Merge pull request #129620 from neolit123/1.33-update-all-cp-components-check

kubeadm: graduate WaitForAllControlPlaneComponents to Beta

cmd/kubeadm/app/cmd/phases/init/waitcontrolplane.go

@@ -25,14 +25,17 @@ import (
 	"github.com/lithammer/dedent"
 	"github.com/pkg/errors"
 
+	v1 "k8s.io/api/core/v1"
 	clientset "k8s.io/client-go/kubernetes"
 	kubeletconfig "k8s.io/kubelet/config/v1beta1"
 
 	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/phases/workflow"
 	"k8s.io/kubernetes/cmd/kubeadm/app/componentconfigs"
+	"k8s.io/kubernetes/cmd/kubeadm/app/constants"
 	"k8s.io/kubernetes/cmd/kubeadm/app/features"
 	"k8s.io/kubernetes/cmd/kubeadm/app/util/apiclient"
 	dryrunutil "k8s.io/kubernetes/cmd/kubeadm/app/util/dryrun"
+	staticpodutil "k8s.io/kubernetes/cmd/kubeadm/app/util/staticpod"
 )
 
 var (
@@ -122,10 +125,15 @@ func runWaitControlPlanePhase(c workflow.RunData) error {
 		return handleError(err)
 	}
 
+	var podMap map[string]*v1.Pod
 	waiter.SetTimeout(data.Cfg().Timeouts.ControlPlaneComponentHealthCheck.Duration)
 	if features.Enabled(data.Cfg().ClusterConfiguration.FeatureGates, features.WaitForAllControlPlaneComponents) {
-		err = waiter.WaitForControlPlaneComponents(&data.Cfg().ClusterConfiguration,
+		podMap, err = staticpodutil.ReadMultipleStaticPodsFromDisk(data.ManifestDir(),
-			data.Cfg().LocalAPIEndpoint.AdvertiseAddress)
+			constants.ControlPlaneComponents...)
+		if err == nil {
+			err = waiter.WaitForControlPlaneComponents(podMap,
+				data.Cfg().LocalAPIEndpoint.AdvertiseAddress)
+		}
 	} else {
 		err = waiter.WaitForAPI()
 	}

cmd/kubeadm/app/cmd/phases/join/waitcontrolplane.go

@@ -26,9 +26,11 @@ import (
 	"k8s.io/klog/v2"
 
 	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/phases/workflow"
+	"k8s.io/kubernetes/cmd/kubeadm/app/constants"
 	"k8s.io/kubernetes/cmd/kubeadm/app/features"
 	"k8s.io/kubernetes/cmd/kubeadm/app/util/apiclient"
 	dryrunutil "k8s.io/kubernetes/cmd/kubeadm/app/util/dryrun"
+	staticpodutil "k8s.io/kubernetes/cmd/kubeadm/app/util/staticpod"
 )
 
 // NewWaitControlPlanePhase is a hidden phase that runs after the control-plane and etcd phases
@@ -71,7 +73,12 @@ func runWaitControlPlanePhase(c workflow.RunData) error {
 	}
 
 	waiter.SetTimeout(data.Cfg().Timeouts.ControlPlaneComponentHealthCheck.Duration)
-	if err := waiter.WaitForControlPlaneComponents(&initCfg.ClusterConfiguration,
+	pods, err := staticpodutil.ReadMultipleStaticPodsFromDisk(data.ManifestDir(),
+		constants.ControlPlaneComponents...)
+	if err != nil {
+		return err
+	}
+	if err = waiter.WaitForControlPlaneComponents(pods,
 		data.Cfg().ControlPlane.LocalAPIEndpoint.AdvertiseAddress); err != nil {
 		return err
 	}

