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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
Specify timestamp format, should be 'double', 'iso8601' (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​
​
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

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' (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

Last modified 2mo ago