{"record":{"id":"c7e51c02835d9e31","repo":"apache/hadoop","slug":"this-is-not-a-dfs","errorCode":null,"errorMessage":"This is not a DFS","messagePattern":"This is not a DFS","errorType":"exception","errorClass":"IOException","httpStatus":null,"severity":"error","filePath":"hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/SecondaryNameNode.java","lineNumber":457,"sourceCode":"          }\n        });\n        return b.booleanValue();\n      } catch (InterruptedException e) {\n        throw new RuntimeException(e);\n      }\n  }\n  \n  InetSocketAddress getNameNodeAddress() {\n    return nameNodeAddr;\n  }\n\n  /**\n   * Returns the Jetty server that the Namenode is listening on.\n   */\n  private URL getInfoServer() throws IOException {\n    URI fsName = FileSystem.getDefaultUri(conf);\n    if (!HdfsConstants.HDFS_URI_SCHEME.equalsIgnoreCase(fsName.getScheme())) {\n      throw new IOException(\"This is not a DFS\");\n    }\n\n    final String scheme = DFSUtil.getHttpClientScheme(conf);\n    URI address = DFSUtil.getInfoServerWithDefaultHost(fsName.getHost(), conf,\n        scheme);\n    LOG.debug(\"Will connect to NameNode at \" + address);\n    return address.toURL();\n  }\n\n  /**\n   * Start the web server.\n   */\n  @VisibleForTesting\n  public void startInfoServer() throws IOException {\n    final InetSocketAddress httpAddr = getHttpAddress(conf);\n    final String httpsAddrString = conf.getTrimmed(\n        DFSConfigKeys.DFS_NAMENODE_SECONDARY_HTTPS_ADDRESS_KEY,\n        DFSConfigKeys.DFS_NAMENODE_SECONDARY_HTTPS_ADDRESS_DEFAULT);","sourceCodeStart":439,"sourceCodeEnd":475,"githubUrl":"https://github.com/apache/hadoop/blob/2add9630210752f88ceb1bb74eb65e37bf41da8e/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/SecondaryNameNode.java#L439-L475","documentation":"Error \"This is not a DFS\" thrown in apache/hadoop.","triggerScenarios":"The SecondaryNameNode is pointed at a nameservice that is not a DistributedFileSystem.","commonSituations":"Misconfigured fs.defaultFS or namenode address pointing at a non-HDFS filesystem.","solutions":["Run this checkpoint/geteditsize operation against a DFS (HDFS) nameservice, not a non-HDFS filesystem."],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"2add9630210752f88ceb1bb74eb65e37bf41da8e","analyzedAt":"2026-08-22T19:55:07.957Z","schemaVersion":2},"datasetVersion":"2026-08-22T20:17:22.307Z"}