Merge pull request #322 from lixiang233/move_pod_sort

Move sortPodsBasedOnPriority to pod util

pkg/descheduler/pod/pods.go

@@ -23,6 +23,7 @@ import (
 	"k8s.io/apimachinery/pkg/fields"
 	clientset "k8s.io/client-go/kubernetes"
 	"sigs.k8s.io/descheduler/pkg/utils"
+	"sort"
 )
 
 // ListPodsOnANode lists all of the pods on a node
@@ -68,3 +69,27 @@ func IsBurstablePod(pod *v1.Pod) bool {
 func IsGuaranteedPod(pod *v1.Pod) bool {
 	return utils.GetPodQOS(pod) == v1.PodQOSGuaranteed
 }
+
+// SortPodsBasedOnPriorityLowToHigh sorts pods based on their priorities from low to high.
+// If pods have same priorities, they will be sorted by QoS in the following order:
+// BestEffort, Burstable, Guaranteed
+func SortPodsBasedOnPriorityLowToHigh(pods []*v1.Pod) {
+	sort.Slice(pods, func(i, j int) bool {
+		if pods[i].Spec.Priority == nil && pods[j].Spec.Priority != nil {
+			return true
+		}
+		if pods[j].Spec.Priority == nil && pods[i].Spec.Priority != nil {
+			return false
+		}
+		if (pods[j].Spec.Priority == nil && pods[i].Spec.Priority == nil) || (*pods[i].Spec.Priority == *pods[j].Spec.Priority) {
+			if IsBestEffortPod(pods[i]) {
+				return true
+			}
+			if IsBurstablePod(pods[i]) && IsGuaranteedPod(pods[j]) {
+				return true
+			}
+			return false
+		}
+		return *pods[i].Spec.Priority < *pods[j].Spec.Priority
+	})
+}

pkg/descheduler/pod/pods_test.go

@@ -19,6 +19,7 @@ package pod
 import (
 	"context"
 	"fmt"
+	"reflect"
 	"strings"
 	"testing"
 
@@ -29,6 +30,11 @@ import (
 	"sigs.k8s.io/descheduler/test"
 )
 
+var (
+	lowPriority  = int32(0)
+	highPriority = int32(10000)
+)
+
 func TestListPodsOnANode(t *testing.T) {
 	testCases := []struct {
 		name             string
@@ -67,3 +73,43 @@ func TestListPodsOnANode(t *testing.T) {
 		}
 	}
 }
+
+func TestSortPodsBasedOnPriorityLowToHigh(t *testing.T) {
+	n1 := test.BuildTestNode("n1", 4000, 3000, 9, nil)
+
+	p1 := test.BuildTestPod("p1", 400, 0, n1.Name, func(pod *v1.Pod) {
+		test.SetPodPriority(pod, lowPriority)
+	})
+
+	// BestEffort
+	p2 := test.BuildTestPod("p2", 400, 0, n1.Name, func(pod *v1.Pod) {
+		test.SetPodPriority(pod, highPriority)
+		test.MakeBestEffortPod(pod)
+	})
+
+	// Burstable
+	p3 := test.BuildTestPod("p3", 400, 0, n1.Name, func(pod *v1.Pod) {
+		test.SetPodPriority(pod, highPriority)
+		test.MakeBurstablePod(pod)
+	})
+
+	// Guaranteed
+	p4 := test.BuildTestPod("p4", 400, 100, n1.Name, func(pod *v1.Pod) {
+		test.SetPodPriority(pod, highPriority)
+		test.MakeGuaranteedPod(pod)
+	})
+
+	// Best effort with nil priorities.
+	p5 := test.BuildTestPod("p5", 400, 100, n1.Name, test.MakeBestEffortPod)
+	p5.Spec.Priority = nil
+
+	p6 := test.BuildTestPod("p6", 400, 100, n1.Name, test.MakeGuaranteedPod)
+	p6.Spec.Priority = nil
+
+	podList := []*v1.Pod{p4, p3, p2, p1, p6, p5}
+
+	SortPodsBasedOnPriorityLowToHigh(podList)
+	if !reflect.DeepEqual(podList[len(podList)-1], p4) {
+		t.Errorf("Expected last pod in sorted list to be %v which of highest priority and guaranteed but got %v", p4, podList[len(podList)-1])
+	}
+}

pkg/descheduler/strategies/lownodeutilization.go

@@ -247,7 +247,7 @@ func evictPodsFromTargetNodes(
 			evictablePods = append(append(burstablePods, bestEffortPods...), guaranteedPods...)
 
