sgl-router: experimental Rust HTTP router for SGLang worker pools (#25851)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

experimental/sgl-router/tests/e2e/k8s_integration/manifests/namespace.yaml

@@ -0,0 +1,4 @@
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: sgl-router-test

experimental/sgl-router/tests/e2e/k8s_integration/manifests/rbac-cluster-scoped.yaml

@@ -0,0 +1,33 @@
+# Cluster-wide RBAC for the cross-namespace discovery test.
+# Distinct ServiceAccount/ClusterRole names to avoid collision with
+# the namespace-scoped Role in rbac.yaml used by the default router.
+apiVersion: v1
+kind: ServiceAccount
+metadata:
+  name: sgl-router-cluster
+  namespace: sgl-router-test
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: ClusterRole
+metadata:
+  name: sgl-router-cluster
+rules:
+  - apiGroups: ["discovery.k8s.io"]
+    resources: ["endpointslices"]
+    verbs: ["get", "list", "watch"]
+  - apiGroups: [""]
+    resources: ["services", "pods"]
+    verbs: ["get", "list", "watch"]
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: ClusterRoleBinding
+metadata:
+  name: sgl-router-cluster
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: ClusterRole
+  name: sgl-router-cluster
+subjects:
+  - kind: ServiceAccount
+    name: sgl-router-cluster
+    namespace: sgl-router-test

experimental/sgl-router/tests/e2e/k8s_integration/manifests/rbac.yaml

@@ -0,0 +1,34 @@
+apiVersion: v1
+kind: ServiceAccount
+metadata:
+  name: sgl-router
+  namespace: sgl-router-test
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: Role
+metadata:
+  name: sgl-router
+  namespace: sgl-router-test
+rules:
+  # EndpointSlice watch (k8s discovery backend)
+  - apiGroups: ["discovery.k8s.io"]
+    resources: ["endpointslices"]
+    verbs: ["get", "list", "watch"]
+  # Service list/watch (needed to resolve EndpointSlice owner)
+  - apiGroups: [""]
+    resources: ["services", "pods"]
+    verbs: ["get", "list", "watch"]
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: RoleBinding
+metadata:
+  name: sgl-router
+  namespace: sgl-router-test
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: Role
+  name: sgl-router
+subjects:
+  - kind: ServiceAccount
+    name: sgl-router
+    namespace: sgl-router-test

experimental/sgl-router/tests/e2e/k8s_integration/manifests/router-cluster-scoped.yaml

@@ -0,0 +1,60 @@
+# sgl-router deployment with ClusterRole for cross-namespace discovery test.
+# Watches workers in ALL namespaces via cluster-scoped EndpointSlice access.
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: sgl-router-cluster
+  namespace: sgl-router-test
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: sgl-router-cluster
+  template:
+    metadata:
+      labels:
+        app: sgl-router-cluster
+    spec:
+      serviceAccountName: sgl-router-cluster
+      containers:
+        - name: router
+          image: sgl-router:e2e
+          imagePullPolicy: Never
+          args:
+            - "--config"
+            - "/etc/config/router-cluster.toml"
+          ports:
+            - containerPort: 8091
+              name: http
+          readinessProbe:
+            httpGet:
+              path: /readyz
+              port: 8091
+            initialDelaySeconds: 3
+            periodSeconds: 3
+          livenessProbe:
+            httpGet:
+              path: /healthz
+              port: 8091
+            initialDelaySeconds: 5
+            periodSeconds: 10
+          volumeMounts:
+            - name: config
+              mountPath: /etc/config
+      volumes:
+        - name: config
+          configMap:
+            name: sgl-router-cluster-config
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: sgl-router-cluster
+  namespace: sgl-router-test
+spec:
+  selector:
+    app: sgl-router-cluster
+  ports:
+    - name: http
+      port: 8091
+      targetPort: 8091

experimental/sgl-router/tests/e2e/k8s_integration/manifests/router.yaml

@@ -0,0 +1,58 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: sgl-router
+  namespace: sgl-router-test
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: sgl-router
+  template:
+    metadata:
+      labels:
+        app: sgl-router
+    spec:
+      serviceAccountName: sgl-router
+      containers:
+        - name: router
+          image: sgl-router:e2e
+          imagePullPolicy: Never
+          args:
+            - "--config"
+            - "/etc/config/router.toml"
+          ports:
+            - containerPort: 8090
+              name: http
+          readinessProbe:
+            httpGet:
+              path: /readyz
+              port: 8090
+            initialDelaySeconds: 3
+            periodSeconds: 3
+          livenessProbe:
+            httpGet:
+              path: /healthz
+              port: 8090
+            initialDelaySeconds: 5
+            periodSeconds: 10
+          volumeMounts:
+            - name: config
+              mountPath: /etc/config
+      volumes:
+        - name: config
+          configMap:
+            name: sgl-router-config
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: sgl-router
+  namespace: sgl-router-test
+spec:
+  selector:
+    app: sgl-router
+  ports:
+    - name: http
+      port: 8090
+      targetPort: 8090