prometheus/node_exporter · error

invalid value in numastat

Error message

invalid value in numastat: %w

What it means

This error is returned by parseMemInfoNumaStat in collector/meminfo_numa_linux.go:177 when strconv.ParseFloat fails on the second field (parts[1]) of a numastat line. The collector expects a numeric counter value; a non-numeric token aborts parsing of the node's numastat file. The underlying strconv error is wrapped via %w.

Solutions

1. Check the failing value column in /sys/devices/system/node/node*/numastat
2. Skip or coerce non-numeric values if a patched kernel emits headers or text entries
3. Verify kernel version for numastat format changes and update the parser accordingly
4. Rebuild with -tags nomeminfo_numa to opt out of this collector
5. Report unexpected numastat content upstream if produced by a stock kernel

Example fix

// before
fv, err := strconv.ParseFloat(parts[1], 64)
if err != nil {
	return nil, fmt.Errorf("invalid value in numastat: %w", err)
}
// after (skip non-numeric values)
fv, err := strconv.ParseFloat(parts[1], 64)
if err != nil {
	continue
}

// Validate the value field is numeric before parse
parts := strings.Fields(line)
if len(parts) == 2 {
	if _, err := strconv.ParseFloat(parts[1], 64); err != nil {
		return fmt.Errorf("non-numeric numastat value %q in %q", parts[1], line)
	}
}

_, err := parseMemInfoNumaStat(f, node)
if err != nil {
	var numErr *strconv.NumError
	if errors.As(err, &numErr) {
		// skip node's numastat metrics and continue collection
	}
	return err
}

When it happens

Trigger: parseMemInfoNumaStat reads a well-formed 2-field line like 'numa_hit xyz' where the value field is not a valid float — e.g. alphabetic characters, hex values, or a header-like line with text in the value column.

Common situations: Nonstandard kernels exposing textual numastat entries; container/virtualization layers emitting placeholder text; corrupted sysfs reads; parsing test fixtures with bad values.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

Related errors

• line scan did not return 2 fields
• invalid value in meminfo
• invalid line in meminfo
• couldn't get NUMA meminfo
• device node string didn't match regexp

AI-assisted analysis of prometheus/node_exporter@17ddd77c59 (2026-09-07). Data as JSON: /api/errors/a06ddcb3ca1b3e53. Report an issue: GitHub.

Appendix: source

Thrown at collector/meminfo_numa_linux.go:177

func parseMemInfoNumaStat(r io.Reader, nodeNumber string) ([]meminfoMetric, error) {
	var (
		numaStat []meminfoMetric
		scanner  = bufio.NewScanner(r)
	)

	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if line == "" {
			continue
		}
		parts := strings.Fields(line)
		if len(parts) != 2 {
			return nil, fmt.Errorf("line scan did not return 2 fields: %s", line)
		}

		fv, err := strconv.ParseFloat(parts[1], 64)
		if err != nil {
			return nil, fmt.Errorf("invalid value in numastat: %w", err)
		}

		numaStat = append(numaStat, meminfoMetric{parts[0] + "_total", prometheus.CounterValue, nodeNumber, fv})
	}
	return numaStat, scanner.Err()
}

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