}
	if spec.Volume != nil {
		return spec.Name(), nil
	} else if spec.PersistentVolume != nil {
		if spec.PersistentVolume.Spec.PersistentVolumeSource.GCEPersistentDisk != nil {
			return spec.PersistentVolume.Spec.PersistentVolumeSource.GCEPersistentDisk.PDName, nil
		} else if spec.PersistentVolume.Spec.PersistentVolumeSource.NFS != nil {
			return spec.PersistentVolume.Spec.PersistentVolumeSource.NFS.Server, nil

// with apply.
type PersistentVolumeSourceApplyConfiguration struct {
	GCEPersistentDisk    *GCEPersistentDiskVolumeSourceApplyConfiguration    `json:"gcePersistentDisk,omitempty"`
	AWSElasticBlockStore *AWSElasticBlockStoreVolumeSourceApplyConfiguration `json:"awsElasticBlockStore,omitempty"`

		},
		Spec: v1.PersistentVolumeSpec{
			Capacity: v1.ResourceList{
				v1.ResourceName(v1.ResourceStorage): resource.MustParse("1G"),
			},
			PersistentVolumeSource: v1.PersistentVolumeSource{
				GCEPersistentDisk: &v1.GCEPersistentDiskVolumeSource{},
			},
			AccessModes: []v1.PersistentVolumeAccessMode{v1.ReadWriteOnce, v1.ReadOnlyMany},
			// this one we're pretending is already bound

		ObjectMeta: metav1.ObjectMeta{
			Name: "pod1",
			UID:  "pod1uid",
		},
		Spec: v1.PodSpec{
			Volumes: []v1.Volume{
				{
					Name: "volume-name",
					VolumeSource: v1.VolumeSource{
						GCEPersistentDisk: &v1.GCEPersistentDiskVolumeSource{
							PDName: "fake-device1",
						},
					},
				},
			},
		},
	}
	volumeSpec := &volume.Spec{Volume: &pod.Spec.Volumes[0]}
	devicePath := "fake/device/path"

	for _, existingVolume := range pod.Spec.Volumes {
		// Same GCE disk mounted by multiple pods conflicts unless all pods mount it read-only.
		if volume.GCEPersistentDisk != nil && existingVolume.GCEPersistentDisk != nil {
			disk, existingDisk := volume.GCEPersistentDisk, existingVolume.GCEPersistentDisk
			if disk.PDName == existingDisk.PDName && !(disk.ReadOnly && existingDisk.ReadOnly) {
				return true
			}
		}

		ObjectMeta: metav1.ObjectMeta{
			Name: "pod3",
			UID:  "pod3uid",
		},
		Spec: v1.PodSpec{
			Volumes: []v1.Volume{
				{
					Name: "volume-name",
					VolumeSource: v1.VolumeSource{
						GCEPersistentDisk: &v1.GCEPersistentDiskVolumeSource{
							PDName: "fake-device1",
						},
					},
				},
			},
		},
	}

	volumeSpec := &volume.Spec{Volume: &pod.Spec.Volumes[0]}

					Name:      "kube-apiserver",
					Namespace: "default",
				},
				Spec: v1.PodSpec{
					Volumes: []v1.Volume{
						{
							Name: migratedVolume,
							VolumeSource: v1.VolumeSource{
								GCEPersistentDisk: &v1.GCEPersistentDiskVolumeSource{
									PDName:    "test-disk",
									FSType:    "ext4",
									Partition: 0,
									ReadOnly:  false,
								},
							},
						},
					},
				},

	FilterVolume: func(vol *v1.Volume) (string, bool) {
		if vol.GCEPersistentDisk != nil {
			return vol.GCEPersistentDisk.PDName, true
		}
		return "", false
	},

	FilterPersistentVolume: func(pv *v1.PersistentVolume) (string, bool) {
		if pv.Spec.GCEPersistentDisk != nil {
			return pv.Spec.GCEPersistentDisk.PDName, true
		}
		return "", false
	},

	b.Capacity = &value
	return b
}

// WithGCEPersistentDisk sets the GCEPersistentDisk field in the declarative configuration to the given value
// and returns the receiver, so that objects can be built by chaining "With" function invocations.
// If called multiple times, the GCEPersistentDisk field is set to the value of the last call.

		VolumeSource: v1.VolumeSource{
			GCEPersistentDisk: &v1.GCEPersistentDiskVolumeSource{},
		},
	}).Obj()
	twoGCEPDPod := st.MakePod().Volume(v1.Volume{
		VolumeSource: v1.VolumeSource{
			GCEPersistentDisk: &v1.GCEPersistentDiskVolumeSource{},
		},
	}).Volume(v1.Volume{
		VolumeSource: v1.VolumeSource{
			GCEPersistentDisk: &v1.GCEPersistentDiskVolumeSource{},
		},
	}).Obj()