Use resource request instead of resource limit to deal with resource

plugin/pkg/scheduler/algorithm/priorities/priorities.go

@@ -43,29 +43,30 @@ func calculateScore(requested int64, capacity int64, node string) int {
 
 // For each of these resources, a pod that doesn't request the resource explicitly
 // will be treated as having requested the amount indicated below, for the purpose
-// of computing priority only. This ensures that when scheduling zero-limit pods, such
-// pods will not all be scheduled to the machine with the smallest in-use limit,
-// and that when scheduling regular pods, such pods will not see zero-limit pods as
+// of computing priority only. This ensures that when scheduling zero-request pods, such
+// pods will not all be scheduled to the machine with the smallest in-use request,
+// and that when scheduling regular pods, such pods will not see zero-request pods as
 // consuming no resources whatsoever. We chose these values to be similar to the
 // resources that we give to cluster addon pods (#10653). But they are pretty arbitrary.
-const defaultMilliCpuLimit int64 = 100             // 0.1 core
-const defaultMemoryLimit int64 = 200 * 1024 * 1024 // 200 MB
+// As described in #11713, we use request instead of limit to deal with resource requirements.
+const defaultMilliCpuRequest int64 = 100             // 0.1 core
+const defaultMemoryRequest int64 = 200 * 1024 * 1024 // 200 MB
 
 // TODO: Consider setting default as a fixed fraction of machine capacity (take "capacity api.ResourceList"
 // as an additional argument here) rather than using constants
-func getNonzeroLimits(limits *api.ResourceList) (int64, int64) {
+func getNonzeroRequests(requests *api.ResourceList) (int64, int64) {
 	var out_millicpu, out_memory int64
 	// Override if un-set, but not if explicitly set to zero
-	if (*limits.Cpu() == resource.Quantity{}) {
-		out_millicpu = defaultMilliCpuLimit
+	if (*requests.Cpu() == resource.Quantity{}) {
+		out_millicpu = defaultMilliCpuRequest
 	} else {
-		out_millicpu = limits.Cpu().MilliValue()
+		out_millicpu = requests.Cpu().MilliValue()
 	}
 	// Override if un-set, but not if explicitly set to zero
-	if (*limits.Memory() == resource.Quantity{}) {
-		out_memory = defaultMemoryLimit
+	if (*requests.Memory() == resource.Quantity{}) {
+		out_memory = defaultMemoryRequest
 	} else {
-		out_memory = limits.Memory().Value()
+		out_memory = requests.Memory().Value()
 	}
 	return out_millicpu, out_memory
 }
@@ -80,7 +81,7 @@ func calculateResourceOccupancy(pod *api.Pod, node api.Node, pods []*api.Pod) al
 
 	for _, existingPod := range pods {
 		for _, container := range existingPod.Spec.Containers {
-			cpu, memory := getNonzeroLimits(&container.Resources.Limits)
+			cpu, memory := getNonzeroRequests(&container.Resources.Requests)
 			totalMilliCPU += cpu
 			totalMemory += memory
 		}
@@ -88,7 +89,7 @@ func calculateResourceOccupancy(pod *api.Pod, node api.Node, pods []*api.Pod) al
 	// Add the resources requested by the current pod being scheduled.
 	// This also helps differentiate between differently sized, but empty, minions.
 	for _, container := range pod.Spec.Containers {
-		cpu, memory := getNonzeroLimits(&container.Resources.Limits)
+		cpu, memory := getNonzeroRequests(&container.Resources.Requests)
 		totalMilliCPU += cpu
 		totalMemory += memory
 	}
@@ -196,7 +197,7 @@ func calculateBalancedResourceAllocation(pod *api.Pod, node api.Node, pods []*ap
 	score := int(0)
 	for _, existingPod := range pods {
 		for _, container := range existingPod.Spec.Containers {
-			cpu, memory := getNonzeroLimits(&container.Resources.Limits)
+			cpu, memory := getNonzeroRequests(&container.Resources.Requests)
 			totalMilliCPU += cpu
 			totalMemory += memory
 		}
@@ -204,7 +205,7 @@ func calculateBalancedResourceAllocation(pod *api.Pod, node api.Node, pods []*ap
 	// Add the resources requested by the current pod being scheduled.
 	// This also helps differentiate between differently sized, but empty, minions.
 	for _, container := range pod.Spec.Containers {
-		cpu, memory := getNonzeroLimits(&container.Resources.Limits)
+		cpu, memory := getNonzeroRequests(&container.Resources.Requests)
 		totalMilliCPU += cpu
 		totalMemory += memory
 	}

plugin/pkg/scheduler/algorithm/priorities/priorities_test.go

@@ -40,7 +40,7 @@ func makeMinion(node string, milliCPU, memory int64) api.Node {
 	}
 }
 
