Merge pull request kubernetes#105238 from damemi/1.21-revert-102925

Revert 102925: Fix Node Resources plugins score when there are pods with no requests
openshift · Oct 5, 2021 · 6e21f33 · 6e21f33
2 parents 60d7177 + 971c49d
commit 6e21f33
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Showing 2 changed files with 21 additions and 40 deletions.
diff --git a/pkg/scheduler/framework/plugins/noderesources/balanced_allocation.go b/pkg/scheduler/framework/plugins/noderesources/balanced_allocation.go
@@ -80,16 +80,12 @@ func NewBalancedAllocation(_ runtime.Object, h framework.Handle) (framework.Plug
 
 // todo: use resource weights in the scorer function
 func balancedResourceScorer(requested, allocable resourceToValueMap, includeVolumes bool, requestedVolumes int, allocatableVolumes int) int64 {
-	// This to find a node which has most balanced CPU, memory and volume usage.
 	cpuFraction := fractionOfCapacity(requested[v1.ResourceCPU], allocable[v1.ResourceCPU])
 	memoryFraction := fractionOfCapacity(requested[v1.ResourceMemory], allocable[v1.ResourceMemory])
-	// fractions might be greater than 1 because pods with no requests get minimum
-	// values.
-	if cpuFraction > 1 {
-		cpuFraction = 1
-	}
-	if memoryFraction > 1 {
-		memoryFraction = 1
+	// This to find a node which has most balanced CPU, memory and volume usage.
+	if cpuFraction >= 1 || memoryFraction >= 1 {
+		// if requested >= capacity, the corresponding host should never be preferred.
+		return 0
 	}
 
 	if includeVolumes && utilfeature.DefaultFeatureGate.Enabled(features.BalanceAttachedNodeVolumes) && allocatableVolumes > 0 {

diff --git a/pkg/scheduler/framework/plugins/noderesources/balanced_allocation_test.go b/pkg/scheduler/framework/plugins/noderesources/balanced_allocation_test.go
@@ -213,13 +213,6 @@ func TestNodeResourcesBalancedAllocation(t *testing.T) {
 			},
 		},
 	}
-	nonZeroContainer := v1.PodSpec{
-		Containers: []v1.Container{{}},
-	}
-	nonZeroContainer1 := v1.PodSpec{
-		NodeName:   "machine1",
-		Containers: []v1.Container{{}},
-	}
 	tests := []struct {
 		pod          *v1.Pod
 		pods         []*v1.Pod
@@ -275,24 +268,6 @@ func TestNodeResourcesBalancedAllocation(t *testing.T) {
 				{Spec: machine2Spec, ObjectMeta: metav1.ObjectMeta{Labels: labels1}},
 			},
 		},
-		{
-			// Node1 scores on 0-MaxNodeScore scale
-			// CPU Fraction: 300 / 250 = 100%
-			// Memory Fraction: 600 / 10000 = 60%
-			// Node1 Score: MaxNodeScore - (100-60)*MaxNodeScore = 60
-			// Node2 scores on 0-MaxNodeScore scale
-			// CPU Fraction: 100 / 250 = 40%
-			// Memory Fraction: 200 / 10000 = 20%
-			// Node2 Score: MaxNodeScore - (40-20)*MaxNodeScore= 80
-			pod:          &v1.Pod{Spec: nonZeroContainer},
-			nodes:        []*v1.Node{makeNode("machine1", 250, 1000*1024*1024), makeNode("machine2", 250, 1000*1024*1024)},
-			expectedList: []framework.NodeScore{{Name: "machine1", Score: 60}, {Name: "machine2", Score: 80}},
-			name:         "no resources requested, pods scheduled",
-			pods: []*v1.Pod{
-				{Spec: nonZeroContainer1},
-				{Spec: nonZeroContainer1},
-			},
-		},
 		{
 			// Node1 scores on 0-MaxNodeScore scale
 			// CPU Fraction: 6000 / 10000 = 60%
@@ -351,17 +326,27 @@ func TestNodeResourcesBalancedAllocation(t *testing.T) {
 		},
 		{
 			// Node1 scores on 0-MaxNodeScore scale
-			// CPU Fraction: 6000 / 6000 = 1
+			// CPU Fraction: 6000 / 4000 > 100% ==> Score := 0
 			// Memory Fraction: 0 / 10000 = 0
-			// Node1 Score: MaxNodeScore - (1 - 0) * MaxNodeScore = 0
+			// Node1 Score: 0
 			// Node2 scores on 0-MaxNodeScore scale
-			// CPU Fraction: 6000 / 6000 = 1
+			// CPU Fraction: 6000 / 4000 > 100% ==> Score := 0
 			// Memory Fraction 5000 / 10000 = 50%
-			// Node2 Score: MaxNodeScore - (1 - 0.5) * MaxNodeScore = 50
+			// Node2 Score: 0
 			pod:          &v1.Pod{Spec: cpuOnly},
-			nodes:        []*v1.Node{makeNode("machine1", 6000, 10000), makeNode("machine2", 6000, 10000)},
-			expectedList: []framework.NodeScore{{Name: "machine1", Score: 0}, {Name: "machine2", Score: 50}},
-			name:         "requested resources at node capacity",
+			nodes:        []*v1.Node{makeNode("machine1", 4000, 10000), makeNode("machine2", 4000, 10000)},
+			expectedList: []framework.NodeScore{{Name: "machine1", Score: 0}, {Name: "machine2", Score: 0}},
+			name:         "requested resources exceed node capacity",
+			pods: []*v1.Pod{
+				{Spec: cpuOnly},
+				{Spec: cpuAndMemory},
+			},
+		},
+		{
+			pod:          &v1.Pod{Spec: noResources},
+			nodes:        []*v1.Node{makeNode("machine1", 0, 0), makeNode("machine2", 0, 0)},
+			expectedList: []framework.NodeScore{{Name: "machine1", Score: 0}, {Name: "machine2", Score: 0}},
+			name:         "zero node resources, pods scheduled with resources",
 			pods: []*v1.Pod{
 				{Spec: cpuOnly},
 				{Spec: cpuAndMemory},