Add option to ignore pods with PVCs from eviction

README.md

@@ -111,6 +111,7 @@ parameters associated with the strategies can be configured too. By default, all
 The policy also includes common configuration for all the strategies:
 - `nodeSelector` - limiting the nodes which are processed
 - `evictLocalStoragePods` - allowing to evict pods with local storage
+- `ignorePvcPods` - set whether PVC pods should be evicted or ignored (defaults to `false`)
 - `maxNoOfPodsToEvictPerNode` - maximum number of pods evicted from each node (summed through all strategies)
 
 ```yaml
@@ -119,6 +120,7 @@ kind: "DeschedulerPolicy"
 nodeSelector: prod=dev
 evictLocalStoragePods: true
 maxNoOfPodsToEvictPerNode: 40
+ignorePvcPods: false
 strategies:
   ...
 ```
@@ -497,9 +499,10 @@ When the descheduler decides to evict pods from a node, it employs the following
 never evicted because these pods won't be recreated.
 * Pods associated with DaemonSets are never evicted.
 * Pods with local storage are never evicted (unless `evictLocalStoragePods: true` is set)
+* Pods with PVCs are evicted unless `ignorePvcPods: true` is set.
 * In `LowNodeUtilization` and `RemovePodsViolatingInterPodAntiAffinity`, pods are evicted by their priority from low to high, and if they have same priority,
 best effort pods are evicted before burstable and guaranteed pods.
-* All types of pods with the annotation descheduler.alpha.kubernetes.io/evict are evicted. This
+* All types of pods with the annotation `descheduler.alpha.kubernetes.io/evict` are eligible for eviction. This
   annotation is used to override checks which prevent eviction and users can select which pod is evicted.
   Users should know how and if the pod will be recreated.
 

pkg/api/types.go

@@ -35,6 +35,9 @@ type DeschedulerPolicy struct {
 	// EvictLocalStoragePods allows pods using local storage to be evicted.
 	EvictLocalStoragePods *bool
 
+	// IgnorePVCPods prevents pods with PVCs from being evicted.
+	IgnorePVCPods *bool
+
 	// MaxNoOfPodsToEvictPerNode restricts maximum of pods to be evicted per node.
 	MaxNoOfPodsToEvictPerNode *int
 }

pkg/api/v1alpha1/types.go

@@ -35,6 +35,9 @@ type DeschedulerPolicy struct {
 	// EvictLocalStoragePods allows pods using local storage to be evicted.
 	EvictLocalStoragePods *bool `json:"evictLocalStoragePods,omitempty"`
 
+	// IgnorePVCPods prevents pods with PVCs from being evicted.
+	IgnorePVCPods *bool `json:"ignorePvcPods,omitempty"`
+
 	// MaxNoOfPodsToEvictPerNode restricts maximum of pods to be evicted per node.
 	MaxNoOfPodsToEvictPerNode *int `json:"maxNoOfPodsToEvictPerNode,omitempty"`
 }

pkg/api/v1alpha1/zz_generated.conversion.go

@@ -122,6 +122,7 @@ func autoConvert_v1alpha1_DeschedulerPolicy_To_api_DeschedulerPolicy(in *Desched
 	out.Strategies = *(*api.StrategyList)(unsafe.Pointer(&in.Strategies))
 	out.NodeSelector = (*string)(unsafe.Pointer(in.NodeSelector))
 	out.EvictLocalStoragePods = (*bool)(unsafe.Pointer(in.EvictLocalStoragePods))
+	out.IgnorePVCPods = (*bool)(unsafe.Pointer(in.IgnorePVCPods))
 	out.MaxNoOfPodsToEvictPerNode = (*int)(unsafe.Pointer(in.MaxNoOfPodsToEvictPerNode))
 	return nil
 }
@@ -135,6 +136,7 @@ func autoConvert_api_DeschedulerPolicy_To_v1alpha1_DeschedulerPolicy(in *api.Des
 	out.Strategies = *(*StrategyList)(unsafe.Pointer(&in.Strategies))
 	out.NodeSelector = (*string)(unsafe.Pointer(in.NodeSelector))
 	out.EvictLocalStoragePods = (*bool)(unsafe.Pointer(in.EvictLocalStoragePods))
+	out.IgnorePVCPods = (*bool)(unsafe.Pointer(in.IgnorePVCPods))
 	out.MaxNoOfPodsToEvictPerNode = (*int)(unsafe.Pointer(in.MaxNoOfPodsToEvictPerNode))
 	return nil
 }

