Trace GC sweeps and (opt-in) health probes

Co-Authored-By: Claude <noreply@anthropic.com>

cmd/main.go

@@ -94,6 +94,7 @@ func main() {
 	var leaseCooldown, maxLeaseTTL time.Duration
 	var showVersion bool
 	var gcpWireFullPayloads bool
+	var traceHealthProbes bool
 
 	flag.StringVar(&metricsAddr, "metrics-bind-address", "0", "The address the metrics endpoint binds to. "+
 		"Use :8443 for HTTPS or :8080 for HTTP, or leave as 0 to disable the metrics service.")
@@ -134,6 +135,9 @@ func main() {
 		"Print the commit the binary was built from and exit.")
 	flag.BoolVar(&gcpWireFullPayloads, "gcp-wire-log-full-payloads", false,
 		"Log GCP V(5) wire payloads verbatim instead of eliding fields larger than 1KiB.")
+	flag.BoolVar(&traceHealthProbes, "trace-health-probes", false,
+		"Emit one trace span per health probe. Off by default: probes run about "+
+			"once per second per proxy and would dominate trace volume.")
 
 	opts := zap.Options{
 		Development: true,
@@ -277,6 +281,7 @@ func main() {
 	engine := health.NewEngine(mgr.GetClient())
 	engine.Workers = healthWorkers
 	engine.Metrics = m
+	engine.TraceProbes = traceHealthProbes
 	if err := mgr.Add(engine); err != nil {
 		setupLog.Error(err, "Failed to add health engine")
 		os.Exit(1)