feat: refactoring thresholds and usage assessment

this commit refactors the thresholds and usage assessment for the node
utilization plugins. both high and low plugins are affected by this
change.

pkg/framework/plugins/nodeutilization/highnodeutilization.go

@@ -28,6 +28,7 @@ import (
 	nodeutil "sigs.k8s.io/descheduler/pkg/descheduler/node"
 
 	podutil "sigs.k8s.io/descheduler/pkg/descheduler/pod"
+	"sigs.k8s.io/descheduler/pkg/framework/plugins/nodeutilization/normalizer"
 	frameworktypes "sigs.k8s.io/descheduler/pkg/framework/types"
 )
 
@@ -42,6 +43,7 @@ type HighNodeUtilization struct {
 	podFilter                func(pod *v1.Pod) bool
 	underutilizationCriteria []interface{}
 	resourceNames            []v1.ResourceName
+	extendedResourceNames    []v1.ResourceName
 	targetThresholds         api.ResourceThresholds
 	usageClient              usageClient
 }
@@ -57,7 +59,7 @@ func NewHighNodeUtilization(args runtime.Object, handle frameworktypes.Handle) (
 
 	targetThresholds := make(api.ResourceThresholds)
 	setDefaultForThresholds(highNodeUtilizatioArgs.Thresholds, targetThresholds)
-	resourceNames := getResourceNames(targetThresholds)
+	resourceNames := getResourceNames(highNodeUtilizatioArgs.Thresholds)
 
 	underutilizationCriteria := []interface{}{
 		"CPU", highNodeUtilizatioArgs.Thresholds[v1.ResourceCPU],
@@ -77,14 +79,19 @@ func NewHighNodeUtilization(args runtime.Object, handle frameworktypes.Handle) (
 		return nil, fmt.Errorf("error initializing pod filter function: %v", err)
 	}
 
+	extendedResourceNames := uniquifyResourceNames(
+		append(resourceNames, v1.ResourceCPU, v1.ResourceMemory, v1.ResourcePods),
+	)
+
 	return &HighNodeUtilization{
 		handle:                   handle,
 		args:                     highNodeUtilizatioArgs,
 		resourceNames:            resourceNames,
+		extendedResourceNames:    extendedResourceNames,
 		targetThresholds:         targetThresholds,
 		underutilizationCriteria: underutilizationCriteria,
 		podFilter:                podFilter,
-		usageClient:              newRequestedUsageClient(resourceNames, handle.GetPodsAssignedToNodeFunc()),
+		usageClient:              newRequestedUsageClient(extendedResourceNames, handle.GetPodsAssignedToNodeFunc()),
 	}, nil
 }
 
@@ -102,11 +109,18 @@ func (h *HighNodeUtilization) Balance(ctx context.Context, nodes []*v1.Node) *fr
 	}
 
