Merge pull request #474 from lixiang233/Ft_include_soft_constraints

Add a parameter to include soft topology spread constraints

README.md

@@ -317,10 +317,14 @@ This strategy makes sure that pods violating [topology spread constraints](https
 are evicted from nodes. Specifically, it tries to evict the minimum number of pods required to balance topology domains to within each constraint's `maxSkew`.
 This strategy requires k8s version 1.18 at a minimum.
 
+By default, this strategy only deals with hard constraints, setting parameter `includeSoftConstraints` to `true` will
+include soft constraints.
+
 **Parameters:**
 
 |Name|Type|
 |---|---|
+|`includeSoftConstraints`|bool|
 |`thresholdPriority`|int (see [priority filtering](#priority-filtering))|
 |`thresholdPriorityClassName`|string (see [priority filtering](#priority-filtering))|
 |`namespaces`|(see [namespace filtering](#namespace-filtering))|
@@ -333,6 +337,8 @@ kind: "DeschedulerPolicy"
 strategies:
   "RemovePodsViolatingTopologySpreadConstraint":
      enabled: true
+     params:
+       includeSoftConstraints: false
 ```
 
 

pkg/api/types.go

@@ -69,6 +69,7 @@ type StrategyParameters struct {
 	PodsHavingTooManyRestarts         *PodsHavingTooManyRestarts
 	PodLifeTime                       *PodLifeTime
 	RemoveDuplicates                  *RemoveDuplicates
+	IncludeSoftConstraints            bool
 	Namespaces                        *Namespaces
 	ThresholdPriority                 *int32
 	ThresholdPriorityClassName        string

pkg/api/v1alpha1/types.go

@@ -67,6 +67,7 @@ type StrategyParameters struct {
 	PodsHavingTooManyRestarts         *PodsHavingTooManyRestarts         `json:"podsHavingTooManyRestarts,omitempty"`
 	PodLifeTime                       *PodLifeTime                       `json:"podLifeTime,omitempty"`
 	RemoveDuplicates                  *RemoveDuplicates                  `json:"removeDuplicates,omitempty"`
+	IncludeSoftConstraints            bool                               `json:"includeSoftConstraints"`
 	Namespaces                        *Namespaces                        `json:"namespaces"`
 	ThresholdPriority                 *int32                             `json:"thresholdPriority"`
 	ThresholdPriorityClassName        string                             `json:"thresholdPriorityClassName"`

pkg/api/v1alpha1/zz_generated.conversion.go

@@ -284,6 +284,7 @@ func autoConvert_v1alpha1_StrategyParameters_To_api_StrategyParameters(in *Strat
 	out.PodsHavingTooManyRestarts = (*api.PodsHavingTooManyRestarts)(unsafe.Pointer(in.PodsHavingTooManyRestarts))
 	out.PodLifeTime = (*api.PodLifeTime)(unsafe.Pointer(in.PodLifeTime))
 	out.RemoveDuplicates = (*api.RemoveDuplicates)(unsafe.Pointer(in.RemoveDuplicates))
+	out.IncludeSoftConstraints = in.IncludeSoftConstraints
 	out.Namespaces = (*api.Namespaces)(unsafe.Pointer(in.Namespaces))
 	out.ThresholdPriority = (*int32)(unsafe.Pointer(in.ThresholdPriority))
 	out.ThresholdPriorityClassName = in.ThresholdPriorityClassName
@@ -301,6 +302,7 @@ func autoConvert_api_StrategyParameters_To_v1alpha1_StrategyParameters(in *api.S
 	out.PodsHavingTooManyRestarts = (*PodsHavingTooManyRestarts)(unsafe.Pointer(in.PodsHavingTooManyRestarts))
 	out.PodLifeTime = (*PodLifeTime)(unsafe.Pointer(in.PodLifeTime))
 	out.RemoveDuplicates = (*RemoveDuplicates)(unsafe.Pointer(in.RemoveDuplicates))
+	out.IncludeSoftConstraints = in.IncludeSoftConstraints
 	out.Namespaces = (*Namespaces)(unsafe.Pointer(in.Namespaces))
 	out.ThresholdPriority = (*int32)(unsafe.Pointer(in.ThresholdPriority))
 	out.ThresholdPriorityClassName = in.ThresholdPriorityClassName

pkg/descheduler/strategies/topologyspreadconstraint.go

@@ -125,9 +125,8 @@ func RemovePodsViolatingTopologySpreadConstraint(
 		namespaceTopologySpreadConstraints := make(map[v1.TopologySpreadConstraint]struct{})
 		for _, pod := range namespacePods.Items {
 			for _, constraint := range pod.Spec.TopologySpreadConstraints {
-				// Only deal with hard topology constraints
+				// Ignore soft topology constraints if they are not included
-				// TODO(@damemi): add support for soft constraints
+				if (strategy.Params == nil || !strategy.Params.IncludeSoftConstraints) && constraint.WhenUnsatisfiable != v1.DoNotSchedule {
-				if constraint.WhenUnsatisfiable != v1.DoNotSchedule {
 					continue
 				}
 				namespaceTopologySpreadConstraints[constraint] = struct{}{}