 			// sort the evictable Pods based on priority. This also sorts them based on QoS. If there are multiple pods with same priority, they are sorted based on QoS tiers.
-			sortPodsBasedOnPriority(evictablePods)
+			podutil.SortPodsBasedOnPriorityLowToHigh(evictablePods)
 			evictPods(ctx, evictablePods, targetThresholds, nodeCapacity, node.usage, &totalPods, &totalCPU, &totalMem, taintsOfLowNodes, podEvictor, node.node)
 		} else {
 			// TODO: Remove this when we support only priority.
@@ -338,28 +338,6 @@ func sortNodesByUsage(nodes []NodeUsageMap) {
 	})
 }
 
-// sortPodsBasedOnPriority sorts pods based on priority and if their priorities are equal, they are sorted based on QoS tiers.
-func sortPodsBasedOnPriority(evictablePods []*v1.Pod) {
-	sort.Slice(evictablePods, func(i, j int) bool {
-		if evictablePods[i].Spec.Priority == nil && evictablePods[j].Spec.Priority != nil {
-			return true
-		}
-		if evictablePods[j].Spec.Priority == nil && evictablePods[i].Spec.Priority != nil {
-			return false
-		}
-		if (evictablePods[j].Spec.Priority == nil && evictablePods[i].Spec.Priority == nil) || (*evictablePods[i].Spec.Priority == *evictablePods[j].Spec.Priority) {
-			if podutil.IsBestEffortPod(evictablePods[i]) {
-				return true
-			}
-			if podutil.IsBurstablePod(evictablePods[i]) && podutil.IsGuaranteedPod(evictablePods[j]) {
-				return true
-			}
-			return false
-		}
-		return *evictablePods[i].Spec.Priority < *evictablePods[j].Spec.Priority
-	})
-}
-
 // createNodePodsMap returns nodepodsmap with evictable pods on node.
 func createNodePodsMap(ctx context.Context, client clientset.Interface, nodes []*v1.Node) NodePodsMap {
 	npm := NodePodsMap{}

pkg/descheduler/strategies/lownodeutilization_test.go

@@ -22,15 +22,13 @@ import (
 	"strings"
 	"testing"
 
-	"reflect"
-
 	v1 "k8s.io/api/core/v1"
 	"k8s.io/api/policy/v1beta1"
 	"k8s.io/apimachinery/pkg/api/resource"
 	"k8s.io/apimachinery/pkg/fields"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
-	serializer "k8s.io/apimachinery/pkg/runtime/serializer"
+	"k8s.io/apimachinery/pkg/runtime/serializer"
 	"k8s.io/apimachinery/pkg/watch"
 	"k8s.io/client-go/kubernetes/fake"
 	core "k8s.io/client-go/testing"
@@ -45,30 +43,6 @@ var (
 	highPriority = int32(10000)
 )
 
