{"record":{"id":"8af68fbdfd26ce1a","repo":"prometheus/node_exporter","slug":"error-obtaining-sysctl-info-w","errorCode":null,"errorMessage":"error obtaining sysctl info: %w","messagePattern":"error obtaining sysctl info: %w","errorType":"error_code","errorClass":null,"httpStatus":null,"severity":"error","filePath":"collector/sysctl_linux.go","lineNumber":97,"sourceCode":"\n\t\tfor _, metric := range metrics {\n\t\t\tch <- metric\n\t\t}\n\t}\n\treturn nil\n}\n\nfunc (c *sysctlCollector) newMetrics(s *sysctl) ([]prometheus.Metric, error) {\n\tvar (\n\t\tvalues any\n\t\tlength int\n\t\terr    error\n\t)\n\n\tif s.numeric {\n\t\tvalues, err = c.fs.SysctlInts(s.name)\n\t\tif err != nil {\n\t\t\treturn nil, fmt.Errorf(\"error obtaining sysctl info: %w\", err)\n\t\t}\n\t\tlength = len(values.([]int))\n\t} else {\n\t\tvalues, err = c.fs.SysctlStrings(s.name)\n\t\tif err != nil {\n\t\t\treturn nil, fmt.Errorf(\"error obtaining sysctl info: %w\", err)\n\t\t}\n\t\tlength = len(values.([]string))\n\t}\n\n\tswitch length {\n\tcase 0:\n\t\treturn nil, fmt.Errorf(\"sysctl %s has no values\", s.name)\n\tcase 1:\n\t\tif len(s.keys) > 0 {\n\t\t\treturn nil, fmt.Errorf(\"sysctl %s has only one value, but expected %v\", s.name, s.keys)\n\t\t}\n\t\treturn []prometheus.Metric{s.newConstMetric(values)}, nil","sourceCodeStart":79,"sourceCodeEnd":115,"githubUrl":"https://github.com/prometheus/node_exporter/blob/17ddd77c59ba27e1508e9f7894b1e55b44d6aed3/collector/sysctl_linux.go#L79-L115","documentation":"newMetrics reads a numeric sysctl via c.fs.SysctlInts(s.name); any procfs read failure (missing file, permission, parse error) is wrapped as 'error obtaining sysctl info'. It is returned per-sysctl and surfaces in Update's error output, skipping that sysctl's metrics.","triggerScenarios":"A configured --collector.sysctl --collector.sysctl.include=<name> references a sysctl that does not exist on this kernel, or exists but cannot be read as integers by procfs (permissions, or value not parseable as []int).","commonSituations":"Include list copied from another kernel version where the sysctl was renamed/removed; hardened kernels restricting /proc/sys reads to root; sysctl whose content procfs cannot parse.","solutions":["Verify the sysctl exists: `sysctl <name>` or `cat /proc/sys/<path>`","Remove/adjust the include filter entry for sysctls absent on this kernel","Run the exporter with permission to read the file (or relax the file's perms)","Check procfs can parse it; if not, extend prometheus/procfs upstream"],"exampleFix":"// before\n--collector.sysctl.include='vm.fake_stat'\n// after\n--collector.sysctl.include='vm.stat'","handlingStrategy":"validation","validationCode":"if _, err := os.Stat(filepath.Join(\"/proc/sys\", strings.ReplaceAll(name, \".\", \"/\"))); err != nil { /* skip this sysctl */ }","typeGuard":null,"tryCatchPattern":"if err := coll.Update(ch); err != nil {\n    if strings.Contains(err.Error(), \"error obtaining sysctl info\") {\n        logger.Warn(\"sysctl unavailable on this kernel\", \"err\", err)\n    }\n}","preventionTips":["Generate the include list from the actual host: `sysctl -a | cut -d' ' -f1`","Re-verify include lists after kernel upgrades","Keep prometheus/procfs up to date"],"tags":["linux","sysctl","procfs","permissions","configuration"],"backgroundTag":"file-read-failed","analyzedSha":"17ddd77c59ba27e1508e9f7894b1e55b44d6aed3","analyzedAt":"2026-09-07T17:54:06.211Z","contentChangedAt":"2026-09-07T17:54:06.211Z","schemaVersion":2},"datasetVersion":"2026-09-16T04:17:20.429Z"}