apache/hadoop · error · AccessControlException

The operation is not allowed because the path: {} is a mount

Error message

The operation is not allowed because the path: {} is a mount point

What it means

Error "The operation is not allowed because the path: {} is a mount point" thrown in apache/hadoop.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/RouterRpcServer.java:2177

    try {
      if (failIfLocked) {
        // check if there is any mount point under the path
        final List<String> mountPoints =
            this.subclusterResolver.getMountPoints(path);
        if (mountPoints != null) {
          StringBuilder sb = new StringBuilder();
          sb.append("The operation is not allowed because ");
          if (mountPoints.isEmpty()) {
            sb.append("the path: ")
                .append(path)
                .append(" is a mount point");
          } else {
            sb.append("there are mount points: ")
                .append(String.join(",", mountPoints))
                .append(" under the path: ")
                .append(path);
          }
          throw new AccessControlException(sb.toString());
        }
      }

      // Check the location for this path
      final PathLocation location =
          this.subclusterResolver.getDestinationForPath(path);
      if (location == null) {
        throw new NoLocationException(path, this.subclusterResolver.getClass());
      }

      // We may block some write operations
      if (opCategory.get() == OperationCategory.WRITE) {
        // Check if the path is in a read only mount point
        if (isPathReadOnly(path)) {
          if (this.rpcMonitor != null) {
            this.rpcMonitor.routerFailureReadOnly();
          }
          throw new IOException(path + " is in a read only mount point");

View on GitHub (pinned to 2add963021)

Solutions

1. Target the underlying destination path in the subcluster directly instead of the mount point.
2. If the intent was to modify the mount itself, use dfsrouteradmin mount table commands.
3. Choose a non-mount-point path for the operation.

When it happens

Trigger: A write/metadata operation was attempted directly on a path that is a mount point.

Common situations: Users or jobs trying to delete/rename/chmod the mount point directory itself rather than content beneath it.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/8597bd41bd4e43c5. Report an issue: GitHub.