apache/hadoop · error · IllegalArgumentException

Failed to specify server's Kerberos principal name

Error message

Failed to specify server's Kerberos principal name

What it means

Error "Failed to specify server's Kerberos principal name" thrown in apache/hadoop.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/SaslRpcClient.java:341

    String serverKeyPattern = conf.get(serverKey + ".pattern");
    if (serverKeyPattern != null && !serverKeyPattern.isEmpty()) {
      Pattern pattern = GlobPattern.compile(serverKeyPattern);
      if (!pattern.matcher(serverPrincipal).matches()) {
        throw new IllegalArgumentException(String.format(
            "Server has invalid Kerberos principal: %s,"
                + " doesn't match the pattern: %s",
            serverPrincipal, serverKeyPattern));
      }
    } else {
      // check that the server advertised principal matches our conf
      String confPrincipal = SecurityUtil.getServerPrincipal(
          conf.get(serverKey), serverAddr.getAddress());
      if (LOG.isDebugEnabled()) {
        LOG.debug("getting serverKey: " + serverKey + " conf value: " + conf.get(serverKey)
            + " principal: " + confPrincipal);
      }
      if (confPrincipal == null || confPrincipal.isEmpty()) {
        throw new IllegalArgumentException(
            "Failed to specify server's Kerberos principal name");
      }
      KerberosName name = new KerberosName(confPrincipal);
      if (name.getHostName() == null) {
        throw new IllegalArgumentException(
            "Kerberos principal name does NOT have the expected hostname part: "
                + confPrincipal);
      }
      if (!serverPrincipal.equals(confPrincipal)) {
        throw new IllegalArgumentException(String.format(
            "Server has invalid Kerberos principal: %s, expecting: %s",
            serverPrincipal, confPrincipal));
      }
    }
    return serverPrincipal;
  }

  /**

View on GitHub (pinned to 2add963021)

Solutions

1. Set the server Kerberos principal (e.g. via the protocol-specific principal config) before establishing the SASL connection.
2. Verify the keytab and principal are configured and the login (loginUserFromKeytab) succeeded.
3. Check logs for earlier Kerberos login failures that left the principal unset.

When it happens

Trigger: Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/SaslRpcClient.java:341 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/1abf0e19f27d295c. Report an issue: GitHub.