apache/hadoop · error · InvalidJobConfException

Output directory not set in JobConf.

Error message

Output directory not set in JobConf.

What it means

Error "Output directory not set in JobConf." thrown in apache/hadoop.

Source

Thrown at hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapred/FileOutputFormat.java:117

        throw new IllegalArgumentException("Compression codec " + name + 
                                           " was not found.", e);
      }
    }
    return codecClass;
  }
  
  public abstract RecordWriter<K, V> getRecordWriter(FileSystem ignored,
                                               JobConf job, String name,
                                               Progressable progress)
    throws IOException;

  public void checkOutputSpecs(FileSystem ignored, JobConf job) 
    throws FileAlreadyExistsException, 
           InvalidJobConfException, IOException {
    // Ensure that the output directory is set and not already there
    Path outDir = getOutputPath(job);
    if (outDir == null && job.getNumReduceTasks() != 0) {
      throw new InvalidJobConfException("Output directory not set in JobConf.");
    }
    if (outDir != null) {
      FileSystem fs = outDir.getFileSystem(job);
      // normalize the output directory
      outDir = fs.makeQualified(outDir);
      setOutputPath(job, outDir);
      
      // get delegation token for the outDir's file system
      TokenCache.obtainTokensForNamenodes(job.getCredentials(), 
                                          new Path[] {outDir}, job);
      
      // check its existence
      if (fs.exists(outDir)) {
        throw new FileAlreadyExistsException("Output directory " + outDir + 
                                             " already exists");
      }
    }
  }

View on GitHub (pinned to 2add963021)

Solutions

1. Set the output directory with FileOutputFormat.setOutputPath(job, path) or mapreduce.output.fileoutputformat.outputdir before submitting the job.

When it happens

Trigger: Thrown at hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapred/FileOutputFormat.java:117 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/334436b05a886bfc. Report an issue: GitHub.