node_exporter/collector/zfs_linux.go

439 lines
12 KiB
Go

// Copyright 2016 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//go:build !nozfs
// +build !nozfs
package collector
import (
"bufio"
"errors"
"fmt"
"io"
"log/slog"
"os"
"path/filepath"
"strconv"
"strings"
"github.com/prometheus/client_golang/prometheus"
)
// constants from https://github.com/zfsonlinux/zfs/blob/master/lib/libspl/include/sys/kstat.h
// kept as strings for comparison thus avoiding conversion to int
const (
// kstatDataChar = "0"
// kstatDataInt32 = "1"
// kstatDataUint32 = "2"
kstatDataInt64 = "3"
kstatDataUint64 = "4"
// kstatDataLong = "5"
// kstatDataUlong = "6"
// kstatDataString = "7"
)
var (
errZFSNotAvailable = errors.New("ZFS / ZFS statistics are not available")
zfsPoolStatesName = [...]string{"online", "degraded", "faulted", "offline", "removed", "unavail", "suspended"}
)
type zfsCollector struct {
linuxProcpathBase string
linuxZpoolIoPath string
linuxZpoolObjsetPath string
linuxZpoolStatePath string
linuxPathMap map[string]string
logger *slog.Logger
}
// NewZFSCollector returns a new Collector exposing ZFS statistics.
func NewZFSCollector(logger *slog.Logger) (Collector, error) {
return &zfsCollector{
linuxProcpathBase: "spl/kstat/zfs",
linuxZpoolIoPath: "/*/io",
linuxZpoolObjsetPath: "/*/objset-*",
linuxZpoolStatePath: "/*/state",
linuxPathMap: map[string]string{
"zfs_abd": "abdstats",
"zfs_arc": "arcstats",
"zfs_dbuf": "dbufstats",
"zfs_dmu_tx": "dmu_tx",
"zfs_dnode": "dnodestats",
"zfs_fm": "fm",
"zfs_vdev_cache": "vdev_cache_stats", // vdev_cache is deprecated
"zfs_vdev_mirror": "vdev_mirror_stats",
"zfs_xuio": "xuio_stats", // no known consumers of the XUIO interface on Linux exist
"zfs_zfetch": "zfetchstats",
"zfs_zil": "zil",
},
logger: logger,
}, nil
}
func (c *zfsCollector) Update(ch chan<- prometheus.Metric) error {
if _, err := c.openProcFile(c.linuxProcpathBase); err != nil {
if err == errZFSNotAvailable {
c.logger.Debug(err.Error())
return ErrNoData
}
}
for subsystem := range c.linuxPathMap {
if err := c.updateZfsStats(subsystem, ch); err != nil {
if err == errZFSNotAvailable {
c.logger.Debug(err.Error())
// ZFS /proc files are added as new features to ZFS arrive, it is ok to continue
continue
}
return err
}
}
// Pool stats
return c.updatePoolStats(ch)
}
func (c *zfsCollector) openProcFile(path string) (*os.File, error) {
file, err := os.Open(procFilePath(path))
if err != nil {
// file not found error can occur if:
// 1. zfs module is not loaded
// 2. zfs version does not have the feature with metrics -- ok to ignore
c.logger.Debug("Cannot open file for reading", "path", procFilePath(path))
return nil, errZFSNotAvailable
}
return file, nil
}
func (c *zfsCollector) updateZfsStats(subsystem string, ch chan<- prometheus.Metric) error {
file, err := c.openProcFile(filepath.Join(c.linuxProcpathBase, c.linuxPathMap[subsystem]))
if err != nil {
return err
}
defer file.Close()
return c.parseProcfsFile(file, c.linuxPathMap[subsystem], func(s zfsSysctl, v interface{}) {
var valueAsFloat64 float64
switch value := v.(type) {
case int64:
valueAsFloat64 = float64(value)
case uint64:
valueAsFloat64 = float64(value)
}
ch <- c.constSysctlMetric(subsystem, s, valueAsFloat64)
})
}
func (c *zfsCollector) updatePoolStats(ch chan<- prometheus.Metric) error {
zpoolPaths, err := filepath.Glob(procFilePath(filepath.Join(c.linuxProcpathBase, c.linuxZpoolIoPath)))
if err != nil {
return err
}
for _, zpoolPath := range zpoolPaths {
file, err := os.Open(zpoolPath)
if err != nil {
// this file should exist, but there is a race where an exporting pool can remove the files -- ok to ignore
c.logger.Debug("Cannot open file for reading", "path", zpoolPath)
return errZFSNotAvailable
}
err = c.parsePoolProcfsFile(file, zpoolPath, func(poolName string, s zfsSysctl, v uint64) {
ch <- c.constPoolMetric(poolName, s, v)
})
file.Close()
if err != nil {
return err
}
}
zpoolObjsetPaths, err := filepath.Glob(procFilePath(filepath.Join(c.linuxProcpathBase, c.linuxZpoolObjsetPath)))
if err != nil {
return err
}
for _, zpoolPath := range zpoolObjsetPaths {
file, err := os.Open(zpoolPath)
if err != nil {
// This file should exist, but there is a race where an exporting pool can remove the files. Ok to ignore.
