chore: remove cpu_manager_state on cpuManagerPolicy change

After we closed `kubelet`, remove `/var/lib/kubelet/cpu_manager_state` if there are any changes in `cpuManagerPolicy`.
We do not add any other safeguards, so it's user responsibility to cordon/drain the node in advance.

Also minor fixes in other files.

Closes #7504

Signed-off-by: Dmitriy Matrenichev <dmitry.matrenichev@siderolabs.com>

internal/app/machined/pkg/controllers/k8s/kubelet_service.go

@@ -9,6 +9,7 @@ import (
 	"context"
 	"crypto/x509"
 	"encoding/base64"
+	stdjson "encoding/json"
 	"encoding/pem"
 	"errors"
 	"fmt"
@@ -19,7 +20,10 @@ import (
 
 	"github.com/cosi-project/runtime/pkg/controller"
 	"github.com/cosi-project/runtime/pkg/resource"
+	"github.com/cosi-project/runtime/pkg/safe"
 	"github.com/cosi-project/runtime/pkg/state"
+	"github.com/siderolabs/gen/channel"
+	"github.com/siderolabs/gen/optional"
 	"github.com/siderolabs/go-pointer"
 	"go.uber.org/zap"
 	"k8s.io/apimachinery/pkg/runtime"
@@ -89,10 +93,8 @@ func (ctrl *KubeletServiceController) Run(ctx context.Context, r controller.Runt
 	}
 
 	for {
-		select {
+		if _, ok := channel.RecvWithContext(ctx, r.EventCh()); !ok && ctx.Err() != nil {
-		case <-ctx.Done():
+			return nil //nolint:nilerr
-			return nil
-		case <-r.EventCh():
 		}
 
 		_, err := r.Get(ctx, resource.NewMetadata(files.NamespaceName, files.EtcFileStatusType, "machine-id", resource.VersionUndefined))
@@ -141,13 +143,11 @@ func (ctrl *KubeletServiceController) Run(ctx context.Context, r controller.Runt
 	r.QueueReconcile()
 
 	for {
-		select {
+		if _, ok := channel.RecvWithContext(ctx, r.EventCh()); !ok && ctx.Err() != nil {
-		case <-ctx.Done():
+			return nil //nolint:nilerr
-			return nil
-		case <-r.EventCh():
 		}
 
-		cfg, err := r.Get(ctx, resource.NewMetadata(k8s.NamespaceName, k8s.KubeletSpecType, k8s.KubeletID, resource.VersionUndefined))
+		cfg, err := safe.ReaderGetByID[*k8s.KubeletSpec](ctx, r, k8s.KubeletID)
 		if err != nil {
 			if state.IsNotFoundError(err) {
 				continue
@@ -156,9 +156,9 @@ func (ctrl *KubeletServiceController) Run(ctx context.Context, r controller.Runt
 			return fmt.Errorf("error getting config: %w", err)
 		}
 
-		cfgSpec := cfg.(*k8s.KubeletSpec).TypedSpec()
+		cfgSpec := cfg.TypedSpec()
 
-		secret, err := r.Get(ctx, resource.NewMetadata(secrets.NamespaceName, secrets.KubeletType, secrets.KubeletID, resource.VersionUndefined))
+		secret, err := safe.ReaderGetByID[*secrets.Kubelet](ctx, r, secrets.KubeletID)
 		if err != nil {
 			if state.IsNotFoundError(err) {
 				continue
@@ -167,7 +167,7 @@ func (ctrl *KubeletServiceController) Run(ctx context.Context, r controller.Runt
 			return fmt.Errorf("error getting secrets: %w", err)
 		}
 
-		secretSpec := secret.(*secrets.Kubelet).TypedSpec()
+		secretSpec := secret.TypedSpec()
 
 		if err = ctrl.writePKI(secretSpec); err != nil {
 			return fmt.Errorf("error writing kubelet PKI: %w", err)
@@ -190,17 +190,21 @@ func (ctrl *KubeletServiceController) Run(ctx context.Context, r controller.Runt
 
