Add a collector for DRBD.

This collector exposes most of the useful information that can be found
in /proc/drbd. Sizes are normalised to be in bytes, as /proc/drbd uses
kibibytes.

README.md

@@ -42,6 +42,7 @@ Name     | Description | OS
 ---------|-------------|----
 bonding | Exposes the number of configured and active slaves of Linux bonding interfaces. | Linux
 devstat | Exposes device statistics | Dragonfly, FreeBSD
+drbd | Exposes Distributed Replicated Block Device statistics | Linux
 gmond | Exposes statistics from Ganglia. | _any_
 interrupts | Exposes detailed interrupts statistics. | Linux, OpenBSD
 ipvs | Exposes IPVS status from `/proc/net/ip_vs` and stats from `/proc/net/ip_vs_stats`. | Linux

collector/drbd_linux.go

@@ -0,0 +1,211 @@
+// 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.
+
+package collector
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/common/log"
+)
+
+// Numerical metric provided by /proc/drbd.
+type drbdNumericalMetric struct {
+	desc       *prometheus.Desc
+	valueType  prometheus.ValueType
+	multiplier float64
+}
+
+func newDrbdNumericalMetric(name string, desc string, valueType prometheus.ValueType, multiplier float64) drbdNumericalMetric {
+	return drbdNumericalMetric{
+		desc: prometheus.NewDesc(
+			prometheus.BuildFQName(Namespace, "drbd", name),
+			desc,
+			[]string{"device"}, nil),
+		valueType:  valueType,
+		multiplier: multiplier,
+	}
+}
+
+// String pair metric provided by /proc/drbd.
+type drbdStringPairMetric struct {
+	desc      *prometheus.Desc
+	valueOkay string
+}
+
+func (metric *drbdStringPairMetric) isOkay(value string) float64 {
+	if value == metric.valueOkay {
+		return 1
+	}
+	return 0
+}
+
+func newDrbdStringPairMetric(name string, desc string, valueOkay string) drbdStringPairMetric {
+	return drbdStringPairMetric{
+		desc: prometheus.NewDesc(
+			prometheus.BuildFQName(Namespace, "drbd", name),
+			desc,
+			[]string{"device", "node"}, nil),
+		valueOkay: valueOkay,
+	}
+}
+
+var (
+	drbdNumericalMetrics = map[string]drbdNumericalMetric{
+		"ns": newDrbdNumericalMetric(
+			"network_sent_bytes",
+			"Volume of net data sent to the partner via the network connection.",
+			prometheus.CounterValue,
+			1024),
+		"nr": newDrbdNumericalMetric(
+			"network_received_bytes",
+			"Volume of net data received by the partner via the network connection.",
+			prometheus.CounterValue,
+			1),
+		"dw": newDrbdNumericalMetric(
+			"disk_written_bytes",
+			"Net data written on local hard disk.",
+			prometheus.CounterValue,
+			1024),
+		"dr": newDrbdNumericalMetric(
+			"disk_read_bytes",
+			"Net data read from local hard disk.",
+			prometheus.CounterValue,
+			1024),
+		"al": newDrbdNumericalMetric(
+			"activitylog_writes",
+			"Number of updates of the activity log area of the meta data.",
+			prometheus.CounterValue,
+			1),
+		"bm": newDrbdNumericalMetric(
+			"bitmap_writes",
+			"Number of updates of the bitmap area of the meta data.",
+			prometheus.CounterValue,
+			1),
+		"lo": newDrbdNumericalMetric(
+			"local_pending",
+			"Number of open requests to the local I/O sub-system.",
+			prometheus.GaugeValue,
+			1),
+		"pe": newDrbdNumericalMetric(
+			"remote_pending",
