apache/hadoop · error · IllegalArgumentException

channelModeString + " is not a valid value for fs.s3a.ssl.ch

Error message

channelModeString + " is not a valid value for fs.s3a.ssl.channel.mode

What it means

Error "channelModeString + " is not a valid value for fs.s3a.ssl.channel.mode" thrown in apache/hadoop.

Source

Thrown at hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/impl/NetworkBinding.java:77

   * @param httpClientBuilder the http client builder.
   * @throws IOException if there is an error while initializing the
   * {@code SSLSocketFactory} other than classloader problems.
   */
  public static void bindSSLChannelMode(Configuration conf,
      ApacheHttpClient.Builder httpClientBuilder) throws IOException {

    // Validate that SSL_CHANNEL_MODE is set to a valid value.
    String channelModeString = conf.getTrimmed(
            SSL_CHANNEL_MODE, DEFAULT_SSL_CHANNEL_MODE.name());
    DelegatingSSLSocketFactory.SSLChannelMode channelMode = null;
    for (DelegatingSSLSocketFactory.SSLChannelMode mode :
            DelegatingSSLSocketFactory.SSLChannelMode.values()) {
      if (mode.name().equalsIgnoreCase(channelModeString)) {
        channelMode = mode;
      }
    }
    if (channelMode == null) {
      throw new IllegalArgumentException(channelModeString +
              " is not a valid value for " + SSL_CHANNEL_MODE);
    }

    DelegatingSSLSocketFactory.initializeDefaultFactory(channelMode);
    try {
      // use reflection to load in our own binding class.
      // this is *probably* overkill, but it is how we can be fully confident
      // that no attempt will be made to load/link to the AWS Shaded SDK except
      // within this try/catch block
      Class<? extends ConfigureAWSSocketFactory> clazz =
          (Class<? extends ConfigureAWSSocketFactory>) Class.forName(BINDING_CLASSNAME);
      clazz.getConstructor()
          .newInstance()
          .configureSocketFactory(httpClientBuilder, channelMode);
    } catch (ClassNotFoundException | NoSuchMethodException |
            IllegalAccessException | InstantiationException |
            InvocationTargetException | LinkageError  e) {
      LOG.debug("Unable to create class {}, value of {} will be ignored",

View on GitHub (pinned to 2add963021)

Solutions

1. Set fs.s3a.ssl.channel.mode to a valid value such as default or openssl.

When it happens

Trigger: Thrown at hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/impl/NetworkBinding.java:77 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

• SSL/TLS and certificate errors — how TLS handshakes and certificate validation fail.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/1f171c31f37f25a3. Report an issue: GitHub.