feat: update stagedUpdateRun to use latest resource snapshot

apis/placement/v1beta1/stageupdate_types.go

@@ -186,8 +186,8 @@ type UpdateRunSpec struct {
 
 	// The resource snapshot index of the selected resources to be updated across clusters.
 	// The index represents a group of resource snapshots that includes all the resources a ResourcePlacement selected.
-	// +kubebuilder:validation:Required
 	// +kubebuilder:validation:XValidation:rule="self == oldSelf",message="resourceSnapshotIndex is immutable"
+	// +kubebuilder:validation:Optional
 	ResourceSnapshotIndex string `json:"resourceSnapshotIndex"`
 
 	// The name of the update strategy that specifies the stages and the sequence
@@ -374,6 +374,11 @@ type UpdateRunStatus struct {
 	// +kubebuilder:validation:Optional
 	PolicyObservedClusterCount int `json:"policyObservedClusterCount,omitempty"`
 
+	// ResourceSnapshotIndexUsed records the resource snapshot index that the update run is based on.
+	// The index represents the same resource snapshots as specified in the spec field, or the latest.
+	// +kubbebuilder:validation:Optional
+	ResourceSnapshotIndexUsed string `json:"resourceSnapshotIndexUsed,omitempty"`
+
 	// ApplyStrategy is the apply strategy that the stagedUpdateRun is using.
 	// It is the same as the apply strategy in the CRP when the staged update run starts.
 	// The apply strategy is not updated during the update run even if it changes in the CRP.

config/crd/bases/placement.kubernetes-fleet.io_clusterstagedupdateruns.yaml

@@ -1200,7 +1200,6 @@ spec:
                 type: string
             required:
             - placementName
-            - resourceSnapshotIndex
             - stagedRolloutStrategyName
             type: object
             x-kubernetes-validations:
@@ -1895,6 +1894,11 @@ spec:
                   All clusters involved in the update run are selected from the list of clusters scheduled by the CRP according
                   to the current policy.
                 type: string
+              resourceSnapshotIndexUsed:
+                description: |-
+                  ResourceSnapshotIndexUsed records the resource snapshot index that the update run is based on.
+                  The index represents the same resource snapshots as specified in the spec field, or the latest.
+                type: string
               stagedUpdateStrategySnapshot:
                 description: |-
                   UpdateStrategySnapshot is the snapshot of the UpdateStrategy used for the update run.

config/crd/bases/placement.kubernetes-fleet.io_stagedupdateruns.yaml

@@ -120,7 +120,6 @@ spec:
                 type: string
             required:
             - placementName
-            - resourceSnapshotIndex
             - stagedRolloutStrategyName
             type: object
             x-kubernetes-validations:
@@ -815,6 +814,11 @@ spec:
                   All clusters involved in the update run are selected from the list of clusters scheduled by the CRP according
                   to the current policy.
                 type: string
+              resourceSnapshotIndexUsed:
+                description: |-
+                  ResourceSnapshotIndexUsed records the resource snapshot index that the update run is based on.
+                  The index represents the same resource snapshots as specified in the spec field, or the latest.
+                type: string
               stagedUpdateStrategySnapshot:
                 description: |-
                   UpdateStrategySnapshot is the snapshot of the UpdateStrategy used for the update run.

pkg/controllers/updaterun/execution.go

@@ -96,7 +96,7 @@ func (r *Reconciler) executeUpdatingStage(
 	updateRunSpec := updateRun.GetUpdateRunSpec()
 	updatingStageStatus := &updateRunStatus.StagesStatus[updatingStageIndex]
 	// The parse error is ignored because the initialization should have caught it.
-	resourceIndex, _ := strconv.Atoi(updateRunSpec.ResourceSnapshotIndex)
+	resourceIndex, _ := strconv.Atoi(updateRunStatus.ResourceSnapshotIndexUsed)
 	resourceSnapshotName := fmt.Sprintf(placementv1beta1.ResourceSnapshotNameFmt, updateRunSpec.PlacementName, resourceIndex)
 	updateRunRef := klog.KObj(updateRun)
 	// Create the map of the toBeUpdatedBindings.

pkg/controllers/updaterun/execution_integration_test.go

@@ -160,7 +160,7 @@ var _ = Describe("UpdateRun execution tests - double stages", func() {
 			Expect(k8sClient.Create(ctx, updateRun)).To(Succeed())
 