c.logger.Debug("Cannot open file for reading", "path", zpoolPath)
return errZFSNotAvailable
}
err = c.parsePoolObjsetFile(file, zpoolPath, func(poolName string, datasetName string, s zfsSysctl, v uint64) {
ch <- c.constPoolObjsetMetric(poolName, datasetName, s, v)
})
file.Close()
if err != nil {
return err
}
}
zpoolStatePaths, err := filepath.Glob(procFilePath(filepath.Join(c.linuxProcpathBase, c.linuxZpoolStatePath)))
if err != nil {
return err
}
if zpoolStatePaths == nil {
c.logger.Debug("No pool state files found")
return nil
}
for _, zpoolPath := range zpoolStatePaths {
file, err := os.Open(zpoolPath)
if err != nil {
// This file should exist, but there is a race where an exporting pool can remove the files. Ok to ignore.
c.logger.Debug("Cannot open file for reading", "path", zpoolPath)
return errZFSNotAvailable
}
err = c.parsePoolStateFile(file, zpoolPath, func(poolName string, stateName string, isActive uint64) {
ch <- c.constPoolStateMetric(poolName, stateName, isActive)
})
file.Close()
if err != nil {
return err
}
}
return nil
}
func (c *zfsCollector) parseProcfsFile(reader io.Reader, fmtExt string, handler func(zfsSysctl, interface{})) error {
scanner := bufio.NewScanner(reader)
parseLine := false
for scanner.Scan() {
parts := strings.Fields(scanner.Text())
if !parseLine && len(parts) == 3 && parts[0] == "name" && parts[1] == "type" && parts[2] == "data" {
// Start parsing from here.
parseLine = true
continue
}
if !parseLine || len(parts) < 3 {
continue
}
// kstat data type (column 2) should be KSTAT_DATA_UINT64, otherwise ignore
// TODO: when other KSTAT_DATA_* types arrive, much of this will need to be restructured
key := fmt.Sprintf("kstat.zfs.misc.%s.%s", fmtExt, parts[0])
switch parts[1] {
case kstatDataUint64:
value, err := strconv.ParseUint(parts[2], 10, 64)
if err != nil {
return fmt.Errorf("could not parse expected unsigned integer value for %q: %w", key, err)
}
handler(zfsSysctl(key), value)
case kstatDataInt64:
value, err := strconv.ParseInt(parts[2], 10, 64)
if err != nil {
return fmt.Errorf("could not parse expected signed integer value for %q: %w", key, err)
}
handler(zfsSysctl(key), value)
}
}
if !parseLine {
return fmt.Errorf("did not parse a single %q metric", fmtExt)
}
return scanner.Err()
}
func (c *zfsCollector) parsePoolProcfsFile(reader io.Reader, zpoolPath string, handler func(string, zfsSysctl, uint64)) error {
scanner := bufio.NewScanner(reader)
parseLine := false
var fields []string
for scanner.Scan() {
line := strings.Fields(scanner.Text())
if !parseLine && len(line) >= 12 && line[0] == "nread" {
//Start parsing from here.
