apache/hadoop · error · IOException

Failed to connect to: ${url}

Error message

Failed to connect to: ${url}

What it means

Error "Failed to connect to: ${url}" thrown in apache/hadoop.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/crypto/key/kms/KMSClientProvider.java:519

  private HttpURLConnection createConnection(final URL url, String method)
      throws IOException {
    HttpURLConnection conn;
    try {
      final String doAsUser = getDoAsUser();
      conn = getActualUgi().doAs(new PrivilegedExceptionAction
          <HttpURLConnection>() {
        @Override
        public HttpURLConnection run() throws Exception {
          DelegationTokenAuthenticatedURL authUrl =
              createAuthenticatedURL();
          return authUrl.openConnection(url, authToken, doAsUser);
        }
      });
    } catch (ConnectException ex) {
      String msg = "Failed to connect to: " + url.toString();
      LOG.warn(msg);
      throw new IOException(msg, ex);
    } catch (SocketTimeoutException ex) {
      LOG.warn("Failed to connect to {}:{}", url.getHost(), url.getPort());
      throw ex;
    } catch (IOException ex) {
      throw ex;
    } catch (UndeclaredThrowableException ex) {
      throw new IOException(ex.getUndeclaredThrowable());
    } catch (Exception ex) {
      throw new IOException(ex);
    }
    conn.setUseCaches(false);
    conn.setRequestMethod(method);
    if (method.equals(HTTP_POST) || method.equals(HTTP_PUT)) {
      conn.setDoOutput(true);
    }
    conn = configureConnection(conn);
    return conn;
  }

View on GitHub (pinned to 2add963021)

Solutions

1. Verify network connectivity and that the KMS server is running at the configured URL.

Example fix

curl the KMS endpoint and fix firewall/DNS issues.

When it happens

Trigger: Raised at runtime when the documented precondition or configuration requirement for this operation is violated.

Common situations: Misconfigured or missing property, invalid user input, or calling the API before its prerequisites are met.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/e2413cfe37c538dc. Report an issue: GitHub.