MULTIARCH-5369 Improve transparency for PreferredDuringSchedulingIgnoredDuringExecution configuration

  This improves user experience by providing clear feedback about:
  1. The precedence order: PPC (by priority) → CPPC
  2. Which configuration successfully set preferences
  3. When and why configurations were overridden or skipped

  Labels added:
  - multiarch.openshift.io/preferred-affinity-source: tracks config source
  - LabelValueAllDuplicates: indicates all architectures were duplicates

  Events added:
  - ArchAwarePreferredAffinityAllDuplicates: all architectures already set
  - ArchAwarePreferredAffinityPluginDisabled: plugin not enabled

Author: AnnaZivkovic

controllers/podplacement/events.go

@@ -11,16 +11,19 @@ const (
 	ArchitectureAwareSchedulingGateRemovalFailure = "ArchAwareSchedGateRemovalFailed"
 	ArchitectureAwareSchedulingGateRemovalSuccess = "ArchAwareSchedGateRemovalSuccess"
 	NoSupportedArchitecturesFound                 = "NoSupportedArchitecturesFound"
+	ArchitecturePreferredAffinityAllDuplicates    = "ArchAwarePreferredAffinityAllDuplicates"
+	ArchitecturePreferredAffinityPluginDisabled   = "ArchAwarePreferredAffinityPluginDisabled"
 
-	SchedulingGateAddedMsg                   = "Successfully gated with the " + utils.SchedulingGateName + " scheduling gate"
-	SchedulingGateRemovalSuccessMsg          = "Successfully removed the " + utils.SchedulingGateName + " scheduling gate"
-	SchedulingGateRemovalFailureMsg          = "Failed to remove the scheduling gate \"" + utils.SchedulingGateName + "\""
-	ArchitecturePredicatesConflictMsg        = "All the scheduling predicates already include architecture-specific constraints"
-	ArchitecturePredicateSetupMsg            = "Set the supported architectures to "
-	ArchitecturePreferredPredicateSetupMsg   = "Set the architecture preferences in the nodeAffinity"
-	ArchitecturePreferredPredicateSkippedMsg = "The node affinity already includes architecture preferences"
-	ImageArchitectureInspectionErrorMsg      = "Failed to retrieve the supported architectures: "
-	NoSupportedArchitecturesFoundMsg         = "Pod cannot be scheduled due to incompatible image architectures; container images have no supported architectures in common"
-	ArchitectureAwareGatedPodIgnoredMsg      = "The gated pod has been modified and is no longer eligible for architecture-aware scheduling"
-	ImageInspectionErrorMaxRetriesMsg        = "Failed to retrieve the supported architectures after multiple retries"
+	SchedulingGateAddedMsg                         = "Successfully gated with the " + utils.SchedulingGateName + " scheduling gate"
+	SchedulingGateRemovalSuccessMsg                = "Successfully removed the " + utils.SchedulingGateName + " scheduling gate"
+	SchedulingGateRemovalFailureMsg                = "Failed to remove the scheduling gate \"" + utils.SchedulingGateName + "\""
+	ArchitecturePredicatesConflictMsg              = "All the scheduling predicates already include architecture-specific constraints"
+	ArchitecturePredicateSetupMsg                  = "Set the supported architectures to "
+	ArchitecturePreferredPredicateSetupMsg         = "Set the architecture preferences in the nodeAffinity: "
+	ArchitecturePreferredAffinityAllDuplicatesMsg  = "All specified architecture preferences were already set by higher-priority configurations"
+	ArchitecturePreferredAffinityPluginDisabledMsg = "NodeAffinityScoring plugin is not enabled"
+	ImageArchitectureInspectionErrorMsg            = "Failed to retrieve the supported architectures: "
+	NoSupportedArchitecturesFoundMsg               = "Pod cannot be scheduled due to incompatible image architectures; container images have no supported architectures in common"
+	ArchitectureAwareGatedPodIgnoredMsg            = "The gated pod has been modified and is no longer eligible for architecture-aware scheduling"
+	ImageInspectionErrorMaxRetriesMsg              = "Failed to retrieve the supported architectures after multiple retries"
 )

controllers/podplacement/pod_model.go

@@ -167,7 +167,8 @@ func (pod *Pod) setRequiredArchNodeAffinity(requirement corev1.NodeSelectorRequi
 }
 