-func setRSOwnerRef(pod *v1.Pod)          { pod.ObjectMeta.OwnerReferences = test.GetReplicaSetOwnerRefList() }
-func setDSOwnerRef(pod *v1.Pod)          { pod.ObjectMeta.OwnerReferences = test.GetDaemonSetOwnerRefList() }
-func setNormalOwnerRef(pod *v1.Pod)      { pod.ObjectMeta.OwnerReferences = test.GetNormalPodOwnerRefList() }
-func setHighPriority(pod *v1.Pod)        { pod.Spec.Priority = &highPriority }
-func setLowPriority(pod *v1.Pod)         { pod.Spec.Priority = &lowPriority }
-func setNodeUnschedulable(node *v1.Node) { node.Spec.Unschedulable = true }
-
-func makeBestEffortPod(pod *v1.Pod) {
-	pod.Spec.Containers[0].Resources.Requests = nil
-	pod.Spec.Containers[0].Resources.Requests = nil
-	pod.Spec.Containers[0].Resources.Limits = nil
-	pod.Spec.Containers[0].Resources.Limits = nil
-}
-
-func makeBurstablePod(pod *v1.Pod) {
-	pod.Spec.Containers[0].Resources.Limits = nil
-	pod.Spec.Containers[0].Resources.Limits = nil
-}
-
-func makeGuaranteedPod(pod *v1.Pod) {
-	pod.Spec.Containers[0].Resources.Limits[v1.ResourceCPU] = pod.Spec.Containers[0].Resources.Requests[v1.ResourceCPU]
-	pod.Spec.Containers[0].Resources.Limits[v1.ResourceMemory] = pod.Spec.Containers[0].Resources.Requests[v1.ResourceMemory]
-}
-
 func TestLowNodeUtilization(t *testing.T) {
 	ctx := context.Background()
 	n1NodeName := "n1"
@@ -99,19 +73,19 @@ func TestLowNodeUtilization(t *testing.T) {
 			nodes: map[string]*v1.Node{
 				n1NodeName: test.BuildTestNode(n1NodeName, 4000, 3000, 9, nil),
 				n2NodeName: test.BuildTestNode(n2NodeName, 4000, 3000, 10, nil),
-				n3NodeName: test.BuildTestNode(n3NodeName, 4000, 3000, 10, setNodeUnschedulable),
+				n3NodeName: test.BuildTestNode(n3NodeName, 4000, 3000, 10, test.SetNodeUnschedulable),
 			},
 			pods: map[string]*v1.PodList{
 				n1NodeName: {
 					Items: []v1.Pod{
 						// These won't be evicted.
-						*test.BuildTestPod("p1", 400, 0, n1NodeName, setDSOwnerRef),
-						*test.BuildTestPod("p2", 400, 0, n1NodeName, setDSOwnerRef),
-						*test.BuildTestPod("p3", 400, 0, n1NodeName, setDSOwnerRef),
-						*test.BuildTestPod("p4", 400, 0, n1NodeName, setDSOwnerRef),
+						*test.BuildTestPod("p1", 400, 0, n1NodeName, test.SetDSOwnerRef),
+						*test.BuildTestPod("p2", 400, 0, n1NodeName, test.SetDSOwnerRef),
+						*test.BuildTestPod("p3", 400, 0, n1NodeName, test.SetDSOwnerRef),
+						*test.BuildTestPod("p4", 400, 0, n1NodeName, test.SetDSOwnerRef),
 						*test.BuildTestPod("p5", 400, 0, n1NodeName, func(pod *v1.Pod) {
 							// A pod with local storage.
-							setNormalOwnerRef(pod)
+							test.SetNormalOwnerRef(pod)
 							pod.Spec.Volumes = []v1.Volume{
 								{
 									Name: "sample",
@@ -135,7 +109,7 @@ func TestLowNodeUtilization(t *testing.T) {
 				},
 				n2NodeName: {
 					Items: []v1.Pod{
-						*test.BuildTestPod("p9", 400, 0, n1NodeName, setRSOwnerRef),
+						*test.BuildTestPod("p9", 400, 0, n1NodeName, test.SetRSOwnerRef),
 					},
 				},
 				n3NodeName: {},
@@ -155,21 +129,21 @@ func TestLowNodeUtilization(t *testing.T) {
 			nodes: map[string]*v1.Node{
 				n1NodeName: test.BuildTestNode(n1NodeName, 4000, 3000, 9, nil),
 				n2NodeName: test.BuildTestNode(n2NodeName, 4000, 3000, 10, nil),
-				n3NodeName: test.BuildTestNode(n3NodeName, 4000, 3000, 10, setNodeUnschedulable),
+				n3NodeName: test.BuildTestNode(n3NodeName, 4000, 3000, 10, test.SetNodeUnschedulable),
 			},
 			pods: map[string]*v1.PodList{
 				n1NodeName: {
 					Items: []v1.Pod{
-						*test.BuildTestPod("p1", 400, 0, n1NodeName, setRSOwnerRef),
-						*test.BuildTestPod("p2", 400, 0, n1NodeName, setRSOwnerRef),
-						*test.BuildTestPod("p3", 400, 0, n1NodeName, setRSOwnerRef),
-						*test.BuildTestPod("p4", 400, 0, n1NodeName, setRSOwnerRef),
-						*test.BuildTestPod("p5", 400, 0, n1NodeName, setRSOwnerRef),
+						*test.BuildTestPod("p1", 400, 0, n1NodeName, test.SetRSOwnerRef),