+			"Number of requests sent to the partner, but that have not yet been answered by the latter.",
+			prometheus.GaugeValue,
+			1),
+		"ua": newDrbdNumericalMetric(
+			"remote_unacknowledged",
+			"Number of requests received by the partner via the network connection, but that have not yet been answered.",
+			prometheus.GaugeValue,
+			1),
+		"ap": newDrbdNumericalMetric(
+			"application_pending",
+			"Number of block I/O requests forwarded to DRBD, but not yet answered by DRBD.",
+			prometheus.GaugeValue,
+			1),
+		"ep": newDrbdNumericalMetric(
+			"epochs",
+			"Number of Epochs currently on the fly.",
+			prometheus.GaugeValue,
+			1),
+		"oos": newDrbdNumericalMetric(
+			"out_of_sync_bytes",
+			"Amount of data known to be out of sync.",
+			prometheus.GaugeValue,
+			1024),
+	}
+	drbdStringPairMetrics = map[string]drbdStringPairMetric{
+		"ro": newDrbdStringPairMetric(
+			"node_role_is_primary",
+			"Whether the role of the node is in the primary state.",
+			"Primary"),
+		"ds": newDrbdStringPairMetric(
+			"disk_state_is_up_to_date",
+			"Whether the disk of the node is up to date.",
+			"UpToDate"),
+	}
+
+	drbdConnected = prometheus.NewDesc(
+		prometheus.BuildFQName(Namespace, "drbd", "connected"),
+		"Whether DRBD is connected to the partner.",
+		[]string{"device"}, nil)
+)
+
+type drbdCollector struct{}
+
+func init() {
+	Factories["drbd"] = NewDrbdCollector
+}
+
+func NewDrbdCollector() (Collector, error) {
+	return &drbdCollector{}, nil
+}
+
+func (c *drbdCollector) Update(ch chan<- prometheus.Metric) (err error) {
+	statsFile := procFilePath("drbd")
+	f, err := os.Open(statsFile)
+	if err != nil {
+		if os.IsNotExist(err) {
+			log.Debugf("Not collecting DRBD statistics, as %s does not exist: %s", statsFile)
+			return nil
+		}
+		return err
+	}
+	defer f.Close()
+
+	scanner := bufio.NewScanner(f)
+	scanner.Split(bufio.ScanWords)
+	device := "unknown"
+	for scanner.Scan() {
+		field := scanner.Text()
+		if kv := strings.Split(field, ":"); len(kv) == 2 {
+			if id, err := strconv.ParseUint(kv[0], 10, 64); err == nil && kv[1] == "" {
+				device = fmt.Sprintf("drbd%d", id)
+			} else if metric, ok := drbdNumericalMetrics[kv[0]]; ok {
+				// Numerical value.
+				value, _ := strconv.ParseFloat(kv[1], 64)
+				ch <- prometheus.MustNewConstMetric(
+					metric.desc, metric.valueType,
+					value*metric.multiplier, device)
+			} else if metric, ok := drbdStringPairMetrics[kv[0]]; ok {
+				// String pair value.
+				values := strings.Split(kv[1], "/")
+				ch <- prometheus.MustNewConstMetric(
+					metric.desc, prometheus.GaugeValue,
+					metric.isOkay(values[0]), device, "local")
+				ch <- prometheus.MustNewConstMetric(
+					metric.desc, prometheus.GaugeValue,
+					metric.isOkay(values[1]), device, "remote")
+			} else if kv[0] == "cs" {
+				// Connection state.
+				var connected float64 = 0
+				if kv[1] == "Connected" {
+					connected = 1
+				}
+				ch <- prometheus.MustNewConstMetric(
+					drbdConnected, prometheus.GaugeValue,
+					connected, device)
+
+			} else {
+				log.Infof("Don't know how to process key-value pair [%s: %s]", kv[0], kv[1])
+			}
+		} else {
+			log.Infof("Don't know how to process string %s", field)
+		}
+	}
+	return nil
+}