-func TestZeroLimit(t *testing.T) {
+func TestZeroRequest(t *testing.T) {
 	// A pod with no resources. We expect spreading to count it as having the default resources.
 	noResources := api.PodSpec{
 		Containers: []api.Container{
@@ -49,16 +49,16 @@ func TestZeroLimit(t *testing.T) {
 	}
 	noResources1 := noResources
 	noResources1.NodeName = "machine1"
-	// A pod with the same resources as a 0-limit pod gets by default as its resources (for spreading).
+	// A pod with the same resources as a 0-request pod gets by default as its resources (for spreading).
 	small := api.PodSpec{
 		Containers: []api.Container{
 			{
 				Resources: api.ResourceRequirements{
-					Limits: api.ResourceList{
+					Requests: api.ResourceList{
 						"cpu": resource.MustParse(
-							strconv.FormatInt(defaultMilliCpuLimit, 10) + "m"),
+							strconv.FormatInt(defaultMilliCpuRequest, 10) + "m"),
 						"memory": resource.MustParse(
-							strconv.FormatInt(defaultMemoryLimit, 10)),
+							strconv.FormatInt(defaultMemoryRequest, 10)),
 					},
 				},
 			},
@@ -71,11 +71,11 @@ func TestZeroLimit(t *testing.T) {
 		Containers: []api.Container{
 			{
 				Resources: api.ResourceRequirements{
-					Limits: api.ResourceList{
+					Requests: api.ResourceList{
 						"cpu": resource.MustParse(
-							strconv.FormatInt(defaultMilliCpuLimit*3, 10) + "m"),
+							strconv.FormatInt(defaultMilliCpuRequest*3, 10) + "m"),
 						"memory": resource.MustParse(
-							strconv.FormatInt(defaultMemoryLimit*3, 10)),
+							strconv.FormatInt(defaultMemoryRequest*3, 10)),
 					},
 				},
 			},
@@ -91,13 +91,13 @@ func TestZeroLimit(t *testing.T) {
 		nodes []api.Node
 		test  string
 	}{
-		// The point of these next two tests is to show you get the same priority for a zero-limit pod
-		// as for a pod with the defaults limits, both when the zero-limit pod is already on the machine
-		// and when the zero-limit pod is the one being scheduled.
+		// The point of these next two tests is to show you get the same priority for a zero-request pod
+		// as for a pod with the defaults requests, both when the zero-request pod is already on the machine
+		// and when the zero-request pod is the one being scheduled.
 		{
 			pod:   &api.Pod{Spec: noResources},
-			nodes: []api.Node{makeMinion("machine1", 1000, defaultMemoryLimit*10), makeMinion("machine2", 1000, defaultMemoryLimit*10)},
-			test:  "test priority of zero-limit pod with machine with zero-limit pod",
+			nodes: []api.Node{makeMinion("machine1", 1000, defaultMemoryRequest*10), makeMinion("machine2", 1000, defaultMemoryRequest*10)},
+			test:  "test priority of zero-request pod with machine with zero-request pod",
 			pods: []*api.Pod{
 				{Spec: large1}, {Spec: noResources1},
 				{Spec: large2}, {Spec: small2},
@@ -105,8 +105,8 @@ func TestZeroLimit(t *testing.T) {
 		},
 		{
 			pod:   &api.Pod{Spec: small},
-			nodes: []api.Node{makeMinion("machine1", 1000, defaultMemoryLimit*10), makeMinion("machine2", 1000, defaultMemoryLimit*10)},
-			test:  "test priority of nonzero-limit pod with machine with zero-limit pod",
+			nodes: []api.Node{makeMinion("machine1", 1000, defaultMemoryRequest*10), makeMinion("machine2", 1000, defaultMemoryRequest*10)},
+			test:  "test priority of nonzero-request pod with machine with zero-request pod",
 			pods: []*api.Pod{
 				{Spec: large1}, {Spec: noResources1},
 				{Spec: large2}, {Spec: small2},
@@ -115,8 +115,8 @@ func TestZeroLimit(t *testing.T) {
