add readiness and liveness for vpa admission

Author: jklaw90

vertical-pod-autoscaler/deploy/admission-controller-deployment.yaml

@@ -43,6 +43,21 @@ spec:
             - containerPort: 8000
             - name: prometheus
               containerPort: 8944
+          livenessProbe:
+            httpGet:
+              path: /healthz
+              port: 8000
+              scheme: HTTPS
+            initialDelaySeconds: 5
+            periodSeconds: 10
+            failureThreshold: 3
+          readinessProbe:
+            httpGet:
+              path: /healthz
+              port: 8000
+              scheme: HTTPS
+            periodSeconds: 10
+            failureThreshold: 3
       volumes:
         - name: tls-certs
           secret:

vertical-pod-autoscaler/pkg/admission-controller/main.go

@@ -151,6 +151,10 @@ func main() {
 		as.Serve(w, r)
 		healthCheck.UpdateLastActivity()
 	})
+	http.HandleFunc("/healthz", func(w http.ResponseWriter, r *http.Request) {
+		healthCheck.ServeHTTP(w, r)
+		healthCheck.UpdateLastActivity()
+	})
 	var mutatingWebhookClient typedadmregv1.MutatingWebhookConfigurationInterface
 	if *registerWebhook {
 		mutatingWebhookClient = kubeClient.AdmissionregistrationV1().MutatingWebhookConfigurations()