cmd/kubeadm/app/features/features.go

@@ -53,7 +53,7 @@ var InitFeatureGates = FeatureList{
 		DeprecationMessage: "Deprecated in favor of the core kubelet feature UserNamespacesSupport which is beta since 1.30." +
 			" Once UserNamespacesSupport graduates to GA, kubeadm will start using it and RootlessControlPlane will be removed.",
 	},
-	WaitForAllControlPlaneComponents: {FeatureSpec: featuregate.FeatureSpec{Default: false, PreRelease: featuregate.Alpha}},
+	WaitForAllControlPlaneComponents: {FeatureSpec: featuregate.FeatureSpec{Default: true, PreRelease: featuregate.Beta}},
 	ControlPlaneKubeletLocalMode:     {FeatureSpec: featuregate.FeatureSpec{Default: false, PreRelease: featuregate.Alpha}},
 	NodeLocalCRISocket:               {FeatureSpec: featuregate.FeatureSpec{Default: false, PreRelease: featuregate.Alpha}},
 }

cmd/kubeadm/app/phases/upgrade/staticpods_test.go

@@ -30,6 +30,7 @@ import (
 	"github.com/pkg/errors"
 	"go.etcd.io/etcd/client/pkg/v3/transport"
 
+	v1 "k8s.io/api/core/v1"
 	"k8s.io/client-go/tools/clientcmd"
 	certutil "k8s.io/client-go/util/cert"
 
@@ -99,7 +100,7 @@ func NewFakeStaticPodWaiter(errsToReturn map[string]error) apiclient.Waiter {
 }
 
 // WaitForControlPlaneComponents just returns a dummy nil, to indicate that the program should just proceed
-func (w *fakeWaiter) WaitForControlPlaneComponents(cfg *kubeadmapi.ClusterConfiguration, apiServerAddress string) error {
+func (w *fakeWaiter) WaitForControlPlaneComponents(podsMap map[string]*v1.Pod, apiServerAddress string) error {
 	return nil
 }
 

cmd/kubeadm/app/util/apiclient/wait.go

@@ -23,6 +23,7 @@ import (
 	"io"
 	"net"
 	"net/http"
+	"strings"
 	"time"
 
 	"github.com/pkg/errors"
@@ -34,14 +35,27 @@ import (
 	"k8s.io/apimachinery/pkg/util/wait"
 	clientset "k8s.io/client-go/kubernetes"
 
-	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
 	"k8s.io/kubernetes/cmd/kubeadm/app/constants"
 )
 
+const (
+	// TODO: switch to /livez once all components support it
+	// and delete the endpointHealthz constant.
+	// https://github.com/kubernetes/kubernetes/issues/118158
+	endpointHealthz = "healthz"
+	endpointLivez   = "livez"
+
+	argPort        = "secure-port"
+	argBindAddress = "bind-address"
+	// By default, for kube-api-server, kubeadm does not apply a --bind-address flag.
+	// Check --advertise-address instead.
+	argAdvertiseAddress = "advertise-address"
+)
+
 // Waiter is an interface for waiting for criteria in Kubernetes to happen
 type Waiter interface {
 	// WaitForControlPlaneComponents waits for all control plane components to be ready.
-	WaitForControlPlaneComponents(cfg *kubeadmapi.ClusterConfiguration, apiServerAddress string) error
+	WaitForControlPlaneComponents(podMap map[string]*v1.Pod, apiServerAddress string) error
 	// WaitForAPI waits for the API Server's /healthz endpoint to become "ok"
 	// TODO: remove WaitForAPI once WaitForAllControlPlaneComponents goes GA:
 	// https://github.com/kubernetes/kubeadm/issues/2907
@@ -77,80 +91,147 @@ func NewKubeWaiter(client clientset.Interface, timeout time.Duration, writer io.
 	}
 }
 
+// controlPlaneComponent holds a component name and an URL
+// on which to perform health checks.
 type controlPlaneComponent struct {
 	name string
 	url  string
 }
 
