From c25d4ea107bc40f75f801fe20cdcb9ca33ee68c0 Mon Sep 17 00:00:00 2001
From: Pierangelo Di Pilato <pierangelodipilato@gmail.com>
Date: Tue, 6 Oct 2020 09:33:16 +0200
Subject: [PATCH] Allow override QPS and Burst via flag.

Add `--kube-api-qps` and `--kube-api-burst` command-line flags
to control client QPS and Burst respectively.

The default value is set to 0 to keep backward compatibility.

Signed-off-by: Pierangelo Di Pilato <pierangelodipilato@gmail.com>
---
 injection/sharedmain/main.go | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/injection/sharedmain/main.go b/injection/sharedmain/main.go
index 33d45391e2..dcd8dc33b3 100644
--- a/injection/sharedmain/main.go
+++ b/injection/sharedmain/main.go
@@ -21,6 +21,7 @@ import (
 	"errors"
 	"flag"
 	"log"
+	"math"
 	"net/http"
 	"os"
 	"os/user"
@@ -323,6 +324,9 @@ func ParseAndGetConfigOrDie() *rest.Config {
 			"The address of the Kubernetes API server. Overrides any value in kubeconfig. Only required if out-of-cluster.")
 		kubeconfig = flag.String("kubeconfig", "",
 			"Path to a kubeconfig. Only required if out-of-cluster.")
+
+		burst = flag.Int("kube-api-burst", 0, "Maximum burst for throttle.")
+		qps   = flag.Float64("kube-api-qps", 0, "Maximum QPS to the server from the client.")
 	)
 	klog.InitFlags(flag.CommandLine)
 	flag.Parse()
@@ -332,9 +336,27 @@ func ParseAndGetConfigOrDie() *rest.Config {
 		log.Fatal("Error building kubeconfig: ", err)
 	}
 
+	validBurstOrDie(*burst)
+	validQPSOrDie(*qps)
+
+	cfg.Burst = *burst
+	cfg.QPS = float32(*qps)
+
 	return cfg
 }
 
+func validBurstOrDie(burst int) {
+	if burst < 0 {
+		log.Fatal("Invalid burst value", burst)
+	}
+}
+
+func validQPSOrDie(qps float64) {
+	if qps < 0 || qps > math.MaxFloat32 {
+		log.Fatal("Invalid QPS value", qps)
+	}
+}
+
 // MemStatsOrDie sets up reporting on Go memory usage every 30 seconds or dies
 // by calling log.Fatalf.
 func MemStatsOrDie(ctx context.Context) {