apache/hadoop · error · UnsupportedOperationException

Mkdirs is not supported in pseudo local file system.

Error message

Mkdirs is not supported in pseudo local file system.

What it means

PseudoLocalFs.mkdirs() unconditionally throws UnsupportedOperationException. The pseudo local file system has no directory hierarchy: only the root '/' exists and all files live directly under it, so directory creation is meaningless. File 'creation' is just name-format validation; content appears only when a reader opens the file.

Source

Thrown at hadoop-tools/hadoop-gridmix/src/main/java/org/apache/hadoop/mapred/gridmix/PseudoLocalFs.java:311

      throw new UnsupportedOperationException();
    }

    @Override
    public boolean seekToNewSource(long targetPos) throws IOException {
      throw new UnsupportedOperationException();
    }
  }

  @Override
  public FSDataOutputStream append(Path path, int bufferSize,
      Progressable progress) throws IOException {
    throw new UnsupportedOperationException("Append is not supported"
        + " in pseudo local file system.");
  }

  @Override
  public boolean mkdirs(Path f, FsPermission permission) throws IOException {
    throw new UnsupportedOperationException("Mkdirs is not supported"
        + " in pseudo local file system.");
  }

  @Override
  public boolean rename(Path src, Path dst) throws IOException {
    throw new UnsupportedOperationException("Rename is not supported"
        + " in pseudo local file system.");
  }

  @Override
  public boolean delete(Path path, boolean recursive) {
    throw new UnsupportedOperationException("File deletion is not supported "
        + "in pseudo local file system.");
  }

  @Override
  public void setWorkingDirectory(Path newDir) {
    throw new UnsupportedOperationException("SetWorkingDirectory "

View on GitHub (pinned to 2add963021)

Solutions

Remove pseudo:/// paths from any code path that creates directories; the pseudo FS only serves generated input files
Use a real FileSystem (file:// or hdfs://) for outputs and directory structures
Guard with a scheme check (fs.getUri().getScheme()) and skip mkdirs for 'pseudo'

Defensive patterns

Strategy: try-catch

Validate before calling

if ("pseudo".equals(fs.getUri().getScheme())) {
  // PseudoLocalFs: only root '/' exists; skip directory creation
}

Try / catch

try {
  fs.mkdirs(dir, perm);
} catch (UnsupportedOperationException e) {
  // pseudo-local FS has no directories; ignore only if dir is pseudo:///
}

Prevention

Route outputs and directory-creating tools (distcp -p, committers) to real file systems
Treat PseudoLocalFs as a read-only generated-input source only

When it happens

Trigger: Calling FileSystem.mkdirs(Path) or mkdirs(Path, FsPermission) on PseudoLocalFs; utilities that pre-create parent directories before writing files (distcp with -p, FileContext.mkdir, most output committers) when given pseudo:/// destinations.

Common situations: Using pseudo:// paths as map/reduce output directories in gridmix jobs; feeding pseudo-local paths into copy tools that replicate source directory structure; generic code that calls mkdirs for every parent in a path.

Related errors

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/58bdbe2a5f408d0d. Report an issue: GitHub.