-const (
+// getControlPlaneComponentAddressAndPort parses the command in a static Pod
-	// TODO: switch to /livez once all components support it
+// container and extracts the values of the given args.
-	// and delete the endpointHealthz constant.
+func getControlPlaneComponentAddressAndPort(pod *v1.Pod, name string, args []string) ([]string, error) {
-	// https://github.com/kubernetes/kubernetes/issues/118158
+	var (
-	endpointHealthz = "healthz"
+		values    = make([]string, len(args))
-	endpointLivez   = "livez"
+		container *v1.Container
-)
-
-// getControlPlaneComponents takes a ClusterConfiguration and returns a slice of
-// control plane components and their health check URLs.
-func getControlPlaneComponents(cfg *kubeadmapi.ClusterConfiguration, defaultAddressAPIServer string) []controlPlaneComponent {
-	const (
-		portArg        = "secure-port"
-		bindAddressArg = "bind-address"
-		// By default, for kube-api-server, kubeadm does not apply a --bind-address flag.
-		// Check --advertise-address instead, which can override the defaultAddressAPIServer value.
-		advertiseAddressArg = "advertise-address"
-		// By default kubeadm deploys the kube-controller-manager and kube-scheduler
-		// with --bind-address=127.0.0.1. This should match get{Scheduler|ControllerManager}Command().
-		defaultAddressKCM       = "127.0.0.1"
-		defaultAddressScheduler = "127.0.0.1"
 	)
 
-	portAPIServer, idx := kubeadmapi.GetArgValue(cfg.APIServer.ExtraArgs, portArg, -1)
+	if pod == nil {
-	if idx == -1 {
+		return values, errors.Errorf("got nil Pod for component %q", name)
+	}
+
+	for i, c := range pod.Spec.Containers {
+		if len(c.Command) == 0 {
+			continue
+		}
+		if c.Command[0] == name {
+			container = &pod.Spec.Containers[i]
+			break
+		}
+	}
+	if container == nil {
+		return values, errors.Errorf("the Pod has no container command starting with %q", name)
+	}
+
+	for _, line := range container.Command {
+		for i, arg := range args {
+			line = strings.TrimSpace(line)
+			if !strings.HasPrefix(line, "--"+arg) && !strings.HasPrefix(line, "-"+arg) {
+				continue
+			}
+			_, value, found := strings.Cut(line, "=")
+			if !found {
+				_, value, _ = strings.Cut(line, " ")
+			}
+			values[i] = value
+		}
+	}
+	return values, nil
+}
+
+// getControlPlaneComponents reads the static Pods of control plane components
+// and returns a slice of 'controlPlaneComponent'.
+func getControlPlaneComponents(podMap map[string]*v1.Pod, addressAPIServer string) ([]controlPlaneComponent, error) {
+	var (
+		// By default kubeadm deploys the kube-controller-manager and kube-scheduler
+		// with --bind-address=127.0.0.1. This should match get{Scheduler|ControllerManager}Command().
+		addressKCM       = "127.0.0.1"
+		addressScheduler = "127.0.0.1"
+
 		portAPIServer = fmt.Sprintf("%d", constants.KubeAPIServerPort)
-	}
+		portKCM       = fmt.Sprintf("%d", constants.KubeControllerManagerPort)
-	portKCM, idx := kubeadmapi.GetArgValue(cfg.ControllerManager.ExtraArgs, portArg, -1)
-	if idx == -1 {
-		portKCM = fmt.Sprintf("%d", constants.KubeControllerManagerPort)
-	}
-	portScheduler, idx := kubeadmapi.GetArgValue(cfg.Scheduler.ExtraArgs, portArg, -1)
-	if idx == -1 {
 		portScheduler = fmt.Sprintf("%d", constants.KubeSchedulerPort)
+
+		errs   []error
+		result []controlPlaneComponent
+	)
+
+	type componentConfig struct {
+		name        string
+		podKey      string
+		args        []string
+		defaultAddr string
+		defaultPort string
+		endpoint    string
 	}
 
