apache/hadoop · error · IllegalArgumentException

Invalid server principal ${serverPrincipal}decoded from clie

Error message

Invalid server principal ${serverPrincipal}decoded from client request

What it means

Error "Invalid server principal ${serverPrincipal}decoded from client request" thrown in apache/hadoop.

Source

Thrown at hadoop-common-project/hadoop-auth/src/main/java/org/apache/hadoop/security/authentication/server/KerberosAuthenticationHandler.java:333

      response.setHeader(WWW_AUTHENTICATE, KerberosAuthenticator.NEGOTIATE);
      response.setStatus(HttpServletResponse.SC_UNAUTHORIZED);
      if (authorization == null) {
        LOG.trace("SPNEGO starting for url: {}", request.getRequestURL());
      } else {
        LOG.warn("'" + KerberosAuthenticator.AUTHORIZATION +
            "' does not start with '" +
            KerberosAuthenticator.NEGOTIATE + "' :  {}", authorization);
      }
    } else {
      authorization = authorization.substring(
          KerberosAuthenticator.NEGOTIATE.length()).trim();
      final Base64 base64 = new Base64(0);
      final byte[] clientToken = base64.decode(authorization);
      try {
        final String serverPrincipal =
            KerberosUtil.getTokenServerName(clientToken);
        if (!serverPrincipal.startsWith("HTTP/")) {
          throw new IllegalArgumentException(
              "Invalid server principal " + serverPrincipal +
              "decoded from client request");
        }
        token = Subject.doAs(serverSubject,
            new PrivilegedExceptionAction<AuthenticationToken>() {
              @Override
              public AuthenticationToken run() throws Exception {
                return runWithPrincipal(serverPrincipal, clientToken,
                      base64, response);
              }
            });
      } catch (PrivilegedActionException ex) {
        if (ex.getException() instanceof IOException) {
          throw (IOException) ex.getException();
        } else {
          throw new AuthenticationException(ex.getException());
        }
      } catch (Exception ex) {

View on GitHub (pinned to 2add963021)

Solutions

1. Verify the client request carries a valid Kerberos service ticket and that the server's JAAS/keytab setup matches the expected server principal.

Example fix

kinit and retry; ensure SPN HTTP/fqdn@REALM matches keytab.

When it happens

Trigger: Raised at runtime when the documented precondition or configuration requirement for this operation is violated.

Common situations: Misconfigured or missing property, invalid user input, or calling the API before its prerequisites are met.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/5084b055a488613e. Report an issue: GitHub.