feat(operator): add SGLang selection topology controller

deploy/operator/cmd/main.go

@@ -772,6 +772,15 @@ func registerControllers(
 		return fmt.Errorf("unable to create DynamoModel controller: %w", err)
 	}
 
+	if err = (&controller.SelectionTopologyReconciler{
+		Client:        mgr.GetClient(),
+		Recorder:      mgr.GetEventRecorderFor("selection-topology"),
+		Config:        operatorCfg,
+		RuntimeConfig: runtimeConfig,
+	}).SetupWithManager(mgr); err != nil {
+		return fmt.Errorf("unable to create SelectionTopology controller: %w", err)
+	}
+
 	if err = (&controller.CheckpointReconciler{
 		Client:        mgr.GetClient(),
 		Config:        operatorCfg,

deploy/operator/internal/consts/consts.go

@@ -56,6 +56,10 @@ const (
 	KubeAnnotationDisableImagePullSecretDiscovery = "nvidia.com/disable-image-pull-secret-discovery"
 	KubeAnnotationDynamoDiscoveryBackend          = "nvidia.com/dynamo-discovery-backend"
 	KubeAnnotationDynamoKubeDiscoveryMode         = "nvidia.com/dynamo-kube-discovery-mode"
+	KubeAnnotationDynamoSelectionAdapter          = "nvidia.com/dynamo-selection-adapter"
+	KubeAnnotationDynamoSelectionServiceURL       = "nvidia.com/dynamo-selection-service-url"
+	KubeAnnotationDynamoSelectionTenantID         = "nvidia.com/dynamo-selection-tenant-id"
+	KubeAnnotationDynamoSelectionRequireKVEvents  = "nvidia.com/dynamo-selection-require-kv-events"
 
 	KubeLabelDynamoGraphDeploymentName = "nvidia.com/dynamo-graph-deployment-name"
 	KubeLabelDynamoComponent           = "nvidia.com/dynamo-component"
@@ -230,6 +234,7 @@ const (
 	ResourceTypeDynamoModel                         = "DynamoModel"
 	ResourceTypeDynamoGraphDeploymentRequest        = "DynamoGraphDeploymentRequest"
 	ResourceTypeDynamoGraphDeploymentScalingAdapter = "DynamoGraphDeploymentScalingAdapter"
+	ResourceTypeSelectionTopology                   = "SelectionTopology"
 
 	// Resource state constants - used in status reporting and metrics
 	ResourceStateReady    = "ready"

deploy/operator/internal/controller/selection_topology_adapter_sglang.go

@@ -0,0 +1,55 @@
+/*
+ * SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package controller
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/ai-dynamo/dynamo/deploy/operator/internal/enginemetadata/sglang"
+	"github.com/ai-dynamo/dynamo/deploy/operator/internal/selectionservice"
+)
+
+const selectionAdapterExternalSGLang = "external-sglang"
+
+type sglangMetadataFetcher interface {
+	Fetch(context.Context) (sglang.MetadataSnapshot, error)
+}
+
+type sglangMetadataClientFactory func(endpoint string) (sglangMetadataFetcher, error)
+
+type externalSGLangSelectionAdapter struct {
+	MetadataClientFactory sglangMetadataClientFactory
+}
+
+func (a externalSGLangSelectionAdapter) BuildWorker(ctx context.Context, reg selectionWorkerRegistration) (selectionservice.WorkerRequest, error) {
+	metadataClientFactory := a.MetadataClientFactory
+	if metadataClientFactory == nil {
+		metadataClientFactory = func(endpoint string) (sglangMetadataFetcher, error) {
+			return sglang.NewMetadataClient(endpoint, selectionSGLangRequestTimeout)
+		}
+	}
+	metadataClient, err := metadataClientFactory(reg.WorkerEndpoint)
+	if err != nil {
+		return selectionservice.WorkerRequest{}, fmt.Errorf("create SGLang metadata client for %q: %w", reg.WorkerEndpoint, err)
+	}
+	metadata, err := metadataClient.Fetch(ctx)
+	if err != nil {
+		return selectionservice.WorkerRequest{}, fmt.Errorf("fetch SGLang metadata from %q: %w", reg.WorkerEndpoint, err)
+	}
+	worker, err := sglang.BuildWorkerRequest(sglang.WorkerRegistration{
+		WorkerID:        reg.WorkerID,
+		WorkerEndpoint:  reg.WorkerEndpoint,
+		TenantID:        reg.TenantID,
+		StableRoutingID: reg.StableRoutingID,
+		RequireKVEvents: reg.RequireKVEvents,
+		TopologyDomains: reg.TopologyDomains,
+	}, metadata)
+	if err != nil {
+		return selectionservice.WorkerRequest{}, fmt.Errorf("build SGLang worker request for %q: %w", reg.WorkerEndpoint, err)
+	}
+	return worker, nil
+}