Add e2e tests for TopologySpreadConstraint

hack/kind_config.yaml

@@ -3,4 +3,16 @@ apiVersion: kind.x-k8s.io/v1alpha4
 nodes:
 - role: control-plane
 - role: worker
+  kubeadmConfigPatches:
+    - |
+      kind: JoinConfiguration
+      nodeRegistration:
+        kubeletExtraArgs:
+          node-labels: "topology.kubernetes.io/zone=local-a"
 - role: worker
+  kubeadmConfigPatches:
+    - |
+      kind: JoinConfiguration
+      nodeRegistration:
+        kubeletExtraArgs:
+          node-labels: "topology.kubernetes.io/zone=local-b"

test/e2e/e2e_test.go

@@ -62,11 +62,11 @@ func MakePodSpec(priorityClassName string, gracePeriod *int64) v1.PodSpec {
 			Resources: v1.ResourceRequirements{
 				Limits: v1.ResourceList{
 					v1.ResourceCPU:    resource.MustParse("100m"),
-					v1.ResourceMemory: resource.MustParse("1000Mi"),
+					v1.ResourceMemory: resource.MustParse("200Mi"),
 				},
 				Requests: v1.ResourceList{
 					v1.ResourceCPU:    resource.MustParse("100m"),
-					v1.ResourceMemory: resource.MustParse("800Mi"),
+					v1.ResourceMemory: resource.MustParse("100Mi"),
 				},
 			},
 		}},
@@ -209,15 +209,7 @@ func TestLowNodeUtilization(t *testing.T) {
 		t.Errorf("Error listing node with %v", err)
 	}
 
-	var nodes []*v1.Node
+	nodes, workerNodes := splitNodesAndWorkerNodes(nodeList.Items)
-	var workerNodes []*v1.Node
-	for i := range nodeList.Items {
-		node := nodeList.Items[i]
-		nodes = append(nodes, &node)
-		if _, exists := node.Labels["node-role.kubernetes.io/master"]; !exists {
-			workerNodes = append(workerNodes, &node)
-		}
-	}
 
 	t.Log("Creating testing namespace")
 	testNamespace := &v1.Namespace{ObjectMeta: metav1.ObjectMeta{Name: "e2e-" + strings.ToLower(t.Name())}}
@@ -1288,3 +1280,16 @@ func waitForPodRunning(ctx context.Context, t *testing.T, clientSet clientset.In
 		t.Fatalf("Error waiting for pod running: %v", err)
 	}
 }
+
+func splitNodesAndWorkerNodes(nodes []v1.Node) ([]*v1.Node, []*v1.Node) {
+	var allNodes []*v1.Node
+	var workerNodes []*v1.Node
+	for i := range nodes {
+		node := nodes[i]
+		allNodes = append(allNodes, &node)
+		if _, exists := node.Labels["node-role.kubernetes.io/master"]; !exists {
+			workerNodes = append(workerNodes, &node)
+		}
+	}
+	return allNodes, workerNodes
+}

