---
id: kafka-emitter
title: "Kafka Emitter"
---

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To use this Apache Druid extension, make sure to [include](../../development/extensions.md#loading-extensions) `kafka-emitter` extension.

## Introduction

This extension emits Druid metrics to [Apache Kafka](https://kafka.apache.org) directly with JSON format.<br>
Currently, Kafka has not only their nice ecosystem but also consumer API readily available.
So, If you currently use Kafka, It's easy to integrate various tool or UI
to monitor the status of your Druid cluster with this extension.

## Configuration

All the configuration parameters for the Kafka emitter are under `druid.emitter.kafka`.

|property|description|required?|default|
|--------|-----------|---------|-------|
|`druid.emitter.kafka.bootstrap.servers`|Comma-separated Kafka broker. (`[hostname:port],[hostname:port]...`)|yes|none|
|`druid.emitter.kafka.metric.topic`|Kafka topic name for emitter's target to emit service metric.|yes|none|
|`druid.emitter.kafka.alert.topic`|Kafka topic name for emitter's target to emit alert.|yes|none|
|`druid.emitter.kafka.producer.config`|JSON formatted configuration which user want to set additional properties to Kafka producer.|no|none|
|`druid.emitter.kafka.clusterName`|Optional value to specify name of your druid cluster. It can help make groups in your monitoring environment. |no|none|

### Example

```
druid.emitter.kafka.bootstrap.servers=hostname1:9092,hostname2:9092
druid.emitter.kafka.metric.topic=druid-metric
druid.emitter.kafka.alert.topic=druid-alert
druid.emitter.kafka.producer.config={"max.block.ms":10000}
```