The 'fluent-logger-ruby' library is used to post records from Ruby applications to Fluentd.

This article explains how to use the fluent-logger-ruby library.


  • Basic knowledge of Ruby

  • Basic knowledge of Fluentd

  • Ruby 1.9 or later

Installing Fluentd

Please refer to the following documents to install fluentd.

Modifying the Config File

Next, please configure Fluentd to use the forward Input plugin as its data source.

  @type forward
  port 24224
<match fluentd.test.**>
  @type stdout

Please restart your agent once these lines are in place.

# for rpm/deb only
$ sudo /etc/init.d/td-agent restart

Using fluent-logger-ruby

First, add the 'fluent-logger' gem to your Gemfile.

gem 'fluent-logger', "~> 0.4.3"

Next, please initialize and post the records as shown below.

require 'fluent-logger', :host=>'localhost', :port=>24224)"fluentd.test.follow", {"from"=>"userA", "to"=>"userB"})

Executing the script will send the logs to Fluentd.

$ ruby test.rb

The logs should be output to /var/log/td-agent/td-agent.log or stdout of the Fluentd process via the stdout Output plugin.

Production Deployments

Output Plugins

Various output plugins are available for writing records to other destinations:

High-Availability Configurations of Fluentd

For high-traffic websites (more than 5 application nodes), we recommend using a high availability configuration of td-agent. This will improve data transfer reliability and query performance.


Monitoring Fluentd itself is also important. The article below describes general monitoring methods for td-agent.

If this article is incorrect or outdated, or omits critical information, please let us know. Fluentd is a open source project under Cloud Native Computing Foundation (CNCF). All components are available under the Apache 2 License.

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