add new preevectionfilter plugin with args

pkg/framework/plugins/defaultevictor/defaultevictor.go

@@ -0,0 +1,193 @@
+/*
+Copyright 2022 The Kubernetes Authors.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+    http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package defaultevictor
+
+import (
+	// "context"
+	"context"
+	"fmt"
+
+	v1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/labels"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/util/errors"
+	"k8s.io/klog/v2"
+	nodeutil "sigs.k8s.io/descheduler/pkg/descheduler/node"
+	podutil "sigs.k8s.io/descheduler/pkg/descheduler/pod"
+	"sigs.k8s.io/descheduler/pkg/framework"
+	"sigs.k8s.io/descheduler/pkg/utils"
+)
+
+const (
+	PluginName            = "DefaultEvictor"
+	evictPodAnnotationKey = "descheduler.alpha.kubernetes.io/evict"
+)
+
+var _ framework.EvictorPlugin = &DefaultEvictor{}
+
+type constraint func(pod *v1.Pod) error
+
+// DefaultEvictor is the first EvictorPlugin, which defines the default extension points of the
+// pre-baked evictor that is shipped.
+// Even though we name this plugin DefaultEvictor, it does not actually evict anything,
+// This plugin is only meant to customize other actions (extension points) of the evictor,
+// like filtering, sorting, and other ones that might be relevant in the future
+type DefaultEvictor struct {
+	constraints []constraint
+}
+
+// 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
+}
+
+// HaveEvictAnnotation checks if the pod have evict annotation
+func HaveEvictAnnotation(pod *v1.Pod) bool {
+	_, found := pod.ObjectMeta.Annotations[evictPodAnnotationKey]
+	return found
+}
+
+// New builds plugin from its arguments while passing a handle
+func New(args runtime.Object, handle framework.Handle) (framework.Plugin, error) {
+	defaultEvictorArgs, ok := args.(*DefaultEvictorArgs)
+	if !ok {
+		return nil, fmt.Errorf("want args to be of type defaultEvictorFilterArgs, got %T", args)
+	}
+
+	ev := &DefaultEvictor{}
+
+	if defaultEvictorArgs.EvictFailedBarePods {
+		klog.V(1).InfoS("Warning: EvictFailedBarePods is set to True. This could cause eviction of pods without ownerReferences.")
+		ev.constraints = append(ev.constraints, func(pod *v1.Pod) error {
+			ownerRefList := podutil.OwnerRef(pod)
+			// Enable evictFailedBarePods to evict bare pods in failed phase
+			if len(ownerRefList) == 0 && pod.Status.Phase != v1.PodFailed {
+				return fmt.Errorf("pod does not have any ownerRefs and is not in failed phase")
+			}
+			return nil
+		})
+	} else {
+		ev.constraints = append(ev.constraints, func(pod *v1.Pod) error {
+			ownerRefList := podutil.OwnerRef(pod)
+			if len(ownerRefList) == 0 {
+				return fmt.Errorf("pod does not have any ownerRefs")
+			}
+			return nil
+		})
+	}
+	if !defaultEvictorArgs.EvictSystemCriticalPods {
+		ev.constraints = append(ev.constraints, func(pod *v1.Pod) error {
+			if utils.IsCriticalPriorityPod(pod) {
+				return fmt.Errorf("pod has system critical priority")
+			}
+			return nil
+		})
+
+		if defaultEvictorArgs.PriorityThreshold != nil && (defaultEvictorArgs.PriorityThreshold.Value != nil || len(defaultEvictorArgs.PriorityThreshold.Name) > 0) {
+			thresholdPriority, err := utils.GetPriorityValueFromPriorityThreshold(context.TODO(), handle.ClientSet(), defaultEvictorArgs.PriorityThreshold)
+			if err != nil {
+				return nil, fmt.Errorf("failed to get priority threshold: %v", err)
+			}
+			ev.constraints = append(ev.constraints, func(pod *v1.Pod) error {
+				if IsPodEvictableBasedOnPriority(pod, thresholdPriority) {
+					return nil
+				}
+				return fmt.Errorf("pod has higher priority than specified priority class threshold")
+			})
+		}
+	} else {
+		klog.V(1).InfoS("Warning: EvictSystemCriticalPods is set to True. This could cause eviction of Kubernetes system pods.")
+	}
+	if !defaultEvictorArgs.EvictLocalStoragePods {
+		ev.constraints = append(ev.constraints, func(pod *v1.Pod) error {
+			if utils.IsPodWithLocalStorage(pod) {
+				return fmt.Errorf("pod has local storage and descheduler is not configured with evictLocalStoragePods")
+			}
+			return nil
+		})
+	}
+	if defaultEvictorArgs.IgnorePvcPods {
+		ev.constraints = append(ev.constraints, func(pod *v1.Pod) error {
+			if utils.IsPodWithPVC(pod) {
+				return fmt.Errorf("pod has a PVC and descheduler is configured to ignore PVC pods")
+			}
+			return nil
+		})
+	}
+	if defaultEvictorArgs.NodeFit {
+		ev.constraints = append(ev.constraints, func(pod *v1.Pod) error {
+			nodes, err := nodeutil.ReadyNodes(context.TODO(), handle.ClientSet(), handle.SharedInformerFactory().Core().V1().Nodes(), defaultEvictorArgs.NodeSelector)
+			if err != nil {
+				return fmt.Errorf("could not list nodes when processing NodeFit")
+			}
+			if !nodeutil.PodFitsAnyOtherNode(handle.GetPodsAssignedToNodeFunc(), pod, nodes) {
+				return fmt.Errorf("pod does not fit on any other node because of nodeSelector(s), Taint(s), or nodes marked as unschedulable")
+			}
+			return nil
+		})
+	}
+	if defaultEvictorArgs.LabelSelector != nil && !defaultEvictorArgs.LabelSelector.Empty() {
+		ev.constraints = append(ev.constraints, func(pod *v1.Pod) error {
+			if !defaultEvictorArgs.LabelSelector.Matches(labels.Set(pod.Labels)) {
+				return fmt.Errorf("pod labels do not match the labelSelector filter in the policy parameter")
+			}
+			return nil
+		})
+	}
+
+	return ev, nil
+}
+
+// Name retrieves the plugin name
+func (d *DefaultEvictor) Name() string {
+	return PluginName
+}
+
+func (d *DefaultEvictor) Filter(pod *v1.Pod) bool {
+	checkErrs := []error{}
+
+	if HaveEvictAnnotation(pod) {
+		return true
+	}
+
+	ownerRefList := podutil.OwnerRef(pod)
+	if utils.IsDaemonsetPod(ownerRefList) {
+		checkErrs = append(checkErrs, fmt.Errorf("pod is a DaemonSet pod"))
+	}
+
+	if utils.IsMirrorPod(pod) {
+		checkErrs = append(checkErrs, fmt.Errorf("pod is a mirror pod"))
+	}
+
+	if utils.IsStaticPod(pod) {
+		checkErrs = append(checkErrs, fmt.Errorf("pod is a static pod"))
+	}
+
+	if utils.IsPodTerminating(pod) {
+		checkErrs = append(checkErrs, fmt.Errorf("pod is terminating"))
+	}
+
+	for _, c := range d.constraints {
+		if err := c(pod); err != nil {
+			checkErrs = append(checkErrs, err)
+		}
+	}
+
+	if len(checkErrs) > 0 {
+		klog.V(4).InfoS("Pod fails the following checks", "pod", klog.KObj(pod), "checks", errors.NewAggregate(checkErrs).Error())
+		return false
+	}
+
+	return true
+}