Send Syslog Data to InfluxDB

This article shows how to collect syslog data into InfluxDB using Fluentd.

Prerequisites

• A basic understanding of Fluentd

• A running instance of rsyslogd

• InfluxDB

• Your InfluxDB access token

• Chronograf

You can install Fluentd via major packaging systems.

• Installation

Step 1: Install InfluxDB

You can install InfluxDB via major packaging systems.

• Install InfluxDB OSS v2

Once it is installed, you can run it with:

$ sudo systemctl start influxdb

Then, run the initial setup process and create/configure the following:

• Create influxdb user

• Create proper operation token

• Set fluent organization

• Create test bucket

• Crete access API token

See Set up InfluxDB.

Then, you can verify that InfluxDB is running:

$ curl --header "Authorization: Token (INFLUXDB_ACCESS_TOKEN_HERE)" "http://localhost:8086/query?q=show+databases"

If InfluxDB is running normally, you will see an object that contains the _monitoring, _tasks and test database:

{"results":[{"statement_id":0,"series":[{"name":"databases","columns":["name"],"values":[["_monitoring"],["_tasks"],["test"]]}]}]}

We are done for now.

Step 2: Install Fluentd and the InfluxDB plugin

You can install Fluentd via major packaging systems.

• Installation

Next, install the InfluxDB output plugin:

If out_influxdb (fluent-plugin-influxdb-v2) is not installed yet, please install it manually.

See Plugin Management section how to install fluent-plugin-influxdb-v2 on your environment.

Finally, configure /etc/fluent/fluentd.conf as follows:

<source>
  @type syslog
  port 42185
  tag system
</source>

<match system.*.*>
  @type influxdb
  url http://localhost:8086
  org fluent
  bucket test
  token "ACCESS_TOKEN_HERE"
  use_ssl false
  <buffer>
    flush_interval 10s # for testing
  <buffer>
</match>

Restart fluentd with sudo systemctl restart fluentd.

Step 3: Configure rsyslogd

If remote rsyslogd instances are already collecting data into the aggregator rsyslogd, the settings for rsyslog should remain unchanged. However, if this is a brand new setup, create /etc/rsyslogd.d/90-fluentd.conf and append the following line:

*.* @localhost:42185

You should replace localhost with the IP address of your aggregator server. Also, there is nothing special about port 42185 (do make sure this port is open though).

Now, restart rsyslogd:

$ sudo systemctl restart rsyslog

Step 4: Confirm Data Flow

Your syslog data should be flowing into InfluxDB every 10 seconds (this is configured by flush_interval).

For visualizing incoming data, you can use the InfluxDB UI by default and as an option, you can use Chronograf with InfluxDB v2.

You can install Chronograf via major packaging systems.

• Install Chronograf

Then, go to http://localhost:8888 and clicking on Explore brings up the query interface that lets you write SQL queries against your log data.

And then click Visualization and select the line chart:

Now, switch to Queries to count the number of lines of syslog messages per facility/priority:

SELECT COUNT(ident) FROM test.autogen./^system\./ GROUP BY time(1s)

Click on Submit Query to get a graph like this:

Here is another screenshot for the system.daemon.info series:

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