 			By("Validating the initialization succeeded and the execution started")
-			initialized := generateSucceededInitializationStatus(crp, updateRun, policySnapshot, updateStrategy, clusterResourceOverride)
+			initialized := generateSucceededInitializationStatus(crp, updateRun, testResourceSnapshotIndex, policySnapshot, updateStrategy, clusterResourceOverride)
 			wantStatus = generateExecutionStartedStatus(updateRun, initialized)
 			validateClusterStagedUpdateRunStatus(ctx, updateRun, wantStatus, "")
 
@@ -521,7 +521,7 @@ var _ = Describe("UpdateRun execution tests - double stages", func() {
 			Expect(k8sClient.Create(ctx, updateRun)).To(Succeed())
 
 			By("Validating the initialization succeeded and the execution started")
-			initialized := generateSucceededInitializationStatus(crp, updateRun, policySnapshot, updateStrategy, clusterResourceOverride)
+			initialized := generateSucceededInitializationStatus(crp, updateRun, testResourceSnapshotIndex, policySnapshot, updateStrategy, clusterResourceOverride)
 			wantStatus = generateExecutionStartedStatus(updateRun, initialized)
 			validateClusterStagedUpdateRunStatus(ctx, updateRun, wantStatus, "")
 
@@ -680,7 +680,7 @@ var _ = Describe("UpdateRun execution tests - single stage", func() {
 			Expect(k8sClient.Create(ctx, updateRun)).To(Succeed())
 
 			By("Validating the initialization succeeded and the execution started")
-			initialized := generateSucceededInitializationStatusForSmallClusters(crp, updateRun, policySnapshot, updateStrategy)
+			initialized := generateSucceededInitializationStatusForSmallClusters(crp, updateRun, testResourceSnapshotIndex, policySnapshot, updateStrategy)
 			wantStatus = generateExecutionStartedStatus(updateRun, initialized)
 			validateClusterStagedUpdateRunStatus(ctx, updateRun, wantStatus, "")
 
@@ -774,7 +774,7 @@ var _ = Describe("UpdateRun execution tests - single stage", func() {
 			Expect(k8sClient.Create(ctx, updateRun)).To(Succeed())
 
 			By("Validating the initialization succeeded and the execution started")
-			initialized := generateSucceededInitializationStatusForSmallClusters(crp, updateRun, policySnapshot, updateStrategy)
+			initialized := generateSucceededInitializationStatusForSmallClusters(crp, updateRun, testResourceSnapshotIndex, policySnapshot, updateStrategy)
 			wantStatus = generateExecutionStartedStatus(updateRun, initialized)
 			validateClusterStagedUpdateRunStatus(ctx, updateRun, wantStatus, "")
 
@@ -883,7 +883,7 @@ var _ = Describe("UpdateRun execution tests - single stage", func() {
 			Expect(k8sClient.Create(ctx, updateRun)).To(Succeed())
 
 			By("Validating the initialization succeeded and the execution started")
-			initialized := generateSucceededInitializationStatusForSmallClusters(crp, updateRun, policySnapshot, updateStrategy)
+			initialized := generateSucceededInitializationStatusForSmallClusters(crp, updateRun, testResourceSnapshotIndex, policySnapshot, updateStrategy)
 			wantStatus = generateExecutionStartedStatus(updateRun, initialized)
 			validateClusterStagedUpdateRunStatus(ctx, updateRun, wantStatus, "")
 
@@ -1014,7 +1014,7 @@ var _ = Describe("UpdateRun execution tests - single stage", func() {
 			Expect(k8sClient.Create(ctx, updateRun)).To(Succeed())
 
 			By("Validating the initialization succeeded and the execution started")
-			initialized := generateSucceededInitializationStatusForSmallClusters(crp, updateRun, policySnapshot, updateStrategy)
+			initialized := generateSucceededInitializationStatusForSmallClusters(crp, updateRun, testResourceSnapshotIndex, policySnapshot, updateStrategy)
 			wantStatus = generateExecutionStartedStatus(updateRun, initialized)
 			validateClusterStagedUpdateRunStatus(ctx, updateRun, wantStatus, "")
 
@@ -1106,7 +1106,7 @@ var _ = Describe("UpdateRun execution tests - single stage", func() {
 			Expect(k8sClient.Create(ctx, updateRun)).To(Succeed())
 
 			By("Validating the initialization succeeded and the execution started")
-			initialized := generateSucceededInitializationStatusForSmallClusters(crp, updateRun, policySnapshot, updateStrategy)
+			initialized := generateSucceededInitializationStatusForSmallClusters(crp, updateRun, testResourceSnapshotIndex, policySnapshot, updateStrategy)
 			wantStatus = generateExecutionStartedStatus(updateRun, initialized)
 			validateClusterStagedUpdateRunStatus(ctx, updateRun, wantStatus, "")
 
