Small refactor to accomodate descheduling only evictable pods

Signed-off-by: ravisantoshgudimetla <ravisantoshgudimetla@gmail.com>

pkg/descheduler/pod/pods.go

@@ -27,6 +27,35 @@ import (
 	"k8s.io/kubernetes/pkg/kubelet/types"
 )
 
+// IsEvictable checks if a pod is evictable or not.
+func IsEvictable(pod *v1.Pod) bool {
+	sr, err := CreatorRef(pod)
+	if err != nil {
+		sr = nil
+	}
+	if IsMirrorPod(pod) || IsPodWithLocalStorage(pod) || sr == nil || IsDaemonsetPod(sr) || IsCriticalPod(pod) {
+		return false
+	}
+	return true
+}
+
+// ListEvictablePodsOnNode returns the list of evictable pods on node.
+func ListEvictablePodsOnNode(client clientset.Interface, node *v1.Node) ([]*v1.Pod, error) {
+	pods, err := ListPodsOnANode(client, node)
+	if err != nil {
+		return []*v1.Pod{}, err
+	}
+	evictablePods := make([]*v1.Pod, 0)
+	for _, pod := range pods {
+		if !IsEvictable(pod) {
+			continue
+		} else {
+			evictablePods = append(evictablePods, pod)
+		}
+	}
+	return evictablePods, nil
+}
+
 func ListPodsOnANode(client clientset.Interface, node *v1.Node) ([]*v1.Pod, error) {
 	podList, err := client.CoreV1().Pods(v1.NamespaceAll).List(
 		metav1.ListOptions{FieldSelector: fields.SelectorFromSet(fields.Set{"spec.nodeName": node.Name}).String()})
@@ -38,7 +67,6 @@ func ListPodsOnANode(client clientset.Interface, node *v1.Node) ([]*v1.Pod, erro
 	for i := range podList.Items {
 		pods = append(pods, &podList.Items[i])
 	}
-
 	return pods, nil
 }
 

pkg/descheduler/strategies/duplicates.go

@@ -70,7 +70,7 @@ func deleteDuplicatePods(client clientset.Interface, policyGroupVersion string,
 
 // ListDuplicatePodsOnANode lists duplicate pods on a given node.
 func ListDuplicatePodsOnANode(client clientset.Interface, node *v1.Node) DuplicatePodsMap {
-	pods, err := podutil.ListPodsOnANode(client, node)
+	pods, err := podutil.ListEvictablePodsOnNode(client, node)
 	if err != nil {
 		return nil
 	}
@@ -81,13 +81,9 @@ func ListDuplicatePodsOnANode(client clientset.Interface, node *v1.Node) Duplica
 func FindDuplicatePods(pods []*v1.Pod) DuplicatePodsMap {
 	dpm := DuplicatePodsMap{}
 	for _, pod := range pods {
-		sr, err := podutil.CreatorRef(pod)
-		if err != nil || sr == nil {
-			continue
-		}
-		if podutil.IsMirrorPod(pod) || podutil.IsDaemonsetPod(sr) || podutil.IsPodWithLocalStorage(pod) || podutil.IsCriticalPod(pod) {
-			continue
-		}
+		// Ignoring the error here as in the ListDuplicatePodsOnNode function we call ListEvictablePodsOnNode
+		// which checks for error.
+		sr, _ := podutil.CreatorRef(pod)
 		s := strings.Join([]string{sr.Reference.Kind, sr.Reference.Namespace, sr.Reference.Name}, "/")
 		dpm[s] = append(dpm[s], pod)
 	}

pkg/descheduler/strategies/lownodeutilization.go

@@ -284,12 +284,8 @@ func NodeUtilization(node *v1.Node, pods []*v1.Pod) (api.ResourceThresholds, []*
 	gPods := []*v1.Pod{}
 	totalReqs := map[v1.ResourceName]resource.Quantity{}
 	for _, pod := range pods {
-		sr, err := podutil.CreatorRef(pod)
-		if err != nil {
-			sr = nil
-		}
-
-		if podutil.IsMirrorPod(pod) || podutil.IsPodWithLocalStorage(pod) || sr == nil || podutil.IsDaemonsetPod(sr) || podutil.IsCriticalPod(pod) {
+		// We need to compute the usage of nonRemovablePods unless it is a best effort pod. So, cannot use podutil.ListEvictablePodsOnNode
+		if !podutil.IsEvictable(pod) {
 			nonRemovablePods = append(nonRemovablePods, pod)
 			if podutil.IsBestEffortPod(pod) {
 				continue

pkg/descheduler/strategies/pod_antiaffinity.go

@@ -44,7 +44,7 @@ func removePodsWithAffinityRules(client clientset.Interface, policyGroupVersion
 	podsEvicted := 0
 	for _, node := range nodes {
 		glog.V(1).Infof("Processing node: %#v\n", node.Name)
-		pods, err := podutil.ListPodsOnANode(client, node)
+		pods, err := podutil.ListEvictablePodsOnNode(client, node)
 		if err != nil {
 			return 0
 		}

pkg/descheduler/strategies/pod_antiaffinity_test.go

@@ -19,7 +19,6 @@ package strategies
 import (
 	"testing"
 
-	"fmt"
 	"github.com/kubernetes-incubator/descheduler/test"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
@@ -34,6 +33,9 @@ func TestPodAntiAffinity(t *testing.T) {
 	p2 := test.BuildTestPod("p2", 100, 0, node.Name)
 	p3 := test.BuildTestPod("p3", 100, 0, node.Name)
 	p3.Labels = map[string]string{"foo": "bar"}
+	p1.Annotations = test.GetNormalPodAnnotation()
+	p2.Annotations = test.GetNormalPodAnnotation()
+	p3.Annotations = test.GetNormalPodAnnotation()
 	p1.Spec.Affinity = &v1.Affinity{
 		PodAntiAffinity: &v1.PodAntiAffinity{
 			RequiredDuringSchedulingIgnoredDuringExecution: []v1.PodAffinityTerm{
@@ -80,7 +82,6 @@ func TestPodAntiAffinity(t *testing.T) {
 	expectedEvictedPodCount := 1
 	podsEvicted := removePodsWithAffinityRules(fakeClient, "v1", []*v1.Node{node}, false)
 	if podsEvicted != expectedEvictedPodCount {
-		fmt.Println(podsEvicted)
 		t.Errorf("Unexpected no of pods evicted")
 	}
 }