collector/fixtures/e2e-output.txt

@@ -375,6 +375,53 @@ node_disk_writes_merged{device="nvme0n1"} 43950
 node_disk_writes_merged{device="sda"} 1.1134226e+07
 node_disk_writes_merged{device="sr0"} 0
 node_disk_writes_merged{device="vda"} 2.0711856e+07
+# HELP node_drbd_activitylog_writes Number of updates of the activity log area of the meta data.
+# TYPE node_drbd_activitylog_writes counter
+node_drbd_activitylog_writes{device="drbd1"} 1100
+# HELP node_drbd_application_pending Number of block I/O requests forwarded to DRBD, but not yet answered by DRBD.
+# TYPE node_drbd_application_pending gauge
+node_drbd_application_pending{device="drbd1"} 12348
+# HELP node_drbd_bitmap_writes Number of updates of the bitmap area of the meta data.
+# TYPE node_drbd_bitmap_writes counter
+node_drbd_bitmap_writes{device="drbd1"} 221
+# HELP node_drbd_connected Whether DRBD is connected to the partner.
+# TYPE node_drbd_connected gauge
+node_drbd_connected{device="drbd1"} 1
+# HELP node_drbd_disk_read_bytes Net data read from local hard disk.
+# TYPE node_drbd_disk_read_bytes counter
+node_drbd_disk_read_bytes{device="drbd1"} 1.2154539008e+11
+# HELP node_drbd_disk_state_is_up_to_date Whether the disk of the node is up to date.
+# TYPE node_drbd_disk_state_is_up_to_date gauge
+node_drbd_disk_state_is_up_to_date{device="drbd1",node="local"} 1
+node_drbd_disk_state_is_up_to_date{device="drbd1",node="remote"} 1
+# HELP node_drbd_disk_written_bytes Net data written on local hard disk.
+# TYPE node_drbd_disk_written_bytes counter
+node_drbd_disk_written_bytes{device="drbd1"} 2.8941845504e+10
+# HELP node_drbd_epochs Number of Epochs currently on the fly.
+# TYPE node_drbd_epochs gauge
+node_drbd_epochs{device="drbd1"} 1
+# HELP node_drbd_local_pending Number of open requests to the local I/O sub-system.
+# TYPE node_drbd_local_pending gauge
+node_drbd_local_pending{device="drbd1"} 12345
+# HELP node_drbd_network_received_bytes Volume of net data received by the partner via the network connection.
+# TYPE node_drbd_network_received_bytes counter
+node_drbd_network_received_bytes{device="drbd1"} 1.0961011e+07
+# HELP node_drbd_network_sent_bytes Volume of net data sent to the partner via the network connection.
+# TYPE node_drbd_network_sent_bytes counter
+node_drbd_network_sent_bytes{device="drbd1"} 1.7740228608e+10
+# HELP node_drbd_node_role_is_primary Whether the role of the node is in the primary state.
+# TYPE node_drbd_node_role_is_primary gauge
+node_drbd_node_role_is_primary{device="drbd1",node="local"} 1
+node_drbd_node_role_is_primary{device="drbd1",node="remote"} 1
+# HELP node_drbd_out_of_sync_bytes Amount of data known to be out of sync.
+# TYPE node_drbd_out_of_sync_bytes gauge
+node_drbd_out_of_sync_bytes{device="drbd1"} 1.2645376e+07
+# HELP node_drbd_remote_pending Number of requests sent to the partner, but that have not yet been answered by the latter.
+# TYPE node_drbd_remote_pending gauge
+node_drbd_remote_pending{device="drbd1"} 12346
+# HELP node_drbd_remote_unacknowledged Number of requests received by the partner via the network connection, but that have not yet been answered.
+# TYPE node_drbd_remote_unacknowledged gauge
+node_drbd_remote_unacknowledged{device="drbd1"} 12347
 # HELP node_entropy_available_bits Bits of available entropy.
 # TYPE node_entropy_available_bits gauge
 node_entropy_available_bits 1337

collector/fixtures/proc/drbd

@@ -0,0 +1,5 @@
+version: 8.4.3 (api:1/proto:86-101)
+srcversion: 1A9F77B1CA5FF92235C2213 
+
+ 1: cs:Connected ro:Primary/Primary ds:UpToDate/UpToDate C r-----
+    ns:17324442 nr:10961011 dw:28263521 dr:118696670 al:1100 bm:221 lo:12345 pe:12346 ua:12347 ap:12348 ep:1 wo:d oos:12349

end-to-end-test.sh

@@ -5,6 +5,7 @@ set -euf -o pipefail
 collectors=$(cat << COLLECTORS
   conntrack
   diskstats
+  drbd
   entropy
   filefd
   hwmon