implement glusterfs volume plugin

cmd/kubelet/app/plugins.go

@@ -28,6 +28,7 @@ import (
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/volume/empty_dir"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/volume/gce_pd"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/volume/git_repo"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/volume/glusterfs"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/volume/host_path"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/volume/iscsi"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/volume/nfs"
@@ -55,6 +56,8 @@ func ProbeVolumePlugins() []volume.VolumePlugin {
 	allPlugins = append(allPlugins, nfs.ProbeVolumePlugins()...)
 	allPlugins = append(allPlugins, secret.ProbeVolumePlugins()...)
 	allPlugins = append(allPlugins, iscsi.ProbeVolumePlugins()...)
+	allPlugins = append(allPlugins, glusterfs.ProbeVolumePlugins()...)
+
 	return allPlugins
 }
 

examples/examples_test.go

@@ -181,6 +181,9 @@ func TestExampleObjectSchemas(t *testing.T) {
 		"../examples/iscsi/v1beta3": {
 			"iscsi": &api.Pod{},
 		},
+		"../examples/glusterfs/v1beta3": {
+			"glusterfs": &api.Pod{},
+		},
 	}
 
 	for path, expected := range cases {

examples/glusterfs/README.md

+## Glusterfs
+
+[Glusterfs](http://www.gluster.org) is an open source scale-out filesystem. These examples provide information about how to allow containers use Glusterfs volumes.
+
+The example assumes that the Glusterfs client package is installed on all nodes.
+
+### Prerequisites
+
+Install Glusterfs client package on the Kubernetes hosts.
+
+### Create a POD
+
+The following *volume* spec illustrates a sample configuration.
+
+```js
+{
+     "name": "glusterfsvol",
+     "glusterfs": {
+        "endpoints": "glusterfs-cluster",
+        "path": "kube_vol",
+        "readOnly": true
+    }
+}
+```
+
+The parameters are explained as the followings. 
+
+- **endpoints** is endpoints name that represents a Gluster cluster configuration. *kubelet* is optimized to avoid mount storm, it will randomly pick one from the endpoints to mount. If this host is unresponsive, the next Gluster host in the endpoints is automatically selected. 
+- **path** is the Glusterfs volume name. 
+- **readOnly** is the boolean that sets the mountpoint readOnly or readWrite. 
+
+Detailed POD and Gluster cluster endpoints examples can be found at [v1beta3/](v1beta3/) and [endpoints/](endpoints/)
+
+```shell
+# create gluster cluster endpoints
+$ kubectl create -f examples/glusterfs/endpoints/glusterfs-endpoints.json
+# create a container using gluster volume
+$ kubectl create -f examples/glusterfs/v1beta3/glusterfs.json
+```
+Once that's up you can list the pods and endpoint in the cluster, to verify that the master is running:
+
+```shell
+$ kubectl get endpoints
+$ kubectl get pods
+```
+
+If you ssh to that machine, you can run `docker ps` to see the actual pod and `mount` to see if the Glusterfs volume is mounted.
\ No newline at end of file

examples/glusterfs/endpoints/glusterfs-endpoints.json

+{
+    "apiVersion": "v1beta1",
+    "id": "glusterfs-cluster",
+    "kind": "Endpoints",
+    "metadata": {
+        "name": "glusterfs-cluster"
+    },
+    "Endpoints": [
+        "10.16.154.81:0",
+        "10.16.154.82:0",
+        "10.16.154.83:0"
+    ]
+}
\ No newline at end of file

examples/glusterfs/v1beta3/glusterfs.json

+{
+    "apiVersion": "v1beta3",
+    "id": "glusterfs",
+    "kind": "Pod",
+    "metadata": {
+        "name": "glusterfs"
+    },
+    "spec": {
+        "containers": [
+            {
+                "name": "glusterfs",
+                "image": "kubernetes/pause",
+                "volumeMounts": [
+                    {
+                        "mountPath": "/mnt/glusterfs",
+                        "name": "glusterfsvol"
+                    }
+                ]
+            }
+        ],
+        "volumes": [
+            {
+                "name": "glusterfsvol",
+                "glusterfs": {
+                    "endpoints": "glusterfs-cluster",
+                    "path": "kube_vol",
+                    "readOnly": true
+                }
+            }
+        ]
+    }
+}
\ No newline at end of file

