Skip to content

Getting Started

Verified against the v1.19 series. Commands assume a Unix shell with Ruby installed.

Prerequisites

  • Ruby 3.2 or later (fluentd.gemspec:28, README Prerequisites)

Install

bash
gem install fluentd

A first working setup

The README Quick Start gets you from install to a confirmed event in four commands (source 1).

  1. Generate a sample configuration directory.

    bash
    fluentd -s conf
  2. Start Fluentd with that configuration in the background.

    bash
    fluentd -c conf/fluent.conf &
  3. Send a test event. fluent-cat ships with the gem and forwards a JSON record under the tag you give it.

    bash
    echo '{"json":"message"}' | fluent-cat debug.test

The generated conf/fluent.conf includes a <match debug.**> block using the stdout output, so the event prints to the terminal where Fluentd is running.

Verify it works

Look at the Fluentd output. A successful round trip prints a line tagged debug.test with your record, similar to:

text
2026-06-23 12:00:00.000000000 +0000 debug.test: {"json":"message"}

If the event appears, input, routing, and output are all working.

Where to go next

For production concerns such as high availability, buffer tuning, secure forward with TLS, and Kubernetes deployment via fluent-operator or Helm, see the official documentation and the fluent GitHub organization (source 1).