 		// The point of this test is to verify that we're not just getting the same score no matter what we schedule.
 		{
 			pod:   &api.Pod{Spec: large},
-			nodes: []api.Node{makeMinion("machine1", 1000, defaultMemoryLimit*10), makeMinion("machine2", 1000, defaultMemoryLimit*10)},
-			test:  "test priority of larger pod with machine with zero-limit pod",
+			nodes: []api.Node{makeMinion("machine1", 1000, defaultMemoryRequest*10), makeMinion("machine2", 1000, defaultMemoryRequest*10)},
+			test:  "test priority of larger pod with machine with zero-request pod",
 			pods: []*api.Pod{
 				{Spec: large1}, {Spec: noResources1},
 				{Spec: large2}, {Spec: small2},
@@ -138,7 +138,7 @@ func TestZeroLimit(t *testing.T) {
 			t.Errorf("unexpected error: %v", err)
 		}
 		for _, hp := range list {
-			if test.test == "test priority of larger pod with machine with zero-limit pod" {
+			if test.test == "test priority of larger pod with machine with zero-request pod" {
 				if hp.Score == expectedPriority {
 					t.Errorf("%s: expected non-%d for all priorities, got list %#v", test.test, expectedPriority, list)
 				}
@@ -174,7 +174,7 @@ func TestLeastRequested(t *testing.T) {
 		Containers: []api.Container{
 			{
 				Resources: api.ResourceRequirements{
-					Limits: api.ResourceList{
+					Requests: api.ResourceList{
 						"cpu":    resource.MustParse("1000m"),
 						"memory": resource.MustParse("0"),
 					},
@@ -182,7 +182,7 @@ func TestLeastRequested(t *testing.T) {
 			},
 			{
 				Resources: api.ResourceRequirements{
-					Limits: api.ResourceList{
+					Requests: api.ResourceList{
 						"cpu":    resource.MustParse("2000m"),
 						"memory": resource.MustParse("0"),
 					},
@@ -197,7 +197,7 @@ func TestLeastRequested(t *testing.T) {
 		Containers: []api.Container{
 			{
 				Resources: api.ResourceRequirements{
-					Limits: api.ResourceList{
+					Requests: api.ResourceList{
 						"cpu":    resource.MustParse("1000m"),
 						"memory": resource.MustParse("2000"),
 					},
@@ -205,7 +205,7 @@ func TestLeastRequested(t *testing.T) {
 			},
 			{
 				Resources: api.ResourceRequirements{
-					Limits: api.ResourceList{
+					Requests: api.ResourceList{
 						"cpu":    resource.MustParse("2000m"),
 						"memory": resource.MustParse("3000"),
 					},
@@ -506,7 +506,7 @@ func TestBalancedResourceAllocation(t *testing.T) {
 		Containers: []api.Container{
 			{
 				Resources: api.ResourceRequirements{
-					Limits: api.ResourceList{
+					Requests: api.ResourceList{
 						"cpu":    resource.MustParse("1000m"),
 						"memory": resource.MustParse("0"),
 					},
@@ -514,7 +514,7 @@ func TestBalancedResourceAllocation(t *testing.T) {
 			},
 			{
 				Resources: api.ResourceRequirements{
-					Limits: api.ResourceList{
+					Requests: api.ResourceList{
 						"cpu":    resource.MustParse("2000m"),
 						"memory": resource.MustParse("0"),
 					},
@@ -529,7 +529,7 @@ func TestBalancedResourceAllocation(t *testing.T) {
 		Containers: []api.Container{
 			{
 				Resources: api.ResourceRequirements{
-					Limits: api.ResourceList{
+					Requests: api.ResourceList{
 						"cpu":    resource.MustParse("1000m"),
 						"memory": resource.MustParse("2000"),
 					},
@@ -537,7 +537,7 @@ func TestBalancedResourceAllocation(t *testing.T) {
 			},
 			{
 				Resources: api.ResourceRequirements{
-					Limits: api.ResourceList{
+					Requests: api.ResourceList{
 						"cpu":    resource.MustParse("2000m"),
 						"memory": resource.MustParse("3000"),
 					},