druid/docs/content/development/extensions-contrib/kafka-simple.md

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Kafka Simple Consumer

To use this extension, make sure to include druid-kafka-eight-simpleConsumer extension.

Firehose

This is an experimental firehose to ingest data from kafka using kafka simple consumer api. Currently, this firehose would only work inside standalone realtime nodes. The configuration for KafkaSimpleConsumerFirehose is similar to the Kafka Eight Firehose , except firehose should be replaced with firehoseV2 like this:

"firehoseV2": {
  "type" : "kafka-0.8-v2",
  "brokerList" :  ["localhost:4443"],
  "queueBufferLength":10001,
  "resetOffsetToEarliest":"true",
  "partitionIdList" : ["0"],
  "clientId" : "localclient",
  "feed": "wikipedia"
}

property	description	required?
type	kafka-0.8-v2	yes
brokerList	list of the kafka brokers	yes
queueBufferLength	the buffer length for kafka message queue	no default(20000)
resetOffsetToEarliest	in case of kafkaOffsetOutOfRange error happens, consumer should starts from the earliest or latest message available	true
partitionIdList	list of kafka partition ids	yes
clientId	the clientId for kafka SimpleConsumer	yes
feed	kafka topic	yes

For using this firehose at scale and possibly in production, it is recommended to set replication factor to at least three, which means at least three Kafka brokers in the brokerList. For a 1*10^4 events per second kafka topic, keeping one partition can work properly, but more partitions could be added if higher throughput is required.