What causes "Wrong FS: {path}, expected: {this.getUri()}" in apache/hadoop?

Operate on each path with its own handle: FileSystem.get(path.toUri(), conf) or use FileContext, which resolves the FS per path

apache/hadoop · error · InvalidPathException

Wrong FS: {path}, expected: {this.getUri()}

Error message

Wrong FS: {path}, expected: {this.getUri()}

What it means

AbstractFileSystem.checkPath requires the path's scheme and host (both case-insensitive) to match the FS instance's own URI; it also rejects a path with a host when this instance has none. Operating on a path that belongs to a different cluster or filesystem through the wrong handle throws InvalidPathException("Wrong FS: ...").

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/AbstractFileSystem.java:395

        }
        throw new InvalidPathException("relative paths not allowed:" + 
            path);
      } else {
        throw new InvalidPathException(
            "Path without scheme with non-null authority:" + path);
      }
    }
    String thisScheme = this.getUri().getScheme();
    String thisHost = this.getUri().getHost();
    String thatHost = uri.getHost();
    
    // Schemes and hosts must match.
    // Allow for null Authority for file:///
    if (!thisScheme.equalsIgnoreCase(thatScheme) ||
       (thisHost != null && 
            !thisHost.equalsIgnoreCase(thatHost)) ||
       (thisHost == null && thatHost != null)) {
      throw new InvalidPathException("Wrong FS: " + path + ", expected: "
          + this.getUri());
    }
    
    // Ports must match, unless this FS instance is using the default port, in
    // which case the port may be omitted from the given URI
    int thisPort = this.getUri().getPort();
    int thatPort = uri.getPort();
    if (thatPort == -1) { // -1 => defaultPort of Uri scheme
      thatPort = this.getUriDefaultPort();
    }
    if (thisPort != thatPort) {
      throw new InvalidPathException("Wrong FS: " + path
          + " and port=" + thatPort
          + ", expected: "
          + this.getUri()
          + " with port=" + thisPort);
    }
  }

View on GitHub (pinned to 2add963021)

Solutions

Operate on each path with its own handle: FileSystem.get(path.toUri(), conf) or use FileContext, which resolves the FS per path
Fix fs.defaultFS / HA nameservice config so the handle matches the paths
For cross-filesystem copies, use FileUtil.copy(srcFS, src, dstFS, dst, deleteSource, overwrite) instead of single-handle operations

Example fix

// before
FileSystem hA = FileSystem.get(new URI("hdfs://clusterA:8020"), conf);
hA.rename(new Path("hdfs://clusterB:8020/x"), new Path("hdfs://clusterB:8020/y")); // Wrong FS

// after
FileSystem hB = FileSystem.get(new Path("hdfs://clusterB:8020/x").toUri(), conf);
hB.rename(new Path("/x"), new Path("/y"));

Defensive patterns

Strategy: validation

Validate before calling

URI fsUri = afs.getUri();
URI pUri = p.toUri();
boolean schemeOk = pUri.getScheme() != null && fsUri.getScheme().equalsIgnoreCase(pUri.getScheme());
boolean hostOk = fsUri.getHost() == null ? pUri.getHost() == null : fsUri.getHost().equalsIgnoreCase(pUri.getHost());
if (!schemeOk || !hostOk) {
  afs = AbstractFileSystem.get(pUri, conf); // rebind to the path's own file system
}

Try / catch

catch (InvalidPathException e) { if (e.getMessage().startsWith("Wrong FS")) { afs = AbstractFileSystem.get(p.toUri(), conf); /* retry with correct handle */ } else throw e; }

Prevention

Derive the handle from the path (FileSystem.get(path.toUri(), conf)) instead of reusing a cached one
Use FileContext, which resolves the file system per path
For cross-cluster work use FileUtil.copy between two handles rather than single-handle ops

When it happens

Trigger: An AbstractFileSystem/FileSystem handle created for hdfs://clusterA used with a path hdfs://clusterB/x; passing file:///tmp/x to an HDFS instance; an instance whose URI has null host (file:///) given a path carrying a host.

Common situations: Cached FileSystem instances reused across clusters in a long-lived service; migration/distcp jobs carrying absolute source-cluster paths; wrong fs.defaultFS; viewfs mount tables routing to a different nameservice than the handle.

Related errors

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/de7f96607f31483d. Report an issue: GitHub.