From 0b4716c909cf813dcd9c9b39cbaa7221d08e07e1 Mon Sep 17 00:00:00 2001
From: Justin Kulikauskas <jkulikau@redhat.com>
Date: Thu, 20 Apr 2023 16:54:12 -0400
Subject: [PATCH] Add flags for client QPS and burst configuration

The recommended settings are 1:15:20 for concurrency:qps:burst. But they
should be independently configurable here. A higher-level controller
like a helm chart or addon-controller should make it simpler to adjust
these all at once in a supported way, while still allowing for full
overrides.

Refs:
 - https://issues.redhat.com/browse/ACM-4297

Signed-off-by: Justin Kulikauskas <jkulikau@redhat.com>
---
 deploy/manager/manager.yaml |  2 ++
 deploy/operator.yaml        |  2 ++
 main.go                     | 19 +++++++++++++++++++
 3 files changed, 23 insertions(+)

diff --git a/deploy/manager/manager.yaml b/deploy/manager/manager.yaml
index 7c295638..4bca795a 100644
--- a/deploy/manager/manager.yaml
+++ b/deploy/manager/manager.yaml
@@ -24,6 +24,8 @@ spec:
             - "--enable-lease=true"
             - "--log-level=2"
             - "--v=0"
+            - "--client-max-qps=35"
+            - "--client-burst=50"
           imagePullPolicy: Always
           env:
             - name: WATCH_NAMESPACE
diff --git a/deploy/operator.yaml b/deploy/operator.yaml
index 9fa9a025..fcb312cf 100644
--- a/deploy/operator.yaml
+++ b/deploy/operator.yaml
@@ -49,6 +49,8 @@ spec:
         - --enable-lease=true
         - --log-level=2
         - --v=0
+        - --client-max-qps=35
+        - --client-burst=50
         command:
         - config-policy-controller
         env:
diff --git a/main.go b/main.go
index c3f57123..ce95a6e4 100644
--- a/main.go
+++ b/main.go
@@ -73,6 +73,8 @@ type ctrlOpts struct {
 	targetKubeConfig      string
 	metricsAddr           string
 	probeAddr             string
+	clientQPS             float32
+	clientBurst           uint
 	frequency             uint
 	decryptionConcurrency uint8
 	evaluationConcurrency uint8
@@ -152,6 +154,9 @@ func main() {
 		os.Exit(1)
 	}
 
+	cfg.Burst = int(opts.clientBurst)
+	cfg.QPS = opts.clientQPS
+
 	// Set a field selector so that a watch on CRDs will be limited to just the configuration policy CRD.
 	cacheSelectors := cache.SelectorsByObject{
 		&extensionsv1.CustomResourceDefinition{}: {
@@ -514,5 +519,19 @@ func setupOpts(flags *pflag.FlagSet) *ctrlOpts {
 		"Disable custom metrics collection",
 	)
 
+	flags.Float32Var(
+		&opts.clientQPS,
+		"client-max-qps",
+		30, // 15 * concurrency is recommended
+		"The max queries per second that will be made against the kubernetes API server.",
+	)
+
+	flags.UintVar(
+		&opts.clientBurst,
+		"client-burst",
+		45, // the controller-runtime defaults are 20:30 (qps:burst) - this matches that ratio
+		"The maximum burst before client requests will be throttled.",
+	)
+
 	return opts
 }