ReadOnly
+	// TODO: move these up into the Kubelet.
+	util := &GCEDiskUtil{}
+	mounter := &DiskMounter{}
+	return &GCEPersistentDisk{
+		Name:      volume.Name,
+		PodID:     podID,
+		RootDir:   rootDir,
+		PDName:    PDName,
+		FSType:    FSType,
+		Partition: partition,
+		ReadOnly:  readOnly,
+		util:      util,
+		mounter:   mounter}, nil
+}
+
 // CreateVolumeBuilder returns a Builder capable of mounting a volume described by an
 // *api.Volume, or an error.
 func CreateVolumeBuilder(volume *api.Volume, podID string, rootDir string) (Builder, error) {
@@ -133,12 +267,18 @@ func CreateVolumeBuilder(volume *api.Volume, podID string, rootDir string) (Buil
 		return nil, nil
 	}
 	var vol Builder
+	var err error
 	// TODO(jonesdl) We should probably not check every pointer and directly
 	// resolve these types instead.
 	if source.HostDir != nil {
 		vol = createHostDir(volume)
 	} else if source.EmptyDir != nil {
 		vol = createEmptyDir(volume, podID, rootDir)
+	} else if source.GCEPersistentDisk != nil {
+		vol, err = createGCEPersistentDisk(volume, podID, rootDir)
+		if err != nil {
+			return nil, err
+		}
 	} else {
 		return nil, ErrUnsupportedVolumeType
 	}
@@ -150,6 +290,13 @@ func CreateVolumeCleaner(kind string, name string, podID string, rootDir string)
 	switch kind {
 	case "empty":
 		return &EmptyDir{name, podID, rootDir}, nil
+	case "gce-pd":
+		return &GCEPersistentDisk{
+			Name:    name,
+			PodID:   podID,
+			RootDir: rootDir,
+			util:    &GCEDiskUtil{},
+			mounter: &DiskMounter{}}, nil
 	default:
 		return nil, ErrUnsupportedVolumeType
 	}
@@ -159,10 +306,9 @@ func CreateVolumeCleaner(kind string, name string, podID string, rootDir string)
 // presently active and mounted. Returns a map of Cleaner types.
 func GetCurrentVolumes(rootDirectory string) map[string]Cleaner {
 	currentVolumes := make(map[string]Cleaner)
-	mountPath := rootDirectory
-	podIDDirs, err := ioutil.ReadDir(mountPath)
+	podIDDirs, err := ioutil.ReadDir(rootDirectory)
 	if err != nil {
-		glog.Errorf("Could not read directory: %s, (%s)", mountPath, err)
+		glog.Errorf("Could not read directory: %s, (%s)", rootDirectory, err)
 	}
 	// Volume information is extracted from the directory structure:
 	// (ROOT_DIR)/(POD_ID)/volumes/(VOLUME_KIND)/(VOLUME_NAME)
@@ -171,7 +317,10 @@ func GetCurrentVolumes(rootDirectory string) map[string]Cleaner {
 			continue
 		}
 		podID := podIDDir.Name()
-		podIDPath := path.Join(mountPath, podID, "volumes")
+		podIDPath := path.Join(rootDirectory, podID, "volumes")
+		if _, err := os.Stat(podIDPath); os.IsNotExist(err) {
+			continue
+		}
 		volumeKindDirs, err := ioutil.ReadDir(podIDPath)
 		if err != nil {
 			glog.Errorf("Could not read directory: %s, (%s)", podIDPath, err)
@@ -189,7 +338,7 @@ func GetCurrentVolumes(rootDirectory string) map[string]Cleaner {
 				// TODO(thockin) This should instead return a reference to an extant volume object
 				cleaner, err := CreateVolumeCleaner(volumeKind, volumeName, podID, rootDirectory)
 				if err != nil {
-					glog.Errorf("Could not create volume cleaner: %s, (%s)", volumeNameDirs, err)
+					glog.Errorf("Could not create volume cleaner: %s, (%s)", volumeNameDir.Name(), err)
 					continue
 				}
 				currentVolumes[identifier] = cleaner

pkg/volume/volume_test.go

@@ -20,22 +20,52 @@ import (
 	"io/ioutil"
 	"os"
 	"path"
+	"reflect"
 	"testing"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 )
 
