Available languages | en | ja |

Free Alternative to Splunk Using Fluentd

Splunk is a great tool for searching logs, but its high cost makes it prohibitive for many teams. In this article, we present a free and open source alternative to Splunk by combining three open source projects: Elasticsearch, Kibana, and Fluentd.

Click to See the Demo

Elasticsearch is an open source search engine known for its ease of use. Kibana is an open source Web UI that makes Elasticsearch user friendly for marketers, engineers and data scientists alike.

By combining these three tools (Fluentd + Elasticsearch + Kibana) we get a scalable, flexible, easy to use log search engine with a great Web UI that provides an open-source Splunk alternative, all for free!

In this guide, we will go over installation, setup, and basic use of this combined log search solution. The contents of this article were tested on Mac OS X Mountain Lion. If you’re not familiar with Fluentd, please learn more about Fluentd first.

Table of Contents


Java for Elasticsearch

Please confirm that your Java version is 6 or higher.

$ java -version
java version "1.6.0_45"
Java(TM) SE Runtime Environment (build 1.6.0_45-b06-451-11M4406)
Java HotSpot(TM) 64-Bit Server VM (build 20.45-b01-451, mixed mode)

Now that we’ve checked for prerequisites, we’re now ready to install and set up the three open source tools.

Set Up Elasticsearch

To install Elasticsearch, please download and extract the Elasticsearch package as shown below.

$ curl -O https://download.elasticsearch.org/elasticsearch/elasticsearch/elasticsearch-0.90.0.RC2.tar.gz
$ tar zxvf elasticsearch-0.90.0.RC2.tar.gz
$ cd elasticsearch-0.90.0.RC2/

Once installation is complete, start Elasticsearch.

$ ./bin/elasticsearch -f

Setup Kibana

To install Kibana, download it via the official webpage and extract it. Kibana is a HTML / CSS / JavaScript application.

$ curl -O https://download.elasticsearch.org/kibana/kibana/kibana-3.0.0milestone5.tar.gz
$ tar zxvf kibana-3.0.0milestone5.tar.gz
$ cd kibana-3.0.0milestone5/

Once installation is complete, start Kibana and open index.html. You can modify Kibana’s configuration via config.js.

$ open index.html

Setup Fluentd (td-agent)

In this guide We’ll install td-agent, the stable release of Fluentd. Please refer to the guides below for detailed installation steps.

Next, we’ll install the Elasticsearch plugin for Fluentd: fluent-plugin-elasticsearch.

$ /usr/lib64/fluent/ruby/bin/fluent-gem install fluent-plugin-elasticsearch

We’ll configure td-agent (Fluentd) to interface properly with Elasticsearch. Please modify /etc/td-agent/td-agent.conf as shown below:

  type syslog
  port 42185
  tag syslog

  type forward

<match syslog.**>
  type elasticsearch
  logstash_format true
  flush_interval 10s # for testing

fluent-plugin-elasticsearch comes with a logstash_format option that allows Kibana to search stored event logs in Elasticsearch.

Once everything has been set up and configured, we’ll start td-agent.

$ sudo /etc/init.d/td-agent start

Setup rsyslogd

In our final step, we’ll forward the logs from your rsyslogd to Fluentd. Please add the following line to your /etc/rsyslog.conf, and restart rsyslog. This will forward your local syslog to Fluentd, and Fluentd in turn will forward the logs to Elasticsearch.

*.* @

Please restart the rsyslog service once the modification is complete.

$ sudo /etc/init.d/rsyslog restart

Store and Search Event Logs

Once Fluentd receives some event logs from rsyslog and has flushed them to Elasticsearch, you can search the stored logs using Kibana by accessing in your browser.

To manually send logs to Elasticsearch, please use the logger command.

$ logger -t test foobar

When debugging your td-agent configuration, using out_copy + out_stdout will be useful. All the logs including errors can be found at /etc/td-agent/td-agent.log.

<match syslog.**>
  type copy
    # for debug (see /var/log/td-agent.log)
    type stdout
    type elasticsearch
    logstash_format true
    flush_interval 10s # for testing

Demo Environment

Please access the Kibana Demo Environment from the link below.


This article introduced the combination of Fluentd and Kibana (with Elasticsearch) which achieves a free alternative to Splunk: storing and searching machine logs. The examples provided in this article have not been tuned.

If you will be using these components in production, you may want to modify some of the configurations (e.g. JVM, Elasticsearch, Fluentd buffer, etc.) according to your needs.

Learn More

Last updated: 2014-03-12 18:27:35 UTC

Available languages | en | ja |

If this article is incorrect or outdated, or omits critical information, please let us know.

Interested in the Fluentd Newsletters?