{"record":{"id":"7244328f4d4088f3","repo":"apache/hadoop","slug":"incompatible-build-versions-active-name-node-bv","errorCode":null,"errorMessage":"Incompatible build versions: active name-node BV = {nsInfo.getBuildVersion()}; backup node BV = {Storage.getBuildVersion()}","messagePattern":"Incompatible build versions: active name-node BV = (.+?); backup node BV = (.+?)","errorType":"exception","errorClass":"IOException","httpStatus":null,"severity":"error","filePath":"hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/BackupNode.java","lineNumber":424,"sourceCode":"      LOG.error(msg);\n      throw new IOException(msg); // stop the node\n    }\n    nnRpcAddress = nnReg.getAddress();\n  }\n\n  // TODO: move to a common with DataNode util class\n  private static NamespaceInfo handshake(NamenodeProtocol namenode)\n  throws IOException, SocketTimeoutException {\n    NamespaceInfo nsInfo;\n    nsInfo = namenode.versionRequest();  // throws SocketTimeoutException \n    String errorMsg = null;\n    // verify build version\n    if( ! nsInfo.getBuildVersion().equals( Storage.getBuildVersion())) {\n      errorMsg = \"Incompatible build versions: active name-node BV = \" \n        + nsInfo.getBuildVersion() + \"; backup node BV = \"\n        + Storage.getBuildVersion();\n      LOG.error(errorMsg);\n      throw new IOException(errorMsg);\n    }\n    assert HdfsServerConstants.NAMENODE_LAYOUT_VERSION == nsInfo.getLayoutVersion() :\n      \"Active and backup node layout versions must be the same. Expected: \"\n      + HdfsServerConstants.NAMENODE_LAYOUT_VERSION + \" actual \"+ nsInfo.getLayoutVersion();\n    return nsInfo;\n  }\n\n  @Override\n  protected String getNameServiceId(Configuration conf) {\n    return DFSUtil.getBackupNameServiceId(conf);\n  }\n\n  @Override\n  protected HAState createHAState(Configuration conf) {\n    return new BackupState();\n  }\n\n  @Override // NameNode","sourceCodeStart":406,"sourceCodeEnd":442,"githubUrl":"https://github.com/apache/hadoop/blob/2add9630210752f88ceb1bb74eb65e37bf41da8e/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/BackupNode.java#L406-L442","documentation":"Error \"Incompatible build versions: active name-node BV = {nsInfo.getBuildVersion()}; backup node BV = {Storage.getBuildVersion()}\" thrown in apache/hadoop.","triggerScenarios":"BackupNode handshake with the active NameNode when the two run incompatible build versions.","commonSituations":"See trigger scenarios.","solutions":["Upgrade the BackupNode to the same Hadoop build version as the active NameNode.","Do not mix different Hadoop versions between active and backup NameNodes."],"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"}