Kafka

Kafka output plugin allows to ingest your records into an Apache Kafka service. This plugin use the official librdkafka C library (built-in dependency)

Configuration Parameters

Key Description default
format Specify data format, options available: json, msgpack. json
message_key Optional key to store the message
message_key_field If set, the value of Message_Key_Field in the record will indicate the message key. If not set nor found in the record, Message_Key will be used (if set).
timestamp_key Set the key to store the record timestamp @timestamp
timestamp_format ‘iso8601’ or ‘double’ double
brokers Single of multiple list of Kafka Brokers, e.g: 192.168.1.3:9092, 192.168.1.4:9092.
topics Single entry or list of topics separated by comma (,) that Fluent Bit will use to send messages to Kafka. If only one topic is set, that one will be used for all records. Instead if multiple topics exists, the one set in the record by Topic_Key will be used. fluent-bit
topic_key If multiple Topics exists, the value of Topic_Key in the record will indicate the topic to use. E.g: if Topic_Key is router and the record is {“key1”: 123, “router”: “route_2”}, Fluent Bit will use topic route_2. Note that if the value of Topic_Key is not present in Topics, then by default the first topic in the Topics list will indicate the topic to be used.
dynamic_topic adds unknown topics (found in Topic_Key) to Topics. So in Topics only a default topic needs to be configured Off
queue_full_retries Fluent Bit queues data into rdkafka library, if for some reason the underlaying library cannot flush the records the queue might fills up blocking new addition of records. The queue_full_retries option set the number of local retries to enqueue the data. The default value is 10 times, the interval between each retry is 1 second. Setting the queue_full_retries value to 0 set’s an unlimited number of retries. 10
rdkafka.{property} {property} can be any librdkafka properties

Setting rdkafka.log.connection.close to false and rdkafka.request.required.acks to 1 are examples of recommended settings of librdfkafka properties.

Getting Started

In order to insert records into Apache Kafka, you can run the plugin from the command line or through the configuration file:

Command Line

The kafka plugin, can read the parameters from the command line in two ways, through the -p argument (property), e.g:

  1. $ fluent-bit -i cpu -o kafka -p brokers=192.168.1.3:9092 -p topics=test

Configuration File

In your main configuration file append the following Input & Output sections:

  1. [INPUT]
  2. Name cpu
  3. [OUTPUT]
  4. Name kafka
  5. Match *
  6. Brokers 192.168.1.3:9092
  7. Topics test