Add CRI fake runtimes for RuntimeConfig rpc

Also update the CRI RuntimeService inteface to include the new
RuntimeConfig rpc.

pkg/kubelet/cri/remote/fake/fake_runtime.go

@@ -356,3 +356,13 @@ func (f *RemoteRuntime) ListPodSandboxMetrics(ctx context.Context, req *kubeapi.
 
 	return &kubeapi.ListPodSandboxMetricsResponse{PodMetrics: podMetrics}, nil
 }
+
+// RuntimeConfig returns the configuration information of the runtime.
+func (f *RemoteRuntime) RuntimeConfig(ctx context.Context, req *kubeapi.RuntimeConfigRequest) (*kubeapi.RuntimeConfigResponse, error) {
+	resp, err := f.RuntimeService.RuntimeConfig(ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	return resp, nil
+}

pkg/kubelet/cri/remote/remote_runtime.go

@@ -865,3 +865,18 @@ func (r *remoteRuntimeService) ListPodSandboxMetrics(ctx context.Context) ([]*ru
 
 	return resp.GetPodMetrics(), nil
 }
+
+// RuntimeConfig returns the configuration information of the runtime.
+func (r *remoteRuntimeService) RuntimeConfig(ctx context.Context) (*runtimeapi.RuntimeConfigResponse, error) {
+	ctx, cancel := context.WithTimeout(ctx, r.timeout)
+	defer cancel()
+
+	resp, err := r.runtimeClient.RuntimeConfig(ctx, &runtimeapi.RuntimeConfigRequest{})
+	if err != nil {
+		klog.ErrorS(err, "RuntimeConfig from runtime service failed")
+		return nil, err
+	}
+	klog.V(10).InfoS("[RemoteRuntimeService] RuntimeConfigResponse", "linuxConfig", resp.GetLinux())
+
+	return resp, nil
+}

pkg/kubelet/kuberuntime/instrumented_services.go

@@ -361,3 +361,12 @@ func (in instrumentedRuntimeService) ListPodSandboxMetrics(ctx context.Context)
 	recordError(operation, err)
 	return out, err
 }
+
+func (in instrumentedRuntimeService) RuntimeConfig(ctx context.Context) (*runtimeapi.RuntimeConfigResponse, error) {
+	const operation = "runtime_config"
+	defer recordOperation(operation, time.Now())
+
+	out, err := in.service.RuntimeConfig(ctx)
+	recordError(operation, err)
+	return out, err
+}

staging/src/k8s.io/cri-api/pkg/apis/services.go

@@ -115,6 +115,8 @@ type RuntimeService interface {
 	UpdateRuntimeConfig(ctx context.Context, runtimeConfig *runtimeapi.RuntimeConfig) error
 	// Status returns the status of the runtime.
 	Status(ctx context.Context, verbose bool) (*runtimeapi.StatusResponse, error)
+	// RuntimeConfig returns the configuration information of the runtime.
+	RuntimeConfig(ctx context.Context) (*runtimeapi.RuntimeConfigResponse, error)
 }
 
 // ImageManagerService interface should be implemented by a container image

staging/src/k8s.io/cri-api/pkg/apis/testing/fake_runtime_service.go

@@ -72,6 +72,7 @@ type FakeRuntimeService struct {
 	FakePodSandboxMetrics  map[string]*runtimeapi.PodSandboxMetrics
 	FakeMetricDescriptors  map[string]*runtimeapi.MetricDescriptor
 	FakeContainerMetrics   map[string]*runtimeapi.ContainerMetrics
+	FakeLinuxConfiguration *runtimeapi.LinuxRuntimeConfiguration
 
 	ErrorOnSandboxCreate bool
 }
@@ -780,3 +781,16 @@ func (r *FakeRuntimeService) ListPodSandboxMetrics(_ context.Context) ([]*runtim
 
 	return result, nil
 }
+
+// RuntimeConfig returns runtime configuration of the FakeRuntimeService.
+func (r *FakeRuntimeService) RuntimeConfig(_ context.Context) (*runtimeapi.RuntimeConfigResponse, error) {
+	r.Lock()
+	defer r.Unlock()
+
+	r.Called = append(r.Called, "RuntimeConfig")
+	if err := r.popError("RuntimeConfig"); err != nil {
+		return nil, err
+	}
+
+	return &runtimeapi.RuntimeConfigResponse{Linux: r.FakeLinuxConfiguration}, nil
+}