def _tar(name, root, path=None, compress='bzip2'):
    '''
    Pack up image in a tar format
    '''
    if path is None:
        path = os.path.join(salt.syspaths.BASE_FILE_ROOTS_DIR, 'img')
    if not __salt__['file.directory_exists'](path):
        try:
            __salt__['file.mkdir'](path)
        except Exception as exc:
            return {'Error': salt.utils.stringutils.to_unicode(pprint.pformat(exc))}

    compression, ext = _compress(compress)

    tarfile = '{0}/{1}.tar.{2}'.format(path, name, ext)
    out = __salt__['archive.tar'](
        options='{0}pcf'.format(compression),
        tarfile=tarfile,
        sources='.',
        dest=root,
    )
Pack up image in a tar format