pkg/api/testing/fuzzer.go

@@ -174,6 +174,7 @@ func FuzzerFor(t *testing.T, version string, src rand.Source) *fuzz.Fuzzer {
 			// Exactly one of the fields should be set.
 			//FIXME: the fuzz can still end up nil.  What if fuzz allowed me to say that?
 			fuzzOneOf(c, &vs.HostPath, &vs.EmptyDir, &vs.GCEPersistentDisk, &vs.GitRepo, &vs.Secret, &vs.NFS, &vs.ISCSI)
+			fuzzOneOf(c, &vs.HostPath, &vs.EmptyDir, &vs.GCEPersistentDisk, &vs.GitRepo, &vs.Secret, &vs.NFS, &vs.ISCSI, &vs.Glusterfs)
 		},
 		func(d *api.DNSPolicy, c fuzz.Continue) {
 			policies := []api.DNSPolicy{api.DNSClusterFirst, api.DNSDefault}

pkg/api/types.go

@@ -198,6 +198,8 @@ type VolumeSource struct {
 	// ISCSIVolumeSource represents an ISCSI Disk resource that is attached to a
 	// kubelet's host machine and then exposed to the pod.
 	ISCSI *ISCSIVolumeSource `json:"iscsi"`
+	// Glusterfs represents a Glusterfs mount on the host that shares a pod's lifetime
+	Glusterfs *GlusterfsVolumeSource `json:"glusterfs"`
 }
 
 // Similar to VolumeSource but meant for the administrator who creates PVs.
@@ -210,6 +212,8 @@ type PersistentVolumeSource struct {
 	// This is useful for development and testing only.
 	// on-host storage is not supported in any way
 	HostPath *HostPathVolumeSource `json:"hostPath"`
+	// Glusterfs represents a Glusterfs volume that is attached to a host and exposed to the pod
+	Glusterfs *GlusterfsVolumeSource `json:"glusterfs"`
 }
 
 type PersistentVolume struct {
@@ -421,6 +425,19 @@ type NFSVolumeSource struct {
 	ReadOnly bool `json:"readOnly,omitempty"`
 }
 
+// GlusterfsVolumeSource represents a Glusterfs Mount that lasts the lifetime of a pod
+type GlusterfsVolumeSource struct {
+	// Required: EndpointsName is the endpoint name that details Glusterfs topology
+	EndpointsName string `json:"endpoints"`
+
+	// Required: Path is the Glusterfs volume path
+	Path string `json:"path"`
+
+	// Optional: Defaults to false (read/write). ReadOnly here will force
+	// the Glusterfs to be mounted with read-only permissions
+	ReadOnly bool `json:"readOnly,omitempty"`
+}
+
 // ContainerPort represents a network port in a single container
 type ContainerPort struct {
 	// Optional: If specified, this must be a DNS_LABEL.  Each named port

pkg/api/v1beta1/conversion.go

@@ -1179,6 +1179,9 @@ func init() {
 			if err := s.Convert(&in.NFS, &out.NFS, 0); err != nil {
 				return err
 			}
+			if err := s.Convert(&in.Glusterfs, &out.Glusterfs, 0); err != nil {
+				return err
+			}
 			return nil
 		},
 		func(in *VolumeSource, out *newer.VolumeSource, s conversion.Scope) error {
@@ -1203,6 +1206,9 @@ func init() {
 			if err := s.Convert(&in.NFS, &out.NFS, 0); err != nil {
 				return err
 			}
+			if err := s.Convert(&in.Glusterfs, &out.Glusterfs, 0); err != nil {
+				return err
+			}
 			return nil
 		},
 

pkg/api/v1beta1/types.go

@@ -114,6 +114,8 @@ type VolumeSource struct {
 	// ISCSI represents an ISCSI Disk resource that is attached to a
 	// kubelet's host machine and then exposed to the pod.
 	ISCSI *ISCSIVolumeSource `json:"iscsi" description:"iSCSI disk attached to host machine on demand"`
+	// Glusterfs represents a Glusterfs mount on the host that shares a pod's lifetime
+	Glusterfs *GlusterfsVolumeSource `json:"glusterfs" description:"Glusterfs volume that will be mounted on the host machine "`
 }
 