-func TestCreateVolumeBuilders(t *testing.T) {
-	tempDir, err := ioutil.TempDir("", "CreateVolumes")
+type MockDiskUtil struct{}
+
+// TODO(jonesdl) To fully test this, we could create a loopback device
+// and mount that instead.
+func (util *MockDiskUtil) AttachDisk(PD *GCEPersistentDisk) error {
+	err := os.MkdirAll(path.Join(PD.RootDir, "global", "pd", PD.PDName), 0750)
 	if err != nil {
-		t.Errorf("Unexpected error: %v", err)
+		return err
 	}
-	defer os.RemoveAll(tempDir)
+	return nil
+}
+
+func (util *MockDiskUtil) DetachDisk(PD *GCEPersistentDisk, devicePath string) error {
+	err := os.RemoveAll(path.Join(PD.RootDir, "global", "pd", PD.PDName))
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+type MockMounter struct{}
+
+func (mounter *MockMounter) Mount(source string, target string, fstype string, flags uintptr, data string) error {
+	return nil
+}
+
+func (mounter *MockMounter) Unmount(target string, flags int) error {
+	return nil
+}
+
+func (mounter *MockMounter) RefCount(vol Interface) (string, int, error) {
+	return "", 0, nil
+}
+
+func TestCreateVolumeBuilders(t *testing.T) {
+	tempDir := "CreateVolumes"
 	createVolumesTests := []struct {
 		volume api.Volume
 		path   string
 		podID  string
-		kind   string
 	}{
 		{
 			api.Volume{
@@ -45,7 +75,6 @@ func TestCreateVolumeBuilders(t *testing.T) {
 				},
 			},
 			"/dir/path",
-			"my-id",
 			"",
 		},
 		{
@@ -57,9 +86,18 @@ func TestCreateVolumeBuilders(t *testing.T) {
 			},
 			path.Join(tempDir, "/my-id/volumes/empty/empty-dir"),
 			"my-id",
-			"empty",
 		},
-		{api.Volume{}, "", "", ""},
+		{
+			api.Volume{
+				Name: "gce-pd",
+				Source: &api.VolumeSource{
+					GCEPersistentDisk: &api.GCEPersistentDisk{"my-disk", "ext4", 0, false},
+				},
+			},
+			path.Join(tempDir, "/my-id/volumes/gce-pd/gce-pd"),
+			"my-id",
+		},
+		{api.Volume{}, "", ""},
 		{
 			api.Volume{
 				Name:   "empty-dir",
@@ -67,7 +105,6 @@ func TestCreateVolumeBuilders(t *testing.T) {
 			},
 			"",
 			"",
-			"",
 		},
 	}
 	for _, createVolumesTest := range createVolumesTests {
@@ -79,7 +116,7 @@ func TestCreateVolumeBuilders(t *testing.T) {
 			}
 			continue
 		}
-		if tt.volume.Source.HostDir == nil && tt.volume.Source.EmptyDir == nil {
+		if tt.volume.Source.HostDir == nil && tt.volume.Source.EmptyDir == nil && tt.volume.Source.GCEPersistentDisk == nil {
 			if err != ErrUnsupportedVolumeType {
 				t.Errorf("Unexpected error: %v", err)
 			}
@@ -88,22 +125,68 @@ func TestCreateVolumeBuilders(t *testing.T) {
 		if err != nil {
 			t.Errorf("Unexpected error: %v", err)
 		}
-		err = vb.SetUp()
-		if err != nil {
-			t.Errorf("Unexpected error: %v", err)
-		}
 		path := vb.GetPath()
 		if path != tt.path {
 			t.Errorf("Unexpected bind path. Expected %v, got %v", tt.path, path)
 		}
-		vc, err := CreateVolumeCleaner(tt.kind, tt.volume.Name, tt.podID, tempDir)
-		if tt.kind == "" {
-			if err != ErrUnsupportedVolumeType {
-				t.Errorf("Unexpected error: %v", err)
-			}
+	}
+}
+
+func TestCreateVolumeCleaners(t *testing.T) {
+	tempDir := "CreateVolumeCleaners"
+	createVolumeCleanerTests := []struct {
+		kind  string
+		name  string
+		podID string
+	}{
+		{"empty", "empty-vol", "my-id"},
+		{"", "", ""},
+		{"gce-pd", "gce-pd-vol", "my-id"},
+	}
+	for _, tt := range createVolumeCleanerTests {
+		vol, err := CreateVolumeCleaner(tt.kind, tt.name, tt.podID, tempDir)
+		if tt.kind == "" && err != nil && vol == nil {
 			continue
 		}
-		err = vc.TearDown()
+		if err != nil {
+			t.Errorf("Unexpected error occured: %s", err)
+		}
+		actualKind := reflect.TypeOf(vol).Elem().Name()
+		if tt.kind == "empty" && actualKind != "EmptyDir" {
+			t.Errorf("CreateVolumeCleaner returned invalid type. Expected EmptyDirectory, got %v, %v", tt.kind, actualKind)
+		}
+		if tt.kind == "gce-pd" && actualKind != "GCEPersistentDisk" {
+			t.Errorf("CreateVolumeCleaner returned invalid type. Expected PersistentDisk, got %v, %v", tt.kind, actualKind)
+		}
+	}
+}
+
+func TestSetUpAndTearDown(t *testing.T) {
+	tempDir, err := ioutil.TempDir("", "CreateVolumes")
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+	defer os.RemoveAll(tempDir)
+	fakeID := "my-id"
+	type VolumeTester interface {
+		Builder
+		Cleaner
+	}
+	volumes := []VolumeTester{
+		&EmptyDir{"empty", fakeID, tempDir},
+		&GCEPersistentDisk{"pd", fakeID, tempDir, "pd-disk", "ext4", "", false, &MockDiskUtil{}, &MockMounter{}},
+	}
+
+	for _, vol := range volumes {
+		err = vol.SetUp()
+		path := vol.GetPath()
+		if err != nil {
+			t.Errorf("Unexpected error: %v", err)
+		}
+		if _, err := os.Stat(path); os.IsNotExist(err) {
+			t.Errorf("SetUp() failed, volume path not created: %v", path)
+		}
+		err = vol.TearDown()
 		if err != nil {
 			t.Errorf("Unexpected error: %v", err)
 		}