Add flag enable-label-propagation for label propagation feature

pkg/flags/flags.go

@@ -115,6 +115,7 @@ var (
 		EnableL4NetLBDualStack         bool
 		EnableMultipleIGs              bool
 		EnableServiceMetrics           bool
+		EnableNEGLabelPropagation      bool
 		MaxIGSize                      int
 	}{
 		GCERateLimitScale: 1.0,
@@ -265,6 +266,7 @@ L7 load balancing. CSV values accepted. Example: -node-port-ranges=80,8080,400-5
 	flag.IntVar(&F.MaxIGSize, "max-ig-size", 1000, "Max number of instances in Instance Group")
 	flag.DurationVar(&F.MetricsExportInterval, "metrics-export-interval", 10*time.Minute, `Period for calculating and exporting metrics related to state of managed objects.`)
 	flag.DurationVar(&F.NegMetricsExportInterval, "neg-metrics-export-interval", 5*time.Second, `Period for calculating and exporting internal neg controller metrics, not usage.`)
+	flag.BoolVar(&F.EnableNEGLabelPropagation, "enable-label-propagation", false, "Enable NEG endpoint label propagation")
 }
 
 type RateLimitSpecs struct {