 // Similar to VolumeSource but meant for the administrator who creates PVs.
@@ -126,6 +128,8 @@ type PersistentVolumeSource struct {
 	// This is useful for development and testing only.
 	// on-host storage is not supported in any way.
 	HostPath *HostPathVolumeSource `json:"hostPath" description:"a HostPath provisioned by a developer or tester; for develment use only"`
+	// Glusterfs represents a Glusterfs volume that is attached to a host and exposed to the pod
+	Glusterfs *GlusterfsVolumeSource `json:"glusterfs" description:"Glusterfs volume resource provisioned by an admin"`
 }
 
 type PersistentVolume struct {
@@ -1493,3 +1497,16 @@ type SecretList struct {
 
 	Items []Secret `json:"items" description:"items is a list of secret objects"`
 }
+
+// GlusterfsVolumeSource represents a Glusterfs Mount that lasts the lifetime of a pod
+type GlusterfsVolumeSource struct {
+	// Required: EndpointsName is the endpoint name that details Glusterfs topology
+	EndpointsName string `json:"endpoints" description:"gluster hosts endpoints name"`
+
+	// Required: Path is the Glusterfs volume path
+	Path string `json:"path" description:"path to gluster volume"`
+
+	// Optional: Defaults to false (read/write). ReadOnly here will force
+	// the Glusterfs volume to be mounted with read-only permissions
+	ReadOnly bool `json:"readOnly,omitempty" description:"Glusterfs volume to be mounted with read-only permissions"`
+}

pkg/api/v1beta2/conversion.go

@@ -1106,6 +1106,9 @@ func init() {
 			if err := s.Convert(&in.NFS, &out.NFS, 0); err != nil {
 				return err
 			}
+			if err := s.Convert(&in.Glusterfs, &out.Glusterfs, 0); err != nil {
+				return err
+			}
 			return nil
 		},
 		func(in *VolumeSource, out *newer.VolumeSource, s conversion.Scope) error {
@@ -1130,6 +1133,9 @@ func init() {
 			if err := s.Convert(&in.NFS, &out.NFS, 0); err != nil {
 				return err
 			}
+			if err := s.Convert(&in.Glusterfs, &out.Glusterfs, 0); err != nil {
+				return err
+			}
 			return nil
 		},
 

pkg/api/v1beta2/types.go

@@ -83,6 +83,8 @@ type VolumeSource struct {
 	// ISCSI represents an ISCSI Disk resource that is attached to a
 	// kubelet's host machine and then exposed to the pod.
 	ISCSI *ISCSIVolumeSource `json:"iscsi" description:"iSCSI disk attached to host machine on demand"`
+	// Glusterfs represents a Glusterfs mount on the host that shares a pod's lifetime
+	Glusterfs *GlusterfsVolumeSource `json:"glusterfs" description:"Glusterfs volume that will be mounted on the host machine "`
 }
 
 // Similar to VolumeSource but meant for the administrator who creates PVs.
@@ -95,6 +97,8 @@ type PersistentVolumeSource struct {
 	// This is useful for development and testing only.
 	// on-host storage is not supported in any way.
 	HostPath *HostPathVolumeSource `json:"hostPath" description:"a HostPath provisioned by a developer or tester; for develment use only"`
+	// Glusterfs represents a Glusterfs volume that is attached to a host and exposed to the pod
+	Glusterfs *GlusterfsVolumeSource `json:"glusterfs" description:"Glusterfs volume resource provisioned by an admin"`
 }
 
 type PersistentVolume struct {
@@ -307,6 +311,19 @@ type ISCSIVolumeSource struct {
 	ReadOnly bool `json:"readOnly,omitempty" description:"read-only if true, read-write otherwise (false or unspecified)"`
 }
 
