Enabling PLAINTEXT inter broker security

[cs user]

Hi All,

I'm dipping my toes into kafka security, I'm following the guide here:
http://kafka.apache.org/documentation.html#security_sasl_plain_brokerconfig
 and http://kafka.apache.org/documentation.html#security_sasl_brokerconfig

My jaas config file looks like:

    KafkaServer {
        org.apache.kafka.common.security.plain.PlainLoginModule required
        username="admin"
        password="admin-secret"
        user_admin="admin-secret"
        user_alice="alice-secret";
    };

I pass the following to kafka on startup to load the above in:

-Djava.security.auth.login.config=/etc/kafka/kafka_server_jaas.conf


I'm using the following for my broker settings, using PLAINTEXT throughout:

    listeners=SASL_PLAINTEXT://host.name:port
    security.inter.broker.protocol=SASL_SSL
    sasl.mechanism.inter.broker.protocol=PLAIN
    sasl.enabled.mechanisms=PLAIN



However when kafka starts up I get the following error message:

Caused by: javax.security.auth.login.LoginException: unable to find
LoginModule class: org.apache.kafka.common.security.plain.PlainLoginModule

Any idea why I would be getting this error?

Thanks!