Monitoring Docker containers on an Ubuntu server using Icinga involves setting up the Icinga agent to execute Docker-specific monitoring checks and configuring the Icinga server to process and display these checks. Here is a step-by-step guide to achieve this.

Step 1: Install Docker Monitoring Plugin

On the Icinga Agent Server: You need to have a plugin that can monitor Docker. One common choice is the check_docker plugin, which can be found on GitHub. You will have to manually download and install this plugin.

$ cd /usr/lib/nagios/plugins
$ sudo wget https://exchange.icinga.com/elacheche/Docker%20containers%20check/files/12915/docker_check.py
$ sudo chmod +x docker_check.py

Install Python and Docker SDK for Python: The check_docker plugin requires Python and the Docker SDK for Python.

$ sudo apt-get update
$ sudo apt-get install python3 python3-pip
$ sudo pip3 install docker

	# Update the apt package index and install packages to allow apt to use a repository over HTTPS:
	$ sudo apt-get update
	$ sudo apt-get install ca-certificates curl gnupg lsb-release
	# Add Docker’s official GPG key:
	$ sudo mkdir -p /etc/apt/keyrings
	$ curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
	# Use the following command to set up the repository:
	$ echo \
	"deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu \
	$(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
	# Install Docker Engine
	$ sudo apt-get update
	$ sudo apt-get install docker-ce docker-ce-cli containerd.io docker-compose-plugin

view raw install-docker-ubuntu.sh hosted with by GitHub

Step 2: Configure Icinga Agent

Add Command Definitions: You need to define a command in Icinga for the Docker check. Create or edit a configuration file in the Icinga agent:

sudo nano /etc/icinga2/conf.d/commands.conf
Add the following definition:

object CheckCommand "docker_check" {
    command = [ "/usr/bin/python3", "/usr/lib/nagios/plugins/docker_check.py" ]
    arguments = {
        "--containers" = "$docker_containers$"
        "--stats" = "$docker_stats$"
    }
}

Step 3: Configure Icinga Server

Define Host Object: If not already done, define the host object for the Docker server in your Icinga server configuration:

object Host "docker-server" {
    import "generic-host"
    address = "docker-agent-ip"
    check_command = "hostalive"
}

Define Service for Docker Monitoring: Create a service definition to monitor Docker:

apply Service "docker-status" {
    import "generic-service"
    check_command = "docker_check"
    vars.docker_containers = "all"
    vars.docker_stats = "true"
    assign where host.name == "docker-server"
}

Reload Icinga 2: After configuring the service and command, reload Icinga 2 to apply the changes:

$ sudo systemctl reload icinga2

Step 4: Verify the Configuration

Icinga Web 2: Log into Icinga Web 2 and check the 'Services' section. You should see your new service for monitoring Docker. Ensure that it is reporting the status of Docker containers as expected.

Troubleshooting: If the checks aren't working as expected, look at the logs in /var/log/icinga2/icinga2.log for any errors. Check the permissions of the check_docker.py script and ensure that the Icinga user can execute it and has access to Docker via the Docker group.

Rajesh Kumar

I’m a DevOps/SRE/DevSecOps/Cloud Expert passionate about sharing knowledge and experiences. I am working at Cotocus. I blog tech insights at DevOps School, travel stories at Holiday Landmark, stock market tips at Stocks Mantra, health and fitness guidance at My Medic Plus, product reviews at I reviewed , and SEO strategies at Wizbrand. 

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