Make k8s client rate limiter parameters configurable (#3848)

Co-authored-by: Taketoshi Fujiwara <t-b-fujiwara@mercari.com>

charts/gha-runner-scale-set-controller/templates/deployment.yaml

@@ -85,6 +85,12 @@ spec:
         {{- range .Values.flags.excludeLabelPropagationPrefixes }}
         - "--exclude-label-propagation-prefix={{ . }}"
         {{- end }}
+        {{- with .Values.flags.k8sClientRateLimiterQPS }}
+        - "--k8s-client-rate-limiter-qps={{ . }}"
+        {{- end }}
+        {{- with .Values.flags.k8sClientRateLimiterBurst }}
+        - "--k8s-client-rate-limiter-burst={{ . }}"
+        {{- end }}
         command:
         - "/manager"
         {{- with .Values.metrics }}

charts/gha-runner-scale-set-controller/values.yaml

@@ -135,3 +135,7 @@ flags:
   ## Labels that match prefix specified in the list are excluded from propagation.
   # excludeLabelPropagationPrefixes:
   #   - "argocd.argoproj.io/instance"
+
+  ## Defines the K8s client rate limiter parameters.
+  # k8sClientRateLimiterQPS: 20
+  # k8sClientRateLimiterBurst: 30

main.go

@@ -105,6 +105,9 @@ func main() {
 		opts = actionsgithubcom.OptionsWithDefault()
 
 		commonRunnerLabels commaSeparatedStringSlice
+
+		k8sClientRateLimiterQPS   int
+		k8sClientRateLimiterBurst int
 	)
 	var c github.Config
 	err = envconfig.Process("github", &c)
@@ -148,6 +151,8 @@ func main() {
 	flag.BoolVar(&autoScalingRunnerSetOnly, "auto-scaling-runner-set-only", false, "Make controller only reconcile AutoRunnerScaleSet object.")
 	flag.StringVar(&updateStrategy, "update-strategy", "immediate", `Resources reconciliation strategy on upgrade with running/pending jobs. Valid values are: "immediate", "eventual". Defaults to "immediate".`)
 	flag.Var(&autoScalerImagePullSecrets, "auto-scaler-image-pull-secrets", "The default image-pull secret name for auto-scaler listener container.")
+	flag.IntVar(&k8sClientRateLimiterQPS, "k8s-client-rate-limiter-qps", 20, "The QPS value of the K8s client rate limiter.")
+	flag.IntVar(&k8sClientRateLimiterBurst, "k8s-client-rate-limiter-burst", 30, "The burst value of the K8s client rate limiter.")
 	flag.Parse()
 
 	runnerPodDefaults.RunnerImagePullSecrets = runnerImagePullSecrets
@@ -219,7 +224,11 @@ func main() {
 		})
 	}
 
-	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{
+	cfg := ctrl.GetConfigOrDie()
+	cfg.QPS = float32(k8sClientRateLimiterQPS)
+	cfg.Burst = k8sClientRateLimiterBurst
+
+	mgr, err := ctrl.NewManager(cfg, ctrl.Options{
 		Scheme: scheme,
 		Metrics: metricsserver.Options{
 			BindAddress: metricsAddr,