+// GlusterfsVolumeSource represents a Glusterfs Mount that lasts the lifetime of a pod
+type GlusterfsVolumeSource struct {
+	// Required: EndpointsName is the endpoint name that details Glusterfs topology
+	EndpointsName string `json:"endpoints" description:"gluster hosts endpoints name"`
+
+	// Required: Path is the Glusterfs volume path
+	Path string `json:"path" description:"path to gluster volume"`
+
+	// Optional: Defaults to false (read/write). ReadOnly here will force
+	// the Glusterfs volume to be mounted with read-only permissions
+	ReadOnly bool `json:"readOnly,omitempty" description:"glusterfs volume to be mounted with read-only permissions"`
+}
+
 // VolumeMount describes a mounting of a Volume within a container.
 //
 // https://github.com/GoogleCloudPlatform/kubernetes/blob/master/docs/volumes.md

pkg/api/v1beta3/types.go

@@ -215,6 +215,8 @@ type VolumeSource struct {
 	// ISCSI represents an ISCSI Disk resource that is attached to a
 	// kubelet's host machine and then exposed to the pod.
 	ISCSI *ISCSIVolumeSource `json:"iscsi" description:"iSCSI disk attached to host machine on demand"`
+	// Glusterfs represents a Glusterfs mount on the host that shares a pod's lifetime
+	Glusterfs *GlusterfsVolumeSource `json:"glusterfs" description:"Glusterfs volume that will be mounted on the host machine "`
 }
 
 // Similar to VolumeSource but meant for the administrator who creates PVs.
@@ -227,6 +229,8 @@ type PersistentVolumeSource struct {
 	// This is useful for development and testing only.
 	// on-host storage is not supported in any way.
 	HostPath *HostPathVolumeSource `json:"hostPath" description:"a HostPath provisioned by a developer or tester; for develment use only"`
+	// Glusterfs represents a Glusterfs volume that is attached to a host and exposed to the pod
+	Glusterfs *GlusterfsVolumeSource `json:"glusterfs" description:"Glusterfs volume resource provisioned by an admin"`
 }
 
 type PersistentVolume struct {
@@ -343,6 +347,19 @@ type EmptyDirVolumeSource struct {
 	Medium StorageType `json:"medium" description:"type of storage used to back the volume; must be an empty string (default) or Memory"`
 }
 
+// GlusterfsVolumeSource represents a Glusterfs Mount that lasts the lifetime of a pod
+type GlusterfsVolumeSource struct {
+	// Required: EndpointsName is the endpoint name that details Glusterfs topology
+	EndpointsName string `json:"endpoints" description:"gluster hosts endpoints name"`
+
+	// Required: Path is the Glusterfs volume path
+	Path string `json:"path" description:"path to gluster volume"`
+
+	// Optional: Defaults to false (read/write). ReadOnly here will force
+	// the Glusterfs volume to be mounted with read-only permissions
+	ReadOnly bool `json:"readOnly,omitempty" description:"glusterfs volume to be mounted with read-only permissions"`
+}
+
 // StorageType defines ways that storage can be allocated to a volume.
 type StorageType string
 

pkg/api/validation/validation.go

@@ -311,6 +311,10 @@ func validateSource(source *api.VolumeSource) errs.ValidationErrorList {
 		numVolumes++
 		allErrs = append(allErrs, validateISCSIVolumeSource(source.ISCSI).Prefix("iscsi")...)
 	}
+	if source.Glusterfs != nil {
+		numVolumes++
+		allErrs = append(allErrs, validateGlusterfs(source.Glusterfs).Prefix("glusterfs")...)
+	}
 	if numVolumes != 1 {
 		allErrs = append(allErrs, errs.NewFieldInvalid("", source, "exactly 1 volume type is required"))
 	}
@@ -386,6 +390,17 @@ func validateNFS(nfs *api.NFSVolumeSource) errs.ValidationErrorList {
 	return allErrs
 }
 
