munin-stress-ng

Munin plugin to provide throughput statistics for cpu memory and disk, written in bash

On load testing a web server running in a cloud VPS on shared hardware, I noticed huge variation in latency but couldn't find any real cause, so wrote this to check the VPS throughput.

The idea is:

• Run stress-ng to exercise the cpu, memory and disk to 100% for a short period. Output sequential measurements to a log over an extended period of time
• Every munin collection period, calculate the minimum, average, maximum and standard deviation of the measurements, display on a graph, and delete the log

Developed and tested on Ubuntu 18.04 only

Dependencies

• munin
• bash
• stress-ng
• stat
• date
• awk
• lshw

How to use

1. Clone the repo

2. Link the stress-ng file to your plugins, for example:

ln -s /path/to/stress-ng /etc/munin/plugins/stress_ng

3. Configure the plugin to run as root:

nano /etc/munin/plugin-conf.d/munin-node

[stress_ng]
user root

4. service munin-node restart

5. Start the stress-ng process: ./stress-ng start

6. Check the process status: ./stress-ng status

The plugin uses the /tmp folder to store three files with munin-stress-ng prefix: .yml, .log and .pid

To stop stress testing

./stress-ng stop

To remove the plugin

1. Unlink the plugin: rm /etc/munin/plugins/stress_ng

2. service munin-node restart

Once munin stops reading data, the stress-ng task will terminate