nfd-topology-updater: Add liveness probe

Signed-off-by: Oleg Zhurakivskyy <[email protected]>

cmd/nfd-topology-updater/main.go

@@ -36,6 +36,7 @@ const (
 	// ProgramName is the canonical name of this program
 	ProgramName       = "nfd-topology-updater"
 	kubeletSecurePort = 10250
+	GrpcHealthPort    = 8082
 )
 
 var DefaultKubeletStateDir = path.Join(string(hostpath.VarDir), "lib", "kubelet")
@@ -54,6 +55,7 @@ func main() {
 	utils.ConfigureGrpcKlog()
 
 	// Get new TopologyUpdater instance
+	args.GrpcHealthPort = GrpcHealthPort
 	instance, err := topology.NewTopologyUpdater(*args, *resourcemonitorArgs)
 	if err != nil {
 		klog.ErrorS(err, "failed to initialize topology updater instance")

deployment/base/topologyupdater-daemonset/topologyupdater-daemonset.yaml

@@ -19,6 +19,17 @@ spec:
         - name: nfd-topology-updater
           image: gcr.io/k8s-staging-nfd/node-feature-discovery:master
           imagePullPolicy: Always
+          livenessProbe:
+            grpc:
+              port: 8082
+            initialDelaySeconds: 10
+            periodSeconds: 10
+          readinessProbe:
+            grpc:
+              port: 8082
+            initialDelaySeconds: 5
+            periodSeconds: 10
+            failureThreshold: 10
           command:
             - "nfd-topology-updater"
           args: []

deployment/helm/node-feature-discovery/templates/topologyupdater.yaml

@@ -41,6 +41,17 @@ spec:
       - name: topology-updater
         image: "{{ .Values.image.repository }}:{{ .Values.image.tag | default .Chart.AppVersion }}"
         imagePullPolicy: "{{ .Values.image.pullPolicy }}"
+        livenessProbe:
+          grpc:
+            port: 8082
+          initialDelaySeconds: 10
+          periodSeconds: 10
+        readinessProbe:
+          grpc:
+            port: 8082
+          initialDelaySeconds: 5
+          periodSeconds: 10
+          failureThreshold: 10
         env:
         - name: NODE_NAME
           valueFrom:

deployment/helm/node-feature-discovery/values.yaml

@@ -483,6 +483,20 @@ topologyUpdater:
     readOnlyRootFilesystem: true
     runAsUser: 0
 
+  # livenessProbe: {}
+    ## NOTE: Currently not configurable, defaults are provided for the sake of extra documentation.
+    # grpc:
+    #   port: 8082
+    # initialDelaySeconds: 10
+    # periodSeconds: 10
+  # readinessProbe: {}
+    ## NOTE: Currently not configurable, defaults are provided for the sake of extra documentation.
+    # grpc:
+    #   port: 8082
+    # initialDelaySeconds: 5
+    # periodSeconds: 10
+    # failureThreshold: 10
+
   resources: {}
     # We usually recommend not to specify default resources and to leave this as a conscious
     # choice for the user. This also increases chances charts run on environments with little

pkg/nfd-topology-updater/nfd-topology-updater.go

@@ -18,12 +18,16 @@ package nfdtopologyupdater
 
 import (
 	"fmt"
+	"net"
 	"net/url"
 	"os"
 	"path/filepath"
 
 	"golang.org/x/net/context"
 
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/health"
+	"google.golang.org/grpc/health/grpc_health_v1"
 	"k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/types"
@@ -58,6 +62,7 @@ type Args struct {
 	KubeConfigFile  string
 	ConfigFile      string
 	KubeletStateDir string
+	GrpcHealthPort  int
 
 	Klog map[string]*utils.KlogFlagVal
 }
@@ -85,6 +90,7 @@ type nfdTopologyUpdater struct {
 	ownerRefs           []metav1.OwnerReference
 	k8sClient           k8sclient.Interface
 	kubeletConfigFunc   func() (*kubeletconfigv1beta1.KubeletConfiguration, error)
+	healthServer        *grpc.Server
 }
 
 // NewTopologyUpdater creates a new NfdTopologyUpdater instance.
@@ -128,6 +134,29 @@ func (w *nfdTopologyUpdater) detectTopologyPolicyAndScope() (string, string, err
 	return klConfig.TopologyManagerPolicy, klConfig.TopologyManagerScope, nil
 }
 
+func (w *nfdTopologyUpdater) startGrpcHealthServer(errChan chan<- error) error {
+	lis, err := net.Listen("tcp", fmt.Sprintf(":%d", w.args.GrpcHealthPort))
+	if err != nil {
+		return fmt.Errorf("failed to listen: %w", err)
+	}
+
+	s := grpc.NewServer()
+	grpc_health_v1.RegisterHealthServer(s, health.NewServer())
+	klog.InfoS("gRPC health server serving", "port", w.args.GrpcHealthPort)
+
+	go func() {
+		defer func() {
+			lis.Close()
+		}()
+		if err := s.Serve(lis); err != nil {
+			errChan <- fmt.Errorf("gRPC health server exited with an error: %w", err)
+		}
+		klog.InfoS("gRPC health server stopped")
+	}()
+	w.healthServer = s
+	return nil
+}
+
 // Run nfdTopologyUpdater. Returns if a fatal error is encountered, or, after
 // one request if OneShot is set to 'true' in the updater args.
 func (w *nfdTopologyUpdater) Run() error {
@@ -187,8 +216,20 @@ func (w *nfdTopologyUpdater) Run() error {
 		return fmt.Errorf("failed to obtain node resource information: %w", err)
 	}
 
+	grpcErr := make(chan error, 1)
+
+	// Start gRPC server for liveness probe (at this point we're "live")
+	if w.args.GrpcHealthPort != 0 {
+		if err := w.startGrpcHealthServer(grpcErr); err != nil {
+			return fmt.Errorf("failed to start gRPC health server: %w", err)
+		}
+	}
+
 	for {
 		select {
+		case err := <-grpcErr:
+			return fmt.Errorf("error in serving gRPC: %w", err)
+
 		case info := <-w.eventSource:
 			klog.V(4).InfoS("event received, scanning...", "event", info.Event)
 			scanResponse, err := resScan.Scan()
@@ -217,6 +258,9 @@ func (w *nfdTopologyUpdater) Run() error {
 
 		case <-w.stop:
 			klog.InfoS("shutting down nfd-topology-updater")
+			if w.healthServer != nil {
+				w.healthServer.GracefulStop()
+			}
 			return nil
 		}
 	}