Merge pull request #5893 from XiShanYongYe-Chang/inject-preservedLabe…

…lState

Inject preservedLabelState to the failover to clusters

pkg/controllers/binding/common.go

@@ -23,6 +23,7 @@ import (
 	apiextensionsv1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/util/sets"
 	"k8s.io/klog/v2"
 	"k8s.io/utils/ptr"
 	"sigs.k8s.io/controller-runtime/pkg/client"
@@ -43,34 +44,18 @@ func ensureWork(
 	overrideManager overridemanager.OverrideManager, binding metav1.Object, scope apiextensionsv1.ResourceScope,
 ) error {
 	var targetClusters []workv1alpha2.TargetCluster
-	var placement *policyv1alpha1.Placement
-	var requiredByBindingSnapshot []workv1alpha2.BindingSnapshot
-	var replicas int32
-	var conflictResolutionInBinding policyv1alpha1.ConflictResolution
-	var suspension *policyv1alpha1.Suspension
-	var preserveResourcesOnDeletion *bool
+	var bindingSpec workv1alpha2.ResourceBindingSpec
 	switch scope {
 	case apiextensionsv1.NamespaceScoped:
 		bindingObj := binding.(*workv1alpha2.ResourceBinding)
-		targetClusters = bindingObj.Spec.Clusters
-		requiredByBindingSnapshot = bindingObj.Spec.RequiredBy
-		placement = bindingObj.Spec.Placement
-		replicas = bindingObj.Spec.Replicas
-		conflictResolutionInBinding = bindingObj.Spec.ConflictResolution
-		suspension = bindingObj.Spec.Suspension
-		preserveResourcesOnDeletion = bindingObj.Spec.PreserveResourcesOnDeletion
+		bindingSpec = bindingObj.Spec
 	case apiextensionsv1.ClusterScoped:
 		bindingObj := binding.(*workv1alpha2.ClusterResourceBinding)
-		targetClusters = bindingObj.Spec.Clusters
-		requiredByBindingSnapshot = bindingObj.Spec.RequiredBy
-		placement = bindingObj.Spec.Placement
-		replicas = bindingObj.Spec.Replicas
-		conflictResolutionInBinding = bindingObj.Spec.ConflictResolution
-		suspension = bindingObj.Spec.Suspension
-		preserveResourcesOnDeletion = bindingObj.Spec.PreserveResourcesOnDeletion
+		bindingSpec = bindingObj.Spec
 	}
 
-	targetClusters = mergeTargetClusters(targetClusters, requiredByBindingSnapshot)
+	targetClusters = bindingSpec.Clusters
+	targetClusters = mergeTargetClusters(targetClusters, bindingSpec.RequiredBy)
 
 	var jobCompletions []workv1alpha2.TargetCluster
 	var err error
@@ -89,7 +74,7 @@ func ensureWork(
 
 		// If and only if the resource template has replicas, and the replica scheduling policy is divided,
 		// we need to revise replicas.
-		if needReviseReplicas(replicas, placement) {
+		if needReviseReplicas(bindingSpec.Replicas, bindingSpec.Placement) {
 			if resourceInterpreter.HookEnabled(clonedWorkload.GroupVersionKind(), configv1alpha1.InterpreterOperationReviseReplica) {
 				clonedWorkload, err = resourceInterpreter.ReviseReplica(clonedWorkload, int64(targetCluster.Replicas))
 				if err != nil {
@@ -121,13 +106,17 @@ func ensureWork(
 		workLabel := mergeLabel(clonedWorkload, binding, scope)
 
 		annotations := mergeAnnotations(clonedWorkload, binding, scope)
-		annotations = mergeConflictResolution(clonedWorkload, conflictResolutionInBinding, annotations)
+		annotations = mergeConflictResolution(clonedWorkload, bindingSpec.ConflictResolution, annotations)
 		annotations, err = RecordAppliedOverrides(cops, ops, annotations)
 		if err != nil {
 			klog.Errorf("Failed to record appliedOverrides, Error: %v", err)
 			return err
 		}
 
+		// we need to figure out if the targetCluster is in the cluster we are going to migrate application to.
+		// If yes, we have to inject the preserved label state to clonedWorkload with the label.
+		clonedWorkload = injectReservedLabelState(bindingSpec, targetCluster, clonedWorkload, len(targetClusters))
+
 		workMeta := metav1.ObjectMeta{
 			Name:        names.GenerateWorkName(clonedWorkload.GetKind(), clonedWorkload.GetName(), clonedWorkload.GetNamespace()),
 			Namespace:   workNamespace,
@@ -141,15 +130,49 @@ func ensureWork(
 			c,
 			workMeta,
 			clonedWorkload,
-			helper.WithSuspendDispatching(shouldSuspendDispatching(suspension, targetCluster)),
-			helper.WithPreserveResourcesOnDeletion(ptr.Deref(preserveResourcesOnDeletion, false)),
+			helper.WithSuspendDispatching(shouldSuspendDispatching(bindingSpec.Suspension, targetCluster)),
+			helper.WithPreserveResourcesOnDeletion(ptr.Deref(bindingSpec.PreserveResourcesOnDeletion, false)),
 		); err != nil {
 			return err
 		}
 	}
 	return nil
 }
 
+// injectReservedLabelState injects the reservedLabelState in to the failover to cluster.
+// We have the following restrictions on whether to perform injection operations:
+//  1. Only the scenario where an application is deployed in one cluster and migrated to
+//     another cluster is considered.
+//  2. If consecutive failovers occur, for example, an application is migrated form clusterA
+//     to clusterB and then to clusterC, the PreservedLabelState before the last failover is
+//     used for injection. If the PreservedLabelState is empty, the injection is skipped.
+//  3. The injection operation is performed only when PurgeMode is set to Immediately.
+func injectReservedLabelState(bindingSpec workv1alpha2.ResourceBindingSpec, moveToCluster workv1alpha2.TargetCluster, workload *unstructured.Unstructured, clustersLen int) *unstructured.Unstructured {
+	if clustersLen > 1 {
+		return workload
+	}
+
+	if len(bindingSpec.GracefulEvictionTasks) == 0 {
+		return workload
+	}
+	targetEvictionTask := bindingSpec.GracefulEvictionTasks[len(bindingSpec.GracefulEvictionTasks)-1]
+
+	if targetEvictionTask.PurgeMode != policyv1alpha1.Immediately {
+		return workload
+	}
+
+	clustersBeforeFailover := sets.NewString(targetEvictionTask.ClustersBeforeFailover...)
+	if clustersBeforeFailover.Has(moveToCluster.Name) {
+		return workload
+	}
+
+	for key, value := range targetEvictionTask.PreservedLabelState {
+		util.MergeLabel(workload, key, value)
+	}
+
+	return workload
+}
+
 func mergeTargetClusters(targetClusters []workv1alpha2.TargetCluster, requiredByBindingSnapshot []workv1alpha2.BindingSnapshot) []workv1alpha2.TargetCluster {
 	if len(requiredByBindingSnapshot) == 0 {
 		return targetClusters