-	addressAPIServer, idx := kubeadmapi.GetArgValue(cfg.APIServer.ExtraArgs, advertiseAddressArg, -1)
+	components := []componentConfig{
-	if idx == -1 {
+		{
-		addressAPIServer = defaultAddressAPIServer
+			name:        "kube-apiserver",
-	}
+			podKey:      constants.KubeAPIServer,
-	addressKCM, idx := kubeadmapi.GetArgValue(cfg.ControllerManager.ExtraArgs, bindAddressArg, -1)
+			args:        []string{argAdvertiseAddress, argPort},
-	if idx == -1 {
+			defaultAddr: addressAPIServer,
-		addressKCM = defaultAddressKCM
+			defaultPort: portAPIServer,
-	}
+			endpoint:    endpointLivez,
-	addressScheduler, idx := kubeadmapi.GetArgValue(cfg.Scheduler.ExtraArgs, bindAddressArg, -1)
+		},
-	if idx == -1 {
+		{
-		addressScheduler = defaultAddressScheduler
+			name:        "kube-controller-manager",
+			podKey:      constants.KubeControllerManager,
+			args:        []string{argBindAddress, argPort},
+			defaultAddr: addressKCM,
+			defaultPort: portKCM,
+			endpoint:    endpointHealthz,
+		},
+		{
+			name:        "kube-scheduler",
+			podKey:      constants.KubeScheduler,
+			args:        []string{argBindAddress, argPort},
+			defaultAddr: addressScheduler,
+			defaultPort: portScheduler,
+			endpoint:    endpointLivez,
+		},
 	}
 
-	getURL := func(address, port, endpoint string) string {
+	for _, component := range components {
-		return fmt.Sprintf(
+		address, port := component.defaultAddr, component.defaultPort
-			"https://%s/%s",
+
-			net.JoinHostPort(address, port),
+		values, err := getControlPlaneComponentAddressAndPort(
-			endpoint,
+			podMap[component.podKey],
+			component.podKey,
+			component.args,
 		)
+		if err != nil {
+			errs = append(errs, err)
+		}
+
+		if len(values[0]) != 0 {
+			address = values[0]
+		}
+		if len(values[1]) != 0 {
+			port = values[1]
+		}
+
+		result = append(result, controlPlaneComponent{
+			name: component.name,
+			url:  fmt.Sprintf("https://%s/%s", net.JoinHostPort(address, port), component.endpoint),
+		})
 	}
-	return []controlPlaneComponent{
+
-		{name: "kube-apiserver", url: getURL(addressAPIServer, portAPIServer, endpointLivez)},
+	if len(errs) > 0 {
-		{name: "kube-controller-manager", url: getURL(addressKCM, portKCM, endpointHealthz)},
+		return nil, utilerrors.NewAggregate(errs)
-		{name: "kube-scheduler", url: getURL(addressScheduler, portScheduler, endpointLivez)},
 	}
+	return result, nil
 }
 
 // WaitForControlPlaneComponents waits for all control plane components to report "ok".
-func (w *KubeWaiter) WaitForControlPlaneComponents(cfg *kubeadmapi.ClusterConfiguration, apiSeverAddress string) error {
+func (w *KubeWaiter) WaitForControlPlaneComponents(podMap map[string]*v1.Pod, apiSeverAddress string) error {
 	fmt.Printf("[control-plane-check] Waiting for healthy control plane components."+
 		" This can take up to %v\n", w.timeout)
 
-	components := getControlPlaneComponents(cfg, apiSeverAddress)
+	components, err := getControlPlaneComponents(podMap, apiSeverAddress)
+	if err != nil {
+		return errors.Wrap(err, "could not parse the address and port of all control plane components")
+	}
 
 	var errs []error
 	errChan := make(chan error, len(components))

cmd/kubeadm/app/util/apiclient/wait_test.go

@@ -21,38 +21,56 @@ import (
 	"reflect"
 	"testing"
 
