munin-plugin-docker

munin plugin to monitor docker, based on python3. It's designed to see overall statistics of your docker environment, not to monitor individual containers.

• Metrics
• Example graphs
• Installation

Metrics

The plugin uses the Docker SDK for Python, all metrics comes from the API.

• containers: number of containers, running and all
• containers uptime: uptime of the running containers
  • max: uptime of the oldest running container
  • min: uptime of the youngest running container
  • median: median of the uptimes
• memory: memory usage of the containers
  • total: memory usage of all the containers together (sum(list))
  • max: the highest memory usage of the containers (max(list))
  • avg: average memory usage of the containers (total/n)
• images: number of images (without intermediate image layers)
• layerssize: good question, it is what the docker API gives back (df call) as LayersSize :) Not very well documented, I guess this is the overall size of the images.
• volumes_n: number of docker volumes
• volumes_size: used disk space by docker local volumes (docker system df)

Example graphs

Installation

Prerequisites

The plugin requires python3 and some python modules. And of course you already have munin-node and docker on the host.

on Ubuntu 22.04 (or higher):

sudo apt install python3 python3-docker

Installing the plugin

• copy docker_stat to the /usr/share/munin/plugins/ directory:

sudo wget https://raw.githubusercontent.com/atommaki/munin-plugin-docker/master/docker_stat -O /usr/share/munin/plugins/docker_stat

• Make it executable:

sudo chmod a+x /usr/share/munin/plugins/docker_stat

• create symlinks to it

sudo ln -s /usr/share/munin/plugins/docker_stat /etc/munin/plugins/docker_stat_containers
sudo ln -s /usr/share/munin/plugins/docker_stat /etc/munin/plugins/docker_stat_containers_uptime
sudo ln -s /usr/share/munin/plugins/docker_stat /etc/munin/plugins/docker_stat_images
sudo ln -s /usr/share/munin/plugins/docker_stat /etc/munin/plugins/docker_stat_memory
sudo ln -s /usr/share/munin/plugins/docker_stat /etc/munin/plugins/docker_stat_layerssize
sudo ln -s /usr/share/munin/plugins/docker_stat /etc/munin/plugins/docker_stat_volumes_n
sudo ln -s /usr/share/munin/plugins/docker_stat /etc/munin/plugins/docker_stat_volumes_size

• Run one of the scripts to see if all the required python modules are installed:

sudo /etc/munin/plugins/docker_stat_memory

• configure munin to run the plugin as root user. Add the following lines to /etc/munin/plugin-conf.d/docker:

[docker*]
user root

• Restart munin-node:

sudo systemctl restart munin-node.service