apache/hadoop · error · IOException

Inconsistent Datanode IDs. Name-node returned {}. Expecting

Error message

Inconsistent Datanode IDs. Name-node returned {}. Expecting {}

What it means

Error "Inconsistent Datanode IDs. Name-node returned {}. Expecting {}" thrown in apache/hadoop.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java:2102

        streamingAddr.getAddress().getHostAddress(), hostName, 
        storage.getDatanodeUuid(), getXferPort(), getInfoPort(),
            infoSecurePort, getIpcPort());
    return new DatanodeRegistration(dnId, storageInfo, 
        new ExportedBlockKeys(), VersionInfo.getVersion());
  }

  /**
   * Check that the registration returned from a NameNode is consistent
   * with the information in the storage. If the storage is fresh/unformatted,
   * sets the storage ID based on this registration.
   * Also updates the block pool's state in the secret manager.
   */
  synchronized void bpRegistrationSucceeded(DatanodeRegistration bpRegistration,
      String blockPoolId) throws IOException {
    id = bpRegistration;

    if(!storage.getDatanodeUuid().equals(bpRegistration.getDatanodeUuid())) {
      throw new IOException("Inconsistent Datanode IDs. Name-node returned "
          + bpRegistration.getDatanodeUuid()
          + ". Expecting " + storage.getDatanodeUuid());
    }
    
    registerBlockPoolWithSecretManager(bpRegistration, blockPoolId);
  }
  
  /**
   * After the block pool has contacted the NN, registers that block pool
   * with the secret manager, updating it with the secrets provided by the NN.
   * @throws IOException on error
   */
  private synchronized void registerBlockPoolWithSecretManager(
      DatanodeRegistration bpRegistration, String blockPoolId) throws IOException {
    ExportedBlockKeys keys = bpRegistration.getExportedKeys();
    if (!hasAnyBlockPoolRegistered) {
      hasAnyBlockPoolRegistered = true;
      isBlockTokenEnabled = keys.isBlockTokenEnabled();

View on GitHub (pinned to 2add963021)

Solutions

1. Ensure the DataNode registers with the same NameNode/cluster it was formatted for; clear stale storage (datanodeUuid in VERSION files) if the node was reimaged.
2. Verify dfs.namenode addresses in hdfs-site.xml point to the intended NameNode and that no other cluster shares these storage directories.

When it happens

Trigger: During registration, the NameNode returns a DataNode ID that differs from the ID this DataNode has stored, indicating storage from a different cluster or node.

Common situations: The NameNode returned a DataNode ID inconsistent with local storage, usually from reusing a data directory on a different node. Clear or correct the storage directories.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/48dc5a9b627cc5dd. Report an issue: GitHub.