parseLine = true
fields = make([]string, len(line))
copy(fields, line)
continue
}
if !parseLine {
continue
}
zpoolPathElements := strings.Split(zpoolPath, "/")
pathLen := len(zpoolPathElements)
if pathLen < 2 {
return fmt.Errorf("zpool path did not return at least two elements")
}
zpoolName := zpoolPathElements[pathLen-2]
zpoolFile := zpoolPathElements[pathLen-1]
for i, field := range fields {
key := fmt.Sprintf("kstat.zfs.misc.%s.%s", zpoolFile, field)
value, err := strconv.ParseUint(line[i], 10, 64)
if err != nil {
return fmt.Errorf("could not parse expected integer value for %q: %w", key, err)
}
handler(zpoolName, zfsSysctl(key), value)
}
}
return scanner.Err()
}
func (c *zfsCollector) parsePoolObjsetFile(reader io.Reader, zpoolPath string, handler func(string, string, zfsSysctl, uint64)) error {
scanner := bufio.NewScanner(reader)
parseLine := false
var zpoolName, datasetName string
for scanner.Scan() {
parts := strings.Fields(scanner.Text())
if !parseLine && len(parts) == 3 && parts[0] == "name" && parts[1] == "type" && parts[2] == "data" {
parseLine = true
continue
}
if !parseLine || len(parts) < 3 {
continue
}
if parts[0] == "dataset_name" {
zpoolPathElements := strings.Split(zpoolPath, "/")
pathLen := len(zpoolPathElements)
zpoolName = zpoolPathElements[pathLen-2]
datasetName = parts[2]
continue
}
if parts[1] == kstatDataUint64 {
key := fmt.Sprintf("kstat.zfs.misc.objset.%s", parts[0])
value, err := strconv.ParseUint(parts[2], 10, 64)
if err != nil {
return fmt.Errorf("could not parse expected integer value for %q", key)
}
handler(zpoolName, datasetName, zfsSysctl(key), value)
}
}
if !parseLine {
return fmt.Errorf("did not parse a single %s %s metric", zpoolName, datasetName)
}
return scanner.Err()
}
func (c *zfsCollector) parsePoolStateFile(reader io.Reader, zpoolPath string, handler func(string, string, uint64)) error {
scanner := bufio.NewScanner(reader)
scanner.Scan()
actualStateName, err := scanner.Text(), scanner.Err()
if err != nil {
return err
}
actualStateName = strings.ToLower(actualStateName)
zpoolPathElements := strings.Split(zpoolPath, "/")
pathLen := len(zpoolPathElements)
if pathLen < 2 {
return fmt.Errorf("zpool path did not return at least two elements")
}
zpoolName := zpoolPathElements[pathLen-2]
for _, stateName := range zfsPoolStatesName {
isActive := uint64(0)
if actualStateName == stateName {
isActive = 1
}
handler(zpoolName, stateName, isActive)
}
return nil
}
func (c *zfsCollector) constSysctlMetric(subsystem string, sysctl zfsSysctl, value float64) prometheus.Metric {
metricName := sysctl.metricName()
return prometheus.MustNewConstMetric(
prometheus.NewDesc(
prometheus.BuildFQName(namespace, subsystem, metricName),
string(sysctl),
nil,
nil,
),
prometheus.UntypedValue,
value,
)
}
func (c *zfsCollector) constPoolMetric(poolName string, sysctl zfsSysctl, value uint64) prometheus.Metric {
metricName := sysctl.metricName()
return prometheus.MustNewConstMetric(
prometheus.NewDesc(
prometheus.BuildFQName(namespace, "zfs_zpool", metricName),
string(sysctl),
[]string{"zpool"},
nil,
),
prometheus.UntypedValue,
float64(value),
poolName,
)
}
func (c *zfsCollector) constPoolObjsetMetric(poolName string, datasetName string, sysctl zfsSysctl, value uint64) prometheus.Metric {
metricName := sysctl.metricName()
return prometheus.MustNewConstMetric(
prometheus.NewDesc(
prometheus.BuildFQName(namespace, "zfs_zpool_dataset", metricName),
string(sysctl),
[]string{"zpool", "dataset"},
nil,
),
prometheus.UntypedValue,
float64(value),
poolName,
datasetName,
)
}
func (c *zfsCollector) constPoolStateMetric(poolName string, stateName string, isActive uint64) prometheus.Metric {
return prometheus.MustNewConstMetric(
prometheus.NewDesc(
prometheus.BuildFQName(namespace, "zfs_zpool", "state"),
"kstat.zfs.misc.state",
[]string{"zpool", "state"},
nil,
),
prometheus.GaugeValue,
float64(isActive),
poolName,
stateName,
)
}
type zfsSysctl string
func (s zfsSysctl) metricName() string {
parts := strings.Split(string(s), ".")
return strings.Replace(parts[len(parts)-1], "-", "_", -1)
}