// +optional
  optional bool readOnly = 3;

  // secretRef is Optional: points to a secret object containing parameters used to connect
  // to OpenStack.
  // +optional
  optional SecretReference secretRef = 4;
}

// Represents a cinder volume resource in Openstack.
// A Cinder volume must exist before mounting to a container.
// The volume must also be in the same region as the kubelet.