## Overview

This template collects Linux metrics from Node Exporter 0.18 and above. Support for older Node Exporter versions is provided as best effort.

### Known Issues

  - Node Exporter 0.16.0 renamed many metrics. CPU utilization for "guest" and "guest_nice" metrics are not supported in this template with Node Exporter < 0.16. Disk IO metrics are not supported. Other metrics provided as best effort. See https://github.com/prometheus/node_exporter/releases/tag/v0.16.0 for details.
    - Version: below 0.16.0
  - Metric node_network_info with label 'device' cannot be found, so network discovery is not possible.
    - Version: below 0.18

#### Notes on filesystem (FS) discovery:
  - The ext4/3/2 FS reserves space for privileged usage, typically set at 5% by default.
  - BTRFS allocates a default of 10% of the volume for its own needs.
  - To mitigate potential disasters, FS usage triggers are based on the maximum available space.
    - Utilization formula: `pused = 100 - 100 * (available / total - free + available)`
  - The FS utilization chart, derived from graph prototypes, reflects FS reserved space as the difference between used and available space from the total volume.

## Setup

1. Set up the node_exporter according to the [`official documentation`](https://prometheus.io/docs/guides/node-exporter/). Use node_exporter v0.18.0 or above.

2. Set the hostname or IP address of the node_exporter host in the `The node_exporter host` parameter. You can also change the Prometheus endpoint port in the `TCP Port node_exporter` parameter if necessary.