What is Node Exporter and configure

A small application called Node Exporter is installed on your PC or server. It functions similar to a detective who is always monitoring the system and collecting information about things like CPU, RAM, disk space, and other things. subsequently, it propagates this data to Prometheus and other monitoring tools.

Setup Node Exporter (Optional)

Here are the steps to set up Node Exporter on Linux:

• Download Node Exporter: Go to the Prometheus GitHub releases page and download the latest version of Node Exporter for Linux.
• Extract the Downloaded File: Once downloaded, extract the Node Exporter file using a tool like tar.
• Move Node Exporter to a Folder: Move the extracted Node Exporter folder to a location like /usr/local/bin/ for easy access.
• Create a Service File: Create a service file for Node Exporter using a text editor like nano or vim. This file tells Linux how to manage Node Exporter.
• Add Service Configuration: In the service file, specify the command to start Node Exporter.
• Reload systemd and Start the Service: Reload systemd to recognize the new service file and start Node Exporter using systemctl commands.
• Enable Auto-Start on Boot: Enable Node Exporter to start automatically whenever the system boots up.
• Check Node Exporter Status: Verify that Node Exporter is running without errors by checking its status.
• Access Metrics: You can now access Node Exporter metrics through a web browser using http://<your_server_ip>:9100/metrics.

Run the Node Exporter Container: Node Exporter image, run the container with the following command:

docker run -d --name=node-exporter -p 9100:9100 prom/node-exporter

List the container by using the below command

docker ps

Step 2: Scrape Container Metrics

• For Ubuntu Users: Edit the prometheus.yml to scrape all your container metrics from http://localhost:9323/metrics.

cd prometheus-2.48.1.linux-amd64
vi prometheus.yml

Here is the simple and sample scrap config file. Based on your requirements update the scrap config file.

global:
  scrape_interval: 10s
scrape_configs:
 - job_name: promethheus
   static_configs:
    - targets:
       - localhost:9090
 - job_name: docker
   static_configs:
    - targets:
       - localhost:9323

• For Windows Users: Edit the configuration file to scrape all your container metrics as shown in the below.

cd prometheus-2.49.1.windows-amd64
vi prometheus.yml

• For Ubuntu Users: Now start the Prometheus server and connect it on.

./prometheus

• For Windows UsersBased: Now start the Prometheus server and connect it as shown in the image below.

./prometheus.exe

Step 3: Setup Alertmanager (Optional)

• Download Alertmanager: Go to the Prometheus website and download the Alertmanager binary that matches your operating system. For Linux, you’ll typically download a tarball.
• Extract the Tarball: Once downloaded, extract the contents of the tarball to a location on your Linux system using the tar command. For example:

tar -xzf alertmanager-*.tar.gz

• Configure Alertmanager: Inside the extracted directory, you’ll find a configuration file named alertmanager.yml or alertmanager. yaml. Customize this file according to your requirements. You’ll typically define the notification integrations (like email, Slack, etc.) and their configurations here.
• Start Alertmanager: After configuring Alertmanager, you can start it by running the Alertmanager binary. You can do this from the directory where you extracted the tarball.

./alertmanager --config.file=alertmanager.yml

You may want to run Alertmanager as a background service or use tools like Systemd to manage it as a service.

• Verify Alertmanager is Running: You can verify that Alertmanager is running by accessing its web interface. By default, it runs on port 9093. Open your web browser and navigate to http://localhost:9093 to access the Alertmanager interface. You should see the Alertmanager UI, indicating that it’s up and running.
• Integrate with Prometheus: Lastly, you need to configure Prometheus to send alerts to Alertmanager. This is typically done by configuring Prometheus’s prometheus.yml file to include an alerting rule file (alerting.rules.yml), where you define the conditions for triggering alerts. In this file, specify the alertmanager_url parameter to point to your Alertmanager instance.

Step 4: Output

There are many metrics exposed in http://localhost:9323/metrics. You can choose any query and execute it on the Prometheus server. For example, to see the number of containers in stop state use this query “engine_daemon_container_states_containers{state=”stopped”}”

To know more about the Installation of Docker, Read this Article.

Docker Metrics: We can visit this URL to see all the exposed metrics of your Docker service.

http://localhost:9323/metrics

Containerization has transformed software development by providing portability and consistency through platforms like Docker. Yet ensuring the health of those containerized applications requires monitoring. Prometheus is a monitoring tool that uses its powerful features to monitor the application and make sure that the application is in good health. In this article first, you will understand what is, and then I will guide you through the steps to monitor your Docker container by using Prometheus.