Expose version info in prometheus (#7812)

Fixes #7795

cmd/metrics.go

@@ -34,11 +34,25 @@ var (
 		},
 		[]string{"request_type"},
 	)
+	minioVersionInfo = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Namespace: "minio",
+			Name:      "version_info",
+			Help:      "Version of current MinIO server instance",
+		},
+		[]string{
+			// current version
+			"version",
+			// commit-id of the current version
+			"commit",
+		},
+	)
 )
 
 func init() {
 	prometheus.MustRegister(httpRequestsDuration)
 	prometheus.MustRegister(newMinioCollector())
+	prometheus.MustRegister(minioVersionInfo)
 }
 
 // newMinioCollector describes the collector
@@ -64,6 +78,9 @@ func (c *minioCollector) Describe(ch chan<- *prometheus.Desc) {
 // Collect is called by the Prometheus registry when collecting metrics.
 func (c *minioCollector) Collect(ch chan<- prometheus.Metric) {
 
+	// Expose MinIO's version information
+	minioVersionInfo.WithLabelValues(Version, CommitID).Add(1)
+
 	// Always expose network stats
 
 	// Network Sent/Received Bytes
@@ -184,7 +201,10 @@ func (c *minioCollector) Collect(ch chan<- prometheus.Metric) {
 func metricsHandler() http.Handler {
 	registry := prometheus.NewRegistry()
 
-	err := registry.Register(httpRequestsDuration)
+	err := registry.Register(minioVersionInfo)
+	logger.LogIf(context.Background(), err)
+
+	err = registry.Register(httpRequestsDuration)
 	logger.LogIf(context.Background(), err)
 
 	err = registry.Register(newMinioCollector())