Change how the metrics server is run in HyperShift

This is to accommodate for the change in the metrics port 60000 from HTTPS to HTTP, which allows the metrics to run without the need for additional permissions to RBAC resources in the kube-system namespace to the HyperShift operator.
Signed-off-by: George Lipceanu <[email protected]>

Author: georgelipceanu

pkg/metrics/server.go

@@ -13,6 +13,8 @@ import (
 	"os"
 	"time"
 
+	ntoconfig "github.com/openshift/cluster-node-tuning-operator/pkg/config"
+
 	"k8s.io/klog/v2"
 
 	"github.com/prometheus/client_golang/prometheus/promhttp"
@@ -47,7 +49,7 @@ func init() {
 // it does so only if the CA bundle changed from the current CA bundle on record.
 func DumpCA(caBundle string) {
 	if caBundle != server.caBundle {
-		server.caBundleCh <- caBundle
+		server.caBundleCh <- caBundle // This will block if no one is listening
 	}
 }
 
@@ -126,6 +128,27 @@ func (Server) Start(ctx context.Context) error {
 // and restarted with the current files.  Every non-nil return from this function is fatal
 // and will restart the whole operator.
 func RunServer(port int, ctx context.Context) error {
+	if ntoconfig.InHyperShift() {
+		klog.Info("starting metrics server.")
+		handler := promhttp.HandlerFor(registry, promhttp.HandlerOpts{})
+		router := http.NewServeMux()
+		router.Handle("/metrics", handler)
+		srv := &http.Server{
+			Addr:    fmt.Sprintf(":%d", port),
+			Handler: router,
+		}
+		go func() {
+			if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+				klog.Errorf("error from metrics server: %v", err)
+			}
+		}()
+		<-ctx.Done()
+		klog.Info("stopping insecure metrics server")
+
+		shutdownCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		defer cancel()
+		return srv.Shutdown(shutdownCtx)
+	}
 	// Set up and start the file watcher.
 	watcher, err := fsnotify.NewWatcher()
 	if watcher == nil || err != nil {