apache/cassandra · error · ConfigurationException

Login config name specified for JMX auth, but no…

Error message

Login config name %s specified for JMX auth, but no configuration is available. Please set config location in cassandra.yaml or with the '%s' system property

What it means

When JMX authentication is configured (cassandra.yaml jmx remote auth specifies a login module/config name) but no JAAS login configuration file location is provided, JMXServerUtils.configureJmxAuthentication throws ConfigurationException at server startup. The config name alone is unusable without the JAAS config file.

Solutions

1. Set the system property -Dcassandra.jmx.server.security.login.config=/path/to/jaas.config
2. Pass the login config file via the JMX server startup option (login_config_file)
3. Remove/comment the login config name in cassandra.yaml if JMX auth is not intended

Example fix

// before (cassandra-env.sh)
JVM_OPTS="$JVM_OPTS -Dcassandra.jmx.remote.auth.login.config=CustomLogin"
// after
JVM_OPTS="$JVM_OPTS -Dcassandra.jmx.remote.auth.login.config=CustomLogin"
JVM_OPTS="$JVM_OPTS -Dcassandra.jmx.server.security.login.config=/etc/cassandra/jaas.config"

String loginConfig = System.getProperty("cassandra.jmx.server.security.login.config");
if (cassandraYamlSetsJmxAuth && (loginConfig == null || loginConfig.isEmpty()))
    throw new IllegalStateException("JMX auth requires -Dcassandra.jmx.server.security.login.config");

try { JMXServerUtils.createJMXServer(...); } catch (ConfigurationException e) { logger.error("JMX startup failed: {}", e.getMessage()); throw e; }

When it happens

Trigger: cassandra.yaml sets jmx remote authentication (login config name) but neither JAVA_SECURITY_AUTH_LOGIN_CONFIG system property (-Dcassandra.jmx.server.security.login.config) nor the login_config_file startup option is set.

Common situations: Enabling JMX auth in cassandra.yaml but forgetting -Dcassandra.jmx.server.security.login.config=... or the --login-config-file option; migrating JMX setups between versions where the property name changed; operator sets the config name but not the file.

Understand the failure class

Background: "is required", "must be set", "missing required field": configuration validation errors across open-source libraries — this error's family across 36 libraries.

Related errors

• Authentication error
• JAAS login configuration missing for JMX authenticator setup
• Can't enable audit log archiving via nodetool unless…
• Can't enable full query log archiving via nodetool unless…
• Cannot set concurrent_validations greater than…

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/ec86b3f38be52fbc. Report an issue: GitHub.

Appendix: source

Thrown at src/java/org/apache/cassandra/utils/JMXServerUtils.java:187

        // If authentication is enabled, initialize the appropriate JMXAuthenticator
        // and stash it in the environment settings.
        // A JAAS configuration entry takes precedence. If one is supplied, use
        // Cassandra's own custom JMXAuthenticator implementation which delegates
        // auth to the LoginModules specified by the JAAS configuration entry.
        // If no JAAS entry is found, an instance of the JDK's own
        // JMXPluggableAuthenticator is created. In that case, the admin may have
        // set a location for the JMX password file which must be added to env
        // before creating the authenticator. If no password file has been
        // explicitly set, it's read from the default location
        // $JAVA_HOME/lib/management/jmxremote.password
        String configEntry = options.login_config_name;
        if (configEntry != null)
        {
            if (Strings.isNullOrEmpty(CassandraRelevantProperties.JAVA_SECURITY_AUTH_LOGIN_CONFIG.getString()))
            {
                if (Strings.isNullOrEmpty(options.login_config_file))
                {
                    throw new ConfigurationException(String.format("Login config name %s specified for JMX auth, but no " +
                                                                   "configuration is available. Please set config " +
                                                                   "location in cassandra.yaml or with the " +
                                                                   "'%s' system property",
                                                                   configEntry,
                                                                   CassandraRelevantProperties.JAVA_SECURITY_AUTH_LOGIN_CONFIG.getKey()));
                }
                else
                {
                    CassandraRelevantProperties.JAVA_SECURITY_AUTH_LOGIN_CONFIG.setString(options.login_config_file);
                }
            }
            env.put(JMXConnectorServer.AUTHENTICATOR, new AuthenticationProxy(configEntry));
        }
        else
        {
            String passwordFile = options.password_file;
            if (passwordFile != null)
            {

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