kubelet: expose node.status.runtimeClasses

For KEP-3857: Recursive Read-only (RRO) mounts

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>

pkg/kubelet/kubelet_node_status.go

@@ -741,6 +741,7 @@ func (kl *Kubelet) defaultNodeStatusFuncs() []func(context.Context, *v1.Node) er
 		nodestatus.DaemonEndpoints(kl.daemonEndpoints),
 		nodestatus.Images(kl.nodeStatusMaxImages, kl.imageManager.GetImageList),
 		nodestatus.GoRuntime(),
+		nodestatus.RuntimeClasses(kl.runtimeState.runtimeHandlers),
 	)
 	// Volume limits
 	setters = append(setters, nodestatus.VolumeLimits(kl.volumePluginMgr.ListVolumePluginWithLimits))

pkg/kubelet/nodestatus/setters.go

@@ -480,6 +480,26 @@ func GoRuntime() Setter {
 	}
 }
 
+// RuntimeClasses returns a Setter that sets RuntimeClasses on the node.
+func RuntimeClasses(fn func() []kubecontainer.RuntimeHandler) Setter {
+	return func(ctx context.Context, node *v1.Node) error {
+		if !utilfeature.DefaultFeatureGate.Enabled(features.RecursiveReadOnlyMounts) {
+			return nil
+		}
+		handlers := fn()
+		node.Status.RuntimeClasses = make([]v1.NodeRuntimeClass, len(handlers))
+		for i, h := range handlers {
+			node.Status.RuntimeClasses[i] = v1.NodeRuntimeClass{
+				Name: h.Name,
+				Features: &v1.NodeRuntimeClassFeatures{
+					RecursiveReadOnlyMounts: &h.SupportsRecursiveReadOnlyMounts,
+				},
+			}
+		}
+		return nil
+	}
+}
+
 // ReadyCondition returns a Setter that updates the v1.NodeReady condition on the node.
 func ReadyCondition(
 	nowFunc func() time.Time, // typically Kubelet.clock.Now