 		// refresh certs only if we are managing the node name (not overridden by the user)
 		if cfgSpec.ExpectedNodename != "" {
-			err = ctrl.refreshKubeletCerts(logger, cfgSpec.ExpectedNodename)
+			err = ctrl.refreshKubeletCerts(cfgSpec.ExpectedNodename, logger)
 			if err != nil {
 				return err
 			}
 		}
 
+		if err = ctrl.handlePolicyChange(cfgSpec, logger); err != nil {
+			return err
+		}
+
 		if err = ctrl.refreshSelfServingCert(); err != nil {
 			return err
 		}
 
-		if err = ctrl.updateKubeconfig(logger, secretSpec.Endpoint); err != nil {
+		if err = ctrl.updateKubeconfig(secretSpec.Endpoint, logger); err != nil {
 			return err
 		}
 
@@ -212,6 +216,83 @@ func (ctrl *KubeletServiceController) Run(ctx context.Context, r controller.Runt
 	}
 }
 
+// handlePolicyChange handles the cpuManagerPolicy change.
+func (ctrl *KubeletServiceController) handlePolicyChange(cfgSpec *k8s.KubeletSpecSpec, logger *zap.Logger) error {
+	const managerFilename = "/var/lib/kubelet/cpu_manager_state"
+
+	oldPolicy, err := loadPolicyFromFile(managerFilename)
+
+	switch {
+	case errors.Is(err, os.ErrNotExist):
+		return nil // no cpu_manager_state file, nothing to do
+	case err != nil:
+		return fmt.Errorf("error loading cpu_manager_state file: %w", err)
+	}
+
+	policy, err := getFromMap[string](cfgSpec.Config, "cpuManagerPolicy")
+	if err != nil {
+		return err
+	}
+
+	newPolicy := policy.ValueOrZero()
+	if equalPolicy(oldPolicy, newPolicy) {
+		return nil
+	}
+
+	logger.Info("cpuManagerPolicy changed", zap.String("old", oldPolicy), zap.String("new", newPolicy))
+
+	err = os.Remove(managerFilename)
+	if err != nil {
+		return fmt.Errorf("error removing cpu_manager_state file: %w", err)
+	}
+
+	return nil
+}
+
+func loadPolicyFromFile(filename string) (string, error) {
+	raw, err := os.ReadFile(filename)
+	if err != nil {
+		return "", err
+	}
+
+	cpuManagerState := struct {
+		Policy string `json:"policyName"`
+	}{}
+
+	if err = stdjson.Unmarshal(raw, &cpuManagerState); err != nil {
+		return "", err
+	}
+
+	return cpuManagerState.Policy, nil
+}
+
+func equalPolicy(current, newOne string) bool {
+	if current == "none" {
+		current = ""
+	}
+
+	if newOne == "none" {
+		newOne = ""
+	}
+
+	return current == newOne
+}
+
+func getFromMap[T any](m map[string]any, key string) (optional.Optional[T], error) {
+	var zero optional.Optional[T]
+
+	res, ok := m[key]
+	if !ok {
+		return zero, nil
+	}
+
+	if res, ok := res.(T); ok {
+		return optional.Some(res), nil
+	}
+
+	return zero, fmt.Errorf("unexpected type for key %q: found %T, expected %T", key, res, *new(T))
+}
+
 func (ctrl *KubeletServiceController) writePKI(secretSpec *secrets.KubeletSpec) error {
 	cfg := struct {
 		Server               string
@@ -289,7 +370,7 @@ func (ctrl *KubeletServiceController) writeConfig(cfgSpec *k8s.KubeletSpecSpec)
 }
 
 // updateKubeconfig updates the kubeconfig of kubelet with the given endpoint if it exists.
-func (ctrl *KubeletServiceController) updateKubeconfig(logger *zap.Logger, newEndpoint *url.URL) error {
+func (ctrl *KubeletServiceController) updateKubeconfig(newEndpoint *url.URL, logger *zap.Logger) error {
 	config, err := clientcmd.LoadFromFile(constants.KubeletKubeconfig)
 	if errors.Is(err, os.ErrNotExist) {
 		return nil
@@ -328,7 +409,7 @@ func (ctrl *KubeletServiceController) updateKubeconfig(logger *zap.Logger, newEn
 // refreshKubeletCerts checks if the existing kubelet certificates match the node hostname.
 // If they don't match, it clears the certificate directory and the removes kubelet's kubeconfig so that
 // they can be regenerated next time kubelet is started.
-func (ctrl *KubeletServiceController) refreshKubeletCerts(logger *zap.Logger, nodename string) error {
+func (ctrl *KubeletServiceController) refreshKubeletCerts(nodename string, logger *zap.Logger) error {
 	cert, err := ctrl.readKubeletClientCertificate()
 	if err != nil {
 		return err

internal/app/machined/pkg/controllers/k8s/kubelet_spec.go

@@ -12,9 +12,10 @@ import (
 	"time"
 
