apache/hadoop · error · UnsupportedOperationException

{} is not supported

Error message

{}  is not supported

What it means

Default branch of the PUT-typed WebHDFS switch on the NameNode (put(), which serves CREATE, MKDIRS, RENAME, SETOWNER, SETSTORAGEPOLICY, SETQUOTA, ALLOWSNAPSHOT, etc.). The op query parameter parsed to a valid Op constant, but that operation is served by another HTTP verb (GET, POST, or DELETE), so the switch falls through to UnsupportedOperationException('<OP> is not supported') — note the doubled space comes from the string concatenation in the source. The client sees an HTTP 400 RemoteException.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/web/resources/NamenodeWebHdfsMethods.java:973

      cp.disableErasureCodingPolicy(ecpolicy.getValue());
      return Response.ok().type(MediaType.APPLICATION_OCTET_STREAM).build();
    case SETECPOLICY:
      validateOpParams(op, ecpolicy);
      cp.setErasureCodingPolicy(fullpath, ecpolicy.getValue());
      return Response.ok().type(MediaType.APPLICATION_OCTET_STREAM).build();
    case SETQUOTA:
      validateOpParams(op, namespaceQuota, storagespaceQuota);
      cp.setQuota(fullpath, namespaceQuota.getValue(),
          storagespaceQuota.getValue(), null);
      return Response.ok().type(MediaType.APPLICATION_OCTET_STREAM).build();
    case SETQUOTABYSTORAGETYPE:
      validateOpParams(op, storagespaceQuota, storageType);
      cp.setQuota(fullpath, HdfsConstants.QUOTA_DONT_SET,
          storagespaceQuota.getValue(),
          StorageType.parseStorageType(storageType.getValue()));
      return Response.ok().type(MediaType.APPLICATION_OCTET_STREAM).build();
    default:
      throw new UnsupportedOperationException(op + "  is not supported");
    }
  }

  /**
   * Handle HTTP POST request for the root.
   *
   * @param ugi User and group information for Hadoop.
   * @param delegation Represents delegation token used for authentication.
   * @param username User parameter.
   * @param doAsUser DoAs parameter for proxy user.
   * @param op Http POST operation parameter.
   * @param concatSrcs The concat source paths parameter.
   * @param bufferSize Buffer size parameter.
   * @param excludeDatanodes Exclude datanodes param.
   * @param newLength NewLength parameter.
   * @param noredirect Overwrite parameter.
   * @return Represents an HTTP response.
   * @throws IOException any IOE raised, or translated exception.

View on GitHub (pinned to 2add963021)

Solutions

1. Check the op in the WebHDFS REST API documentation table and use the HTTP method it lists (GETFILESTATUS->GET, DELETE->DELETE, SETSTORAGEPOLICY->PUT)
2. Fix the client to select the verb from an op-to-method map instead of hardcoding it
3. Reproduce with curl using the documented verb to confirm the cluster is fine
4. If a gateway sits in the path, verify it forwards the original method unchanged

Example fix

# before: GET-only op sent as PUT
curl -X PUT "http://nn:9870/webhdfs/v1/data/f?op=GETFILESTATUS"
# 400 ... UnsupportedOperationException: GETFILESTATUS  is not supported

# after
curl "http://nn:9870/webhdfs/v1/data/f?op=GETFILESTATUS"

private static final Map<String, String> OP_TO_VERB = Map.of(
    "GETFILESTATUS", "GET", "LISTSTATUS", "GET", "OPEN", "GET",
    "MKDIRS", "PUT", "SETSTORAGEPOLICY", "PUT", "RENAME", "PUT",
    "CONCAT", "POST", "UNSETSTORAGEPOLICY", "POST",
    "DELETE", "DELETE", "DELETESNAPSHOT", "DELETE");

static String verbFor(String op) {
  String verb = OP_TO_VERB.get(op.toUpperCase(Locale.ROOT));
  if (verb == null) throw new IllegalArgumentException("unknown WebHDFS op: " + op);
  return verb;
}

static final Set<String> PUT_OPS = Set.of("CREATE", "MKDIRS", "RENAME", "SETREPLICATION",
    "SETOWNER", "SETPERMISSION", "SETTIMES", "SETSTORAGEPOLICY", "SETQUOTA", "SETQUOTABYSTORAGETYPE");
static boolean isPutOp(String op) {
  return PUT_OPS.contains(op.toUpperCase(Locale.ROOT));
}

catch (IOException e) { // RemoteException: java.lang.UnsupportedOperationException
  if (e.getMessage() != null && e.getMessage().endsWith("is not supported")) {
    // op/verb mismatch: re-dispatch with the verb from the op-to-method table
  } else throw e;
}

When it happens

Trigger: Issuing a WebHDFS operation with the wrong verb: curl -X PUT '...?op=GETFILESTATUS' (GET-only), curl -X PUT '...?op=DELETE' (DELETE-only), or curl -X PUT '...?op=CONCAT' (POST-only). Also clients that hardcode one verb for all operations and HTTP gateways that rewrite methods.

Common situations: REST clients generated from a template that fixes the verb; scripts written against older WebHDFS docs where an op moved between methods; curl muscle-memory using -X PUT for every state change; proxies converting verbs (POST-to-PUT rewrites).

Related errors

• {} is not supported
• {} is not supported
• Storage policy name is empty.
• File does not exist: {}
• {} parameter is not null.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/ac6edd60001b864f. Report an issue: GitHub.