'Create disk-less volume backing.
This type of backing is useful for creating volume from image. The
downloaded image from the image service can be copied to a virtual
disk of desired provisioning type and added to the backing VM.
:param name: Name of the backing
:param folder: Folder where the backing is created
:param resource_pool: Resource pool reference
:param host: Host reference
:param ds_name: Name of the datastore used for VM storage
:param profileId: Storage profile ID to be associated with backing
:param extra_config: Key-value pairs to be written to backing\'s
extra-config
:return: Reference to the created backing entity'

def create_backing_disk_less(self, name, folder, resource_pool, host, ds_name, profileId=None, extra_config=None):

    LOG.debug('Creating    disk-less    volume    backing    with    name:    %(name)s    profileId:    %(profile)s    at    folder:    %(folder)s    resource    pool:    %(resource_pool)s    host:    %(host)s    datastore_name:    %(ds_name)s.', {'name': name, 'profile': profileId, 'folder': folder, 'resource_pool': resource_pool, 'host': host, 'ds_name': ds_name})
    create_spec = self._get_create_spec_disk_less(name, ds_name, profileId=profileId, extra_config=extra_config)
    return self._create_backing_int(folder, resource_pool, host, create_spec)