 	"github.com/cosi-project/runtime/pkg/controller"
-	"github.com/cosi-project/runtime/pkg/resource"
+	"github.com/cosi-project/runtime/pkg/safe"
 	"github.com/cosi-project/runtime/pkg/state"
 	"github.com/hashicorp/go-multierror"
+	"github.com/siderolabs/gen/channel"
 	"github.com/siderolabs/gen/slices"
 	"github.com/siderolabs/go-pointer"
 	"go.uber.org/zap"
@@ -78,13 +79,11 @@ func (ctrl *KubeletSpecController) Outputs() []controller.Output {
 //nolint:gocyclo
 func (ctrl *KubeletSpecController) Run(ctx context.Context, r controller.Runtime, logger *zap.Logger) error {
 	for {
-		select {
+		if _, ok := channel.RecvWithContext(ctx, r.EventCh()); !ok && ctx.Err() != nil {
-		case <-ctx.Done():
+			return nil //nolint:nilerr
-			return nil
-		case <-r.EventCh():
 		}
 
-		cfg, err := r.Get(ctx, resource.NewMetadata(k8s.NamespaceName, k8s.KubeletConfigType, k8s.KubeletID, resource.VersionUndefined))
+		cfg, err := safe.ReaderGetByID[*k8s.KubeletConfig](ctx, r, k8s.KubeletID)
 		if err != nil {
 			if state.IsNotFoundError(err) {
 				continue
@@ -93,9 +92,9 @@ func (ctrl *KubeletSpecController) Run(ctx context.Context, r controller.Runtime
 			return fmt.Errorf("error getting config: %w", err)
 		}
 
-		cfgSpec := cfg.(*k8s.KubeletConfig).TypedSpec()
+		cfgSpec := cfg.TypedSpec()
 
-		nodename, err := r.Get(ctx, resource.NewMetadata(k8s.NamespaceName, k8s.NodenameType, k8s.NodenameID, resource.VersionUndefined))
+		nodename, err := safe.ReaderGetByID[*k8s.Nodename](ctx, r, k8s.NodenameID)
 		if err != nil {
 			if state.IsNotFoundError(err) {
 				continue
@@ -104,9 +103,7 @@ func (ctrl *KubeletSpecController) Run(ctx context.Context, r controller.Runtime
 			return fmt.Errorf("error getting nodename: %w", err)
 		}
 
-		nodenameSpec := nodename.(*k8s.Nodename).TypedSpec()
+		expectedNodename := nodename.TypedSpec().Nodename
-
-		expectedNodename := nodenameSpec.Nodename
 
 		args := argsbuilder.Args{
 			"config": "/etc/kubernetes/kubelet.yaml",
@@ -134,20 +131,16 @@ func (ctrl *KubeletSpecController) Run(ctx context.Context, r controller.Runtime
 
 		// if the user supplied node-ip via extra args, no need to pick automatically
 		if !extraArgs.Contains("node-ip") {
-			var nodeIP resource.Resource
+			nodeIP, nodeErr := safe.ReaderGetByID[*k8s.NodeIP](ctx, r, k8s.KubeletID)
-
+			if nodeErr != nil {
-			nodeIP, err = r.Get(ctx, resource.NewMetadata(k8s.NamespaceName, k8s.NodeIPType, k8s.KubeletID, resource.VersionUndefined))
+				if state.IsNotFoundError(nodeErr) {
-			if err != nil {
-				if state.IsNotFoundError(err) {
 					continue
 				}
 
-				return fmt.Errorf("error getting node IPs: %w", err)
+				return fmt.Errorf("error getting node IPs: %w", nodeErr)
 			}
 
