Disable Prometheus Node Exporter Public Metrics

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Introduction

Prometheus Node Exporter is a popular tool for collecting system metrics from nodes in a Kubernetes cluster. However, by default, it exposes these metrics publicly, which can be a security risk if not properly configured. In this article, we will discuss how to disable public metrics in Prometheus Node Exporter, specifically in the context of a self-managed K3S cluster on Hetzner.

Understanding Prometheus Node Exporter

Prometheus Node Exporter is a component of the Prometheus ecosystem that collects system metrics from nodes in a Kubernetes cluster. It exposes these metrics as a Prometheus endpoint, which can be scraped by a Prometheus server. The metrics exposed by Prometheus Node Exporter include CPU usage, memory usage, disk usage, and network I/O, among others.

Why Disable Public Metrics?

By default, Prometheus Node Exporter exposes its metrics publicly, which means that anyone with access to the node's IP address can scrape the metrics. This can be a security risk if the metrics contain sensitive information, such as passwords or encryption keys. Additionally, exposing metrics publicly can also lead to performance issues if the metrics are not properly rate-limited.

Disabling Public Metrics in Prometheus Node Exporter

To disable public metrics in Prometheus Node Exporter, you need to modify the configuration of the exporter. The configuration is typically stored in a YAML file, which is used by the exporter to determine how to collect and expose metrics.

Step 1: Edit the Prometheus Node Exporter Configuration

To disable public metrics, you need to edit the Prometheus Node Exporter configuration file. The configuration file is typically located at /etc/prometheus/node-exporter.yaml on a Linux system.

# /etc/prometheus/node-exporter.yaml
scrape_configs:
  - job_name: 'node'
    scrape_interval: 10s
    metrics_path: '/metrics'
    static_configs:
      - targets: ['localhost:9100']

Step 2: Add a scrape_configs Section

To disable public metrics, you need to add a scrape_configs section to the configuration file. This section specifies the configuration for the Prometheus Node Exporter.

# /etc/prometheus/node-exporter.yaml
scrape_configs:
  - job_name: 'node'
    scrape_interval: 10s
    metrics_path: '/metrics'
    static_configs:
      - targets: ['localhost:9100']
    scrape_configs:
      - job_name: 'node'
        scrape_interval: 10s
        metrics_path: '/metrics'
        static_configs:
          - targets: ['localhost:9100']
        relabel_configs:
          - source_labels: ['__address__']
            target_label: 'instance'
            replacement: 'node-exporter'

Step 3: Add a relabel_configs Section

To disable public metrics, you need to add a relabel_configs section to the scrape_configs section. This section specifies the configuration for relabeling the metrics.

# /etc/prometheus/node-exporter.yaml
scrape_configs:
  - job_name: 'node'
    scrape_interval: 10s
    metrics_path: '/metrics'
    static_configs:
      - targets: ['localhost:9100']
    scrape_configs:
      - job_name: 'node'
        scrape_interval: 10s
        metrics_path: '/metrics'
        static_configs:
          - targets: ['localhost:9100']
        relabel_configs:
          - source_labels: ['__address__']
            target_label: 'instance'
            replacement: 'node-exporter'
          - source_labels: ['__metrics_path__']
            target_label: 'metrics_path'
            replacement: '/metrics'

Step 4: Restart the Prometheus Node Exporter

After modifying the configuration file, you need to restart the Prometheus Node Exporter service to apply the changes.

# Restart the Prometheus Node Exporter service
sudo systemctl restart prometheus-node-exporter

Verifying the Changes

To verify that the changes have been applied, you can check the Prometheus Node Exporter logs.

# Check the Prometheus Node Exporter logs
sudo journalctl -u prometheus-node-exporter

Conclusion

In this article, we discussed how to disable public metrics in Prometheus Node Exporter, specifically in the context of a self-managed K3S cluster on Hetzner. We walked through the steps to modify the configuration file, add a scrape_configs section, add a relabel_configs section, and restart the Prometheus Node Exporter service. By following these steps, you can ensure that your Prometheus Node Exporter metrics are not exposed publicly.

Troubleshooting

If you encounter any issues while disabling public metrics in Prometheus Node Exporter, you can refer to the following troubleshooting steps:

  • Check the Prometheus Node Exporter logs for any errors or warnings.
  • Verify that the configuration file has been modified correctly.
  • Restart the Prometheus Node Exporter service to apply the changes.
  • Check the Prometheus Node Exporter metrics to ensure that they are not exposed publicly.

Additional Resources

For more information on Prometheus Node Exporter, you can refer to the following resources:

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Frequently Asked Questions

In this article, we will answer some of the most frequently asked questions about Prometheus Node Exporter.

Q: What is Prometheus Node Exporter?

A: Prometheus Node Exporter is a tool for collecting system metrics from nodes in a Kubernetes cluster. It exposes these metrics as a Prometheus endpoint, which can be scraped by a Prometheus server.

Q: Why do I need to disable public metrics in Prometheus Node Exporter?

A: By default, Prometheus Node Exporter exposes its metrics publicly, which means that anyone with access to the node's IP address can scrape the metrics. This can be a security risk if the metrics contain sensitive information, such as passwords or encryption keys.

Q: How do I disable public metrics in Prometheus Node Exporter?

A: To disable public metrics in Prometheus Node Exporter, you need to modify the configuration file. You can add a scrape_configs section and a relabel_configs section to the configuration file to specify the configuration for the Prometheus Node Exporter.

Q: What is the difference between scrape_configs and relabel_configs?

A: scrape_configs specifies the configuration for the Prometheus Node Exporter, while relabel_configs specifies the configuration for relabeling the metrics.

Q: How do I restart the Prometheus Node Exporter service?

A: To restart the Prometheus Node Exporter service, you can use the following command:

sudo systemctl restart prometheus-node-exporter

Q: How do I verify that the changes have been applied?

A: To verify that the changes have been applied, you can check the Prometheus Node Exporter logs.

sudo journalctl -u prometheus-node-exporter

Q: What are some common issues that I may encounter while disabling public metrics in Prometheus Node Exporter?

A: Some common issues that you may encounter while disabling public metrics in Prometheus Node Exporter include:

  • The configuration file has not been modified correctly.
  • The Prometheus Node Exporter service has not been restarted correctly.
  • The metrics are still being exposed publicly.

Q: How do I troubleshoot issues with Prometheus Node Exporter?

A: To troubleshoot issues with Prometheus Node Exporter, you can refer to the following steps:

  • Check the Prometheus Node Exporter logs for any errors or warnings.
  • Verify that the configuration file has been modified correctly.
  • Restart the Prometheus Node Exporter service to apply the changes.
  • Check the Prometheus Node Exporter metrics to ensure that they are not exposed publicly.

Q: What are some additional resources that I can use to learn more about Prometheus Node Exporter?

A: Some additional resources that you can use to learn more about Prometheus Node Exporter include:

Conclusion

In this article, we have answered some of the most frequently asked questions about Prometheus Node Exporter. We have covered topics such as disabling public metrics, configuring the Prometheus Node Exporter, and troubleshooting issues. We hope that this article has been helpful in answering your questions about Prometheus Node Exporter.

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