What causes "couldn't get SNMP6 stats: %w" in prometheus/node_exporter?

Confirm whether IPv6 is enabled on the host (ls /proc/net/snmp6); if IPv6 is intentionally disabled, expect/ignore this error or upgrade node_exporter versions that handle it.

prometheus/node_exporter · error

couldn't get SNMP6 stats

Error message

couldn't get SNMP6 stats: %w

What it means

The netstat collector's Update reads /proc/net/snmp6 via the procfs library (proc.Snmp6()) for IPv6 statistics. If reading or parsing that file fails, Update returns this wrapped error, failing the whole scrape even if only IPv6 data is unavailable.

Solutions

Confirm whether IPv6 is enabled on the host (ls /proc/net/snmp6); if IPv6 is intentionally disabled, expect/ignore this error or upgrade node_exporter versions that handle it.
Enable IPv6 if those metrics are required (remove ipv6.disable=1, load ipv6 module).
Check /proc mount permissions and hidepid settings.
Update node_exporter/procfs; report persistent parse failures upstream with kernel details.

Example fix

// before
snmp6Stats, err := c.proc.Snmp6()
if err != nil {
	return fmt.Errorf("couldn't get SNMP6 stats: %w", err)
}
// after (tolerate missing IPv6 support)
snmp6Stats, err := c.proc.Snmp6()
if err != nil {
	if os.IsNotExist(errors.Unwrap(err)) {
		c.logger.Info("IPv6 appears disabled; skipping SNMP6 metrics")
		snmp6Stats = nil
	} else {
		return fmt.Errorf("couldn't get SNMP6 stats: %w", err)
	}
}

Defensive patterns

Strategy: fallback

Validate before calling

import "os"
// Detect IPv6-disabled hosts before enabling SNMP6 expectations:
if _, err := os.Stat("/proc/net/snmp6"); os.IsNotExist(err) {
	// IPv6 disabled; do not require snmp6 metrics
}

Type guard

null

Try / catch

// Treat missing snmp6 as benign when IPv6 is off
stats, err := proc.Snmp6()
if err != nil {
	if os.IsNotExist(errors.Unwrap(err)) {
		logger.Info("IPv6 disabled; skipping SNMP6 stats")
	} else {
		return fmt.Errorf("couldn't get SNMP6 stats: %w", err)
	}
}

Prevention

Document that SNMP6 metrics require IPv6 enabled on the host.
If hosts intentionally run ipv6.disable=1, ignore/silence this collector failure in alerting.
Verify /proc/net/snmp6 exists in your host image before deploying IPv6 dashboards.
Keep node_exporter current so upstream handling of missing snmp6 is picked up.

When it happens

Trigger: c.proc.Snmp6() errors when /proc/net/snmp6 is missing (very common on hosts with IPv6 disabled), unreadable, or unparseable by the procfs library.

Common situations: IPv6 disabled at boot (ipv6.disable=1) or no IPv6 support, so /proc/net/snmp6 doesn't exist; containers without IPv6; kernel/procfs version skew.

Understand the failure class

Background: "failed to read file", EACCES, ENOENT and "could not read <path>" errors: when a program can't read a file from disk — this error's family across 49 libraries.

Related errors

AI-assisted analysis of prometheus/node_exporter@17ddd77c59 (2026-09-07). Data as JSON: /api/errors/cbb2fdbbb464d926. Report an issue: GitHub.

Appendix: source

Thrown at collector/netstat_linux.go:90

	return &netStatCollector{
		proc:         proc,
		fieldPattern: pattern,
		logger:       logger,
	}, nil
}

func (c *netStatCollector) Update(ch chan<- prometheus.Metric) error {
	netStats, err := c.proc.Netstat()
	if err != nil {
		return fmt.Errorf("couldn't get netstats: %w", err)
	}
	snmpStats, err := c.proc.Snmp()
	if err != nil {
		return fmt.Errorf("couldn't get SNMP stats: %w", err)
	}
	snmp6Stats, err := c.proc.Snmp6()
	if err != nil {
		return fmt.Errorf("couldn't get SNMP6 stats: %w", err)
	}

	c.emitStruct(ch, netStats.TcpExt)
	c.emitStruct(ch, netStats.IpExt)
	c.emitStruct(ch, snmpStats.Ip)
	c.emitStruct(ch, snmpStats.Icmp)
	c.emitStruct(ch, snmpStats.IcmpMsg)
	c.emitStruct(ch, snmpStats.Tcp)
	c.emitStruct(ch, snmpStats.Udp)
	c.emitStruct(ch, snmpStats.UdpLite)
	c.emitStruct(ch, snmp6Stats.Ip6)
	c.emitStruct(ch, snmp6Stats.Icmp6)
	c.emitStruct(ch, snmp6Stats.Udp6)
	c.emitStruct(ch, snmp6Stats.UdpLite6)

	return nil
}

View on GitHub (pinned to 17ddd77c59)