-			nodeIPSpec := nodeIP.(*k8s.NodeIP).TypedSpec()
+			nodeIPsString := slices.Map(nodeIP.TypedSpec().Addresses, netip.Addr.String)
-
-			nodeIPsString := slices.Map(nodeIPSpec.Addresses, netip.Addr.String)
 			args["node-ip"] = strings.Join(nodeIPsString, ",")
 		}
 
@@ -181,11 +174,12 @@ func (ctrl *KubeletSpecController) Run(ctx context.Context, r controller.Runtime
 			return fmt.Errorf("error converting to unstructured: %w", err)
 		}
 
-		if err = r.Modify(
+		if err = safe.WriterModify(
 			ctx,
+			r,
 			k8s.NewKubeletSpec(k8s.NamespaceName, k8s.KubeletID),
-			func(r resource.Resource) error {
+			func(r *k8s.KubeletSpec) error {
-				kubeletSpec := r.(*k8s.KubeletSpec).TypedSpec()
+				kubeletSpec := r.TypedSpec()
 
 				kubeletSpec.Image = cfgSpec.Image
 				kubeletSpec.ExtraMounts = cfgSpec.ExtraMounts

internal/app/machined/pkg/system/system.go

@@ -54,8 +54,8 @@ func Services(runtime runtime.Runtime) *singleton {
 	once.Do(func() {
 		instance = &singleton{
 			runtime: runtime,
-			state:   make(map[string]*ServiceRunner),
+			state:   map[string]*ServiceRunner{},
-			running: make(map[string]struct{}),
+			running: map[string]struct{}{},
 		}
 	})
 
@@ -102,7 +102,7 @@ func (s *singleton) Unload(ctx context.Context, serviceIDs ...string) error {
 		return nil
 	}
 
-	servicesToRemove := []string{}
+	servicesToRemove := make([]string, 0, len(serviceIDs))
 
 	for _, id := range serviceIDs {
 		if _, exists := s.state[id]; exists {
@@ -264,7 +264,7 @@ func (s *singleton) StopWithRevDepenencies(ctx context.Context, serviceIDs ...st
 
 //nolint:gocyclo
 func (s *singleton) stopServices(ctx context.Context, services []string, waitForRevDependencies bool) error {
-	servicesToStop := make(map[string]*ServiceRunner)
+	servicesToStop := map[string]*ServiceRunner{}
 
 	if services == nil {
 		for name, svcrunner := range s.state {
@@ -282,7 +282,7 @@ func (s *singleton) stopServices(ctx context.Context, services []string, waitFor
 
 	// build reverse dependencies, and expand the list of services to stop
 	// with services which depend on the one being stopped
-	reverseDependencies := make(map[string][]string)
+	reverseDependencies := map[string][]string{}
 
 	if waitForRevDependencies {
 		// expand the list of services to stop with the list of services which depend
@@ -342,7 +342,7 @@ func (s *singleton) stopServices(ctx context.Context, services []string, waitFor
 	shutdownCtx, shutdownCtxCancel := context.WithTimeout(ctx, 30*time.Second)
 	defer shutdownCtxCancel()
 
-	stoppedConds := []conditions.Condition{}
+	stoppedConds := make([]conditions.Condition, 0, len(servicesToStop))
 
 	for name, svcrunner := range servicesToStop {
 		shutdownWg.Add(1)

pkg/machinery/resources/k8s/deep_copy.generated.go

@@ -224,7 +224,7 @@ func (o KubeletSpecSpec) DeepCopy() KubeletSpecSpec {
 		}
 	}
 	if o.Config != nil {
-		cp.Config = make(map[string]interface{}, len(o.Config))
+		cp.Config = make(map[string]any, len(o.Config))
 		for k2, v2 := range o.Config {
 			cp.Config[k2] = v2
 		}
@@ -302,7 +302,7 @@ func (o KubeletConfigSpec) DeepCopy() KubeletConfigSpec {
 		}
 	}
 	if o.ExtraConfig != nil {
-		cp.ExtraConfig = make(map[string]interface{}, len(o.ExtraConfig))
+		cp.ExtraConfig = make(map[string]any, len(o.ExtraConfig))
 		for k2, v2 := range o.ExtraConfig {
 			cp.ExtraConfig[k2] = v2
 		}

