koord-descheduler: support ignore expected replicas argument (#1419)

Signed-off-by: lisen <lisen@youzan.com>
Co-authored-by: lisen <lisen@youzan.com>

pkg/descheduler/apis/config/types_pluginargs.go

@@ -78,6 +78,10 @@ type MigrationControllerArgs struct {
 	// Value can be an absolute number (ex: 5) or a percentage of desired pods (ex: 10%).
 	MaxUnavailablePerWorkload *intstr.IntOrString
 
+	// SkipCheckExpectedReplicas if enabled, it will allow eviction expectedReplicas equals maxUnavailable or maxMigrating.
+	// Default is false
+	SkipCheckExpectedReplicas *bool
+
 	// ObjectLimiters control the frequency of migration/eviction to make it smoother,
 	// and also protect Pods of the same class from being evicted frequently.
 	// e.g. limiting the frequency of Pods of the same workload being evicted.

pkg/descheduler/apis/config/v1alpha2/types_pluginargs.go

@@ -80,6 +80,10 @@ type MigrationControllerArgs struct {
 	// Value can be an absolute number (ex: 5) or a percentage of desired pods (ex: 10%).
 	MaxUnavailablePerWorkload *intstr.IntOrString `json:"maxUnavailablePerWorkload,omitempty"`
 
+	// SkipCheckExpectedReplicas if enabled, it will allow eviction expectedReplicas equals maxUnavailable or maxMigrating.
+	// Default is false
+	SkipCheckExpectedReplicas *bool `json:"skipCheckExpectedReplicas,omitempty"`
+
 	// ObjectLimiters control the frequency of migration/eviction to make it smoother,
 	// and also protect Pods of the same class from being evicted frequently.
 	// e.g. limiting the frequency of Pods of the same workload being evicted.

pkg/descheduler/controllers/migration/filter.go

@@ -276,11 +276,13 @@ func (r *Reconciler) filterMaxMigratingOrUnavailablePerWorkload(pod *corev1.Pod)
 		return false
 	}
 
-	// TODO(joseph): There are a few special scenarios where should we allow eviction?
-	if expectedReplicas == 1 || int(expectedReplicas) == maxMigrating || int(expectedReplicas) == maxUnavailable {
-		klog.Warningf("maxMigrating(%d) or maxUnavailable(%d) equals to the replicas(%d) of the workload %s/%s/%s(%s) of Pod %q, or the replicas equals to 1, please increase the replicas or update the defense configurations",
-			maxMigrating, maxUnavailable, expectedReplicas, ownerRef.Name, ownerRef.Kind, ownerRef.APIVersion, ownerRef.UID, klog.KObj(pod))
-		return false
+	if r.args.SkipCheckExpectedReplicas == nil || !*r.args.SkipCheckExpectedReplicas {
+		// TODO(joseph): There are a few special scenarios where should we allow eviction?
+		if expectedReplicas == 1 || int(expectedReplicas) == maxMigrating || int(expectedReplicas) == maxUnavailable {
+			klog.Warningf("maxMigrating(%d) or maxUnavailable(%d) equals to the replicas(%d) of the workload %s/%s/%s(%s) of Pod %q, or the replicas equals to 1, please increase the replicas or update the defense configurations",
+				maxMigrating, maxUnavailable, expectedReplicas, ownerRef.Name, ownerRef.Kind, ownerRef.APIVersion, ownerRef.UID, klog.KObj(pod))
+			return false
+		}
 	}
 
 	var expectPhases []sev1alpha1.PodMigrationJobPhase