[#424] morph: Fix cache metrics

Use separate morph cache metrics for node and IR

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

pkg/metrics/innerring.go

@@ -12,6 +12,7 @@ const (
 	innerRingSubsystem    = "ir"
 	innerRingLabelSuccess = "success"
 	innerRingLabelType    = "type"
+	innerRingNamespace    = "frostfs_ir"
 )
 
 // InnerRingServiceMetrics contains metrics collected by inner ring.
@@ -26,19 +27,19 @@ type InnerRingServiceMetrics struct {
 func NewInnerRingMetrics() *InnerRingServiceMetrics {
 	var (
 		epoch = metrics.NewGauge(prometheus.GaugeOpts{
-			Namespace: namespace,
+			Namespace: innerRingNamespace,
 			Subsystem: innerRingSubsystem,
 			Name:      "epoch",
 			Help:      "Current epoch as seen by inner-ring node.",
 		})
 		health = metrics.NewGauge(prometheus.GaugeOpts{
-			Namespace: namespace,
+			Namespace: innerRingNamespace,
 			Subsystem: innerRingSubsystem,
 			Name:      "health",
 			Help:      "Current inner-ring node state.",
 		})
 		eventDuration = metrics.NewHistogramVec(prometheus.HistogramOpts{
-			Namespace: namespace,
+			Namespace: innerRingNamespace,
 			Subsystem: innerRingSubsystem,
 			Name:      "event_duration_seconds",
 			Help:      "Duration of processing of inner-ring events",
@@ -49,7 +50,7 @@ func NewInnerRingMetrics() *InnerRingServiceMetrics {
 		epoch:             epoch,
 		health:            health,
 		eventDuration:     eventDuration,
-		morphCacheMetrics: newMorphCacheMetrics(),
+		morphCacheMetrics: newMorphCacheMetrics(innerRingNamespace),
 	}
 }