RemoveFailedPods: guard against nil descheduler strategy (e.g. in case of default that loads all strategies)

pkg/descheduler/strategies/failedpods.go

@@ -19,7 +19,7 @@ import (
 
 // validatedFailedPodsStrategyParams contains validated strategy parameters
 type validatedFailedPodsStrategyParams struct {
-	*validation.ValidatedStrategyParams
+	validation.ValidatedStrategyParams
 	includingInitContainers bool
 	reasons                 sets.String
 	excludeOwnerKinds       sets.String
@@ -46,9 +46,15 @@ func RemoveFailedPods(
 		evictions.WithLabelSelector(strategyParams.LabelSelector),
 	)
 
+	var labelSelector *metav1.LabelSelector
+	if strategy.Params != nil {
+		labelSelector = strategy.Params.LabelSelector
+	}
+
 	for _, node := range nodes {
 		klog.V(1).InfoS("Processing node", "node", klog.KObj(node))
 		fieldSelectorString := "spec.nodeName=" + node.Name + ",status.phase=" + string(v1.PodFailed)
+
 		pods, err := podutil.ListPodsOnANodeWithFieldSelector(
 			ctx,
 			client,
@@ -57,7 +63,7 @@ func RemoveFailedPods(
 			podutil.WithFilter(evictable.IsEvictable),
 			podutil.WithNamespaces(strategyParams.IncludedNamespaces.UnsortedList()),
 			podutil.WithoutNamespaces(strategyParams.ExcludedNamespaces.UnsortedList()),
-			podutil.WithLabelSelector(strategy.Params.LabelSelector),
+			podutil.WithLabelSelector(labelSelector),
 		)
 		if err != nil {
 			klog.ErrorS(err, "Error listing a nodes failed pods", "node", klog.KObj(node))
@@ -103,7 +109,7 @@ func validateAndParseRemoveFailedPodsParams(
 	}
 
 	return &validatedFailedPodsStrategyParams{
-		ValidatedStrategyParams: strategyParams,
+		ValidatedStrategyParams: *strategyParams,
 		includingInitContainers: includingInitContainers,
 		reasons:                 reasons,
 		excludeOwnerKinds:       excludeOwnerKinds,

pkg/descheduler/strategies/failedpods_test.go

@@ -44,6 +44,13 @@ func TestRemoveFailedPods(t *testing.T) {
 		expectedEvictedPodCount int
 		pods                    []v1.Pod
 	}{
+		{
+			description:             "default empty strategy, 0 failures, 0 evictions",
+			strategy:                api.DeschedulerStrategy{},
+			nodes:                   []*v1.Node{test.BuildTestNode("node1", 2000, 3000, 10, nil)},
+			expectedEvictedPodCount: 0,
+			pods:                    []v1.Pod{}, // no pods come back with field selector phase=Failed
+		},
 		{
 			description:             "0 failures, 0 evictions",
 			strategy:                createStrategy(true, false, nil, nil, nil, false),
@@ -225,6 +232,7 @@ func TestValidRemoveFailedPodsParams(t *testing.T) {
 		params *api.StrategyParameters
 	}{
 		{name: "validate nil params", params: nil},
+		{name: "validate empty params", params: &api.StrategyParameters{}},
 		{name: "validate reasons params", params: &api.StrategyParameters{FailedPods: &api.FailedPods{
 			Reasons: []string{"CreateContainerConfigError"},
 		}}},