Unable to setup fluentd output to kafka with ssl

Question

I have created a sample fluentd.config to send output to kafka with ssl. But while running the fluentd pod with the below config. Getting error

2022-05-11 18:55:05 +0000 [warn]: #0 suppressed same stacktrace

2022-05-11 18:55:07 +0000 [warn]: #0 Send exception occurred: Local: Invalid argument or configuration (invalid_arg) at /fluentd/vendor/bundle/ruby/2.7.0/gems/rdkafka-0.7.0/lib/rdkafka/producer.rb:135:in `produce'

What is the exact config for output kafka with SSL?

  fluent.conf: |
      <source>
        @type dummy
        dummy {"hello":"world"}
        tag test
      </source>
      
      <match test>
        @type rdkafka
        brokers               'test_kafka_broker:9001'
        ssl_ca_cert           '/fluentd/etc/client/ca-cert'
        ssl_client_cert       '/fluentd/etc/client/client-cert.pem'
        ssl_client_cert_key   '/fluentd/etc/client/client.key'
        
        
        <format>
          @type json
        </format>
        topic_key             'test_fluentd_kafka_topic'
     
        <buffer topic>
          flush_interval 10s
        </buffer>
      </match>