EIO

EIO

Error message

fuseConnectAsThreadUid: failed to open a libhdfs connection!  error %d.

What it means

Error "fuseConnectAsThreadUid: failed to open a libhdfs connection! error %d. " thrown in apache/hadoop.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/fuse-dfs/fuse_impls_mkdir.c:44

  struct hdfsConn *conn = NULL;
  hdfsFS fs;
  dfs_context *dfs = (dfs_context*)fuse_get_context()->private_data;
  int ret;

  TRACE1("mkdir", path)

  assert(path);
  assert(dfs);
  assert('/' == *path);

  if (is_protected(path)) {
    ERROR("HDFS trying to create directory %s", path);
    return -EACCES;
  }

  ret = fuseConnectAsThreadUid(&conn);
  if (ret) {
    fprintf(stderr, "fuseConnectAsThreadUid: failed to open a libhdfs "
            "connection!  error %d.\n", ret);
    ret = -EIO;
    goto cleanup;
  }
  fs = hdfsConnGetFs(conn);

  // In theory the create and chmod should be atomic.

  if (hdfsCreateDirectory(fs, path)) {
    ERROR("HDFS could not create directory %s", path);
    ret = (errno > 0) ? -errno : -EIO;
    goto cleanup;
  }

  if (hdfsChmod(fs, path, (short)mode)) {
    ERROR("Could not chmod %s to %d", path, (int)mode);
    ret = (errno > 0) ? -errno : -EIO;
  }

View on GitHub (pinned to 2add963021)

Solutions

Verify the user's Kerberos ticket is valid (kinit) and that libhdfs can connect to the NameNode; then retry the mkdir operation.
Check the error code to distinguish authentication failure from configuration problems (CLASSPATH/HADOOP_CONF_DIR).

When it happens

Trigger: Thrown at hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/fuse-dfs/fuse_impls_mkdir.c:44 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/cad2e023635d6e8d. Report an issue: GitHub.