+func validateGlusterfs(glusterfs *api.GlusterfsVolumeSource) errs.ValidationErrorList {
+	allErrs := errs.ValidationErrorList{}
+	if glusterfs.EndpointsName == "" {
+		allErrs = append(allErrs, errs.NewFieldRequired("endpoints"))
+	}
+	if glusterfs.Path == "" {
+		allErrs = append(allErrs, errs.NewFieldRequired("path"))
+	}
+	return allErrs
+}
+
 func ValidatePersistentVolumeName(name string, prefix bool) (bool, string) {
 	return nameIsDNSSubdomain(name, prefix)
 }

pkg/api/validation/validation_test.go

@@ -519,6 +519,7 @@ func TestValidateVolumes(t *testing.T) {
 		{Name: "gitrepo", VolumeSource: api.VolumeSource{GitRepo: &api.GitRepoVolumeSource{"my-repo", "hashstring"}}},
 		{Name: "iscsidisk", VolumeSource: api.VolumeSource{ISCSI: &api.ISCSIVolumeSource{"127.0.0.1", "iqn.2015-02.example.com:test", 1, "ext4", false}}},
 		{Name: "secret", VolumeSource: api.VolumeSource{Secret: &api.SecretVolumeSource{"my-secret"}}},
+		{Name: "glusterfs", VolumeSource: api.VolumeSource{Glusterfs: &api.GlusterfsVolumeSource{"host1", "path", false}}},
 	}
 	names, errs := validateVolumes(successCase)
 	if len(errs) != 0 {
@@ -530,6 +531,8 @@ func TestValidateVolumes(t *testing.T) {
 	emptyVS := api.VolumeSource{EmptyDir: &api.EmptyDirVolumeSource{}}
 	emptyPortal := api.VolumeSource{ISCSI: &api.ISCSIVolumeSource{"", "iqn.2015-02.example.com:test", 1, "ext4", false}}
 	emptyIQN := api.VolumeSource{ISCSI: &api.ISCSIVolumeSource{"127.0.0.1", "", 1, "ext4", false}}
+	emptyHosts := api.VolumeSource{Glusterfs: &api.GlusterfsVolumeSource{"", "path", false}}
+	emptyPath := api.VolumeSource{Glusterfs: &api.GlusterfsVolumeSource{"host", "", false}}
 	errorCases := map[string]struct {
 		V []api.Volume
 		T errors.ValidationErrorType
@@ -541,6 +544,8 @@ func TestValidateVolumes(t *testing.T) {
 		"name not unique":      {[]api.Volume{{Name: "abc", VolumeSource: emptyVS}, {Name: "abc", VolumeSource: emptyVS}}, errors.ValidationErrorTypeDuplicate, "[1].name"},
 		"empty portal":         {[]api.Volume{{Name: "badportal", VolumeSource: emptyPortal}}, errors.ValidationErrorTypeRequired, "[0].source.iscsi.targetPortal"},
 		"empty iqn":            {[]api.Volume{{Name: "badiqn", VolumeSource: emptyIQN}}, errors.ValidationErrorTypeRequired, "[0].source.iscsi.iqn"},
+		"empty hosts":          {[]api.Volume{{Name: "badhost", VolumeSource: emptyHosts}}, errors.ValidationErrorTypeRequired, "[0].source.glusterfs.endpoints"},
+		"empty path":           {[]api.Volume{{Name: "badpath", VolumeSource: emptyPath}}, errors.ValidationErrorTypeRequired, "[0].source.glusterfs.path"},
 	}
 	for k, v := range errorCases {
 		_, errs := validateVolumes(v.V)

