def upload_volume(self, volume_id, image_name):
        """Uploads a volume in Glance."""
        post_body = Element("volume",
                            image_name=image_name,
                           )
        resp, body = self.post('os-volume_upload_image',
                               str(Document(post_body)),
                               self.headers)
        url = 'volumes/%s/action' % (volume_id)
        resp, body = self.post(url, str(Document(post_body)), self.headers)
        volume = self.xml_to_json(etree.fromstring(body)

        return resp, volume