 // SetPreferredArchNodeAffinity sets the node affinity for the pod to the preferences given in the ClusterPodPlacementConfig.
-func (pod *Pod) SetPreferredArchNodeAffinity(nodeAffinity *plugins.NodeAffinityScoring) {
+// The configSource parameter identifies which configuration is setting the preferences (e.g., "ClusterPodPlacementConfig" or "PodPlacementConfig/my-ppc").
+func (pod *Pod) SetPreferredArchNodeAffinity(nodeAffinity *plugins.NodeAffinityScoring, configSource string) {
 	log := ctrllog.FromContext(pod.Ctx())
 	if pod.Spec.Affinity == nil {
 		pod.Spec.Affinity = &corev1.Affinity{}
@@ -183,6 +184,7 @@ func (pod *Pod) SetPreferredArchNodeAffinity(nodeAffinity *plugins.NodeAffinityS
 
 	seenArchitectures := pod.getExistingPreferredArchitectures()
 	var preferredSchedulingTerms []corev1.PreferredSchedulingTerm
+	var skippedArchitectures []string
 	for _, nodeAffinityScoringPlatformTerm := range nodeAffinity.Platforms {
 		if !seenArchitectures[nodeAffinityScoringPlatformTerm.Architecture] {
 			preferredSchedulingTerm := corev1.PreferredSchedulingTerm{
@@ -200,7 +202,8 @@ func (pod *Pod) SetPreferredArchNodeAffinity(nodeAffinity *plugins.NodeAffinityS
 			preferredSchedulingTerms = append(preferredSchedulingTerms, preferredSchedulingTerm)
 			seenArchitectures[nodeAffinityScoringPlatformTerm.Architecture] = true
 		} else {
-			log.Info("Preferred affinity for pod is already set", "Architecture", nodeAffinityScoringPlatformTerm.Architecture, "Weight", nodeAffinityScoringPlatformTerm.Weight, "Pod.Name", pod.Name, "Pod.Namespace", pod.Namespace)
+			skippedArchitectures = append(skippedArchitectures, nodeAffinityScoringPlatformTerm.Architecture)
+			log.Info("Preferred affinity for pod is already set", "Architecture", nodeAffinityScoringPlatformTerm.Architecture, "Weight", nodeAffinityScoringPlatformTerm.Weight, "Pod.Name", pod.Name, "Pod.Namespace", pod.Namespace, "ConfigSource", configSource)
 		}
 	}
 
@@ -210,7 +213,19 @@ func (pod *Pod) SetPreferredArchNodeAffinity(nodeAffinity *plugins.NodeAffinityS
 		pod.Spec.Affinity.NodeAffinity.PreferredDuringSchedulingIgnoredDuringExecution = append(
 			pod.Spec.Affinity.NodeAffinity.PreferredDuringSchedulingIgnoredDuringExecution, preferredSchedulingTerms...)
 		pod.EnsureLabel(utils.PreferredNodeAffinityLabel, utils.NodeAffinityLabelValueSet)
-		pod.PublishEvent(corev1.EventTypeNormal, ArchitectureAwareNodeAffinitySet, ArchitecturePreferredPredicateSetupMsg)
+		// Set the source label to track which configuration set the preferred affinity
+		// If multiple configs contribute, this will show the most recent one that added preferences
+		pod.EnsureLabel(utils.PreferredNodeAffinitySourceLabel, configSource)
+		pod.PublishEvent(corev1.EventTypeNormal, ArchitectureAwareNodeAffinitySet, fmt.Sprintf("%s  %s", ArchitecturePreferredPredicateSetupMsg, configSource))
+	}
+
+	// If all architectures were already set by higher-priority configs, emit an event
+	if preferredSchedulingTerms == nil && len(skippedArchitectures) > 0 {
+		log.Info("All architectures from config were already set", "ConfigSource", configSource, "SkippedArchitectures", skippedArchitectures)
+		// Mark that all architectures from this config were duplicates
+		pod.EnsureLabel(utils.PreferredNodeAffinityLabel, utils.LabelValueAllDuplicates)
+		pod.PublishEvent(corev1.EventTypeNormal, ArchitecturePreferredAffinityAllDuplicates,
+			fmt.Sprintf("%s (source: %s, architectures: %s)", ArchitecturePreferredAffinityAllDuplicatesMsg, configSource, strings.Join(skippedArchitectures, ", ")))
 	}
 }
 

controllers/podplacement/pod_reconciler.go

@@ -122,7 +122,7 @@ func (r *PodReconciler) processPod(ctx context.Context, pod *Pod) {
 	r.applyPodPlacementConfigs(ctx, pod)
 
 	if cppc != nil && cppc.PluginsEnabled(common.NodeAffinityScoringPluginName) {
-		pod.SetPreferredArchNodeAffinity(cppc.Spec.Plugins.NodeAffinityScoring)
+		pod.SetPreferredArchNodeAffinity(cppc.Spec.Plugins.NodeAffinityScoring, multiarchv1beta1.ClusterPodPlacementConfigKind)
 	}
 
