Writing Custom Queries for node_exporter with Shell Scripts

Overview

By placing files with the *.prom extension in the directory specified by node_exporter’s --collector.textfile.directory option,
the Prometheus server will read the metric information written in them.

The idea is that if you update these *.prom files at regular intervals, you can create your own custom metrics.

Procedure

• For installing and setting up node_exporter itself, please refer to the following.

Node Exporter 構築手順 + Prometheus からAWSオートスケール監視 - 長生村本郷Engineers'Blog

以下に移行しました。 kenzo0107.github.io

In the procedure above, node_exporter is placed at the following location.
Adjust it as appropriate for your environment.

/usr/local/node_exporter/node_exporter

Create the text_collector directory

$ cd /usr/local/node_exporter
$ mkdir text_collector

Create the shell script

This time, we will add a metric for the httpd process count.

• Create /usr/local/node_exporter/text_collector/httpd.sh

Configure cron

# Update node_exporter httpd every 5 minutes
*/5 * * * * /usr/local/node_exporter/text_collector/httpd.sh

Verify httpd.prom is created

• /usr/local/node_exporter/text_collector/httpd.prom

node_httpd_count 24

The node_httpd_count above becomes the metric name.

Restart node_exporter

Specify the directory as follows.

node_expoter --collector.textfile.directory /usr/local/node_exporter/text_collector

Specify and verify the metric you created

It worked!

Using this, you can often get a lot done with shell one-liners ♪

I hope this helps.