Ultra-light docker monitor

This light tool permits:

• to export docker container memory usage in a JSON file stats.json
• display curves of the memory usages using the JSON file

The export and the display are two different parts. This allow to run the display in another machine.

Setup the stats export

Open the cron tab in edition mode:

crontab -e

Then add a new line (to run the check each ten minutes)

*/10 * * * * /path.io/docker-stats-histo/save_docker_stats.sh >>/dev/null  2>&1

Note:

• Normaly cron send task outputs (echo) via mail. As the MTA (Mail Transfert Agent), may not be set up, the crontab line redirect the outputs into /dev/null. It can also be a path to a log file.
• No sudo is needed, crontab is called with current user.

Display stats

This step permits to generate a render from a stats file (generated by the script called by the crontab, see stats export section).

Install

Need python3 with venv module

sudo apt install python3 python3-venv

Run

Go in display folder

cd display

Then to generate a png, just run (install is automatically done if needed)

./render_stats.sh stats.json

It is also possible to see a web version fo the render :

./render_stats.sh stats.json -w

Note: if the stats file is in a remote server, one can use scp to get it: scp alban@eunuque.caracals.org:/path/to/docker-stats-histo/stats.json .