Clarify CPUCFSQuotaPeriod config vs CustomCPUCFSQuotaPeriod feature gate

CHANGELOG/CHANGELOG-1.26.md

@@ -3718,7 +3718,7 @@ name | architectures
 - Fixes spurious `field is immutable` errors validating updates to Event API objects via the `events.k8s.io/v1` API ([#112183](https://github.com/kubernetes/kubernetes/pull/112183), [@liggitt](https://github.com/liggitt)) [SIG Apps]
 - Protobuf serialization of metav1.MicroTime timestamps (used in `Lease` and `Event` API objects) has been corrected to truncate to microsecond precision, to match the documented behavior and JSON/YAML serialization. Any existing persisted data is truncated to microsecond when read from etcd. ([#111936](https://github.com/kubernetes/kubernetes/pull/111936), [@haoruan](https://github.com/haoruan)) [SIG API Machinery]
 - Revert regression that prevented client-go latency metrics to be reported with a template URL to avoid label cardinality. ([#111752](https://github.com/kubernetes/kubernetes/pull/111752), [@aanm](https://github.com/aanm)) [SIG API Machinery]
-- [kubelet] Change default `cpuCFSQuotaPeriod` value with enabled `cpuCFSQuotaPeriod` flag from 100ms to 100µs to match the Linux CFS and k8s defaults. `cpuCFSQuotaPeriod` of 100ms now requires `customCPUCFSQuotaPeriod` flag to be set to work. ([#111520](https://github.com/kubernetes/kubernetes/pull/111520), [@paskal](https://github.com/paskal)) [SIG API Machinery and Node]
+- [kubelet] Change default `cpuCFSQuotaPeriod` value with enabled `cpuCFSQuotaPeriod` flag from 100ms to 100µs to match the Linux CFS and k8s defaults. `cpuCFSQuotaPeriod` of 100ms now requires `CustomCPUCFSQuotaPeriod` feature gate to be enabled. ([#111520](https://github.com/kubernetes/kubernetes/pull/111520), [@paskal](https://github.com/paskal)) [SIG API Machinery and Node]
 
 ### Feature
 

cmd/kubelet/app/options/options.go

@@ -456,7 +456,9 @@ func AddKubeletConfigFlags(mainfs *pflag.FlagSet, c *kubeletconfig.KubeletConfig
 	fs.BoolVar(&c.RunOnce, "runonce", c.RunOnce, "If true, exit after spawning pods from static pod files or remote urls. Exclusive with --enable-server")
 
 	fs.BoolVar(&c.CPUCFSQuota, "cpu-cfs-quota", c.CPUCFSQuota, "Enable CPU CFS quota enforcement for containers that specify CPU limits")
-	fs.DurationVar(&c.CPUCFSQuotaPeriod.Duration, "cpu-cfs-quota-period", c.CPUCFSQuotaPeriod.Duration, "Sets CPU CFS quota period value, cpu.cfs_period_us, defaults to Linux Kernel default")
+	// fs.DurationVar(&c.CPUCFSQuotaPeriod.Duration, "cpu-cfs-quota-period", c.CPUCFSQuotaPeriod.Duration, "Sets CPU CFS quota period value, cpu.cfs_period_us, defaults to Linux Kernel default")
+	fs.DurationVar(&c.CPUCFSQuotaPeriod.Duration, "cpu-cfs-quota-period", c.CPUCFSQuotaPeriod.Duration, "Sets CPU CFS quota period value (cpu.cfs_period_us). Defaults to Linux Kernel default. "+ "Requires the CustomCPUCFSQuotaPeriod feature gate to set non-default values.")
+
 	fs.BoolVar(&c.EnableControllerAttachDetach, "enable-controller-attach-detach", c.EnableControllerAttachDetach, "Enables the Attach/Detach controller to manage attachment/detachment of volumes scheduled to this node, and disables kubelet from executing any attach/detach operations")
 	fs.BoolVar(&c.MakeIPTablesUtilChains, "make-iptables-util-chains", c.MakeIPTablesUtilChains, "If true, kubelet will ensure iptables utility rules are present on host.")
 	fs.StringVar(&c.ContainerLogMaxSize, "container-log-max-size", c.ContainerLogMaxSize, "<Warning: Beta feature> Set the maximum size (e.g. 10Mi) of container log file before it is rotated.")

pkg/generated/openapi/zz_generated.openapi.go

@@ -71137,7 +71137,7 @@ func schema_k8sio_kubelet_config_v1beta1_KubeletConfiguration(ref common.Referen
 					},
 					"cpuCFSQuotaPeriod": {
 						SchemaProps: spec.SchemaProps{
-							Description: "cpuCFSQuotaPeriod is the CPU CFS quota period value, `cpu.cfs_period_us`. The value must be between 1 ms and 1 second, inclusive. Requires the CustomCPUCFSQuotaPeriod feature gate to be enabled. Default: \"100ms\"",
+							Description: "cpuCFSQuotaPeriod is the CPU CFS quota period value, `cpu.cfs_period_us`. The value must be between 1 ms and 1 second, inclusive. Requires enabling the CustomCPUCFSQuotaPeriod feature gate. Default: \"100ms\"",
 							Ref:         ref("k8s.io/apimachinery/pkg/apis/meta/v1.Duration"),
 						},
 					},

pkg/kubelet/apis/config/types.go

@@ -308,6 +308,7 @@ type KubeletConfiguration struct {
 	// specify CPU limits
 	CPUCFSQuota bool
 	// CPUCFSQuotaPeriod sets the CPU CFS quota period value, cpu.cfs_period_us, defaults to 100ms
+	// Default: "100ms". Changing this value requires enabling the CustomCPUCFSQuotaPeriod feature gate.
 	CPUCFSQuotaPeriod metav1.Duration
 	// maxOpenFiles is Number of files that can be opened by Kubelet process.
 	MaxOpenFiles int64