+						*test.BuildTestPod("p2", 400, 0, n1NodeName, test.SetRSOwnerRef),
+						*test.BuildTestPod("p3", 400, 0, n1NodeName, test.SetRSOwnerRef),
+						*test.BuildTestPod("p4", 400, 0, n1NodeName, test.SetRSOwnerRef),
+						*test.BuildTestPod("p5", 400, 0, n1NodeName, test.SetRSOwnerRef),
 						// These won't be evicted.
-						*test.BuildTestPod("p6", 400, 0, n1NodeName, setDSOwnerRef),
+						*test.BuildTestPod("p6", 400, 0, n1NodeName, test.SetDSOwnerRef),
 						*test.BuildTestPod("p7", 400, 0, n1NodeName, func(pod *v1.Pod) {
 							// A pod with local storage.
-							setNormalOwnerRef(pod)
+							test.SetNormalOwnerRef(pod)
 							pod.Spec.Volumes = []v1.Volume{
 								{
 									Name: "sample",
@@ -193,7 +167,7 @@ func TestLowNodeUtilization(t *testing.T) {
 				},
 				n2NodeName: {
 					Items: []v1.Pod{
-						*test.BuildTestPod("p9", 400, 0, n1NodeName, setRSOwnerRef),
+						*test.BuildTestPod("p9", 400, 0, n1NodeName, test.SetRSOwnerRef),
 					},
 				},
 				n3NodeName: {},
@@ -213,21 +187,21 @@ func TestLowNodeUtilization(t *testing.T) {
 			nodes: map[string]*v1.Node{
 				n1NodeName: test.BuildTestNode(n1NodeName, 4000, 3000, 9, nil),
 				n2NodeName: test.BuildTestNode(n2NodeName, 4000, 3000, 10, nil),
-				n3NodeName: test.BuildTestNode(n3NodeName, 4000, 3000, 10, setNodeUnschedulable),
+				n3NodeName: test.BuildTestNode(n3NodeName, 4000, 3000, 10, test.SetNodeUnschedulable),
 			},
 			pods: map[string]*v1.PodList{
 				n1NodeName: {
 					Items: []v1.Pod{
-						*test.BuildTestPod("p1", 400, 300, n1NodeName, setRSOwnerRef),
-						*test.BuildTestPod("p2", 400, 300, n1NodeName, setRSOwnerRef),
-						*test.BuildTestPod("p3", 400, 300, n1NodeName, setRSOwnerRef),
-						*test.BuildTestPod("p4", 400, 300, n1NodeName, setRSOwnerRef),
-						*test.BuildTestPod("p5", 400, 300, n1NodeName, setRSOwnerRef),
+						*test.BuildTestPod("p1", 400, 300, n1NodeName, test.SetRSOwnerRef),
+						*test.BuildTestPod("p2", 400, 300, n1NodeName, test.SetRSOwnerRef),
+						*test.BuildTestPod("p3", 400, 300, n1NodeName, test.SetRSOwnerRef),
+						*test.BuildTestPod("p4", 400, 300, n1NodeName, test.SetRSOwnerRef),
+						*test.BuildTestPod("p5", 400, 300, n1NodeName, test.SetRSOwnerRef),
 						// These won't be evicted.
-						*test.BuildTestPod("p6", 400, 300, n1NodeName, setDSOwnerRef),
+						*test.BuildTestPod("p6", 400, 300, n1NodeName, test.SetDSOwnerRef),
 						*test.BuildTestPod("p7", 400, 300, n1NodeName, func(pod *v1.Pod) {
 							// A pod with local storage.
-							setNormalOwnerRef(pod)
+							test.SetNormalOwnerRef(pod)
 							pod.Spec.Volumes = []v1.Volume{
 								{
 									Name: "sample",
@@ -251,7 +225,7 @@ func TestLowNodeUtilization(t *testing.T) {
 				},
 				n2NodeName: {
 					Items: []v1.Pod{
-						*test.BuildTestPod("p9", 400, 2100, n1NodeName, setRSOwnerRef),
+						*test.BuildTestPod("p9", 400, 2100, n1NodeName, test.SetRSOwnerRef),
 					},
 				},
 				n3NodeName: {},
@@ -272,40 +246,40 @@ func TestLowNodeUtilization(t *testing.T) {
 			nodes: map[string]*v1.Node{
 				n1NodeName: test.BuildTestNode(n1NodeName, 4000, 3000, 9, nil),
 				n2NodeName: test.BuildTestNode(n2NodeName, 4000, 3000, 10, nil),
-				n3NodeName: test.BuildTestNode(n3NodeName, 4000, 3000, 10, setNodeUnschedulable),
+				n3NodeName: test.BuildTestNode(n3NodeName, 4000, 3000, 10, test.SetNodeUnschedulable),
 			},
 			pods: map[string]*v1.PodList{
 				n1NodeName: {
 					Items: []v1.Pod{
 						*test.BuildTestPod("p1", 400, 0, n1NodeName, func(pod *v1.Pod) {
-							setRSOwnerRef(pod)
-							setHighPriority(pod)
+							test.SetRSOwnerRef(pod)
+							test.SetPodPriority(pod, highPriority)
 						}),
 						*test.BuildTestPod("p2", 400, 0, n1NodeName, func(pod *v1.Pod) {
-							setRSOwnerRef(pod)
-							setHighPriority(pod)
+							test.SetRSOwnerRef(pod)
+							test.SetPodPriority(pod, highPriority)
 						}),