@@ -1163,7 +1163,7 @@ var _ = Describe("UpdateRun execution tests - single stage", func() {
 			Expect(k8sClient.Create(ctx, updateRun)).To(Succeed())
 
 			By("Validating the initialization succeeded and the execution started")
-			initialized := generateSucceededInitializationStatusForSmallClusters(crp, updateRun, policySnapshot, updateStrategy)
+			initialized := generateSucceededInitializationStatusForSmallClusters(crp, updateRun, testResourceSnapshotIndex, policySnapshot, updateStrategy)
 			wantStatus = generateExecutionStartedStatus(updateRun, initialized)
 			validateClusterStagedUpdateRunStatus(ctx, updateRun, wantStatus, "")
 		})

pkg/controllers/updaterun/initialization.go

@@ -471,30 +471,10 @@ func validateAfterStageTask(tasks []placementv1beta1.StageTask) error {
 func (r *Reconciler) recordOverrideSnapshots(ctx context.Context, placementKey types.NamespacedName, updateRun placementv1beta1.UpdateRunObj) error {
 	updateRunRef := klog.KObj(updateRun)
 	updateRunSpec := updateRun.GetUpdateRunSpec()
-	placementName := placementKey.Name
 
-	snapshotIndex, err := strconv.Atoi(updateRunSpec.ResourceSnapshotIndex)
-	if err != nil || snapshotIndex < 0 {
-		err := controller.NewUserError(fmt.Errorf("invalid resource snapshot index `%s` provided, expected an integer >= 0", updateRunSpec.ResourceSnapshotIndex))
-		klog.ErrorS(err, "Failed to parse the resource snapshot index", "updateRun", updateRunRef)
-		// no more retries here.
-		return fmt.Errorf("%w: %s", errInitializedFailed, err.Error())
-	}
-
-	resourceSnapshotList, err := controller.ListAllResourceSnapshotWithAnIndex(ctx, r.Client, updateRunSpec.ResourceSnapshotIndex, placementName, placementKey.Namespace)
+	resourceSnapshotObjs, err := r.getResourceSnapshotObjs(ctx, placementKey, updateRun)
 	if err != nil {
-		klog.ErrorS(err, "Failed to list the resourceSnapshots associated with the placement",
-			"placement", placementKey, "resourceSnapshotIndex", snapshotIndex, "updateRun", updateRunRef)
-		// err can be retried.
-		return controller.NewAPIServerError(true, err)
-	}
-
-	resourceSnapshotObjs := resourceSnapshotList.GetResourceSnapshotObjs()
-	if len(resourceSnapshotObjs) == 0 {
-		err := controller.NewUserError(fmt.Errorf("no resourceSnapshots with index `%d` found for placement `%s`", snapshotIndex, placementKey))
-		klog.ErrorS(err, "No specified resourceSnapshots found", "updateRun", updateRunRef)
-		// no more retries here.
-		return fmt.Errorf("%w: %s", errInitializedFailed, err.Error())
+		return err
 	}
 
 	// Look for the master resourceSnapshot.
@@ -509,12 +489,18 @@ func (r *Reconciler) recordOverrideSnapshots(ctx context.Context, placementKey t
 
 	// No masterResourceSnapshot found.
 	if masterResourceSnapshot == nil {
-		err := controller.NewUnexpectedBehaviorError(fmt.Errorf("no master resourceSnapshot found for placement `%s` with index `%d`", placementKey, snapshotIndex))
+		err := controller.NewUnexpectedBehaviorError(fmt.Errorf("no master resourceSnapshot found for placement %s", placementKey))
 		klog.ErrorS(err, "Failed to find master resourceSnapshot", "updateRun", updateRunRef)
 		// no more retries here.
 		return fmt.Errorf("%w: %s", errInitializedFailed, err.Error())
 	}
-	klog.V(2).InfoS("Found master resourceSnapshot", "placement", placementKey, "index", snapshotIndex, "updateRun", updateRunRef)
+
+	klog.V(2).InfoS("Found master resourceSnapshot", "placement", placementKey, "masterResourceSnapshot", masterResourceSnapshot.GetName(), "updateRun", updateRunRef)
+
+	// Record the resource snapshot index used.
+	updateRunStatus := updateRun.GetUpdateRunStatus()
+	updateRunStatus.ResourceSnapshotIndexUsed = masterResourceSnapshot.GetLabels()[placementv1beta1.ResourceIndexLabel]
+	updateRun.SetUpdateRunStatus(*updateRunStatus)
 
 	resourceSnapshotRef := klog.KObj(masterResourceSnapshot)
 	// Fetch all the matching overrides.
@@ -526,7 +512,6 @@ func (r *Reconciler) recordOverrideSnapshots(ctx context.Context, placementKey t
 	}
 