pkg/volume/glusterfs/glusterfs.go

+/*
+Copyright 2015 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 glusterfs
+
+import (
+	"math/rand"
+	"os"
+	"strings"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/types"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util/exec"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util/mount"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/volume"
+	"github.com/golang/glog"
+)
+
+// This is the primary entrypoint for volume plugins.
+func ProbeVolumePlugins() []volume.VolumePlugin {
+	return []volume.VolumePlugin{&glusterfsPlugin{nil}}
+}
+
+type glusterfsPlugin struct {
+	host volume.VolumeHost
+}
+
+var _ volume.VolumePlugin = &glusterfsPlugin{}
+
+const (
+	glusterfsPluginName = "kubernetes.io/glusterfs"
+)
+
+func (plugin *glusterfsPlugin) Init(host volume.VolumeHost) {
+	plugin.host = host
+}
+
+func (plugin *glusterfsPlugin) Name() string {
+	return glusterfsPluginName
+}
+
+func (plugin *glusterfsPlugin) CanSupport(spec *api.Volume) bool {
+	if spec.VolumeSource.Glusterfs != nil {
+		return true
+	}
+	return false
+}
+
+func (plugin *glusterfsPlugin) GetAccessModes() []api.AccessModeType {
+	return []api.AccessModeType{
+		api.ReadWriteOnce,
+		api.ReadOnlyMany,
+		api.ReadWriteMany,
+	}
+}
+
+func (plugin *glusterfsPlugin) NewBuilder(spec *api.Volume, podRef *api.ObjectReference) (volume.Builder, error) {
+	ep_name := spec.VolumeSource.Glusterfs.EndpointsName
+	ns := api.NamespaceDefault
+	ep, err := plugin.host.GetKubeClient().Endpoints(ns).Get(ep_name)
+	if err != nil {
+		glog.Errorf("Glusterfs: failed to get endpoints %s[%v]", ep_name, err)
+		return nil, err
+	}
+	glog.V(1).Infof("Glusterfs: endpoints %v", ep)
+	return plugin.newBuilderInternal(spec, ep, podRef, mount.New(), exec.New())
+}
+
+func (plugin *glusterfsPlugin) newBuilderInternal(spec *api.Volume, ep *api.Endpoints, podRef *api.ObjectReference, mounter mount.Interface, exe exec.Interface) (volume.Builder, error) {
+	return &glusterfs{
+		volName:  spec.Name,
+		hosts:    ep,
+		path:     spec.VolumeSource.Glusterfs.Path,
+		readonly: spec.VolumeSource.Glusterfs.ReadOnly,
+		mounter:  mounter,
+		exe:      exe,
+		podRef:   podRef,
+		plugin:   plugin,
+	}, nil
+}
+
+func (plugin *glusterfsPlugin) NewCleaner(volName string, podUID types.UID) (volume.Cleaner, error) {
+	return plugin.newCleanerInternal(volName, podUID, mount.New())
+}
+
+func (plugin *glusterfsPlugin) newCleanerInternal(volName string, podUID types.UID, mounter mount.Interface) (volume.Cleaner, error) {
+	return &glusterfs{
+		volName: volName,
+		mounter: mounter,
+		podRef:  &api.ObjectReference{UID: podUID},
+		plugin:  plugin,
+	}, nil
+}
+
+// Glusterfs volumes represent a bare host file or directory mount of an Glusterfs export.
+type glusterfs struct {
+	volName  string
+	podRef   *api.ObjectReference
+	hosts    *api.Endpoints
+	path     string
+	readonly bool
+	mounter  mount.Interface
