prometheus/node_exporter · error

failed to retrieve pressure stats

Error message

failed to retrieve pressure stats: %w

What it means

node_exporter's pressure (PSI) collector wraps any failure from reading /proc/pressure/* with this message. It is thrown by Update when fs.PSIStats() returns a non-nil error that is NOT syscall.ENOTSUP (ENOTSUP is special-cased to ErrNoData with a hint to add psi=1 to the kernel command line). Any other I/O or parse error while retrieving pressure stall information produces this wrapped error.

Solutions

1. Verify /proc/pressure/cpu, /proc/pressure/memory and /proc/pressure/io exist and are readable from the exporter process (ls -l /proc/pressure; cat /proc/pressure/cpu).
2. If PSI is disabled, reboot with psi=1 on the kernel command line so the collector gets ENOTSUP -> ErrNoData instead of a hard failure.
3. If running in a container, ensure /proc is mounted and not masked for the path /proc/pressure (docker run without --read-only proc masking, or adjust the runtime spec).
4. Update the prometheus/procfs dependency and node_exporter to versions supporting your kernel's PSI output format.
5. If the collector is unusable in your environment, disable it (--collector.pressure) to silence scrape failures.

Example fix

// before
if err != nil {
    if errors.Is(err, fs.ErrNotExist) {
        return ErrNoData
    }
    return fmt.Errorf("failed to retrieve pressure stats: %w", err)
}
// after
if err != nil {
    if errors.Is(err, fs.ErrNotExist) || errors.Is(err, syscall.ENOTSUP) {
        return ErrNoData // PSI disabled or unavailable: emit nothing, don't fail the scrape
    }
    return fmt.Errorf("failed to retrieve pressure stats: %w", err)
}

// before starting the collector / scraping
for _, r := range []string{"cpu", "memory", "io"} {
    b, err := os.ReadFile("/proc/pressure/" + r)
    if err != nil {
        if errors.Is(err, os.ErrNotExist) {
            log.Printf("PSI unavailable for %s: enable with psi=1 kernel cmdline", r)
        }
        // treat as no-data
    }
    _ = b
}

stats, err := fs.PSIStats("cpu")
if err != nil {
    if errors.Is(err, syscall.ENOTSUP) || errors.Is(err, fs.ErrNotExist) {
        return ErrNoData // PSI disabled: skip gracefully
    }
    return fmt.Errorf("failed to retrieve pressure stats: %w", err)
}

When it happens

Trigger: The pressure collector's Update() calls procfs PSIStats for cpu/memory/io/irq resources; the read or parse of /proc/pressure/<resource> fails with an error other than ENOTSUP (e.g. /proc not mounted, permission issue, or unexpected file contents from an unusual kernel).

Common situations: Running in a container or sandbox where /proc/pressure is not exposed (masked by runtime); very old or vendor kernels that expose malformed PSI data; seccomp/AppArmor policies blocking reads; kernels built without CONFIG_PSI but where the read still fails instead of returning ENOTSUP.

Related errors

• failed to open procfs
• failed to open procfs
• unable to retrieve number of allocated threads
• unable to retrieve limit number of threads
• unable to retrieve limit number of maximum pids allowed

AI-assisted analysis of prometheus/node_exporter@17ddd77c59 (2026-09-07). Data as JSON: /api/errors/6e5e6f29fdcfdc9a. Report an issue: GitHub.

Appendix: source

Thrown at collector/pressure_linux.go:119

func (c *pressureStatsCollector) Update(ch chan<- prometheus.Metric) error {
	foundResources := 0
	for _, res := range psiResources {
		c.logger.Debug("collecting statistics for resource", "resource", res)
		vals, err := c.fs.PSIStatsForResource(res)
		if err != nil {
			if errors.Is(err, os.ErrNotExist) && res != psiResourceIRQ {
				c.logger.Debug("pressure information is unavailable, you need a Linux kernel >= 4.20 and/or CONFIG_PSI enabled for your kernel", "resource", res)
				continue
			}
			if errors.Is(err, os.ErrNotExist) && res == psiResourceIRQ {
				c.logger.Debug("IRQ pressure information is unavailable, you need a Linux kernel >= 6.1 and/or CONFIG_PSI enabled for your kernel", "resource", res)
				continue
			}
			if errors.Is(err, syscall.ENOTSUP) {
				c.logger.Debug("pressure information is disabled, add psi=1 kernel command line to enable it")
				return ErrNoData
			}
			return fmt.Errorf("failed to retrieve pressure stats: %w", err)
		}
		// IRQ pressure does not have 'some' data.
		// See https://github.com/torvalds/linux/blob/v6.9/include/linux/psi_types.h#L65
		if vals.Some == nil && res != psiResourceIRQ {
			c.logger.Debug("pressure information returned no 'some' data")
			return ErrNoData
		}
		if vals.Full == nil && res != psiResourceCPU {
			c.logger.Debug("pressure information returned no 'full' data")
			return ErrNoData
		}
		switch res {
		case psiResourceCPU:
			ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, float64(vals.Some.Total)/1000.0/1000.0)
		case psiResourceIO:
			ch <- prometheus.MustNewConstMetric(c.io, prometheus.CounterValue, float64(vals.Some.Total)/1000.0/1000.0)
			ch <- prometheus.MustNewConstMetric(c.ioFull, prometheus.CounterValue, float64(vals.Full.Total)/1000.0/1000.0)
		case psiResourceMemory:

View on GitHub (pinned to 17ddd77c59)