// +optional
  repeated AllowedFlexVolume allowedFlexVolumes = 18;

  // AllowedCSIDrivers is an allowlist of inline CSI drivers that must be explicitly set to be embedded within a pod spec.
  // An empty value indicates that any CSI driver can be used for inline ephemeral volumes.
  // +optional
  repeated AllowedCSIDriver allowedCSIDrivers = 23;

  // CSI specification and implemented in Kubernetes via the usual PV/PVC mechanism.
  //
  // The other mode is "Ephemeral". In this mode, volumes are defined inline inside the pod spec
  // with CSIVolumeSource and their lifecycle is tied to the lifecycle of that pod.
  // A driver has to be aware of this because it is only going to get a NodePublishVolume call for such a volume.
  //

}

// ExecAction describes a "run in container" action.
message ExecAction {
  // Command is the command line to execute inside the container, the working directory for the
  // command  is root ('/') in the container's filesystem. The command is simply exec'd, it is
  // not run inside a shell, so traditional shell instructions ('|', etc) won't work. To use
  // a shell, you need to explicitly call out to that shell.

  optional string group = 8;

  // version is the preferred version of the resource.  Empty implies the version of the containing resource list
  // For subresources, this may have a different value, for example: v1 (while inside a v1beta1 version of the core resource's group)".
  optional string version = 9;

  // kind is the kind for the resource (e.g. 'Foo' is the kind for a resource 'foo')
  optional string kind = 3;

//
// // Internal package:
//
// 	type MyAPIObject struct {
// 		runtime.TypeMeta `json:",inline"`
// 		MyPlugin runtime.Object `json:"myPlugin"`
// 	}
//
// 	type PluginA struct {
// 		AOption string `json:"aOption"`
// 	}
//
// // External package:
//
// 	type MyAPIObject struct {
// 		runtime.TypeMeta `json:",inline"`
// 		MyPlugin runtime.RawExtension `json:"myPlugin"`
// 	}
//
// 	type PluginA struct {

  // CSI specification and implemented in Kubernetes via the usual PV/PVC mechanism.
  //
  // The other mode is "Ephemeral". In this mode, volumes are defined inline inside the pod spec
  // with CSIVolumeSource and their lifecycle is tied to the lifecycle of that pod.
  // A driver has to be aware of this because it is only going to get a NodePublishVolume call for such a volume.
  //

// in future we may allow also inline volumes in pods.
// Exactly one member can be set.
message VolumeAttachmentSource {
  // persistentVolumeName represents the name of the persistent volume to attach.
  // +optional
  optional string persistentVolumeName = 1;

  // inlineVolumeSpec contains all the information necessary to attach
  // a persistent volume defined by a pod's inline VolumeSource. This field