 						*test.BuildTestPod("p3", 400, 0, n1NodeName, func(pod *v1.Pod) {
-							setRSOwnerRef(pod)
-							setHighPriority(pod)
+							test.SetRSOwnerRef(pod)
+							test.SetPodPriority(pod, highPriority)
 						}),
 						*test.BuildTestPod("p4", 400, 0, n1NodeName, func(pod *v1.Pod) {
-							setRSOwnerRef(pod)
-							setHighPriority(pod)
+							test.SetRSOwnerRef(pod)
+							test.SetPodPriority(pod, highPriority)
 						}),
 						*test.BuildTestPod("p5", 400, 0, n1NodeName, func(pod *v1.Pod) {
-							setRSOwnerRef(pod)
-							setLowPriority(pod)
+							test.SetRSOwnerRef(pod)
+							test.SetPodPriority(pod, lowPriority)
 						}),
 						// These won't be evicted.
 						*test.BuildTestPod("p6", 400, 0, n1NodeName, func(pod *v1.Pod) {
-							setDSOwnerRef(pod)
-							setHighPriority(pod)
+							test.SetDSOwnerRef(pod)
+							test.SetPodPriority(pod, highPriority)
 						}),
 						*test.BuildTestPod("p7", 400, 0, n1NodeName, func(pod *v1.Pod) {
 							// A pod with local storage.
-							setNormalOwnerRef(pod)
-							setLowPriority(pod)
+							test.SetNormalOwnerRef(pod)
+							test.SetPodPriority(pod, lowPriority)
 							pod.Spec.Volumes = []v1.Volume{
 								{
 									Name: "sample",
@@ -329,7 +303,7 @@ func TestLowNodeUtilization(t *testing.T) {
 				},
 				n2NodeName: {
 					Items: []v1.Pod{
-						*test.BuildTestPod("p9", 400, 0, n1NodeName, setRSOwnerRef),
+						*test.BuildTestPod("p9", 400, 0, n1NodeName, test.SetRSOwnerRef),
 					},
 				},
 				n3NodeName: {},
@@ -349,38 +323,38 @@ func TestLowNodeUtilization(t *testing.T) {
 			nodes: map[string]*v1.Node{
 				n1NodeName: test.BuildTestNode(n1NodeName, 4000, 3000, 9, nil),
 				n2NodeName: test.BuildTestNode(n2NodeName, 4000, 3000, 10, nil),
-				n3NodeName: test.BuildTestNode(n3NodeName, 4000, 3000, 10, setNodeUnschedulable),
+				n3NodeName: test.BuildTestNode(n3NodeName, 4000, 3000, 10, test.SetNodeUnschedulable),
 			},
 			// All pods are assumed to be burstable (test.BuildTestNode always sets both cpu/memory resource requests to some value)
 			pods: map[string]*v1.PodList{
 				n1NodeName: {
 					Items: []v1.Pod{
 						*test.BuildTestPod("p1", 400, 0, n1NodeName, func(pod *v1.Pod) {
-							setRSOwnerRef(pod)
-							makeBestEffortPod(pod)
+							test.SetRSOwnerRef(pod)
+							test.MakeBestEffortPod(pod)
 						}),
 						*test.BuildTestPod("p2", 400, 0, n1NodeName, func(pod *v1.Pod) {
-							setRSOwnerRef(pod)
-							makeBestEffortPod(pod)
+							test.SetRSOwnerRef(pod)
+							test.MakeBestEffortPod(pod)
 						}),
 						*test.BuildTestPod("p3", 400, 0, n1NodeName, func(pod *v1.Pod) {
-							setRSOwnerRef(pod)
+							test.SetRSOwnerRef(pod)
 						}),
 						*test.BuildTestPod("p4", 400, 0, n1NodeName, func(pod *v1.Pod) {
-							setRSOwnerRef(pod)
-							makeBestEffortPod(pod)
+							test.SetRSOwnerRef(pod)
+							test.MakeBestEffortPod(pod)
 						}),
 						*test.BuildTestPod("p5", 400, 0, n1NodeName, func(pod *v1.Pod) {
-							setRSOwnerRef(pod)
-							makeBestEffortPod(pod)
+							test.SetRSOwnerRef(pod)
+							test.MakeBestEffortPod(pod)
 						}),
 						// These won't be evicted.
 						*test.BuildTestPod("p6", 400, 0, n1NodeName, func(pod *v1.Pod) {
-							setDSOwnerRef(pod)
+							test.SetDSOwnerRef(pod)
 						}),
 						*test.BuildTestPod("p7", 400, 0, n1NodeName, func(pod *v1.Pod) {
 							// A pod with local storage.
-							setNormalOwnerRef(pod)
+							test.SetNormalOwnerRef(pod)
 							pod.Spec.Volumes = []v1.Volume{
 								{
 									Name: "sample",
@@ -404,7 +378,7 @@ func TestLowNodeUtilization(t *testing.T) {
 				},
 				n2NodeName: {
 					Items: []v1.Pod{
-						*test.BuildTestPod("p9", 400, 0, n1NodeName, setRSOwnerRef),
+						*test.BuildTestPod("p9", 400, 0, n1NodeName, test.SetRSOwnerRef),
 					},
 				},
 				n3NodeName: {},
@@ -495,44 +469,6 @@ func TestLowNodeUtilization(t *testing.T) {
 	}
 }
 
