apache/hadoop · error · UnsupportedActionException

setSafeMode

Error message

setSafeMode

What it means

Error "setSafeMode" thrown in apache/hadoop.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/BackupNode.java:237

    if(checkpointManager != null) {
      checkpointManager.interrupt();
      checkpointManager = null;
    }

    // Abort current log segment - otherwise the NN shutdown code
    // will close it gracefully, which is incorrect.
    if (namesystem != null) {
      getFSImage().getEditLog().abortCurrentLogSegment();
    }

    // Stop name-node threads
    super.stop();
  }
  
  /* @Override */// NameNode
  public boolean setSafeMode(SafeModeAction action)
      throws IOException {
    throw new UnsupportedActionException("setSafeMode");
  }
  
  static class BackupNodeRpcServer extends NameNodeRpcServer implements
      JournalProtocol {
    private BackupNodeRpcServer(Configuration conf, BackupNode nn)
        throws IOException {
      super(conf, nn);
      JournalProtocolServerSideTranslatorPB journalProtocolTranslator = 
          new JournalProtocolServerSideTranslatorPB(this);
      BlockingService service = JournalProtocolService
          .newReflectiveBlockingService(journalProtocolTranslator);
      DFSUtil.addInternalPBProtocol(conf, JournalProtocolPB.class, service,
          this.clientRpcServer);
    }
    
    /** 
     * Verifies a journal request
     */

View on GitHub (pinned to 2add963021)

Solutions

1. Do not call setSafeMode on a BackupNode; run safemode operations against the active NameNode.

When it happens

Trigger: RPC to set safe mode directed at a BackupNode, which does not support the setSafeMode operation.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/b7cd90ba09458aa8. Report an issue: GitHub.