pkg/api/v1alpha1/zz_generated.deepcopy.go

@@ -45,6 +45,11 @@ func (in *DeschedulerPolicy) DeepCopyInto(out *DeschedulerPolicy) {
 		*out = new(bool)
 		**out = **in
 	}
+	if in.IgnorePVCPods != nil {
+		in, out := &in.IgnorePVCPods, &out.IgnorePVCPods
+		*out = new(bool)
+		**out = **in
+	}
 	if in.MaxNoOfPodsToEvictPerNode != nil {
 		in, out := &in.MaxNoOfPodsToEvictPerNode, &out.MaxNoOfPodsToEvictPerNode
 		*out = new(int)

pkg/api/zz_generated.deepcopy.go

@@ -45,6 +45,11 @@ func (in *DeschedulerPolicy) DeepCopyInto(out *DeschedulerPolicy) {
 		*out = new(bool)
 		**out = **in
 	}
+	if in.IgnorePVCPods != nil {
+		in, out := &in.IgnorePVCPods, &out.IgnorePVCPods
+		*out = new(bool)
+		**out = **in
+	}
 	if in.MaxNoOfPodsToEvictPerNode != nil {
 		in, out := &in.MaxNoOfPodsToEvictPerNode, &out.MaxNoOfPodsToEvictPerNode
 		*out = new(int)

pkg/apis/componentconfig/types.go

@@ -50,6 +50,9 @@ type DeschedulerConfiguration struct {
 	// EvictLocalStoragePods allows pods using local storage to be evicted.
 	EvictLocalStoragePods bool
 
+	// IgnorePVCPods sets whether PVC pods should be allowed to be evicted
+	IgnorePVCPods bool
+
 	// Logging specifies the options of logging.
 	// Refer [Logs Options](https://github.com/kubernetes/component-base/blob/master/logs/options.go) for more information.
 	Logging componentbaseconfig.LoggingConfiguration

pkg/apis/componentconfig/v1alpha1/types.go

@@ -50,6 +50,9 @@ type DeschedulerConfiguration struct {
 	// EvictLocalStoragePods allows pods using local storage to be evicted.
 	EvictLocalStoragePods bool `json:"evictLocalStoragePods,omitempty"`
 
+	// IgnorePVCPods sets whether PVC pods should be allowed to be evicted
+	IgnorePVCPods bool `json:"ignorePvcPods,omitempty"`
+
 	// Logging specifies the options of logging.
 	// Refer [Logs Options](https://github.com/kubernetes/component-base/blob/master/logs/options.go) for more information.
 	Logging componentbaseconfig.LoggingConfiguration `json:"logging,omitempty"`

pkg/apis/componentconfig/v1alpha1/zz_generated.conversion.go

@@ -56,6 +56,7 @@ func autoConvert_v1alpha1_DeschedulerConfiguration_To_componentconfig_Deschedule
 	out.NodeSelector = in.NodeSelector
 	out.MaxNoOfPodsToEvictPerNode = in.MaxNoOfPodsToEvictPerNode
 	out.EvictLocalStoragePods = in.EvictLocalStoragePods
+	out.IgnorePVCPods = in.IgnorePVCPods
 	out.Logging = in.Logging
 	return nil
 }
@@ -73,6 +74,7 @@ func autoConvert_componentconfig_DeschedulerConfiguration_To_v1alpha1_Deschedule
 	out.NodeSelector = in.NodeSelector
 	out.MaxNoOfPodsToEvictPerNode = in.MaxNoOfPodsToEvictPerNode
 	out.EvictLocalStoragePods = in.EvictLocalStoragePods
+	out.IgnorePVCPods = in.IgnorePVCPods
 	out.Logging = in.Logging
 	return nil
 }

pkg/descheduler/descheduler.go

@@ -90,6 +90,11 @@ func RunDeschedulerStrategies(ctx context.Context, rs *options.DeschedulerServer
 		evictLocalStoragePods = *deschedulerPolicy.EvictLocalStoragePods
 	}
 
+	ignorePvcPods := false
+	if deschedulerPolicy.IgnorePVCPods != nil {
+		ignorePvcPods = *deschedulerPolicy.IgnorePVCPods
+	}
+
 	maxNoOfPodsToEvictPerNode := rs.MaxNoOfPodsToEvictPerNode
 	if deschedulerPolicy.MaxNoOfPodsToEvictPerNode != nil {
 		maxNoOfPodsToEvictPerNode = *deschedulerPolicy.MaxNoOfPodsToEvictPerNode
@@ -116,6 +121,7 @@ func RunDeschedulerStrategies(ctx context.Context, rs *options.DeschedulerServer
 			maxNoOfPodsToEvictPerNode,
 			nodes,
 			evictLocalStoragePods,
+			ignorePvcPods,
 		)
 