+	exe      exec.Interface
+	plugin   *glusterfsPlugin
+}
+
+// SetUp attaches the disk and bind mounts to the volume path.
+func (glusterfsVolume *glusterfs) SetUp() error {
+	return glusterfsVolume.SetUpAt(glusterfsVolume.GetPath())
+}
+
+func (glusterfsVolume *glusterfs) SetUpAt(dir string) error {
+	mountpoint, err := glusterfsVolume.mounter.IsMountPoint(dir)
+	glog.V(4).Infof("Glusterfs: mount set up: %s %v %v", dir, mountpoint, err)
+	if err != nil && !os.IsNotExist(err) {
+		return err
+	}
+	if mountpoint {
+		return nil
+	}
+	path := glusterfsVolume.path
+	os.MkdirAll(dir, 0750)
+	err = glusterfsVolume.execMount(glusterfsVolume.hosts, path, dir, glusterfsVolume.readonly)
+	if err == nil {
+		return nil
+	}
+
+	// cleanup upon failure
+	glusterfsVolume.cleanup(dir)
+	// return error
+	return err
+}
+
+func (glusterfsVolume *glusterfs) GetPath() string {
+	name := glusterfsPluginName
+	return glusterfsVolume.plugin.host.GetPodVolumeDir(glusterfsVolume.podRef.UID, util.EscapeQualifiedNameForDisk(name), glusterfsVolume.volName)
+}
+
+func (glusterfsVolume *glusterfs) TearDown() error {
+	return glusterfsVolume.TearDownAt(glusterfsVolume.GetPath())
+}
+
+func (glusterfsVolume *glusterfs) TearDownAt(dir string) error {
+	return glusterfsVolume.cleanup(dir)
+}
+
+func (glusterfsVolume *glusterfs) cleanup(dir string) error {
+	mountpoint, err := glusterfsVolume.mounter.IsMountPoint(dir)
+	if err != nil {
+		glog.Errorf("Glusterfs: Error checking IsMountPoint: %v", err)
+		return err
+	}
+	if !mountpoint {
+		return os.RemoveAll(dir)
+	}
+
+	if err := glusterfsVolume.mounter.Unmount(dir, 0); err != nil {
+		glog.Errorf("Glusterfs: Unmounting failed: %v", err)
+		return err
+	}
+	mountpoint, mntErr := glusterfsVolume.mounter.IsMountPoint(dir)
+	if mntErr != nil {
+		glog.Errorf("Glusterfs: IsMountpoint check failed: %v", mntErr)
+		return mntErr
+	}
+	if !mountpoint {
+		if err := os.RemoveAll(dir); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (glusterfsVolume *glusterfs) execMount(hosts *api.Endpoints, path string, mountpoint string, readonly bool) error {
+	var errs error
+	var command exec.Cmd
+	var mountArgs []string
+	var opt []string
+
+	// build option array
+	if readonly == true {
+		opt = []string{"-o", "ro"}
+	} else {
+		opt = []string{"-o", "rw"}
+	}
+
+	l := len(hosts.Subsets)
+	// avoid mount storm, pick a host randomly
+	start := rand.Int() % l
+	// iterate all hosts until mount succeeds.
+	for i := start; i < start+l; i++ {
+		arg := []string{"-t", "glusterfs", hosts.Subsets[i%l].Addresses[0].IP + ":" + path, mountpoint}
+		mountArgs = append(arg, opt...)
+		glog.V(1).Infof("Glusterfs: mount cmd: mount %v", strings.Join(mountArgs, " "))
+		command = glusterfsVolume.exe.Command("mount", mountArgs...)
+
+		_, errs = command.CombinedOutput()
+		if errs == nil {
+			return nil
+		}
+	}
+	glog.Errorf("Glusterfs: mount failed: %v", errs)
+	return errs
+}