-func TestSortPodsByPriority(t *testing.T) {
-	n1 := test.BuildTestNode("n1", 4000, 3000, 9, nil)
-
-	p1 := test.BuildTestPod("p1", 400, 0, n1.Name, setLowPriority)
-
-	// BestEffort
-	p2 := test.BuildTestPod("p2", 400, 0, n1.Name, func(pod *v1.Pod) {
-		setHighPriority(pod)
-		makeBestEffortPod(pod)
-	})
-
-	// Burstable
-	p3 := test.BuildTestPod("p3", 400, 0, n1.Name, func(pod *v1.Pod) {
-		setHighPriority(pod)
-		makeBurstablePod(pod)
-	})
-
-	// Guaranteed
-	p4 := test.BuildTestPod("p4", 400, 100, n1.Name, func(pod *v1.Pod) {
-		setHighPriority(pod)
-		makeGuaranteedPod(pod)
-	})
-
-	// Best effort with nil priorities.
-	p5 := test.BuildTestPod("p5", 400, 100, n1.Name, makeBestEffortPod)
-	p5.Spec.Priority = nil
-
-	p6 := test.BuildTestPod("p6", 400, 100, n1.Name, makeGuaranteedPod)
-	p6.Spec.Priority = nil
-
-	podList := []*v1.Pod{p4, p3, p2, p1, p6, p5}
-
-	sortPodsBasedOnPriority(podList)
-	if !reflect.DeepEqual(podList[len(podList)-1], p4) {
-		t.Errorf("Expected last pod in sorted list to be %v which of highest priority and guaranteed but got %v", p4, podList[len(podList)-1])
-	}
-}
-
 func TestValidateStrategyConfig(t *testing.T) {
 	tests := []struct {
 		name             string
@@ -783,7 +719,7 @@ func TestWithTaints(t *testing.T) {
 		},
 	}
 
