Kafka input to logstash plugin
Your kafka input config needs to be like this instead:
kafka { bootstrap_servers => "localhost:9092" topics => "kafkatest2" }You don't connect to Zookeeper anymore, but directly to one of your Kafka brokers. Also the topic_id setting should read topics instead.
You can find the latest configuration options at: https://www.elastic.co/guide/en/logstash/current/plugins-inputs-kafka.html