node_exporter/collector/diskstats_linux.go

407 lines
12 KiB
Go

// Copyright 2015 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 !nodiskstats
// +build !nodiskstats
package collector
import (
"bufio"
"fmt"
"log/slog"
"os"
"strconv"
"strings"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/procfs/blockdevice"
)
const (
secondsPerTick = 1.0 / 1000.0
// Read sectors and write sectors are the "standard UNIX 512-byte sectors, not any device- or filesystem-specific block size."
// See also https://www.kernel.org/doc/Documentation/block/stat.txt
unixSectorSize = 512.0
diskstatsDefaultIgnoredDevices = "^(z?ram|loop|fd|(h|s|v|xv)d[a-z]|nvme\\d+n\\d+p)\\d+$"
// See udevadm(8).
udevDevicePropertyPrefix = "E:"
// Udev device properties.
udevDMLVLayer = "DM_LV_LAYER"
udevDMLVName = "DM_LV_NAME"
udevDMName = "DM_NAME"
udevDMUUID = "DM_UUID"
udevDMVGName = "DM_VG_NAME"
udevIDATA = "ID_ATA"
udevIDATARotationRateRPM = "ID_ATA_ROTATION_RATE_RPM"
udevIDATASATA = "ID_ATA_SATA"
udevIDATASATASignalRateGen1 = "ID_ATA_SATA_SIGNAL_RATE_GEN1"
udevIDATASATASignalRateGen2 = "ID_ATA_SATA_SIGNAL_RATE_GEN2"
udevIDATAWriteCache = "ID_ATA_WRITE_CACHE"
udevIDATAWriteCacheEnabled = "ID_ATA_WRITE_CACHE_ENABLED"
udevIDFSType = "ID_FS_TYPE"
udevIDFSUsage = "ID_FS_USAGE"
udevIDFSUUID = "ID_FS_UUID"
udevIDFSVersion = "ID_FS_VERSION"
udevIDModel = "ID_MODEL"
udevIDPath = "ID_PATH"
udevIDRevision = "ID_REVISION"
udevIDSerialShort = "ID_SERIAL_SHORT"
udevIDWWN = "ID_WWN"
udevSCSIIdentSerial = "SCSI_IDENT_SERIAL"
)
type typedFactorDesc struct {
desc *prometheus.Desc
valueType prometheus.ValueType
}
type udevInfo map[string]string
func (d *typedFactorDesc) mustNewConstMetric(value float64, labels ...string) prometheus.Metric {
return prometheus.MustNewConstMetric(d.desc, d.valueType, value, labels...)
}
type diskstatsCollector struct {
deviceFilter deviceFilter
fs blockdevice.FS
infoDesc typedFactorDesc
descs []typedFactorDesc
filesystemInfoDesc typedFactorDesc
deviceMapperInfoDesc typedFactorDesc
ataDescs map[string]typedFactorDesc
logger *slog.Logger
getUdevDeviceProperties func(uint32, uint32) (udevInfo, error)
}
func init() {
registerCollector("diskstats", defaultEnabled, NewDiskstatsCollector)
}
// NewDiskstatsCollector returns a new Collector exposing disk device stats.