-	podThatToleratesTaint := test.BuildTestPod("tolerate_pod", 200, 0, n1.Name, setRSOwnerRef)
+	podThatToleratesTaint := test.BuildTestPod("tolerate_pod", 200, 0, n1.Name, test.SetRSOwnerRef)
 	podThatToleratesTaint.Spec.Tolerations = []v1.Toleration{
 		{
 			Key:   "key",
@@ -802,16 +738,16 @@ func TestWithTaints(t *testing.T) {
 			nodes: []*v1.Node{n1, n2, n3},
 			pods: []*v1.Pod{
 				//Node 1 pods
-				test.BuildTestPod(fmt.Sprintf("pod_1_%s", n1.Name), 200, 0, n1.Name, setRSOwnerRef),
-				test.BuildTestPod(fmt.Sprintf("pod_2_%s", n1.Name), 200, 0, n1.Name, setRSOwnerRef),
-				test.BuildTestPod(fmt.Sprintf("pod_3_%s", n1.Name), 200, 0, n1.Name, setRSOwnerRef),
-				test.BuildTestPod(fmt.Sprintf("pod_4_%s", n1.Name), 200, 0, n1.Name, setRSOwnerRef),
-				test.BuildTestPod(fmt.Sprintf("pod_5_%s", n1.Name), 200, 0, n1.Name, setRSOwnerRef),
-				test.BuildTestPod(fmt.Sprintf("pod_6_%s", n1.Name), 200, 0, n1.Name, setRSOwnerRef),
-				test.BuildTestPod(fmt.Sprintf("pod_7_%s", n1.Name), 200, 0, n1.Name, setRSOwnerRef),
-				test.BuildTestPod(fmt.Sprintf("pod_8_%s", n1.Name), 200, 0, n1.Name, setRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_1_%s", n1.Name), 200, 0, n1.Name, test.SetRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_2_%s", n1.Name), 200, 0, n1.Name, test.SetRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_3_%s", n1.Name), 200, 0, n1.Name, test.SetRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_4_%s", n1.Name), 200, 0, n1.Name, test.SetRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_5_%s", n1.Name), 200, 0, n1.Name, test.SetRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_6_%s", n1.Name), 200, 0, n1.Name, test.SetRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_7_%s", n1.Name), 200, 0, n1.Name, test.SetRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_8_%s", n1.Name), 200, 0, n1.Name, test.SetRSOwnerRef),
 				// Node 2 pods
-				test.BuildTestPod(fmt.Sprintf("pod_9_%s", n2.Name), 200, 0, n2.Name, setRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_9_%s", n2.Name), 200, 0, n2.Name, test.SetRSOwnerRef),
 			},
 			evictionsExpected: 1,
 		},
@@ -820,16 +756,16 @@ func TestWithTaints(t *testing.T) {
 			nodes: []*v1.Node{n1, n3withTaints},
 			pods: []*v1.Pod{
 				//Node 1 pods
-				test.BuildTestPod(fmt.Sprintf("pod_1_%s", n1.Name), 200, 0, n1.Name, setRSOwnerRef),
-				test.BuildTestPod(fmt.Sprintf("pod_2_%s", n1.Name), 200, 0, n1.Name, setRSOwnerRef),
-				test.BuildTestPod(fmt.Sprintf("pod_3_%s", n1.Name), 200, 0, n1.Name, setRSOwnerRef),
-				test.BuildTestPod(fmt.Sprintf("pod_4_%s", n1.Name), 200, 0, n1.Name, setRSOwnerRef),
-				test.BuildTestPod(fmt.Sprintf("pod_5_%s", n1.Name), 200, 0, n1.Name, setRSOwnerRef),
-				test.BuildTestPod(fmt.Sprintf("pod_6_%s", n1.Name), 200, 0, n1.Name, setRSOwnerRef),
-				test.BuildTestPod(fmt.Sprintf("pod_7_%s", n1.Name), 200, 0, n1.Name, setRSOwnerRef),
-				test.BuildTestPod(fmt.Sprintf("pod_8_%s", n1.Name), 200, 0, n1.Name, setRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_1_%s", n1.Name), 200, 0, n1.Name, test.SetRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_2_%s", n1.Name), 200, 0, n1.Name, test.SetRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_3_%s", n1.Name), 200, 0, n1.Name, test.SetRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_4_%s", n1.Name), 200, 0, n1.Name, test.SetRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_5_%s", n1.Name), 200, 0, n1.Name, test.SetRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_6_%s", n1.Name), 200, 0, n1.Name, test.SetRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_7_%s", n1.Name), 200, 0, n1.Name, test.SetRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_8_%s", n1.Name), 200, 0, n1.Name, test.SetRSOwnerRef),
 				// Node 3 pods
-				test.BuildTestPod(fmt.Sprintf("pod_9_%s", n3withTaints.Name), 200, 0, n3withTaints.Name, setRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_9_%s", n3withTaints.Name), 200, 0, n3withTaints.Name, test.SetRSOwnerRef),
 			},
 			evictionsExpected: 0,
 		},
@@ -838,16 +774,16 @@ func TestWithTaints(t *testing.T) {
 			nodes: []*v1.Node{n1, n3withTaints},
 			pods: []*v1.Pod{
 				//Node 1 pods
-				test.BuildTestPod(fmt.Sprintf("pod_1_%s", n1.Name), 200, 0, n1.Name, setRSOwnerRef),
-				test.BuildTestPod(fmt.Sprintf("pod_2_%s", n1.Name), 200, 0, n1.Name, setRSOwnerRef),
-				test.BuildTestPod(fmt.Sprintf("pod_3_%s", n1.Name), 200, 0, n1.Name, setRSOwnerRef),
-				test.BuildTestPod(fmt.Sprintf("pod_4_%s", n1.Name), 200, 0, n1.Name, setRSOwnerRef),
-				test.BuildTestPod(fmt.Sprintf("pod_5_%s", n1.Name), 200, 0, n1.Name, setRSOwnerRef),
-				test.BuildTestPod(fmt.Sprintf("pod_6_%s", n1.Name), 200, 0, n1.Name, setRSOwnerRef),
-				test.BuildTestPod(fmt.Sprintf("pod_7_%s", n1.Name), 200, 0, n1.Name, setRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_1_%s", n1.Name), 200, 0, n1.Name, test.SetRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_2_%s", n1.Name), 200, 0, n1.Name, test.SetRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_3_%s", n1.Name), 200, 0, n1.Name, test.SetRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_4_%s", n1.Name), 200, 0, n1.Name, test.SetRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_5_%s", n1.Name), 200, 0, n1.Name, test.SetRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_6_%s", n1.Name), 200, 0, n1.Name, test.SetRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_7_%s", n1.Name), 200, 0, n1.Name, test.SetRSOwnerRef),
 				podThatToleratesTaint,
 				// Node 3 pods
-				test.BuildTestPod(fmt.Sprintf("pod_9_%s", n3withTaints.Name), 200, 0, n3withTaints.Name, setRSOwnerRef),
+				test.BuildTestPod(fmt.Sprintf("pod_9_%s", n3withTaints.Name), 200, 0, n3withTaints.Name, test.SetRSOwnerRef),
 			},
 			evictionsExpected: 1,
 		},

