Merge pull request #27874 from ingvagabund/kubelet-kernel-tunning-behaviour-new-flags

Automatic merge from submit-queue

[kubelet] Introduce --protect-kernel-defaults flag to make the tunable behaviour configurable

Let's make the default behaviour of kernel tuning configurable. The default behaviour is kept modify as has been so far.

pkg/apis/componentconfig/types.go

@@ -397,6 +397,8 @@ type KubeletConfiguration struct {
 	// Currently only cpu and memory are supported. [default=none]
 	// See http://releases.k8s.io/HEAD/docs/user-guide/compute-resources.md for more detail.
 	KubeReserved utilconfig.ConfigurationMap `json:"kubeReserved"`
+	// Default behaviour for kernel tuning
+	ProtectKernelDefaults bool `json:"protectKernelDefaults"`
 }
 
 type KubeSchedulerConfiguration struct {

pkg/apis/componentconfig/v1alpha1/types.go

@@ -452,4 +452,6 @@ type KubeletConfiguration struct {
 	// Currently only cpu and memory are supported. [default=none]
 	// See http://releases.k8s.io/HEAD/docs/user-guide/compute-resources.md for more detail.
 	KubeReserved map[string]string `json:"kubeReserved"`
+	// Default behaviour for kernel tuning
+	ProtectKernelDefaults bool `json:"protectKernelDefaults"`
 }

pkg/apis/componentconfig/v1alpha1/zz_generated.conversion.go

@@ -319,6 +319,7 @@ func autoConvert_v1alpha1_KubeletConfiguration_To_componentconfig_KubeletConfigu
 	} else {
 		out.KubeReserved = nil
 	}
+	out.ProtectKernelDefaults = in.ProtectKernelDefaults
 	return nil
 }
 
@@ -483,6 +484,7 @@ func autoConvert_componentconfig_KubeletConfiguration_To_v1alpha1_KubeletConfigu
 	} else {
 		out.KubeReserved = nil
 	}
+	out.ProtectKernelDefaults = in.ProtectKernelDefaults
 	return nil
 }
 

pkg/apis/componentconfig/v1alpha1/zz_generated.deepcopy.go

@@ -377,6 +377,7 @@ func DeepCopy_v1alpha1_KubeletConfiguration(in interface{}, out interface{}, c *
 		} else {
 			out.KubeReserved = nil
 		}
+		out.ProtectKernelDefaults = in.ProtectKernelDefaults
 		return nil
 	}
 }

pkg/apis/componentconfig/zz_generated.deepcopy.go

@@ -325,6 +325,7 @@ func DeepCopy_componentconfig_KubeletConfiguration(in interface{}, out interface
 		} else {
 			out.KubeReserved = nil
 		}
+		out.ProtectKernelDefaults = in.ProtectKernelDefaults
 		return nil
 	}
 }

pkg/kubelet/cm/container_manager.go

@@ -39,12 +39,13 @@ type ContainerManager interface {
 }
 
 type NodeConfig struct {
-	RuntimeCgroupsName string
-	SystemCgroupsName  string
-	KubeletCgroupsName string
-	ContainerRuntime   string
-	CgroupsPerQOS      bool
-	CgroupRoot         string
+	RuntimeCgroupsName    string
+	SystemCgroupsName     string
+	KubeletCgroupsName    string
+	ContainerRuntime      string
+	CgroupsPerQOS         bool
+	CgroupRoot            string
+	ProtectKernelDefaults bool
 }
 
 type Status struct {

pkg/kubelet/cm/container_manager_linux.go

@@ -199,7 +199,6 @@ func createManager(containerName string) *fs.Manager {
 	}
 }
 
-// TODO: plumb this up as a flag to Kubelet in a future PR
 type KernelTunableBehavior string
 
 const (
@@ -288,8 +287,11 @@ func (cm *containerManagerImpl) setupNode() error {
 	if !f.cpuHardcapping {
 		cm.status.SoftRequirements = fmt.Errorf("CPU hardcapping unsupported")
 	}
-	// TODO: plumb kernel tunable options into container manager, right now, we modify by default
-	if err := setupKernelTunables(KernelTunableModify); err != nil {
+	b := KernelTunableModify
+	if cm.GetNodeConfig().ProtectKernelDefaults {
+		b = KernelTunableError
+	}
+	if err := setupKernelTunables(b); err != nil {
 		return err
 	}