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Fluent Bit is a fast Log Processor and Forwarder for Linux, Windows, Embedded Linux, MacOS and BSD family operating systems. It's part of the Graduated Fluentd Ecosystem and a CNCF sub-project.

Fluent Bit allows to collect log events or metrics from different sources, process them and deliver them to different backends such as Fluentd, Elasticsearch, Splunk, DataDog, Kafka, New Relic, Azure services, AWS services, Google services, NATS, InfluxDB or any custom HTTP end-point.

Fluent Bit comes with full SQL Stream Processing capabilities: data manipulation and analytics using SQL queries.

Fluent Bit runs on x86_64, x86, arm32v7, and arm64v8 architectures.


  • High Performance at low CPU and Memory footprint
  • Data Parsing
  • Reliability and Data Integrity
  • Networking
    • Security: built-in TLS/SSL support
    • Asynchronous I/O
  • Pluggable Architecture and Extensibility: Inputs, Filters and Outputs
  • Monitoring: expose internal metrics over HTTP in JSON and Prometheus format
  • Stream Processing: Perform data selection and transformation using simple SQL queries
    • Create new streams of data using query results
    • Aggregation Windows
    • Data analysis and prediction: Timeseries forecasting
  • Portable: runs on Linux, MacOS, Windows and BSD systems

Fluent Bit in Production

Fluent Bit is used widely in production environments. As of 2022, Fluent Bit surpasses 3 Billion downloads and continues to be deployed over 10 million times a day. The following is a preview of who uses Fluent Bit heavily in production:

If your company uses Fluent Bit and is not listed, feel free to open a GitHub issue and we will add the logo.


Our official project documentation for installation, configuration, deployment and development topics is located here:

Quick Start

Build from Scratch

If you aim to build Fluent Bit from sources, you can go ahead and start with the following commands.

cd build
cmake ..
bin/fluent-bit -i cpu -o stdout -f 1

If you are interested into more details, please refer to the Build & Install section.


  • CMake >= 3.0
  • Flex
  • Bison
  • YAML library/headers
  • OpenSSL library/headers

Linux Packages

We provide packages for most common Linux distributions:

Linux / Docker Container Images

Our Linux containers images are the most common deployment model, thousands of new installation happen every day, learn more about the available images and tags here.

Windows Packages

Fluent Bit is fully supported on Windows environments, get started with these instructions.

Running on s390x

Fluent Bit is supported on Linux on IBM Z(s390x), but the WASM and LUA filter plugins are not.

Plugins: Inputs, Filters and Outputs

Fluent Bit is based in a pluggable architecture where different plugins plays a major role in the data pipeline:

Input Plugins

name title description
collectd Collectd Listen for UDP packets from Collectd.
cpu CPU Usage measure total CPU usage of the system.
disk Disk Usage measure Disk I/Os.
dummy Dummy generate dummy event.
exec Exec executes external program and collects event logs.
forward Forward Fluentd forward protocol.
head Head read first part of files.
health Health Check health of TCP services.
kmsg Kernel Log Buffer read the Linux Kernel log buffer messages.
mem Memory Usage measure the total amount of memory used on the system.
mqtt MQTT start a MQTT server and receive publish messages.
netif Network Traffic measure network traffic.
proc Process Check health of Process.
random Random Generate Random samples.
serial Serial Interface read data information from the serial interface.
stdin Standard Input read data from the standard input.
syslog Syslog read syslog messages from a Unix socket.
systemd Systemd read logs from Systemd/Journald.
tail Tail Tail log files.
tcp TCP Listen for JSON messages over TCP.
thermal Thermal measure system temperature(s).

Filter Plugins

name title description
aws AWS Metadata Enrich logs with AWS Metadata.
expect Expect Validate records match certain criteria in structure.
grep Grep Match or exclude specific records by patterns.
kubernetes Kubernetes Enrich logs with Kubernetes Metadata.
lua Lua Filter records using Lua Scripts.
parser Parser Parse record.
record_modifier Record Modifier Modify record.
rewrite_tag Rewrite Tag Re-emit records under new tag.
stdout Stdout Print records to the standard output interface.
throttle Throttle Apply rate limit to event flow.
nest Nest Nest records under a specified key
modify Modify Modifications to record.

Output Plugins

name title description
azure Azure Log Analytics Ingest records into Azure Log Analytics
bigquery BigQuery Ingest records into Google BigQuery
counter Count Records Simple records counter.
datadog Datadog Ingest logs into Datadog.
es Elasticsearch flush records to a Elasticsearch server.
file File Flush records to a file.
flowcounter FlowCounter Count records.
forward Forward Fluentd forward protocol.
gelf GELF Flush records to Graylog
http HTTP Flush records to an HTTP end point.
influxdb InfluxDB Flush records to InfluxDB time series database.
kafka Apache Kafka Flush records to Apache Kafka
kafka-rest Kafka REST Proxy Flush records to a Kafka REST Proxy server.
loki Loki Flush records to Loki server.
nats NATS Flush records to a NATS server.
null NULL Throw away events.
s3 S3 Flush records to s3
stackdriver Google Stackdriver Logging Flush records to Google Stackdriver Logging service.
stdout Standard Output Flush records to the standard output.
splunk Splunk Flush records to a Splunk Enterprise service
tcp TCP & TLS Flush records to a TCP server.
td Treasure Data Flush records to the Treasure Data cloud service for analytics.


Fluent Bit is an open project, several individuals and companies contribute in different forms like coding, documenting, testing, spreading the word at events within others. If you want to learn more about contributing opportunities please reach out to us through our Community Channels.

If you are interested in contributing to Fluent bit with bug fixes, new features or coding in general, please refer to the code CONTRIBUTING guidelines. You can also refer the Beginners Guide to contributing to Fluent Bit here.

Community & Contact

Feel free to join us on our Slack channel, Mailing List or IRC:


This program is under the terms of the Apache License v2.0.


Fluent Bit is sponsored and maintained by several companies in the Cloud Native community, including all the major cloud providers.

You can see a list of contributors here.