 		for name, f := range strategyFuncs {

pkg/descheduler/evictions/evictions.go

@@ -51,6 +51,7 @@ type PodEvictor struct {
 	maxPodsToEvictPerNode int
 	nodepodCount          nodePodEvictedCount
 	evictLocalStoragePods bool
+	ignorePvcPods         bool
 }
 
 func NewPodEvictor(
@@ -60,6 +61,7 @@ func NewPodEvictor(
 	maxPodsToEvictPerNode int,
 	nodes []*v1.Node,
 	evictLocalStoragePods bool,
+	ignorePvcPods bool,
 ) *PodEvictor {
 	var nodePodCount = make(nodePodEvictedCount)
 	for _, node := range nodes {
@@ -74,6 +76,7 @@ func NewPodEvictor(
 		maxPodsToEvictPerNode: maxPodsToEvictPerNode,
 		nodepodCount:          nodePodCount,
 		evictLocalStoragePods: evictLocalStoragePods,
+		ignorePvcPods:         ignorePvcPods,
 	}
 }
 
@@ -189,6 +192,14 @@ func (pe *PodEvictor) Evictable(opts ...func(opts *Options)) *evictable {
 			return nil
 		})
 	}
+	if pe.ignorePvcPods {
+		ev.constraints = append(ev.constraints, func(pod *v1.Pod) error {
+			if IsPodWithPVC(pod) {
+				return fmt.Errorf("pod has a PVC and descheduler is configured to ignore PVC pods")
+			}
+			return nil
+		})
+	}
 	if options.priority != nil {
 		ev.constraints = append(ev.constraints, func(pod *v1.Pod) error {
 			if IsPodEvictableBasedOnPriority(pod, *options.priority) {
@@ -267,6 +278,15 @@ func IsPodWithLocalStorage(pod *v1.Pod) bool {
 	return false
 }
 
+func IsPodWithPVC(pod *v1.Pod) bool {
+	for _, volume := range pod.Spec.Volumes {
+		if volume.PersistentVolumeClaim != nil {
+			return true
+		}
+	}
+	return false
+}
+
 // IsPodEvictableBasedOnPriority checks if the given pod is evictable based on priority resolved from pod Spec.
 func IsPodEvictableBasedOnPriority(pod *v1.Pod, priority int32) bool {
 	return pod.Spec.Priority == nil || *pod.Spec.Priority < priority

pkg/descheduler/strategies/duplicates_test.go

@@ -210,6 +210,7 @@ func TestFindDuplicatePods(t *testing.T) {
 				testCase.maxPodsToEvictPerNode,
 				[]*v1.Node{node1, node2},
 				false,
+				false,
 			)
 
 			RemoveDuplicatePods(ctx, fakeClient, testCase.strategy, []*v1.Node{node1, node2}, podEvictor)
@@ -405,6 +406,7 @@ func TestRemoveDuplicatesUniformly(t *testing.T) {
 				testCase.maxPodsToEvictPerNode,
 				testCase.nodes,
 				false,
+				false,
 			)
 
 			RemoveDuplicatePods(ctx, fakeClient, testCase.strategy, testCase.nodes, podEvictor)

pkg/descheduler/strategies/lownodeutilization_test.go

@@ -444,6 +444,7 @@ func TestLowNodeUtilization(t *testing.T) {
 				test.maxPodsToEvictPerNode,
 				nodes,
 				false,
+				false,
 			)
 
 			strategy := api.DeschedulerStrategy{
@@ -764,6 +765,7 @@ func TestWithTaints(t *testing.T) {
 				item.evictionsExpected,
 				item.nodes,
 				false,
+				false,
 			)
 
 			LowNodeUtilization(ctx, fakeClient, strategy, item.nodes, podEvictor)

pkg/descheduler/strategies/node_affinity_test.go

@@ -158,6 +158,7 @@ func TestRemovePodsViolatingNodeAffinity(t *testing.T) {
 			tc.maxPodsToEvictPerNode,
 			tc.nodes,
 			false,
+			false,
 		)
 
 		RemovePodsViolatingNodeAffinity(ctx, fakeClient, tc.strategy, tc.nodes, podEvictor)

pkg/descheduler/strategies/node_taint_test.go

@@ -171,6 +171,7 @@ func TestDeletePodsViolatingNodeTaints(t *testing.T) {
 			tc.maxPodsToEvictPerNode,
 			tc.nodes,
 			tc.evictLocalStoragePods,
+			false,
 		)
 
 		RemovePodsViolatingNodeTaints(ctx, fakeClient, api.DeschedulerStrategy{}, tc.nodes, podEvictor)

pkg/descheduler/strategies/pod_antiaffinity_test.go

@@ -120,6 +120,7 @@ func TestPodAntiAffinity(t *testing.T) {
 			test.maxPodsToEvictPerNode,
 			[]*v1.Node{node},
 			false,
+			false,
 		)
 