// Docs from https://www.kernel.org/doc/Documentation/iostats.txt
func NewDiskstatsCollector(logger *slog.Logger) (Collector, error) {
var diskLabelNames = []string{"device"}
fs, err := blockdevice.NewFS(*procPath, *sysPath)
if err != nil {
return nil, fmt.Errorf("failed to open sysfs: %w", err)
}
deviceFilter, err := newDiskstatsDeviceFilter(logger)
if err != nil {
return nil, fmt.Errorf("failed to parse device filter flags: %w", err)
}
collector := diskstatsCollector{
deviceFilter: deviceFilter,
fs: fs,
infoDesc: typedFactorDesc{
desc: prometheus.NewDesc(prometheus.BuildFQName(namespace, diskSubsystem, "info"),
"Info of /sys/block/<block_device>.",
[]string{"device", "major", "minor", "path", "wwn", "model", "serial", "revision"},
nil,
), valueType: prometheus.GaugeValue,
},
descs: []typedFactorDesc{
{
desc: readsCompletedDesc, valueType: prometheus.CounterValue,
},
{
desc: prometheus.NewDesc(
prometheus.BuildFQName(namespace, diskSubsystem, "reads_merged_total"),
"The total number of reads merged.",
diskLabelNames,
nil,
), valueType: prometheus.CounterValue,
},
{
desc: readBytesDesc, valueType: prometheus.CounterValue,
},
{
desc: readTimeSecondsDesc, valueType: prometheus.CounterValue,
},
{
desc: writesCompletedDesc, valueType: prometheus.CounterValue,
},
{
desc: prometheus.NewDesc(
prometheus.BuildFQName(namespace, diskSubsystem, "writes_merged_total"),
"The number of writes merged.",
diskLabelNames,
nil,
), valueType: prometheus.CounterValue,
},
{
desc: writtenBytesDesc, valueType: prometheus.CounterValue,
},
{
desc: writeTimeSecondsDesc, valueType: prometheus.CounterValue,
},
{
desc: prometheus.NewDesc(
prometheus.BuildFQName(namespace, diskSubsystem, "io_now"),
"The number of I/Os currently in progress.",
diskLabelNames,
nil,
), valueType: prometheus.GaugeValue,
},
{
desc: ioTimeSecondsDesc, valueType: prometheus.CounterValue,
},
{
desc: prometheus.NewDesc(
prometheus.BuildFQName(namespace, diskSubsystem, "io_time_weighted_seconds_total"),
"The weighted # of seconds spent doing I/Os.",
diskLabelNames,
nil,
), valueType: prometheus.CounterValue,
},
{
desc: prometheus.NewDesc(
prometheus.BuildFQName(namespace, diskSubsystem, "discards_completed_total"),
"The total number of discards completed successfully.",
diskLabelNames,
nil,
), valueType: prometheus.CounterValue,
},
{
desc: prometheus.NewDesc(
prometheus.BuildFQName(namespace, diskSubsystem, "discards_merged_total"),
"The total number of discards merged.",
diskLabelNames,
nil,
), valueType: prometheus.CounterValue,
},
{
desc: prometheus.NewDesc(
prometheus.BuildFQName(namespace, diskSubsystem, "discarded_sectors_total"),
"The total number of sectors discarded successfully.",
diskLabelNames,
nil,
), valueType: prometheus.CounterValue,
},
{
desc: prometheus.NewDesc(
prometheus.BuildFQName(namespace, diskSubsystem, "discard_time_seconds_total"),
"This is the total number of seconds spent by all discards.",
diskLabelNames,
nil,
), valueType: prometheus.CounterValue,
},
{
desc: prometheus.NewDesc(
prometheus.BuildFQName(namespace, diskSubsystem, "flush_requests_total"),
"The total number of flush requests completed successfully",
diskLabelNames,
nil,
), valueType: prometheus.CounterValue,
},
{
desc: prometheus.NewDesc(
prometheus.BuildFQName(namespace, diskSubsystem, "flush_requests_time_seconds_total"),
"This is the total number of seconds spent by all flush requests.",
diskLabelNames,
nil,
), valueType: prometheus.CounterValue,
},
},
filesystemInfoDesc: typedFactorDesc{
desc: prometheus.NewDesc(prometheus.BuildFQName(namespace, diskSubsystem, "filesystem_info"),
"Info about disk filesystem.",
[]string{"device", "type", "usage", "uuid", "version"},
nil,
), valueType: prometheus.GaugeValue,
},
deviceMapperInfoDesc: typedFactorDesc{
desc: prometheus.NewDesc(prometheus.BuildFQName(namespace, diskSubsystem, "device_mapper_info"),
"Info about disk device mapper.",
[]string{"device", "name", "uuid", "vg_name", "lv_name", "lv_layer"},
nil,
), valueType: prometheus.GaugeValue,
},
ataDescs: map[string]typedFactorDesc{
udevIDATAWriteCache: {
desc: prometheus.NewDesc(prometheus.BuildFQName(namespace, diskSubsystem, "ata_write_cache"),
"ATA disk has a write cache.",
[]string{"device"},
nil,
), valueType: prometheus.GaugeValue,
},
udevIDATAWriteCacheEnabled: {
desc: prometheus.NewDesc(prometheus.BuildFQName(namespace, diskSubsystem, "ata_write_cache_enabled"),
"ATA disk has its write cache enabled.",
[]string{"device"},
nil,
), valueType: prometheus.GaugeValue,
},
udevIDATARotationRateRPM: {
desc: prometheus.NewDesc(prometheus.BuildFQName(namespace, diskSubsystem, "ata_rotation_rate_rpm"),
"ATA disk rotation rate in RPMs (0 for SSDs).",
[]string{"device"},
nil,
), valueType: prometheus.GaugeValue,
},
},
logger: logger,
}
// Only enable getting device properties from udev if the directory is readable.
