# Kafka Kafka output plugin allows to ingest your records into an [Apache Kafka](https://kafka.apache.org/) service. This plugin use the official [librdkafka C library](https://github.com/edenhill/librdkafka) (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 | Specify timestamp format, should be 'double', '[iso8601](https://en.wikipedia.org/wiki/ISO_8601)' (seconds precision) or 'iso8601\_ns' (fractional seconds precision) | double | | brokers | Single or 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 underlying 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](https://github.com/edenhill/librdkafka/blob/master/CONFIGURATION.md) | | > 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 parameters through the **-p** argument (property), e.g: ``` $ 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: ``` [INPUT] Name cpu [OUTPUT] Name kafka Match * Brokers 192.168.1.3:9092 Topics test ``` ### Avro Support Fluent-bit comes with support for avro encoding for the out\_kafka plugin. Avro support is optional and must be activated at build-time by using a build def with cmake: `-DFLB_AVRO_ENCODER=On` such as in the following example which activates: * out\_kafka with avro encoding * fluent-bit's prometheus * metrics via an embedded http endpoint * debugging support * builds the test suites ``` cmake -DFLB_DEV=On -DFLB_OUT_KAFKA=On -DFLB_TLS=On -DFLB_TESTS_RUNTIME=On -DFLB_TESTS_INTERNAL=On -DCMAKE_BUILD_TYPE=Debug -DFLB_HTTP_SERVER=true -DFLB_AVRO_ENCODER=On ../ ``` #### Kafka Configuration File with Avro Encoding This is example fluent-bit config tails kubernetes logs, decorates the log lines with kubernetes metadata via the kubernetes filter, and then sends the fully decorated log lines to a kafka broker encoded with a specific avro schema. ``` [INPUT] Name tail Tag kube.* Alias some-alias Path /logdir/*.log DB /dbdir/some.db Skip_Long_Lines On Refresh_Interval 10 Parser some-parser [FILTER] Name kubernetes Match kube.* Kube_URL https://some_kube_api:443 Kube_CA_File /certs/ca.crt Kube_Token_File /tokens/token Kube_Tag_Prefix kube.var.log.containers. Merge_Log On Merge_Log_Key log_processed [OUTPUT] Name kafka Match * Brokers 192.168.1.3:9092 Topics test Schema_str {"name":"avro_logging","type":"record","fields":[{"name":"timestamp","type":"string"},{"name":"stream","type":"string"},{"name":"log","type":"string"},{"name":"kubernetes","type":{"name":"krec","type":"record","fields":[{"name":"pod_name","type":"string"},{"name":"namespace_name","type":"string"},{"name":"pod_id","type":"string"},{"name":"labels","type":{"type":"map","values":"string"}},{"name":"annotations","type":{"type":"map","values":"string"}},{"name":"host","type":"string"},{"name":"container_name","type":"string"},{"name":"docker_id","type":"string"},{"name":"container_hash","type":"string"},{"name":"container_image","type":"string"}]}},{"name":"cluster_name","type":"string"},{"name":"fabric","type":"string"}]} Schema_id some_schema_id rdkafka.client.id some_client_id rdkafka.debug All rdkafka.enable.ssl.certificate.verification true rdkafka.ssl.certificate.location /certs/some.cert rdkafka.ssl.key.location /certs/some.key rdkafka.ssl.ca.location /certs/some-bundle.crt rdkafka.security.protocol ssl rdkafka.request.required.acks 1 rdkafka.log.connection.close false Format avro rdkafka.log_level 7 rdkafka.metadata.broker.list 192.168.1.3:9092 ```