 		RemovePodsViolatingInterPodAntiAffinity(ctx, fakeClient, api.DeschedulerStrategy{}, []*v1.Node{node}, podEvictor)

pkg/descheduler/strategies/pod_lifetime_test.go

@@ -98,6 +98,19 @@ func TestPodLifeTime(t *testing.T) {
 	p9.ObjectMeta.OwnerReferences = ownerRef1
 	p10.ObjectMeta.OwnerReferences = ownerRef1
 
+	p11 := test.BuildTestPod("p11", 100, 0, node.Name, func(pod *v1.Pod) {
+		pod.Spec.Volumes = []v1.Volume{
+			{
+				Name: "pvc", VolumeSource: v1.VolumeSource{
+					PersistentVolumeClaim: &v1.PersistentVolumeClaimVolumeSource{ClaimName: "foo"},
+				},
+			},
+		}
+		pod.Namespace = "dev"
+		pod.ObjectMeta.CreationTimestamp = olderPodCreationTime
+		pod.ObjectMeta.OwnerReferences = ownerRef1
+	})
+
 	var maxLifeTime uint = 600
 	testCases := []struct {
 		description             string
@@ -105,6 +118,7 @@ func TestPodLifeTime(t *testing.T) {
 		maxPodsToEvictPerNode   int
 		pods                    []v1.Pod
 		expectedEvictedPodCount int
+		ignorePvcPods           bool
 	}{
 		{
 			description: "Two pods in the `dev` Namespace, 1 is new and 1 very is old. 1 should be evicted.",
@@ -169,6 +183,31 @@ func TestPodLifeTime(t *testing.T) {
 			pods:                    []v1.Pod{*p9, *p10},
 			expectedEvictedPodCount: 1,
 		},
+		{
+			description: "does not evict pvc pods with ignorePvcPods set to true",
+			strategy: api.DeschedulerStrategy{
+				Enabled: true,
+				Params: &api.StrategyParameters{
+					PodLifeTime: &api.PodLifeTime{MaxPodLifeTimeSeconds: &maxLifeTime},
+				},
+			},
+			maxPodsToEvictPerNode:   5,
+			pods:                    []v1.Pod{*p11},
+			expectedEvictedPodCount: 0,
+			ignorePvcPods:           true,
+		},
+		{
+			description: "evicts pvc pods with ignorePvcPods set to false (or unset)",
+			strategy: api.DeschedulerStrategy{
+				Enabled: true,
+				Params: &api.StrategyParameters{
+					PodLifeTime: &api.PodLifeTime{MaxPodLifeTimeSeconds: &maxLifeTime},
+				},
+			},
+			maxPodsToEvictPerNode:   5,
+			pods:                    []v1.Pod{*p11},
+			expectedEvictedPodCount: 1,
+		},
 	}
 
 	for _, tc := range testCases {
@@ -186,6 +225,7 @@ func TestPodLifeTime(t *testing.T) {
 			tc.maxPodsToEvictPerNode,
 			[]*v1.Node{node},
 			false,
+			tc.ignorePvcPods,
 		)
 
 		PodLifeTime(ctx, fakeClient, tc.strategy, []*v1.Node{node}, podEvictor)

pkg/descheduler/strategies/toomanyrestarts_test.go

@@ -172,6 +172,7 @@ func TestRemovePodsHavingTooManyRestarts(t *testing.T) {
 			tc.maxPodsToEvictPerNode,
 			[]*v1.Node{node},
 			false,
+			false,
 		)
 
 		RemovePodsHavingTooManyRestarts(ctx, fakeClient, tc.strategy, []*v1.Node{node}, podEvictor)

pkg/descheduler/strategies/topologyspreadconstraint_test.go

@@ -368,6 +368,7 @@ func TestTopologySpreadConstraint(t *testing.T) {
 				100,
 				tc.nodes,
 				false,
+				false,
 			)
 			RemovePodsViolatingTopologySpreadConstraint(ctx, fakeClient, tc.strategy, tc.nodes, podEvictor)
 			podsEvicted := podEvictor.TotalEvicted()

test/e2e/e2e_test.go

@@ -220,6 +220,7 @@ func runPodLifetimeStrategy(ctx context.Context, clientset clientset.Interface,
 			0,
 			nodes,
 			false,
+			false,
 		),
 	)
 }
@@ -648,6 +649,7 @@ func evictPods(ctx context.Context, t *testing.T, clientSet clientset.Interface,
 		0,
 		nodeList,
 		true,
+		false,
 	)
 	for _, node := range nodeList {
 		// Skip the Master Node