Export start_time_seconds metrics on both master & volume servers. (#9046)

These are to be used to track uptimes.

See https://github.com/seaweedfs/seaweedfs/issues/8535 for details.

Co-authored-by: Lisandro Pin <lisandro.pin@proton.ch>

weed/server/master_server.go

@@ -204,6 +204,7 @@ func NewMasterServer(r *mux.Router, option *MasterOption, peers map[string]pb.Se
 		ms.startAdminScripts()
 	}
 
+	stats.MasterStartTimeSeconds.Set(float64(time.Now().Unix()))
 	return ms
 }
 

weed/server/volume_server.go

@@ -142,6 +142,7 @@ func NewVolumeServer(adminMux, publicMux *http.ServeMux, ip string,
 
 	stats.VolumeServerConcurrentDownloadLimit.Set(float64(vs.concurrentDownloadLimit))
 	stats.VolumeServerConcurrentUploadLimit.Set(float64(vs.concurrentUploadLimit))
+	stats.VolumeServerStartTimeSeconds.Set(float64(time.Now().Unix()))
 
 	go vs.heartbeat()
 	go stats.LoopPushingMetric("volumeServer", util.JoinHostPort(ip, port), vs.metricsAddress, vs.metricsIntervalSec)

weed/stats/metrics.go

@@ -54,6 +54,14 @@ var (
 			Help:      "A metric with a constant '1' value labeled by version, commit, sizelimit, goos, and goarch from which SeaweedFS was built.",
 		}, []string{"version", "commit", "sizelimit", "goos", "goarch"})
 
+	MasterStartTimeSeconds = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: Namespace,
+			Subsystem: "master",
+			Name:      "start_time_seconds",
+			Help:      "Start time of the master, as seconds since UNIX epoch.",
+		})
+
 	MasterClientConnectCounter = prometheus.NewCounterVec(
 		prometheus.CounterOpts{
 			Namespace: Namespace,
@@ -216,6 +224,14 @@ var (
 			Help:      "The offset of the filer synchronization service.",
 		}, []string{"sourceFiler", "targetFiler", "clientName", "path"})
 
+	VolumeServerStartTimeSeconds = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: Namespace,
+			Subsystem: "volumeServer",
+			Name:      "start_time_seconds",
+			Help:      "Start time of the volume server, as seconds since UNIX epoch.",
+		})
+
 	VolumeServerRequestCounter = prometheus.NewCounterVec(
 		prometheus.CounterOpts{
 			Namespace: Namespace,
@@ -470,6 +486,7 @@ var (
 func init() {
 	Gather.MustRegister(BuildInfo)
 
+	Gather.MustRegister(MasterStartTimeSeconds)
 	Gather.MustRegister(MasterClientConnectCounter)
 	Gather.MustRegister(MasterRaftIsleader)
 	Gather.MustRegister(MasterAdminLock)
@@ -494,6 +511,7 @@ func init() {
 	Gather.MustRegister(collectors.NewGoCollector())
 	Gather.MustRegister(collectors.NewProcessCollector(collectors.ProcessCollectorOpts{}))
 
+	Gather.MustRegister(VolumeServerStartTimeSeconds)
 	Gather.MustRegister(VolumeServerRequestCounter)
 	Gather.MustRegister(VolumeServerHandlerCounter)
 	Gather.MustRegister(VolumeServerRequestHistogram)