'Makes tmpfile under CONF.instances_path.'

def _create_shared_storage_test_file(self, instance):

    dirpath = CONF.instances_path
    (fd, tmp_file) = tempfile.mkstemp(dir=dirpath)
    LOG.debug('Creating    tmpfile    %s    to    notify    to    other    compute    nodes    that    they    should    mount    the    same    storage.', tmp_file, instance=instance)
    os.close(fd)
    return os.path.basename(tmp_file)