pkg/volume/glusterfs/glusterfs_test.go

+/*
+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 glusterfs
+
+import (
+	"os"
+	"testing"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/types"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util/exec"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util/mount"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/volume"
+)
+
+func TestCanSupport(t *testing.T) {
+	plugMgr := volume.VolumePluginMgr{}
+	plugMgr.InitPlugins(ProbeVolumePlugins(), volume.NewFakeVolumeHost("fake", nil, nil))
+	plug, err := plugMgr.FindPluginByName("kubernetes.io/glusterfs")
+	if err != nil {
+		t.Errorf("Can't find the plugin by name")
+	}
+	if plug.Name() != "kubernetes.io/glusterfs" {
+		t.Errorf("Wrong name: %s", plug.Name())
+	}
+	if !plug.CanSupport(&api.Volume{VolumeSource: api.VolumeSource{Glusterfs: &api.GlusterfsVolumeSource{}}}) {
+		t.Errorf("Expected true")
+	}
+	if plug.CanSupport(&api.Volume{VolumeSource: api.VolumeSource{}}) {
+		t.Errorf("Expected false")
+	}
+}
+
+func TestGetAccessModes(t *testing.T) {
+	plugMgr := volume.VolumePluginMgr{}
+	plugMgr.InitPlugins(ProbeVolumePlugins(), volume.NewFakeVolumeHost("/tmp/fake", nil, nil))
+
+	plug, err := plugMgr.FindPersistentPluginByName("kubernetes.io/glusterfs")
+	if err != nil {
+		t.Errorf("Can't find the plugin by name")
+	}
+	if !contains(plug.GetAccessModes(), api.ReadWriteOnce) || !contains(plug.GetAccessModes(), api.ReadOnlyMany) || !contains(plug.GetAccessModes(), api.ReadWriteMany) {
+		t.Errorf("Expected three AccessModeTypes:  %s, %s, and %s", api.ReadWriteOnce, api.ReadOnlyMany, api.ReadWriteMany)
+	}
+}
+
+func contains(modes []api.AccessModeType, mode api.AccessModeType) bool {
+	for _, m := range modes {
+		if m == mode {
+			return true
+		}
+	}
+	return false
+}
+
+func TestPlugin(t *testing.T) {
+	plugMgr := volume.VolumePluginMgr{}
+	plugMgr.InitPlugins(ProbeVolumePlugins(), volume.NewFakeVolumeHost("/tmp/fake", nil, nil))
+	plug, err := plugMgr.FindPluginByName("kubernetes.io/glusterfs")
+	if err != nil {
+		t.Errorf("Can't find the plugin by name")
+	}
+	spec := &api.Volume{
+		Name:         "vol1",
+		VolumeSource: api.VolumeSource{Glusterfs: &api.GlusterfsVolumeSource{"ep", "vol", false}},
+	}
+	ep := &api.Endpoints{ObjectMeta: api.ObjectMeta{Name: "foo"}, Subsets: []api.EndpointSubset{{
+		Addresses: []api.EndpointAddress{{IP: "127.0.0.1"}}}}}
+	var fcmd exec.FakeCmd
+	fcmd = exec.FakeCmd{
+		CombinedOutputScript: []exec.FakeCombinedOutputAction{
+			// mount
+			func() ([]byte, error) {
+				return []byte{}, nil
+			},
+		},
+	}
+	fake := exec.FakeExec{
+		CommandScript: []exec.FakeCommandAction{
+			func(cmd string, args ...string) exec.Cmd { return exec.InitFakeCmd(&fcmd, cmd, args...) },
+		},
+	}
+	builder, err := plug.(*glusterfsPlugin).newBuilderInternal(spec, ep, &api.ObjectReference{UID: types.UID("poduid")}, &mount.FakeMounter{}, &fake)
+	volumePath := builder.GetPath()
+	if err != nil {
+		t.Errorf("Failed to make a new Builder: %v", err)
+	}
+	if builder == nil {
+		t.Errorf("Got a nil Builder: %v")
+	}
+	path := builder.GetPath()
+	if path != "/tmp/fake/pods/poduid/volumes/kubernetes.io~glusterfs/vol1" {
+		t.Errorf("Got unexpected path: %s", path)
+	}
+	if err := builder.SetUp(); err != nil {
+		t.Errorf("Expected success, got: %v", err)
+	}
+	if _, err := os.Stat(volumePath); err != nil {
+		if os.IsNotExist(err) {
+			t.Errorf("SetUp() failed, volume path not created: %s", volumePath)
+		} else {
+			t.Errorf("SetUp() failed: %v", err)
+		}
+	}
+	cleaner, err := plug.(*glusterfsPlugin).newCleanerInternal("vol1", types.UID("poduid"), &mount.FakeMounter{})
+	if err != nil {
+		t.Errorf("Failed to make a new Cleaner: %v", err)
+	}
+	if cleaner == nil {
+		t.Errorf("Got a nil Cleaner: %v")
+	}
+	if err := cleaner.TearDown(); err != nil {
+		t.Errorf("Expected success, got: %v", err)
+	}
+	if _, err := os.Stat(volumePath); err == nil {
+		t.Errorf("TearDown() failed, volume path still exists: %s", volumePath)
+	} else if !os.IsNotExist(err) {
+		t.Errorf("SetUp() failed: %v", err)
+	}
+}