chore: log average and assessed thresholds

when calculating the average an applying the deviations it would be nice
to also see the assessed values.

this commit makes the descheduler logs these values when using level 3.

Author: ricardomaraschini

pkg/framework/plugins/nodeutilization/highnodeutilization.go

@@ -46,7 +46,6 @@ type HighNodeUtilization struct {
 	handle         frameworktypes.Handle
 	args           *HighNodeUtilizationArgs
 	podFilter      func(pod *v1.Pod) bool
-	criteria       []any
 	resourceNames  []v1.ResourceName
 	highThresholds api.ResourceThresholds
 	usageClient    usageClient
@@ -74,13 +73,6 @@ func NewHighNodeUtilization(
 		highThresholds[rname] = MaxResourcePercentage
 	}
 
-	// criteria is a list of thresholds that are used to determine if a node
-	// is underutilized. it is used only for logging purposes.
-	criteria := []any{}
-	for rname, rvalue := range args.Thresholds {
-		criteria = append(criteria, rname, rvalue)
-	}
-
 	podFilter, err := podutil.
 		NewOptions().
 		WithFilter(handle.Evictor().Filter).
@@ -106,7 +98,6 @@ func NewHighNodeUtilization(
 		args:           args,
 		resourceNames:  resourceNames,
 		highThresholds: highThresholds,
-		criteria:       criteria,
 		podFilter:      podFilter,
 		usageClient: newRequestedUsageClient(
 			resourceNames,
@@ -197,7 +188,7 @@ func (h *HighNodeUtilization) Balance(ctx context.Context, nodes []*v1.Node) *fr
 
 	lowNodes, schedulableNodes := nodeInfos[0], nodeInfos[1]
 
-	klog.V(1).InfoS("Criteria for a node below target utilization", h.criteria...)
+	klog.V(1).InfoS("Criteria for a node below target utilization", thresholdsToKeysAndValues(h.args.Thresholds)...)
 	klog.V(1).InfoS("Number of underutilized nodes", "totalNumber", len(lowNodes))
 
 	if len(lowNodes) == 0 {

pkg/framework/plugins/nodeutilization/lownodeutilization.go

@@ -46,8 +46,6 @@ type LowNodeUtilization struct {
 	handle                frameworktypes.Handle
 	args                  *LowNodeUtilizationArgs
 	podFilter             func(pod *v1.Pod) bool
-	underCriteria         []any
-	overCriteria          []any
 	resourceNames         []v1.ResourceName
 	extendedResourceNames []v1.ResourceName
 	usageClient           usageClient
@@ -92,16 +90,6 @@ func NewLowNodeUtilization(
 		)
 	}
 
-	// underCriteria and overCriteria are slices used for logging purposes.
-	// we assemble them only once.
-	underCriteria, overCriteria := []any{}, []any{}
-	for name := range args.Thresholds {
-		underCriteria = append(underCriteria, name, args.Thresholds[name])
-	}
-	for name := range args.TargetThresholds {
-		overCriteria = append(overCriteria, name, args.TargetThresholds[name])
-	}
-
 	podFilter, err := podutil.
 		NewOptions().
 		WithFilter(handle.Evictor().Filter).
@@ -127,8 +115,6 @@ func NewLowNodeUtilization(
 	return &LowNodeUtilization{
 		handle:                handle,
 		args:                  args,
-		underCriteria:         underCriteria,
-		overCriteria:          overCriteria,
 		resourceNames:         resourceNames,
 		extendedResourceNames: extendedResourceNames,
 		podFilter:             podFilter,
@@ -255,9 +241,9 @@ func (l *LowNodeUtilization) Balance(ctx context.Context, nodes []*v1.Node) *fra
 	lowNodes, highNodes := nodeInfos[0], nodeInfos[1]
 
 	// log messages for nodes with low and high utilization
-	klog.V(1).InfoS("Criteria for a node under utilization", l.underCriteria...)
+	klog.V(1).InfoS("Criteria for a node under utilization", thresholdsToKeysAndValues(l.args.Thresholds)...)
 	klog.V(1).InfoS("Number of underutilized nodes", "totalNumber", len(lowNodes))
-	klog.V(1).InfoS("Criteria for a node above target utilization", l.overCriteria...)
+	klog.V(1).InfoS("Criteria for a node above target utilization", thresholdsToKeysAndValues(l.args.TargetThresholds)...)
 	klog.V(1).InfoS("Number of overutilized nodes", "totalNumber", len(highNodes))
 
 	if len(lowNodes) == 0 {

pkg/framework/plugins/nodeutilization/nodeutilization.go

@@ -130,6 +130,16 @@ func getNodeUsageSnapshot(
 	return nodesMap, nodesUsageMap, podListMap
 }
 
+// thresholdsToKeysAndValues converts a ResourceThresholds into a list of keys
+// and values. this is useful for logging.
+func thresholdsToKeysAndValues(thresholds api.ResourceThresholds) []any {
+	result := []any{}
+	for name, value := range thresholds {
+		result = append(result, name, fmt.Sprintf("%.2f%%", value))
+	}
+	return result
+}
+
 // usageToKeysAndValues converts a ReferencedResourceList into a list of
 // keys and values. this is useful for logging.
 func usageToKeysAndValues(usage api.ReferencedResourceList) []any {
@@ -487,25 +497,37 @@ func assessNodesUsagesAndRelativeThresholds(
 		rawUsages, rawCapacities, ResourceUsageToResourceThreshold,
 	)
 
-	// calculate the average usage and then deviate it according to the
-	// user provided thresholds.
+	// calculate the average usage.
 	average := normalizer.Average(usage)
+	klog.V(3).InfoS(
+		"Assessed average usage",
+		thresholdsToKeysAndValues(average)...,
+	)
+
+	// decrease the provided threshold from the average to get the low
+	// span. also make sure the resulting values are between 0 and 100.
+	lowSpan = normalizer.Clamp(
+		normalizer.Sum(average, normalizer.Negate(lowSpan)), 0, 100,
+	)
+	klog.V(3).InfoS(
+		"Assessed thresholds for underutilized nodes",
+		thresholdsToKeysAndValues(lowSpan)...,
+	)
+
+	// increase the provided threshold from the average to get the high
+	// span. also make sure the resulting values are between 0 and 100.
+	highSpan = normalizer.Clamp(
+		normalizer.Sum(average, highSpan), 0, 100,
+	)
+	klog.V(3).InfoS(
+		"Assessed thresholds for overutilized nodes",
+		thresholdsToKeysAndValues(highSpan)...,
+	)
 
-	// calculate the average usage and then deviate it according to the
-	// user provided thresholds. We also ensure that the value after the
-	// deviation is at least 1%. this call also replicates the thresholds
-	// across all nodes.
+	// replicate the same assessed thresholds to all nodes.
 	thresholds := normalizer.Replicate(
 		slices.Collect(maps.Keys(usage)),
-		normalizer.Map(
-			[]api.ResourceThresholds{
-				normalizer.Sum(average, normalizer.Negate(lowSpan)),
-				normalizer.Sum(average, highSpan),
-			},
-			func(thresholds api.ResourceThresholds) api.ResourceThresholds {
-				return normalizer.Clamp(thresholds, 0, 100)
-			},
-		),
+		[]api.ResourceThresholds{lowSpan, highSpan},
 	)
 
 	return usage, thresholds