From 4afa554f6555620991c9cc41c45391485cc66aa2 Mon Sep 17 00:00:00 2001
From: Antoni Zawodny <zawodny@google.com>
Date: Wed, 30 Oct 2024 11:11:27 +0100
Subject: [PATCH] Add `--concurrent-daemonset-syncs` flag to
 kube-controller-manager

---
 .../app/options/daemonsetcontroller.go               |  7 +++++++
 .../app/options/options_test.go                      | 12 ++++++++++--
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/cmd/kube-controller-manager/app/options/daemonsetcontroller.go b/cmd/kube-controller-manager/app/options/daemonsetcontroller.go
index 8506f8ec05c..0f7c9e98cde 100644
--- a/cmd/kube-controller-manager/app/options/daemonsetcontroller.go
+++ b/cmd/kube-controller-manager/app/options/daemonsetcontroller.go
@@ -17,6 +17,8 @@ limitations under the License.
 package options
 
 import (
+	"fmt"
+
 	"github.com/spf13/pflag"
 
 	daemonconfig "k8s.io/kubernetes/pkg/controller/daemon/config"
@@ -32,6 +34,8 @@ func (o *DaemonSetControllerOptions) AddFlags(fs *pflag.FlagSet) {
 	if o == nil {
 		return
 	}
+
+	fs.Int32Var(&o.ConcurrentDaemonSetSyncs, "concurrent-daemonset-syncs", o.ConcurrentDaemonSetSyncs, "The number of daemonset objects that are allowed to sync concurrently. Larger number = more responsive daemonsets, but more CPU (and network) load")
 }
 
 // ApplyTo fills up DaemonSetController config with options.
@@ -52,5 +56,8 @@ func (o *DaemonSetControllerOptions) Validate() []error {
 	}
 
 	errs := []error{}
+	if o.ConcurrentDaemonSetSyncs < 1 {
+		errs = append(errs, fmt.Errorf("concurrent-daemonset-syncs must be greater than 0, but got %d", o.ConcurrentDaemonSetSyncs))
+	}
 	return errs
 }
diff --git a/cmd/kube-controller-manager/app/options/options_test.go b/cmd/kube-controller-manager/app/options/options_test.go
index 8dd14340811..c2235a9c082 100644
--- a/cmd/kube-controller-manager/app/options/options_test.go
+++ b/cmd/kube-controller-manager/app/options/options_test.go
@@ -98,6 +98,7 @@ var args = []string{
 	"--cluster-signing-legacy-unknown-cert-file=/cluster-signing-legacy-unknown/cert-file",
 	"--cluster-signing-legacy-unknown-key-file=/cluster-signing-legacy-unknown/key-file",
 	"--concurrent-deployment-syncs=10",
+	"--concurrent-daemonset-syncs=10",
 	"--concurrent-horizontal-pod-autoscaler-syncs=10",
 	"--concurrent-statefulset-syncs=15",
 	"--concurrent-endpoint-syncs=10",
@@ -264,7 +265,7 @@ func TestAddFlags(t *testing.T) {
 		},
 		DaemonSetController: &DaemonSetControllerOptions{
 			&daemonconfig.DaemonSetControllerConfiguration{
-				ConcurrentDaemonSetSyncs: 2,
+				ConcurrentDaemonSetSyncs: 10,
 			},
 		},
 		DeploymentController: &DeploymentControllerOptions{
@@ -514,6 +515,13 @@ func TestValidateFlags(t *testing.T) {
 			},
 			wantErr: true,
 		},
+		{
+			name: "concurrent daemonset syncs set to 0",
+			flags: []string{
+				"--concurrent-daemonset-syncs=0",
+			},
+			wantErr: true,
+		},
 	}
 
 	for _, tc := range testcases {
@@ -609,7 +617,7 @@ func TestApplyTo(t *testing.T) {
 				},
 			},
 			DaemonSetController: daemonconfig.DaemonSetControllerConfiguration{
-				ConcurrentDaemonSetSyncs: 2,
+				ConcurrentDaemonSetSyncs: 10,
 			},
 			DeploymentController: deploymentconfig.DeploymentControllerConfiguration{
 				ConcurrentDeploymentSyncs: 10,