pkg/descheduler/strategies/pod_antiaffinity.go

@@ -37,6 +37,8 @@ func RemovePodsViolatingInterPodAntiAffinity(ctx context.Context, client clients
 		if err != nil {
 			return
 		}
+		// sort the evictable Pods based on priority, if there are multiple pods with same priority, they are sorted based on QoS tiers.
+		podutil.SortPodsBasedOnPriorityLowToHigh(pods)
 		totalPods := len(pods)
 		for i := 0; i < totalPods; i++ {
 			if checkPodsWithAntiAffinityExist(pods[i], pods) {

pkg/descheduler/strategies/pod_antiaffinity_test.go

@@ -37,16 +37,33 @@ func TestPodAntiAffinity(t *testing.T) {
 	p2 := test.BuildTestPod("p2", 100, 0, node.Name, nil)
 	p3 := test.BuildTestPod("p3", 100, 0, node.Name, nil)
 	p4 := test.BuildTestPod("p4", 100, 0, node.Name, nil)
+	p5 := test.BuildTestPod("p5", 100, 0, node.Name, nil)
+	p6 := test.BuildTestPod("p6", 100, 0, node.Name, nil)
+	p7 := test.BuildTestPod("p7", 100, 0, node.Name, nil)
 	p2.Labels = map[string]string{"foo": "bar"}
-	p1.ObjectMeta.OwnerReferences = test.GetNormalPodOwnerRefList()
-	p2.ObjectMeta.OwnerReferences = test.GetNormalPodOwnerRefList()
-	p3.ObjectMeta.OwnerReferences = test.GetNormalPodOwnerRefList()
-	p4.ObjectMeta.OwnerReferences = test.GetNormalPodOwnerRefList()
+	p5.Labels = map[string]string{"foo": "bar"}
+	p6.Labels = map[string]string{"foo": "bar"}
+	p7.Labels = map[string]string{"foo1": "bar1"}
+	test.SetNormalOwnerRef(p1)
+	test.SetNormalOwnerRef(p2)
+	test.SetNormalOwnerRef(p3)
+	test.SetNormalOwnerRef(p4)
+	test.SetNormalOwnerRef(p5)
+	test.SetNormalOwnerRef(p6)
+	test.SetNormalOwnerRef(p7)
 
 	// set pod anti affinity
-	setPodAntiAffinity(p1)
-	setPodAntiAffinity(p3)
-	setPodAntiAffinity(p4)
+	setPodAntiAffinity(p1, "foo", "bar")
+	setPodAntiAffinity(p3, "foo", "bar")
+	setPodAntiAffinity(p4, "foo", "bar")
+	setPodAntiAffinity(p5, "foo1", "bar1")
+	setPodAntiAffinity(p6, "foo1", "bar1")
+	setPodAntiAffinity(p7, "foo", "bar")
+
+	// set pod priority
+	test.SetPodPriority(p5, 100)
+	test.SetPodPriority(p6, 50)
+	test.SetPodPriority(p7, 0)
 
 	tests := []struct {
 		description             string
@@ -66,13 +83,19 @@ func TestPodAntiAffinity(t *testing.T) {
 			pods:                    []v1.Pod{*p1, *p2, *p3, *p4},
 			expectedEvictedPodCount: 3,
 		},
+		{
+			description:             "Evict only 1 pod after sorting",
+			maxPodsToEvict:          0,
+			pods:                    []v1.Pod{*p5, *p6, *p7},
+			expectedEvictedPodCount: 1,
+		},
 	}
 
 	for _, test := range tests {
 		// create fake client
 		fakeClient := &fake.Clientset{}
 		fakeClient.Fake.AddReactor("list", "pods", func(action core.Action) (bool, runtime.Object, error) {
-			return true, &v1.PodList{Items: []v1.Pod{*p1, *p2, *p3, *p4}}, nil
+			return true, &v1.PodList{Items: test.pods}, nil
 		})
 		fakeClient.Fake.AddReactor("get", "nodes", func(action core.Action) (bool, runtime.Object, error) {
 			return true, node, nil
@@ -95,7 +118,7 @@ func TestPodAntiAffinity(t *testing.T) {
 	}
 }
 
-func setPodAntiAffinity(inputPod *v1.Pod) {
+func setPodAntiAffinity(inputPod *v1.Pod, labelKey, labelValue string) {
 	inputPod.Spec.Affinity = &v1.Affinity{
 		PodAntiAffinity: &v1.PodAntiAffinity{
 			RequiredDuringSchedulingIgnoredDuringExecution: []v1.PodAffinityTerm{
@@ -103,9 +126,9 @@ func setPodAntiAffinity(inputPod *v1.Pod) {
 					LabelSelector: &metav1.LabelSelector{
 						MatchExpressions: []metav1.LabelSelectorRequirement{
 							{
-								Key:      "foo",
+								Key:      labelKey,
 								Operator: metav1.LabelSelectorOpIn,
-								Values:   []string{"bar"},
+								Values:   []string{labelValue},
 							},
 						},
 					},