 	nodesMap, nodesUsageMap, podListMap := getNodeUsageSnapshot(nodes, h.usageClient)
-	nodeThresholdsMap := getStaticNodeThresholds(nodes, h.args.Thresholds, h.targetThresholds)
-	nodesUsageAsNodeThresholdsMap := nodeUsageToResourceThresholds(nodesUsageMap, nodesMap)
+	capacities := referencedResourceListForNodesCapacity(nodes)
+
+	usage, thresholds := assessNodesUsagesAndStaticThresholds(
+		nodesUsageMap,
+		capacities,
+		h.args.Thresholds,
+		h.targetThresholds,
+	)
+
 	nodeGroups := classifyNodeUsage(
-		nodesUsageAsNodeThresholdsMap,
-		nodeThresholdsMap,
+		usage,
+		thresholds,
 		[]classifierFnc{
 			// underutilized nodes
 			func(nodeName string, usage, threshold api.ResourceThresholds) bool {
@@ -128,7 +142,12 @@ func (h *HighNodeUtilization) Balance(ctx context.Context, nodes []*v1.Node) *fr
 	category := []string{"underutilized", "overutilized"}
 	for i := range nodeGroups {
 		for nodeName := range nodeGroups[i] {
-			klog.InfoS("Node is "+category[i], "node", klog.KObj(nodesMap[nodeName]), "usage", nodesUsageMap[nodeName], "usagePercentage", resourceUsagePercentages(nodesUsageMap[nodeName], nodesMap[nodeName], true))
+			klog.InfoS(
+				fmt.Sprintf("Node is %s", category[i]),
+				"node", klog.KObj(nodesMap[nodeName]),
+				"usage", nodesUsageMap[nodeName],
+				"usagePercentage", normalizer.Round(usage[nodeName]),
+			)
 			nodeInfos[i] = append(nodeInfos[i], NodeInfo{
 				NodeUsage: NodeUsage{
 					node:    nodesMap[nodeName],
@@ -136,8 +155,8 @@ func (h *HighNodeUtilization) Balance(ctx context.Context, nodes []*v1.Node) *fr
 					allPods: podListMap[nodeName],
 				},
 				thresholds: NodeThresholds{
-					lowResourceThreshold:  resourceThresholdsToNodeUsage(nodeThresholdsMap[nodeName][0], nodesMap[nodeName]),
-					highResourceThreshold: resourceThresholdsToNodeUsage(nodeThresholdsMap[nodeName][1], nodesMap[nodeName]),
+					lowResourceThreshold:  resourceThresholdsToNodeUsage(thresholds[nodeName][0], capacities[nodeName], h.extendedResourceNames),
+					highResourceThreshold: resourceThresholdsToNodeUsage(thresholds[nodeName][1], capacities[nodeName], h.extendedResourceNames),
 				},
 			})
 		}
@@ -189,7 +208,7 @@ func (h *HighNodeUtilization) Balance(ctx context.Context, nodes []*v1.Node) *fr
 		h.handle.Evictor(),
 		evictions.EvictOptions{StrategyName: HighNodeUtilizationPluginName},
 		h.podFilter,
-		h.resourceNames,
+		h.extendedResourceNames,
 		continueEvictionCond,
 		h.usageClient,
 		nil,
@@ -199,22 +218,16 @@ func (h *HighNodeUtilization) Balance(ctx context.Context, nodes []*v1.Node) *fr
 }
 
 func setDefaultForThresholds(thresholds, targetThresholds api.ResourceThresholds) {
-	// check if Pods/CPU/Mem are set, if not, set them to 100
-	if _, ok := thresholds[v1.ResourcePods]; !ok {
-		thresholds[v1.ResourcePods] = MaxResourcePercentage
+	if _, ok := thresholds[v1.ResourcePods]; ok {
+		targetThresholds[v1.ResourcePods] = MaxResourcePercentage
 	}
-	if _, ok := thresholds[v1.ResourceCPU]; !ok {
-		thresholds[v1.ResourceCPU] = MaxResourcePercentage
+	if _, ok := thresholds[v1.ResourceCPU]; ok {
+		targetThresholds[v1.ResourceCPU] = MaxResourcePercentage
 	}
-	if _, ok := thresholds[v1.ResourceMemory]; !ok {
-		thresholds[v1.ResourceMemory] = MaxResourcePercentage
+	if _, ok := thresholds[v1.ResourceMemory]; ok {
+		targetThresholds[v1.ResourceMemory] = MaxResourcePercentage
 	}
 
-	// Default targetThreshold resource values to 100
-	targetThresholds[v1.ResourcePods] = MaxResourcePercentage
-	targetThresholds[v1.ResourceCPU] = MaxResourcePercentage
-	targetThresholds[v1.ResourceMemory] = MaxResourcePercentage
-
 	for name := range thresholds {
 		if !nodeutil.IsBasicResource(name) {
 			targetThresholds[name] = MaxResourcePercentage