Kafka producer time outs in wso2 esb - wso2

Question

We are getting below exception with Kafka 2.11 and wso2 esb 6.2 with sasl enabled. SASL mechanism in wso2 esb and Kafka clsuter is PALIN but randmoly seeing Error 2 in logs.
Does anybody experienced this error and any help is appreciated.
Error 1:
java.util.concurrent.ExecutionException: org.apache.kafka.common.errors.TimeoutException: Expiring 1 record(s) for TESTTOPIC: 30051 ms has passed since batch creation plus linger time
Error 2:
[2019-11-02 01:36:50,265] ERROR - [Producer clientId=producer-4526] Connection to node -1 failed authentication due to: Unexpected handshake request with client mechanism PLAIN, enabled mechanisms are [GSSAPI] {org.apache.kafka.clients.NetworkClient}

Answer 1

Based on the Second Error Message *Unexpected handshake request with client mechanism PLAIN, enabled mechanisms are [GSSAPI]*, it would seem that the saslMechanism has not been configured properly on the ESB side. It is configured to GSSAPI Kerberos by default.
I would recommend getting the latest version of the Kafka Connector. You can find the documentation and the relevant links here
One such example of a PLAIN configuration with the Kafka Connector would be :
<kafkaTransport.init>
<bootstrapServers>localhost:9092</bootstrapServers>
<keySerializerClass>org.apache.kafka.common.serialization.StringSerializer</keySerializerClass>
<valueSerializerClass>org.apache.kafka.common.serialization.StringSerializer</valueSerializerClass>
<securityProtocol> SASL_PLAINTEXT </securityProtocol>
<saslMechanism> PLAIN </saslMechanism>
<saslJaasConfig>org.apache.kafka.common.security.plain.PlainLoginModule required username="admin" password="12345"</saslJaasConfig>
<maxPoolSize>100</maxPoolSize>
</kafkaTransport.init>
This is the relevant configuration required to make use of the Kafka Connector. The Security Protocol can be configured to SASL_SSL as well.
Here is one such proxy configuration
<?xml version="1.0" encoding="UTF-8"?>
<proxy xmlns="http://ws.apache.org/ns/synapse"
name="KafkaTransport"
startOnLoad="true"
statistics="disable"
trace="disable"
transports="http,https">
<target>
<inSequence>
<kafkaTransport.init>
<bootstrapServers>localhost:9092</bootstrapServers>
<keySerializerClass>org.apache.kafka.common.serialization.StringSerializer</keySerializerClass>
<valueSerializerClass>org.apache.kafka.common.serialization.StringSerializer</valueSerializerClass>
<securityProtocol>SASL_SSL</securityProtocol>
<saslMechanism>PLAIN</saslMechanism>
<sslKeystoreLocation>/Users/Ibaqu/kafka.client.keystore.jks</sslKeystoreLocation>
<sslKeystorePassword>admin123</sslKeystorePassword>
<sslTruststoreLocation>/Users/Ibaqu/kafka.client.trustore.jks</sslTruststoreLocation>
<sslTruststorePassword>admin123</sslTruststorePassword>
<saslJaasConfig>org.apache.kafka.common.security.plain.PlainLoginModule required username="admin" password="12345";</saslJaasConfig>
<maxPoolSize>100</maxPoolSize>
</kafkaTransport.init>
<kafkaTransport.publishMessages>
<topic>test</topic>
</kafkaTransport.publishMessages>
</inSequence>
</target>
<description/>
</proxy>
You can give this particular proxy a try to test your connection.