nathanmarz/storm · error · IOException

Could not find a ' ' entry in this configuration.

Error message

Could not find a '${section}' entry in this configuration.

What it means

AuthUtils.get(Configuration, section, key) reads a named option from a section of a loaded JAAS login Configuration. It throws IOException when configuration.getAppConfigurationEntry(section) returns null, i.e. the JAAS file loaded successfully but has no entry with the requested section name (e.g. "ServerClient" or the topology-specific section).

Solutions

  1. Add the missing section to the JAAS login configuration file, e.g. `StormClient { org.apache.storm.security.auth.kerberos.KerberosLoginModule required ...; };`.
  2. Rename the section in the JAAS file to match the section name the code requests.
  3. Verify which section name is passed to AuthUtils.get / the transport plugin and align it with the file.
  4. Regenerate the login file from Storm's documented SASL setup so standard sections are present.

Example fix

// before (jaas.conf)
Client { com.sun.security.auth.module.Krb5LoginModule required ...; };
// after
StormClient { org.apache.storm.security.auth.kerberos.KerberosLoginModule required
  useKeyTab=true keyTab="/etc/storm/storm.keytab" principal="storm@REALM";
};
Defensive patterns

Strategy: validation

Validate before calling

// Java
AppConfigurationEntry[] entries = configuration.getAppConfigurationEntry(section);
if (entries == null) throw new IllegalStateException("JAAS file lacks section '" + section + "'; add it or fix the section name");

Type guard

boolean hasSection(Configuration c, String section) {
    return c.getAppConfigurationEntry(section) != null;
}

Try / catch

try {
    String value = AuthUtils.get(configuration, section, key);
} catch (IOException e) {
    if (e.getMessage().contains("entry in this configuration")) {
        LOG.error("Section '" + section + "' missing from JAAS config; expected StormClient/StormServer blocks");
    }
    throw e;
}

Prevention

When it happens

Trigger: Calling AuthUtils.get(loginConf, section, key) where the loaded JAAS configuration has no block matching `section` — e.g. requesting section "StormClient"/"StormServer" while the login file only defines other section names, or passing a topology-name-derived section that the login file doesn't define.

Common situations: JAAS file uses nonstandard section names while code expects Storm's conventional ones (StormClient, StormServer, Client, Server); copy-pasting a Kafka/ZooKeeper JAAS file with sections like KafkaClient; missing topology-specific sections required by SASL transport plugins.

Related errors

AI-assisted analysis of nathanmarz/storm@cdb116e942 (2026-09-12). Data as JSON: /api/errors/0e77b85a108ce80a. Report an issue: GitHub.

Appendix: source

Thrown at storm-core/src/jvm/backtype/storm/security/auth/AuthUtils.java:87

     */
    public static ITransportPlugin GetTransportPlugin(Map storm_conf, Configuration login_conf) {
        ITransportPlugin  transportPlugin = null;
        try {
            String transport_plugin_klassName = (String) storm_conf.get(Config.STORM_THRIFT_TRANSPORT_PLUGIN);
            Class klass = Class.forName(transport_plugin_klassName);
            transportPlugin = (ITransportPlugin)klass.newInstance();
            transportPlugin.prepare(storm_conf, login_conf);
        } catch(Exception e) {
            throw new RuntimeException(e);
        } 
        return transportPlugin;
    }

    public static String get(Configuration configuration, String section, String key) throws IOException {
        AppConfigurationEntry configurationEntries[] = configuration.getAppConfigurationEntry(section);
        if (configurationEntries == null) {
            String errorMessage = "Could not find a '"+ section + "' entry in this configuration.";
            throw new IOException(errorMessage);
        }

        for(AppConfigurationEntry entry: configurationEntries) {
            Object val = entry.getOptions().get(key); 
            if (val != null) 
                return (String)val;
        }
        return null;
    }
}

View on GitHub (pinned to cdb116e942)