Add option to ignore pods with PVCs from eviction

cmd/descheduler/app/options/options.go

@@ -77,4 +77,5 @@ func (rs *DeschedulerServer) AddFlags(fs *pflag.FlagSet) {
 	fs.IntVar(&rs.MaxNoOfPodsToEvictPerNode, "max-pods-to-evict-per-node", rs.MaxNoOfPodsToEvictPerNode, "DEPRECATED: limits the maximum number of pods to be evicted per node by descheduler")
 	// evict-local-storage-pods allows eviction of pods that are using local storage. This is false by default.
 	fs.BoolVar(&rs.EvictLocalStoragePods, "evict-local-storage-pods", rs.EvictLocalStoragePods, "DEPRECATED: enables evicting pods using local storage by descheduler")
+
 }

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/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

@@ -48,4 +48,7 @@ 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"`
 }

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