if stat, err := os.Stat(*udevDataPath); err != nil || !stat.IsDir() {
logger.Error("Failed to open directory, disabling udev device properties", "path", *udevDataPath)
} else {
collector.getUdevDeviceProperties = getUdevDeviceProperties
}
return &collector, nil
}
func (c *diskstatsCollector) Update(ch chan<- prometheus.Metric) error {
diskStats, err := c.fs.ProcDiskstats()
if err != nil {
return fmt.Errorf("couldn't get diskstats: %w", err)
}
for _, stats := range diskStats {
dev := stats.DeviceName
if c.deviceFilter.ignored(dev) {
continue
}
info, err := getUdevDeviceProperties(stats.MajorNumber, stats.MinorNumber)
if err != nil {
c.logger.Debug("Failed to parse udev info", "err", err)
}
// This is usually the serial printed on the disk label.
serial := info[udevSCSIIdentSerial]
// If it's undefined, fallback to ID_SERIAL_SHORT instead.
if serial == "" {
serial = info[udevIDSerialShort]
}
ch <- c.infoDesc.mustNewConstMetric(1.0, dev,
fmt.Sprint(stats.MajorNumber),
fmt.Sprint(stats.MinorNumber),
info[udevIDPath],
info[udevIDWWN],
info[udevIDModel],
serial,
info[udevIDRevision],
)
statCount := stats.IoStatsCount - 3 // Total diskstats record count, less MajorNumber, MinorNumber and DeviceName
for i, val := range []float64{
float64(stats.ReadIOs),
float64(stats.ReadMerges),
float64(stats.ReadSectors) * unixSectorSize,
float64(stats.ReadTicks) * secondsPerTick,
float64(stats.WriteIOs),
float64(stats.WriteMerges),
float64(stats.WriteSectors) * unixSectorSize,
float64(stats.WriteTicks) * secondsPerTick,
float64(stats.IOsInProgress),
float64(stats.IOsTotalTicks) * secondsPerTick,
float64(stats.WeightedIOTicks) * secondsPerTick,
float64(stats.DiscardIOs),
float64(stats.DiscardMerges),
float64(stats.DiscardSectors),
float64(stats.DiscardTicks) * secondsPerTick,
float64(stats.FlushRequestsCompleted),
float64(stats.TimeSpentFlushing) * secondsPerTick,
} {
if i >= statCount {
break
}
ch <- c.descs[i].mustNewConstMetric(val, dev)
}
if fsType := info[udevIDFSType]; fsType != "" {
ch <- c.filesystemInfoDesc.mustNewConstMetric(1.0, dev,
fsType,
info[udevIDFSUsage],
info[udevIDFSUUID],
info[udevIDFSVersion],
)
}
if name := info[udevDMName]; name != "" {
ch <- c.deviceMapperInfoDesc.mustNewConstMetric(1.0, dev,
name,
info[udevDMUUID],
info[udevDMVGName],
info[udevDMLVName],
info[udevDMLVLayer],
)
}
if ata := info[udevIDATA]; ata != "" {
for attr, desc := range c.ataDescs {
str, ok := info[attr]
if !ok {
c.logger.Debug("Udev attribute does not exist", "attribute", attr)
continue
}
if value, err := strconv.ParseFloat(str, 64); err == nil {
ch <- desc.mustNewConstMetric(value, dev)
} else {
c.logger.Error("Failed to parse ATA value", "err", err)
}
}
}
}
return nil
}
func getUdevDeviceProperties(major, minor uint32) (udevInfo, error) {
filename := udevDataFilePath(fmt.Sprintf("b%d:%d", major, minor))
data, err := os.Open(filename)
if err != nil {
return nil, err
}
defer data.Close()
info := make(udevInfo)
scanner := bufio.NewScanner(data)
for scanner.Scan() {
line := scanner.Text()
// We're only interested in device properties.
if !strings.HasPrefix(line, udevDevicePropertyPrefix) {
continue
}
line = strings.TrimPrefix(line, udevDevicePropertyPrefix)
/* TODO: After we drop support for Go 1.17, the condition below can be simplified to:
if name, value, found := strings.Cut(line, "="); found {
info[name] = value
}
*/
if fields := strings.SplitN(line, "=", 2); len(fields) == 2 {
info[fields[0]] = fields[1]
}
}
return info, nil
}