Enable multiple components estimating

Signed-off-by: RainbowMango <[email protected]>

Author: RainbowMango

pkg/scheduler/core/estimation.go

@@ -0,0 +1,101 @@
+/*
+Copyright 2025 The Karmada Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package core
+
+import (
+	"context"
+
+	"k8s.io/klog/v2"
+
+	clusterv1alpha1 "github.com/karmada-io/karmada/pkg/apis/cluster/v1alpha1"
+	policyv1alpha1 "github.com/karmada-io/karmada/pkg/apis/policy/v1alpha1"
+	workv1alpha2 "github.com/karmada-io/karmada/pkg/apis/work/v1alpha2"
+	estimatorclient "github.com/karmada-io/karmada/pkg/estimator/client"
+	"github.com/karmada-io/karmada/pkg/util/names"
+)
+
+// isMultiTemplateSchedulingApplicable checks if the given ResourceBindingSpec
+// meets the criteria for multi-template scheduling:
+//  1. The referenced resource holds multiple pod templates (multiple components).
+//  2. The placement configuration schedules the resource to exactly one cluster.
+//     This is currently determined by checking if spread constraints is set and requires exactly one cluster.
+//
+// Returns true if both conditions are satisfied, false otherwise.
+// Note: We do not infer required cluster number from placement.clusterAffinity and
+// placement.clusterAffinities because it's impossible to determine without cluster metadata
+// whether the affinity rule matches exactly one cluster in the current environment, and the
+// only reliable way is spread constraints.
+func isMultiTemplateSchedulingApplicable(spec *workv1alpha2.ResourceBindingSpec) bool {
+	if spec == nil {
+		return false
+	}
+
+	if len(spec.Components) < 2 {
+		return false
+	}
+
+	// Check if placement targets exactly one cluster
+	if spec.Placement == nil {
+		return false
+	}
+	for i := range spec.Placement.SpreadConstraints {
+		if spec.Placement.SpreadConstraints[i].SpreadByField == policyv1alpha1.SpreadByFieldCluster &&
+			spec.Placement.SpreadConstraints[i].MinGroups == 1 &&
+			spec.Placement.SpreadConstraints[i].MaxGroups == 1 {
+			return true
+		}
+	}
+
+	return false
+}
+
+// calculateMultiTemplateAvailableSets calculates available sets for multi-template scheduling.
+// It uses MaxAvailableComponentSets to estimate capacity for workloads with multiple pod templates.
+func calculateMultiTemplateAvailableSets(ctx context.Context, estimator estimatorclient.ReplicaEstimator, name string, clusters []*clusterv1alpha1.Cluster, spec *workv1alpha2.ResourceBindingSpec, availableTargetClusters []workv1alpha2.TargetCluster) ([]workv1alpha2.TargetCluster, error) {
+	req := estimatorclient.ComponentSetEstimationRequest{
+		Clusters:   clusters,
+		Components: spec.Components,
+		Namespace:  spec.Resource.Namespace,
+	}
+
+	namespacedKey := names.NamespacedKey(spec.Resource.Namespace, spec.Resource.Name)
+	resp, err := estimator.MaxAvailableComponentSets(ctx, req)
+	if err != nil {
+		klog.Errorf("Failed to calculate available component set with estimator(%s) for workload(%s, kind=%s, %s): %v",
+			name, spec.Resource.APIVersion, spec.Resource.Kind, namespacedKey, err)
+		return availableTargetClusters, err
+	}
+
+	for i := range resp {
+		if resp[i].Sets == estimatorclient.UnauthenticReplica {
+			continue
+		}
+
+		// Should find the corresponding cluster by name, not by assuming the order is the same as input,
+		// even if the order is the same, it's not guaranteed.
+		for j := range availableTargetClusters {
+			if availableTargetClusters[j].Name == resp[i].Name {
+				if availableTargetClusters[j].Replicas > resp[i].Sets {
+					availableTargetClusters[j].Replicas = resp[i].Sets
+					break
+				}
+			}
+		}
+	}
+
+	return availableTargetClusters, nil
+}