message VolumeAttachmentSpec {
  // attacher indicates the name of the volume driver that MUST handle this
  // request. This is the name returned by GetPluginName().
  optional string attacher = 1;

  // source represents the volume that should be attached.
  optional VolumeAttachmentSource source = 2;

  // nodeName represents the node that the volume should be attached to.
  optional string nodeName = 3;
}

  // fsGroupPolicy defines if the underlying volume supports changing ownership and
  // permission of the volume before being mounted.
  // Refer to the specific FSGroupPolicy values for additional details.
  //
  // This field is immutable.
  //
  // Defaults to ReadWriteOnceWithFSType, which will examine each volume
  // to determine if Kubernetes should modify ownership and permissions of the volume.

  // persistentVolumeClaimRetentionPolicy describes the lifecycle of persistent
  // volume claims created from volumeClaimTemplates. By default, all persistent
  // volume claims are created as needed and retained until manually deleted. This
  // policy allows the lifecycle to be altered, for example by deleting persistent
  // volume claims when their stateful set is deleted, or when their pod is scaled

  // +optional
  repeated string allowedCapabilities = 4;

  // volumes is an allowlist of volume plugins. Empty indicates that
  // no volumes may be used. To allow all volumes you may use '*'.
  // +optional
  repeated string volumes = 5;

  // hostNetwork determines if the policy allows the use of HostNetwork in the pod spec.
  // +optional

  // The continue option should be set when retrieving more results from the server. Since this value is
  // server defined, clients may only use the continue value from a previous query result with identical
  // query parameters (except for the value of continue) and the server may reject a continue value it
  // does not recognize. If the specified continue value is no longer valid whether due to expiration

  // +optional
  optional string subResource = 4;

  // RequestKind is the fully-qualified type of the original API request (for example, v1.Pod or autoscaling.v1.Scale).
  // If this is specified and differs from the value in "kind", an equivalent match and conversion was performed.
  //
  // For example, if deployments can be modified via apps/v1 and apps/v1beta1, and a webhook registered a rule of

  // The maximum number of DaemonSet pods that can be unavailable during the
  // update. Value can be an absolute number (ex: 5) or a percentage of total
  // number of DaemonSet pods at the start of the update (ex: 10%). Absolute
  // number is calculated from percentage by rounding up.
  // This cannot be 0 if MaxSurge is 0
  // Default value is 1.
  // Example: when this is set to 30%, at most 30% of the total number of nodes

  //   2. Signer whose configured maximum is shorter than the requested duration
  //   3. Signer whose configured minimum is longer than the requested duration
  //
  // The minimum valid value for expirationSeconds is 600, i.e. 10 minutes.
  //
  // +optional
  optional int32 expirationSeconds = 8;

  // usages specifies a set of key usages requested in the issued certificate.
  //

  // APIs may return other objects types at their discretion, such as error conditions, requests for alternate representations, or other operation specific behavior.
  // This value will be null if an APIService reports subresources but supports no operations on the parent resource
  optional k8s.io.apimachinery.pkg.apis.meta.v1.GroupVersionKind responseKind = 2;

  // The maximum number of DaemonSet pods that can be unavailable during the
  // update. Value can be an absolute number (ex: 5) or a percentage of total
  // number of DaemonSet pods at the start of the update (ex: 10%). Absolute
  // number is calculated from percentage by rounding up.
  // This cannot be 0 if MaxSurge is 0
  // Default value is 1.
  // Example: when this is set to 30%, at most 30% of the total number of nodes