hashicorp/nomad · error

failed to determine mount point for %s

Error message

failed to determine mount point for %s

What it means

diskInfo runs `df -k` (with -P on linux) against the absolute path to find the mount point and total capacity. If the df command returns an error (non-zero exit, missing binary, signal), the fingerprinter returns this message.

Source

Thrown at client/fingerprint/storage_unix.go:36

// the total bytes available on the file system.
func (f *StorageFingerprint) diskInfo(path string) (volume string, total uint64, err error) {
	absPath, err := filepath.Abs(path)
	if err != nil {
		return "", 0, fmt.Errorf("failed to determine absolute path for %s", path)
	}

	// Use -k to standardize the output values between darwin and linux
	var dfArgs string
	if runtime.GOOS == "linux" {
		// df on linux needs the -P option to prevent linebreaks on long filesystem paths
		dfArgs = "-kP"
	} else {
		dfArgs = "-k"
	}

	mountOutput, err := exec.Command("df", dfArgs, absPath).Output()
	if err != nil {
		return "", 0, fmt.Errorf("failed to determine mount point for %s", absPath)
	}
	// Output looks something like:
	//	Filesystem 1024-blocks      Used Available Capacity   iused    ifree %iused  Mounted on
	//	/dev/disk1   487385240 423722532  63406708    87% 105994631 15851677   87%   /
	//	[0] volume [1] capacity [2] SKIP  [3] free
	lines := strings.Split(string(mountOutput), "\n")
	if len(lines) < 2 {
		return "", 0, fmt.Errorf("failed to parse `df` output; expected at least 2 lines")
	}
	fields := strings.Fields(lines[1])
	if len(fields) < 4 {
		return "", 0, fmt.Errorf("failed to parse `df` output; expected at least 4 columns")
	}
	volume = fields[0]

	total, err = strconv.ParseUint(fields[1], 10, 64)
	if err != nil {
		return "", 0, fmt.Errorf("failed to parse storage.bytestotal size in kilobytes")

View on GitHub (pinned to 482b49bf1a)

Solutions

1. Install/restore the `df` utility (coreutils) in the host image or container.
2. Confirm the path exists and is accessible: df -k /path/to/dir.
3. Check the client process PATH includes standard binary directories.
4. Provide a static DiskTotalMB override in the storage fingerprint config.

Example fix

// before (Dockerfile)
FROM scratch
// after (Dockerfile)
FROM alpine
RUN apk add --no-cache coreutils

if _, err := exec.LookPath("df"); err != nil {
	return fmt.Errorf("df not available on PATH; install coreutils or set DiskTotalMB override")
}
if _, err := os.Stat(path); err != nil {
	return fmt.Errorf("path %s must exist before df", path)
}

if err := fp.Fingerprint(req); err != nil {
	if strings.Contains(err.Error(), "failed to determine mount point") {
		log.Printf("df failed: %v", err)
		return nil
	}
	return err
}

When it happens

Trigger: exec.Command("df", dfArgs, absPath).Output() errors: df not installed, path does not exist (df exits 1), permission denied, or the binary cannot be executed.

Common situations: Minimal containers/images without coreutils' df; alloc dir deleted before fingerprinting; PATH problems for the Nomad client process; non-executable df binary.

Related errors

• failed to parse `df` output; expected at least 2 lines
• failed to parse `df` output; expected at least 4 columns
• failed to parse storage.bytestotal size in kilobytes
• unable to get CWD from filesystem: %s
• failed to determine disk space for %s: %v

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/f969de94ad0e3c65. Report an issue: GitHub.