apache/hadoop · error · SecurityException

Failed to obtain user group information: {}

Error message

Failed to obtain user group information: {}

What it means

UserProvider is the JAX-RS injection supplier that gives WebHDFS/HttpFS resource classes a UserGroupInformation for the current HTTP request. get() calls JspHelper.getUGI(servletcontext, request, conf, KERBEROS, false); when that throws IOException (SPNEGO/Kerberos failure, bad delegation token, proxy rules) it is rethrown as SecurityException prefixed with SecurityUtil.FAILED_TO_GET_UGI_MSG_HEADER ("Failed to obtain user group information:"). The real reason is the chained IOException.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/web/resources/UserProvider.java:50

import org.apache.hadoop.security.UserGroupInformation.AuthenticationMethod;

/** Inject user information to http operations. */
@Provider
public class UserProvider implements Supplier<UserGroupInformation> {
  @Context
  private HttpServletRequest request;

  @Context
  private ServletContext servletcontext;

  public UserGroupInformation get() {
    final Configuration conf = (Configuration) servletcontext
        .getAttribute(JspHelper.CURRENT_CONF);
    try {
      return JspHelper.getUGI(servletcontext, request, conf,
          AuthenticationMethod.KERBEROS, false);
    } catch (IOException e) {
      throw new SecurityException(
          SecurityUtil.FAILED_TO_GET_UGI_MSG_HEADER + " " + e, e);
    }
  }
}

View on GitHub (pinned to 2add963021)

Solutions

1. Read the NameNode/HttpFS server log for the underlying IOException — the SecurityException message only prefixes it
2. Refresh credentials: kinit again on the client, or restart the daemon with a valid keytab, then retry
3. If using delegation tokens, fetch a fresh one (webhdfs op=GETDELEGATIONTOKEN) or renew before expiry
4. Verify SPNEGO setup: dfs.namenode.kerberos.internal-spnego-principal / HTTP/_HOST@REALM and a valid krb5.conf on the server
5. Check hadoop.proxyuser.* mappings when the request impersonates another user

Example fix

// before: fire request once and crash on SecurityException
Response r = webhdfs.path("/data").queryParam("op", "OPEN").request().get();

// after: catch, re-login from keytab, retry once
try {
  return webhdfs.path("/data").queryParam("op", "OPEN").request().get();
} catch (SecurityException e) {
  UserGroupInformation.getLoginUser().checkTGTAndReloginFromKeytab();
  return webhdfs.path("/data").queryParam("op", "OPEN").request().get();
}

UserGroupInformation ugi = UserGroupInformation.getLoginUser();
ugi.checkTGTAndReloginFromKeytab(); // refresh TGT/keytab before the request

try {
  return callWebHdfs();
} catch (SecurityException e) {
  if (!e.getMessage().startsWith(SecurityUtil.FAILED_TO_GET_UGI_MSG_HEADER)) throw e;
  UserGroupInformation.getLoginUser().checkTGTAndReloginFromKeytab();
  return callWebHdfs(); // one retry after credential refresh
}

When it happens

Trigger: A WebHDFS or HttpFS HTTP request whose authentication fails: expired or absent TGT/keytab on the server, SPNEGO principal misconfiguration, a delegation token that expired or predates a NameNode restart (fresh secret manager), Kerberos clock skew, or disallowed proxyuser impersonation.

Common situations: curl/WebHDFS clients with SPNEGO after TGT expiry; schedulers (Oozie/jobs) holding delegation tokens issued before a restart without persistent token manager config; secure clusters after changes to dfs.namenode.kerberos.* or hadoop.http.authentication.*; NTP drift on the KDC or NameNode.

Related errors

• Security enabled but user not authenticated by filter
• {} parameter is not null.
• WebImageViewer does not support secure mode. To start in non
• The client is configured to only allow connecting to secure
• Parameter [{0}], cannot be NULL

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/6314e4a7c4d6cbf0. Report an issue: GitHub.