test/e2e/e2e_topologyspreadconstraint_test.go

@@ -0,0 +1,170 @@
+package e2e
+
+import (
+	"context"
+	"fmt"
+	"math"
+	"strings"
+	"testing"
+
+	v1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+
+	deschedulerapi "sigs.k8s.io/descheduler/pkg/api"
+	"sigs.k8s.io/descheduler/pkg/descheduler/evictions"
+	eutils "sigs.k8s.io/descheduler/pkg/descheduler/evictions/utils"
+	"sigs.k8s.io/descheduler/pkg/descheduler/strategies"
+)
+
+const zoneTopologyKey string = "topology.kubernetes.io/zone"
+
+func TestTopologySpreadConstraint(t *testing.T) {
+	ctx := context.Background()
+	clientSet, _, stopCh := initializeClient(t)
+	defer close(stopCh)
+	nodeList, err := clientSet.CoreV1().Nodes().List(ctx, metav1.ListOptions{})
+	if err != nil {
+		t.Errorf("Error listing node with %v", err)
+	}
+	nodes, workerNodes := splitNodesAndWorkerNodes(nodeList.Items)
+	t.Log("Creating testing namespace")
+	testNamespace := &v1.Namespace{ObjectMeta: metav1.ObjectMeta{Name: "e2e-" + strings.ToLower(t.Name())}}
+	if _, err := clientSet.CoreV1().Namespaces().Create(ctx, testNamespace, metav1.CreateOptions{}); err != nil {
+		t.Fatalf("Unable to create ns %v", testNamespace.Name)
+	}
+	defer clientSet.CoreV1().Namespaces().Delete(ctx, testNamespace.Name, metav1.DeleteOptions{})
+
+	testCases := map[string]struct {
+		replicaCount int
+		maxSkew      int
+		labelKey     string
+		labelValue   string
+		constraint   v1.UnsatisfiableConstraintAction
+	}{
+		"test-rc-topology-spread-hard-constraint": {
+			replicaCount: 4,
+			maxSkew:      1,
+			labelKey:     "test",
+			labelValue:   "topology-spread-hard-constraint",
+			constraint:   v1.DoNotSchedule,
+		},
+		"test-rc-topology-spread-soft-constraint": {
+			replicaCount: 4,
+			maxSkew:      1,
+			labelKey:     "test",
+			labelValue:   "topology-spread-soft-constraint",
+			constraint:   v1.ScheduleAnyway,
+		},
+	}
+	for name, tc := range testCases {
+		t.Run(name, func(t *testing.T) {
+			t.Logf("Creating RC %s with %d replicas", name, tc.replicaCount)
+			rc := RcByNameContainer(name, testNamespace.Name, int32(tc.replicaCount), map[string]string{tc.labelKey: tc.labelValue}, nil, "")
+			rc.Spec.Template.Spec.TopologySpreadConstraints = makeTopologySpreadConstraints(tc.maxSkew, tc.labelKey, tc.labelValue, tc.constraint)
+			if _, err := clientSet.CoreV1().ReplicationControllers(rc.Namespace).Create(ctx, rc, metav1.CreateOptions{}); err != nil {
+				t.Fatalf("Error creating RC %s %v", name, err)
+			}
+			defer deleteRC(ctx, t, clientSet, rc)
+			waitForRCPodsRunning(ctx, t, clientSet, rc)
+
+			// Create a "Violator" RC that has the same label and is forced to be on the same node using a nodeSelector
+			violatorRcName := name + "-violator"
+			violatorCount := tc.maxSkew + 1
+			violatorRc := RcByNameContainer(violatorRcName, testNamespace.Name, int32(violatorCount), map[string]string{tc.labelKey: tc.labelValue}, nil, "")
+			violatorRc.Spec.Template.Spec.NodeSelector = map[string]string{zoneTopologyKey: workerNodes[0].Labels[zoneTopologyKey]}
+			rc.Spec.Template.Spec.TopologySpreadConstraints = makeTopologySpreadConstraints(tc.maxSkew, tc.labelKey, tc.labelValue, tc.constraint)
+			if _, err := clientSet.CoreV1().ReplicationControllers(rc.Namespace).Create(ctx, violatorRc, metav1.CreateOptions{}); err != nil {
+				t.Fatalf("Error creating RC %s: %v", violatorRcName, err)
+			}
+			defer deleteRC(ctx, t, clientSet, violatorRc)
+			waitForRCPodsRunning(ctx, t, clientSet, violatorRc)
+
+			// Run TopologySpreadConstraint strategy
+			evictionPolicyGroupVersion, err := eutils.SupportEviction(clientSet)
+			if err != nil || len(evictionPolicyGroupVersion) == 0 {
+				t.Fatalf("Error creating eviction policy group for %s: %v", name, err)
+			}
+			podEvictor := evictions.NewPodEvictor(
+				clientSet,
+				evictionPolicyGroupVersion,
+				false,
+				0,
+				nodes,
+				true,
+				false,
+				false,
+			)
+
+			t.Logf("Running RemovePodsViolatingTopologySpreadConstraint strategy for %s", name)
+			strategies.RemovePodsViolatingTopologySpreadConstraint(
+				ctx,
+				clientSet,
+				deschedulerapi.DeschedulerStrategy{
+					Enabled: true,
+					Params: &deschedulerapi.StrategyParameters{
+						IncludeSoftConstraints: tc.constraint != v1.DoNotSchedule,
+					},
+				},
+				nodes,
+				podEvictor,
+			)
+			t.Logf("Finished RemovePodsViolatingTopologySpreadConstraint strategy for %s", name)
+
+			t.Logf("Wait for terminating pods of %s to disappear", name)
+			waitForTerminatingPodsToDisappear(ctx, t, clientSet, rc.Namespace)
+
+			if totalEvicted := podEvictor.TotalEvicted(); totalEvicted > 0 {
+				t.Logf("Total of %d Pods were evicted for %s", totalEvicted, name)
+			} else {
+				t.Fatalf("Pods were not evicted for %s TopologySpreadConstraint", name)
+			}
+
+			pods, err := clientSet.CoreV1().Pods(testNamespace.Name).List(ctx, metav1.ListOptions{LabelSelector: fmt.Sprintf("%s=%s", tc.labelKey, tc.labelValue)})
+			if err != nil {
+				t.Errorf("Error listing pods for %s: %v", name, err)
+			}
+
+			nodePodCountMap := make(map[string]int)
+			for _, pod := range pods.Items {
+				nodePodCountMap[pod.Spec.NodeName]++
+			}
+
+			if len(nodePodCountMap) != len(workerNodes) {
+				t.Errorf("%s Pods were scheduled on only '%d' nodes and were not properly distributed on the nodes", name, len(nodePodCountMap))
+			}
+
+			min, max := getMinAndMaxPodDistribution(nodePodCountMap)
+			if max-min > tc.maxSkew {
+				t.Errorf("Pod distribution for %s is still violating the max skew of %d as it is %d", name, tc.maxSkew, max-min)
+			}
+
+			t.Logf("Pods for %s were distributed in line with max skew of %d", name, tc.maxSkew)
+		})
+	}
+}
+
+func makeTopologySpreadConstraints(maxSkew int, labelKey, labelValue string, constraint v1.UnsatisfiableConstraintAction) []v1.TopologySpreadConstraint {
+	return []v1.TopologySpreadConstraint{
+		{
+			MaxSkew:           int32(maxSkew),
+			TopologyKey:       zoneTopologyKey,
+			WhenUnsatisfiable: constraint,
+			LabelSelector:     &metav1.LabelSelector{MatchLabels: map[string]string{labelKey: labelValue}},
+		},
+	}
+}
+
+func getMinAndMaxPodDistribution(nodePodCountMap map[string]int) (int, int) {
+	min := math.MaxInt32
+	max := math.MinInt32
+	for _, podCount := range nodePodCountMap {
+		if podCount < min {
+			min = podCount
+		}
+		if podCount > max {
+			max = podCount
+		}
+	}
+
+	return min, max
+}