{"record":{"id":"74b298d2d53cdaf6","repo":"apache/seatunnel","slug":"failed-to-login-user-from-keytab-keytabpath-a","errorCode":null,"errorMessage":"Failed to login user from keytab : ${keytabPath} and kerberos principal : ${principal}","messagePattern":"Failed to login user from keytab : (.+?) and kerberos principal : (.+?)","errorType":"exception","errorClass":"IMapStorageException","httpStatus":null,"severity":"critical","filePath":"seatunnel-engine/seatunnel-engine-storage/imap-storage-plugins/imap-storage-file/src/main/java/org/apache/seatunnel/engine/imap/storage/file/config/HdfsConfiguration.java","lineNumber":107,"sourceCode":"        return hadoopConf;\n    }\n\n    /**\n     * Authenticate kerberos\n     *\n     * @param kerberosPrincipal kerberos principal\n     * @param kerberosKeytabFilePath kerberos keytab file path\n     * @param hdfsConf hdfs configuration\n     * @throws IMapStorageException authentication exception\n     */\n    private void authenticateKerberos(\n            String kerberosPrincipal, String kerberosKeytabFilePath, Configuration hdfsConf)\n            throws IMapStorageException {\n        UserGroupInformation.setConfiguration(hdfsConf);\n        try {\n            UserGroupInformation.loginUserFromKeytab(kerberosPrincipal, kerberosKeytabFilePath);\n        } catch (IOException e) {\n            throw new IMapStorageException(\n                    \"Failed to login user from keytab : \"\n                            + kerberosKeytabFilePath\n                            + \" and kerberos principal : \"\n                            + kerberosPrincipal,\n                    e);\n        }\n    }\n}\n","sourceCodeStart":89,"sourceCodeEnd":116,"githubUrl":"https://github.com/apache/seatunnel/blob/cf67b549a7a6c35fa0beb12d83c62892427ea919/seatunnel-engine/seatunnel-engine-storage/imap-storage-plugins/imap-storage-file/src/main/java/org/apache/seatunnel/engine/imap/storage/file/config/HdfsConfiguration.java#L89-L116","documentation":"HdfsConfiguration.authenticateKerberos wraps IOException from UserGroupInformation.loginUserFromKeytab into this IMapStorageException. It means Kerberos authentication against the KDC with the given principal/keytab failed, so no HDFS configuration can be finalized.","triggerScenarios":"Calling buildConfiguration() with kerberos enabled where the keytab file path does not exist or is unreadable, the principal is not in the keytab, KDC is unreachable, or clock skew exceeds tolerance.","commonSituations":"Wrong keytab path after deployment; keytab regenerated on the KDC with new KVNO so the local copy is stale; hostname mismatch between principal _HOST replacement and the actual host; krb5.conf missing or pointing at the wrong realm; large clock drift between nodes and KDC.","solutions":["Verify the keytab file exists and is readable by the process user (ls -l, klist -kt <keytab>).","Confirm the principal is present in the keytab and matches the configured value (klist -kt output).","Regenerate/redistribute the keytab if it is stale, then retry.","Check /etc/krb5.conf realm and KDC reachability (kinit -kt <keytab> <principal> must succeed).","Fix host clock sync (NTP) if clock skew errors appear in the cause."],"exampleFix":"// before\n# config\nkerberosKeytabFilePath: \"/etc/security/keytabs/old.keytab\"\n// after\n# regenerate and deploy keytab, verify, then:\n# kinit -kt /etc/security/keytabs/st.keytab st/_HOST@EXAMPLE.COM\nkerberosKeytabFilePath: \"/etc/security/keytabs/st.keytab\"","handlingStrategy":"validation","validationCode":"boolean keytabUsable = java.nio.file.Files.isReadable(java.nio.file.Paths.get(keytabPath));\n// shell check before deploy:\n// klist -kt /etc/security/keytabs/st.keytab && kinit -kt /etc/security/keytabs/st.keytab st/_HOST@EXAMPLE.COM","typeGuard":null,"tryCatchPattern":"try { Configuration c = hdfsConfiguration.buildConfiguration(config); } catch (IMapStorageException e) { if (e.getMessage().contains(\"Failed to login user from keytab\")) { /* verify keytab/principal/KDC, then retry */ } }","preventionTips":["Verify keytab with klist -kt and a test kinit before each deploy","Sync node clocks with NTP to avoid clock-skew rejections","Distribute fresh keytabs whenever the KDC regenerates them","Ensure krb5.conf exists and points at the correct realm/KDC"],"tags":["kerberos","authentication","hadoop","hdfs"],"backgroundTag":"authentication-required","analyzedSha":"cf67b549a7a6c35fa0beb12d83c62892427ea919","analyzedAt":"2026-09-10T21:44:55.265Z","contentChangedAt":"2026-09-10T21:44:55.265Z","schemaVersion":2},"datasetVersion":"2026-09-14T05:17:10.506Z"}