 	// Pick the overrides associated with each target cluster.
-	updateRunStatus := updateRun.GetUpdateRunStatus()
 	for _, stageStatus := range updateRunStatus.StagesStatus {
 		for i := range stageStatus.Clusters {
 			clusterStatus := &stageStatus.Clusters[i]
@@ -543,6 +528,58 @@ func (r *Reconciler) recordOverrideSnapshots(ctx context.Context, placementKey t
 	return nil
 }
 
+// getResourceSnapshotObjs retrieves the list of resource snapshot objects from the specified ResourceSnapshotIndex.
+// If ResourceSnapshotIndex is unspecified, it returns the list of latest resource snapshots.
+func (r *Reconciler) getResourceSnapshotObjs(ctx context.Context, placementKey types.NamespacedName, updateRun placementv1beta1.UpdateRunObj) ([]placementv1beta1.ResourceSnapshotObj, error) {
+	updateRunRef := klog.KObj(updateRun)
+	updateRunSpec := updateRun.GetUpdateRunSpec()
+	var resourceSnapshotObjs []placementv1beta1.ResourceSnapshotObj
+	if updateRunSpec.ResourceSnapshotIndex != "" {
+		snapshotIndex, err := strconv.Atoi(updateRunSpec.ResourceSnapshotIndex)
+		if err != nil || snapshotIndex < 0 {
+			err := controller.NewUserError(fmt.Errorf("invalid resource snapshot index `%s` provided, expected an integer >= 0", updateRunSpec.ResourceSnapshotIndex))
+			klog.ErrorS(err, "Failed to parse the resource snapshot index", "updateRun", updateRunRef)
+			// no more retries here.
+			return nil, fmt.Errorf("%w: %s", errInitializedFailed, err.Error())
+		}
+
+		resourceSnapshotList, err := controller.ListAllResourceSnapshotWithAnIndex(ctx, r.Client, updateRunSpec.ResourceSnapshotIndex, placementKey.Name, placementKey.Namespace)
+		if err != nil {
+			klog.ErrorS(err, "Failed to list the resourceSnapshots associated with the placement",
+				"placement", placementKey, "resourceSnapshotIndex", snapshotIndex, "updateRun", updateRunRef)
+			// list err can be retried.
+			return nil, controller.NewAPIServerError(true, err)
+		}
+
+		resourceSnapshotObjs = resourceSnapshotList.GetResourceSnapshotObjs()
+		if len(resourceSnapshotObjs) == 0 {
+			err := controller.NewUserError(fmt.Errorf("no resourceSnapshots with index `%d` found for placement `%s`", snapshotIndex, placementKey))
+			klog.ErrorS(err, "No specified resourceSnapshots found", "updateRun", updateRunRef)
+			// no more retries here.
+			return resourceSnapshotObjs, fmt.Errorf("%w: %s", errInitializedFailed, err.Error())
+		}
+		return resourceSnapshotObjs, nil
+	}
+
+	klog.V(2).InfoS("No resource snapshot index specified, fetching latest resource snapshots", "placement", placementKey, "updateRun", updateRunRef)
+	latestResourceSnapshots, err := controller.ListLatestResourceSnapshots(ctx, r.Client, placementKey)
+	if err != nil {
+		klog.ErrorS(err, "Failed to list the latest resourceSnapshots associated with the placement",
+			"placement", placementKey, "updateRun", updateRunRef)
+		// list err can be retried.
+		return nil, controller.NewAPIServerError(true, err)
+	}
+
+	resourceSnapshotObjs = latestResourceSnapshots.GetResourceSnapshotObjs()
+	if len(resourceSnapshotObjs) == 0 {
+		err := fmt.Errorf("no latest resourceSnapshots found for placement `%s`. This might be a transient state, need retry", placementKey)
+		klog.ErrorS(err, "No latest resourceSnapshots found for placement. This might be transient, need retry", "placement", placementKey, "updateRun", updateRunRef)
+		// retryable error.
+		return resourceSnapshotObjs, err
+	}
+	return resourceSnapshotObjs, nil
+}
+
 // recordInitializationSucceeded records the successful initialization condition in the UpdateRun status.
 func (r *Reconciler) recordInitializationSucceeded(ctx context.Context, updateRun placementv1beta1.UpdateRunObj) error {
 	updateRunStatus := updateRun.GetUpdateRunStatus()