influxdata/telegraf

[inputs.disk] Add support to report mount status (mounted vs unmounted)

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#16871 opened on Apr 23, 2025

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feature requesthelp wantedsize/s

Description

Use Case

Request that inputs.disk include a field or tag for mount status (mounted vs unmounted).

Why it's important: Use case (e.g., real-world incident where a failed mount wasn’t detected).

Why inputs.disk is the right place: Because it already collects filesystem stats — but silently ignores unmounted entries.

Why current workarounds aren't ideal: Using inputs.exec and a custom script is a workaround, but built-in support would be more native and scalable.

Expected behavior

Current inputs.disk silently skips unmounted filesystems, which can result in undetected mount failures. We'd like to propose exposing mount state (mounted vs not mounted) as a field or tag.

With this config we can alert on the status to make sure the appropriate teams know there is an issue before the client

Actual behavior

The inputs.disk plugin collects metrics only for currently mounted filesystems. If a filesystem listed in /etc/fstab or otherwise expected to be present is unmounted or fails to mount, it is silently skipped and no metrics are reported for that mount point.

As a result, Telegraf provides no visibility into failed or missing mounts using inputs.disk alone. This can lead to production issues going undetected, especially if services depend on specific mount points being present.

Additional info

No response

Contributor guide

Tech stack
go
Domain
observability
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Go programmingTelegraf plugin architectureFilesystem mount concepts
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65
Research direction
Examine the inputs/disk plugin in Telegraf, specifically how it collects filesystem stats using Go's syscall or statfs. The desired change is to add a new field or tag indicating whether each filesystem is mounted or unmounted. Look at how the plugin handles /etc/fstab or mount points to differentiate between mounted and unmounted entries. Consider that an unmounted filesystem would not appear in the mounted list, so you may need to cross reference with expected mount points. The implementation should be in Go and follow the existing plugin patterns.