pkg/machinery/resources/k8s/kubelet_config.go

@@ -27,18 +27,18 @@ type KubeletConfig = typed.Resource[KubeletConfigSpec, KubeletConfigExtension]
 //
 //gotagsrewrite:gen
 type KubeletConfigSpec struct {
-	Image                        string                 `yaml:"image" protobuf:"1"`
+	Image                        string            `yaml:"image" protobuf:"1"`
-	ClusterDNS                   []string               `yaml:"clusterDNS" protobuf:"2"`
+	ClusterDNS                   []string          `yaml:"clusterDNS" protobuf:"2"`
-	ClusterDomain                string                 `yaml:"clusterDomain" protobuf:"3"`
+	ClusterDomain                string            `yaml:"clusterDomain" protobuf:"3"`
-	ExtraArgs                    map[string]string      `yaml:"extraArgs,omitempty" protobuf:"4"`
+	ExtraArgs                    map[string]string `yaml:"extraArgs,omitempty" protobuf:"4"`
-	ExtraMounts                  []specs.Mount          `yaml:"extraMounts,omitempty" protobuf:"5"`
+	ExtraMounts                  []specs.Mount     `yaml:"extraMounts,omitempty" protobuf:"5"`
-	ExtraConfig                  map[string]interface{} `yaml:"extraConfig,omitempty" protobuf:"6"`
+	ExtraConfig                  map[string]any    `yaml:"extraConfig,omitempty" protobuf:"6"`
-	CloudProviderExternal        bool                   `yaml:"cloudProviderExternal" protobuf:"7"`
+	CloudProviderExternal        bool              `yaml:"cloudProviderExternal" protobuf:"7"`
-	DefaultRuntimeSeccompEnabled bool                   `yaml:"defaultRuntimeSeccompEnabled" protobuf:"8"`
+	DefaultRuntimeSeccompEnabled bool              `yaml:"defaultRuntimeSeccompEnabled" protobuf:"8"`
-	SkipNodeRegistration         bool                   `yaml:"skipNodeRegistration" protobuf:"9"`
+	SkipNodeRegistration         bool              `yaml:"skipNodeRegistration" protobuf:"9"`
-	StaticPodListURL             string                 `yaml:"staticPodListURL" protobuf:"10"`
+	StaticPodListURL             string            `yaml:"staticPodListURL" protobuf:"10"`
-	DisableManifestsDirectory    bool                   `yaml:"disableManifestsDirectory" protobuf:"11"`
+	DisableManifestsDirectory    bool              `yaml:"disableManifestsDirectory" protobuf:"11"`
-	EnableFSQuotaMonitoring      bool                   `yaml:"enableFSQuotaMonitoring" protobuf:"12"`
+	EnableFSQuotaMonitoring      bool              `yaml:"enableFSQuotaMonitoring" protobuf:"12"`
 }
 
 // NewKubeletConfig initializes an empty KubeletConfig resource.

pkg/machinery/resources/k8s/kubelet_spec.go

@@ -24,11 +24,11 @@ type KubeletSpec = typed.Resource[KubeletSpecSpec, KubeletSpecExtension]
 //
 //gotagsrewrite:gen
 type KubeletSpecSpec struct {
-	Image            string                 `yaml:"image" protobuf:"1"`
+	Image            string         `yaml:"image" protobuf:"1"`
-	Args             []string               `yaml:"args,omitempty" protobuf:"2"`
+	Args             []string       `yaml:"args,omitempty" protobuf:"2"`
-	ExtraMounts      []specs.Mount          `yaml:"extraMounts,omitempty" protobuf:"3"`
+	ExtraMounts      []specs.Mount  `yaml:"extraMounts,omitempty" protobuf:"3"`
-	ExpectedNodename string                 `yaml:"expectedNodename,omitempty" protobuf:"4"`
+	ExpectedNodename string         `yaml:"expectedNodename,omitempty" protobuf:"4"`
-	Config           map[string]interface{} `yaml:"config" protobuf:"5"`
+	Config           map[string]any `yaml:"config" protobuf:"5"`
 }
 
 // NewKubeletSpec initializes an empty KubeletSpec resource.