Improve clarity around PodFitsResource by showing pods limits in kubectl describe node

plugin/pkg/scheduler/algorithm/predicates/predicates.go

@@ -105,6 +105,8 @@ type resourceRequest struct {
 	memory   int64
 }
 
+var FailedResourceType string
+
 func getResourceRequest(pod *api.Pod) resourceRequest {
 	result := resourceRequest{}
 	for ix := range pod.Spec.Containers {
@@ -115,7 +117,7 @@ func getResourceRequest(pod *api.Pod) resourceRequest {
 	return result
 }
 
-func CheckPodsExceedingCapacity(pods []*api.Pod, capacity api.ResourceList) (fitting []*api.Pod, notFitting []*api.Pod) {
+func CheckPodsExceedingFreeResources(pods []*api.Pod, capacity api.ResourceList) (fitting []*api.Pod, notFittingCPU, notFittingMemory []*api.Pod) {
 	totalMilliCPU := capacity.Cpu().MilliValue()
 	totalMemory := capacity.Memory().Value()
 	milliCPURequested := int64(0)
@@ -124,9 +126,14 @@ func CheckPodsExceedingCapacity(pods []*api.Pod, capacity api.ResourceList) (fit
 		podRequest := getResourceRequest(pod)
 		fitsCPU := totalMilliCPU == 0 || (totalMilliCPU-milliCPURequested) >= podRequest.milliCPU
 		fitsMemory := totalMemory == 0 || (totalMemory-memoryRequested) >= podRequest.memory
-		if !fitsCPU || !fitsMemory {
-			// the pod doesn't fit
-			notFitting = append(notFitting, pod)
+		if !fitsCPU {
+			// the pod doesn't fit due to CPU limit
+			notFittingCPU = append(notFittingCPU, pod)
+			continue
+		}
+		if !fitsMemory {
+			// the pod doesn't fit due to Memory limit
+			notFittingMemory = append(notFittingMemory, pod)
 			continue
 		}
 		// the pod fits
@@ -150,9 +157,20 @@ func (r *ResourceFit) PodFitsResources(pod *api.Pod, existingPods []*api.Pod, no
 	pods := []*api.Pod{}
 	copy(pods, existingPods)
 	pods = append(existingPods, pod)
-	_, exceeding := CheckPodsExceedingCapacity(pods, info.Status.Capacity)
-	if len(exceeding) > 0 || int64(len(pods)) > info.Status.Capacity.Pods().Value() {
+	_, exceedingCPU, exceedingMemory := CheckPodsExceedingFreeResources(pods, info.Status.Capacity)
+	if int64(len(pods)) > info.Status.Capacity.Pods().Value() {
 		glog.V(4).Infof("Cannot schedule Pod %v, because Node %v is full, running %v out of %v Pods.", pod, node, len(pods)-1, info.Status.Capacity.Pods().Value())
+		FailedResourceType = "PodExceedsMaxPodNumber"
+		return false, nil
+	}
+	if len(exceedingCPU) > 0 {
+		glog.V(4).Infof("Cannot schedule Pod %v, because Node does not have sufficient CPU", pod)
+		FailedResourceType = "PodExceedsFreeCPU"
+		return false, nil
+	}
+	if len(exceedingMemory) > 0 {
+		glog.V(4).Infof("Cannot schedule Pod %v, because Node does not have sufficient Memory", pod)
+		FailedResourceType = "PodExceedsFreeMemory"
 		return false, nil
 	}
 	glog.V(4).Infof("Schedule Pod %v on Node %v is allowed, Node is running only %v out of %v Pods.", pod, node, len(pods)-1, info.Status.Capacity.Pods().Value())

plugin/pkg/scheduler/generic_scheduler.go

@@ -116,6 +116,7 @@ func findNodesThatFit(pod *api.Pod, podLister algorithm.PodLister, predicateFunc
 	for _, node := range nodes.Items {
 		fits := true
 		for name, predicate := range predicateFuncs {
+			predicates.FailedResourceType = ""
 			fit, err := predicate(pod, machineToPods[node.Name], node.Name)
 			if err != nil {
 				return api.NodeList{}, FailedPredicateMap{}, err
@@ -125,6 +126,10 @@ func findNodesThatFit(pod *api.Pod, podLister algorithm.PodLister, predicateFunc
 				if _, found := failedPredicateMap[node.Name]; !found {
 					failedPredicateMap[node.Name] = util.StringSet{}
 				}
+				if predicates.FailedResourceType != "" {
+					failedPredicateMap[node.Name].Insert(predicates.FailedResourceType)
+					break
+				}
 				failedPredicateMap[node.Name].Insert(name)
 				break
 			}