@Override
public long renew(final Token<?> token, final Configuration conf
) throws IOException, InterruptedException {
final UserGroupInformation ugi = UserGroupInformation.getLoginUser();
// update the kerberos credentials, if they are coming from a keytab
ugi.checkTGTAndReloginFromKeytab();
return ugi.doAs(new PrivilegedExceptionAction<Long>() {
@Override
public Long run() throws Exception {
final WebHdfsFileSystem webhdfs = getWebHdfs(token, conf);