Kafka SASL_SSL No JAAS configuration section named 'Client' was found in specified JAAS configuration file - apache-kafka

Question

I'm trying to activate authentication using SASL/PLAIN in my kafka broker.
the JAAS configuration file is as the following
KafkaServer {
org.apache.kafka.common.security.plain.PlainLoginModule required
username="admin"
password="admin-secret"
user_admin="admin-secret"
user_alice="alice-secret";
};
I launch kafka service using the following commands
export KAFKA_OPTS="-Djava.security.auth.login.config=<PATH>kafka_server_jaas.conf
/bin/kafka-server-start.sh /config/server.properties
The kafka service is not started properly and I got these errors in the log
javax.security.auth.login.LoginException: No JAAS configuration section named 'Client' was found in specified JAAS configuration file: '/home/kafka/kafka/config/kafka_server_jaas.conf'.
at org.apache.zookeeper.client.ZooKeeperSaslClient.<init>(ZooKeeperSaslClient.java:189)
at org.apache.zookeeper.ClientCnxn$SendThread.startConnect(ClientCnxn.java:1161)
at org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1210)
[2022-03-16 12:13:16,587] INFO Opening socket connection to server localhost/127.0.0.1:2181. (org.apache.zookeeper.ClientCnxn)
[2022-03-16 12:13:16,588] ERROR [ZooKeeperClient Kafka server] Auth failed, initialized=false connectionState=CONNECTING (kafka.zookeeper.ZooKeeperClient)
[2022-03-16 12:13:16,592] INFO Socket connection established, initiating session, client: /127.0.0.1:46706, server: localhost/127.0.0.1:2181 (org.apache.zookeeper.ClientCnxn)
[2022-03-16 12:13:16,611] INFO Session establishment complete on server localhost/127.0.0.1:2181, session id = 0x100002dd98c0000, negotiated timeout = 18000 (org.apache.zookeeper.ClientCnxn)
[2022-03-16 12:13:16,612] INFO [ZooKeeperClient Kafka server] Connected. (kafka.zookeeper.ZooKeeperClient)
[2022-03-16 12:13:16,752] INFO [feature-zk-node-event-process-thread]: Starting (kafka.server.FinalizedFeatureChangeListener$ChangeNotificationProcessorThread)
[2022-03-16 12:13:16,786] INFO Feature ZK node at path: /feature does not exist (kafka.server.FinalizedFeatureChangeListener)
[2022-03-16 12:13:16,788] INFO Cleared cache (kafka.server.FinalizedFeatureCache)
[2022-03-16 12:13:16,957] INFO Cluster ID = 6WTadNCMRAW4dHoc_JUnIg (kafka.server.KafkaServer)
[2022-03-16 12:13:16,968] ERROR Fatal error during KafkaServer startup. Prepare to shutdown (kafka.server.KafkaServer)
kafka.common.InconsistentClusterIdException: The Cluster ID 6WTadNCMRAW4dHoc_JUnIg doesn't match stored clusterId Some(RJXzPwJeRfawIa_yA0B26A) in meta.properties. The broker is trying to join the wrong cluster. Configured zookeeper.connect may be wrong.
at kafka.server.KafkaServer.startup(KafkaServer.scala:228)
at kafka.Kafka$.main(Kafka.scala:109)
at kafka.Kafka.main(Kafka.scala)
I already added the following lines to server.properties
listeners=SASL_SSL://localhost:9092
security.protocol=SASL_SSL
security.inter.broker.protocol=SASL_SSL
sasl.mechanism.inter.broker.protocol=PLAIN
sasl.enabled.mechanisms=PLAIN

Answer 1

[2022-03-16 12:13:16,968] ERROR Fatal error during KafkaServer startup. Prepare to shutdown (kafka.server.KafkaServer)
kafka.common.InconsistentClusterIdException: The Cluster ID 6WTadNCMRAW4dHoc_JUnIg doesn't match stored clusterId Some(RJXzPwJeRfawIa_yA0B26A) in meta.properties. The broker is trying to join the wrong cluster. Configured zookeeper.connect may be wrong.
at kafka.server.KafkaServer.startup(KafkaServer.scala:228)
at kafka.Kafka$.main(Kafka.scala:109)
at kafka.Kafka.main(Kafka.scala)
This issue occurs when there is a mismatch in cluster ID stored in Zookeeper and Kafka data directories for the broker.
In this case, cluster ID of the broker stored in
Zookeeper data is 6WTadNCMRAW4dHoc_JUnIg
Kafka meta.properties is RJXzPwJeRfawIa_yA0B26A
Reason:
Zookeeper data directory got deleted.
Deleting Zookeeper dataDir and restarting both Zookeeper and Kafka service will not work. Because Zookeeper creates a new Cluster ID and assigns it to the broker when it registers and if there is no entry already. This new cluster ID will be different from the one in meta.properties.
This issue can be fixed by following below steps
delete both Kafka log.dirs and Zookeeper dataDir - results in data loss; Both Kafka and Zookeeper service needs to be restarted
delete meta.properties in Kafka log.dirs directory - no data loss; Kafka service needs to be started anyway
update cluster ID in meta.properties with the value stored in Zookeeper data; In this case, replace RJXzPwJeRfawIa_yA0B26A with 6WTadNCMRAW4dHoc_JUnIg - no data loss; Kafka service needs to be started anyway
javax.security.auth.login.LoginException: No JAAS configuration section named 'Client' was found in specified JAAS configuration file
The Client section is used to authenticate a SASL connection with ZooKeeper. Above error javax.security.auth.login.LoginException is a warning and Kafka will connect to Zookeeper server without SASL authentication if Zookeeper allows it.
[2022-03-16 12:13:16,587] INFO Opening socket connection to server localhost/127.0.0.1:2181. (org.apache.zookeeper.ClientCnxn)
[2022-03-16 12:13:16,588] ERROR [ZooKeeperClient Kafka server] Auth failed, initialized=false connectionState=CONNECTING (kafka.zookeeper.ZooKeeperClient)
[2022-03-16 12:13:16,592] INFO Socket connection established, initiating session, client: /127.0.0.1:46706, server: localhost/127.0.0.1:2181 (org.apache.zookeeper.ClientCnxn)
[2022-03-16 12:13:16,611] INFO Session establishment complete on server localhost/127.0.0.1:2181, session id = 0x100002dd98c0000, negotiated timeout = 18000 (org.apache.zookeeper.ClientCnxn)
The KafkaServer section is used by the Broker and provides SASL configuration options for inter broker connection. The username and password are used by the broker to initiate connections to other brokers. The set of properties user_username defines the passwords for all users to connect to the broker.