 	// Prepare the requirement for the node affinity.
@@ -144,9 +144,15 @@ func (r *PodReconciler) processPod(ctx context.Context, pod *Pod) {
 	}
 	// If the pod has been processed successfully or the max retries have been reached, remove the scheduling gate.
 	if err == nil || pod.maxRetries() {
-		if pod.Labels[utils.PreferredNodeAffinityLabel] == utils.LabelValueNotSet {
-			pod.PublishEvent(corev1.EventTypeNormal, ArchitectureAwareNodeAffinitySet,
-				ArchitecturePreferredPredicateSkippedMsg)
+		// Check why preferred affinity was not set and emit appropriate event
+		preferredAffinityLabel := pod.Labels[utils.PreferredNodeAffinityLabel]
+		if preferredAffinityLabel == utils.LabelValueNotSet {
+			// Plugin was never enabled
+			pod.PublishEvent(corev1.EventTypeNormal, ArchitecturePreferredAffinityPluginDisabled,
+				ArchitecturePreferredAffinityPluginDisabledMsg)
+		} else if preferredAffinityLabel == utils.LabelValueAllDuplicates {
+			// All architectures were already set (this label is set in SetPreferredArchNodeAffinity when all are duplicates)
+			// Event already emitted in SetPreferredArchNodeAffinity, no need to emit again
 		}
 
 		log.V(1).Info("Removing the scheduling gate from pod.")
@@ -188,7 +194,8 @@ func (r *PodReconciler) applyPodPlacementConfigs(ctx context.Context, pod *Pod)
 		if selector == labels.Nothing() || selector.Matches(labels.Set(pod.Labels)) {
 			log.Info("Applying namespace-scoped config", "PodPlacementConfig", ppc.Name)
 			// Apply the configuration, checking for overlaps
-			pod.SetPreferredArchNodeAffinity(ppc.Spec.Plugins.NodeAffinityScoring)
+			configSource := fmt.Sprintf("%s-%s", multiarchv1beta1.PodPlacementConfigResource, ppc.Name)
+			pod.SetPreferredArchNodeAffinity(ppc.Spec.Plugins.NodeAffinityScoring, configSource)
 		}
 	}
 }

pkg/utils/const.go

@@ -21,22 +21,24 @@ const (
 )
 
 const (
-	ArchLabel                       = "kubernetes.io/arch"
-	NodeAffinityLabel               = "multiarch.openshift.io/node-affinity"
-	PreferredNodeAffinityLabel      = "multiarch.openshift.io/preferred-node-affinity"
-	NodeAffinityLabelValueSet       = "set"
-	LabelValueNotSet                = "not-set"
-	HostnameLabel                   = "kubernetes.io/hostname"
-	SchedulingGateLabel             = "multiarch.openshift.io/scheduling-gate"
-	SchedulingGateLabelValueGated   = "gated"
-	SchedulingGateLabelValueRemoved = "removed"
-	PodPlacementFinalizerName       = "finalizers.multiarch.openshift.io/pod-placement"
-	SingleArchLabel                 = "multiarch.openshift.io/single-arch"
-	MultiArchLabel                  = "multiarch.openshift.io/multi-arch"
-	NoSupportedArchLabel            = "multiarch.openshift.io/no-supported-arch"
-	ImageInspectionErrorLabel       = "multiarch.openshift.io/image-inspect-error"
-	ImageInspectionErrorCountLabel  = "multiarch.openshift.io/image-inspect-error-count"
-	LabelGroup                      = "multiarch.openshift.io"
+	ArchLabel                        = "kubernetes.io/arch"
+	NodeAffinityLabel                = "multiarch.openshift.io/node-affinity"
+	PreferredNodeAffinityLabel       = "multiarch.openshift.io/preferred-node-affinity"
+	PreferredNodeAffinitySourceLabel = "multiarch.openshift.io/preferred-affinity-source"
+	NodeAffinityLabelValueSet        = "set"
+	LabelValueNotSet                 = "not-set"
+	LabelValueAllDuplicates          = "all-duplicates"
+	HostnameLabel                    = "kubernetes.io/hostname"
+	SchedulingGateLabel              = "multiarch.openshift.io/scheduling-gate"
+	SchedulingGateLabelValueGated    = "gated"
+	SchedulingGateLabelValueRemoved  = "removed"
+	PodPlacementFinalizerName        = "finalizers.multiarch.openshift.io/pod-placement"
+	SingleArchLabel                  = "multiarch.openshift.io/single-arch"
+	MultiArchLabel                   = "multiarch.openshift.io/multi-arch"
+	NoSupportedArchLabel             = "multiarch.openshift.io/no-supported-arch"
+	ImageInspectionErrorLabel        = "multiarch.openshift.io/image-inspect-error"
+	ImageInspectionErrorCountLabel   = "multiarch.openshift.io/image-inspect-error-count"
+	LabelGroup                       = "multiarch.openshift.io"
 )
 
 const (