-	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
+	v1 "k8s.io/api/core/v1"
+
+	"k8s.io/kubernetes/cmd/kubeadm/app/constants"
 )
 
 func TestGetControlPlaneComponents(t *testing.T) {
-	testcases := []struct {
+	getTestPod := func(command []string) *v1.Pod {
-		name     string
+		pod := &v1.Pod{
-		cfg      *kubeadmapi.ClusterConfiguration
+			Spec: v1.PodSpec{},
-		expected []controlPlaneComponent
+		}
+		if command != nil {
+			pod.Spec.Containers = []v1.Container{{}}
+			if len(command) > 0 {
+				pod.Spec.Containers[0].Command = command
+			}
+		}
+		return pod
+	}
+	testCases := []struct {
+		name          string
+		setup         func() map[string]*v1.Pod
+		expected      []controlPlaneComponent
+		expectedError string
 	}{
 		{
-			name: "port and addresses from config",
+			name: "valid: all port and addresses from config",
-			cfg: &kubeadmapi.ClusterConfiguration{
+			setup: func() map[string]*v1.Pod {
-				APIServer: kubeadmapi.APIServer{
+				var (
-					ControlPlaneComponent: kubeadmapi.ControlPlaneComponent{
+					pod    *v1.Pod
-						ExtraArgs: []kubeadmapi.Arg{
+					podMap = map[string]*v1.Pod{}
-							{Name: "secure-port", Value: "1111"},
+				)
-							{Name: "advertise-address", Value: "fd00:1::"},
+				pod = getTestPod([]string{
-						},
+					constants.KubeAPIServer,
-					},
+					fmt.Sprintf("--%s=%s", argAdvertiseAddress, "fd00:1::"),
-				},
+					fmt.Sprintf("--%s=%s", argPort, "1111"),
-				ControllerManager: kubeadmapi.ControlPlaneComponent{
+				})
-					ExtraArgs: []kubeadmapi.Arg{
+				podMap[constants.KubeAPIServer] = pod
-						{Name: "secure-port", Value: "2222"},
+				pod = getTestPod([]string{
-						{Name: "bind-address", Value: "127.0.0.1"},
+					constants.KubeControllerManager,
-					},
+					fmt.Sprintf("--%s=%s", argBindAddress, "127.0.0.1"),
-				},
+					fmt.Sprintf("--%s=%s", argPort, "2222"),
-				Scheduler: kubeadmapi.ControlPlaneComponent{
+				})
-					ExtraArgs: []kubeadmapi.Arg{
+				podMap[constants.KubeControllerManager] = pod
-						{Name: "secure-port", Value: "3333"},
+				pod = getTestPod([]string{
-						{Name: "bind-address", Value: "127.0.0.1"},
+					constants.KubeScheduler,
-					},
+					fmt.Sprintf("--%s=%s", argBindAddress, "127.0.0.1"),
-				},
+					fmt.Sprintf("--%s=%s", argPort, "3333"),
+				})
+				podMap[constants.KubeScheduler] = pod
+				return podMap
 			},
 			expected: []controlPlaneComponent{
 				{name: "kube-apiserver", url: fmt.Sprintf("https://[fd00:1::]:1111/%s", endpointLivez)},
@@ -61,19 +79,115 @@ func TestGetControlPlaneComponents(t *testing.T) {
 			},
 		},
 		{
-			name: "default ports and addresses",
+			name: "valid: all port and addresses from config (alt. formatting)",
-			cfg:  &kubeadmapi.ClusterConfiguration{},
+			setup: func() map[string]*v1.Pod {
+				var (
+					pod    *v1.Pod
+					podMap = map[string]*v1.Pod{}
+				)
+				pod = getTestPod([]string{
+					constants.KubeAPIServer,
+					fmt.Sprintf("-%s=%s", argAdvertiseAddress, "fd00:1::"),
+					fmt.Sprintf("-%s=%s", argPort, "1111"),
+				})
+				podMap[constants.KubeAPIServer] = pod
+				pod = getTestPod([]string{
+					constants.KubeControllerManager,
+					fmt.Sprintf("-%s %s", argBindAddress, "127.0.0.1"),
+					fmt.Sprintf("-%s %s", argPort, "2222"),
+				})
+				podMap[constants.KubeControllerManager] = pod
+				pod = getTestPod([]string{
+					constants.KubeScheduler,
+					fmt.Sprintf("-%s %s", argBindAddress, "127.0.0.1"),
+					fmt.Sprintf("-%s %s", argPort, "3333"),
+				})
+				podMap[constants.KubeScheduler] = pod
+				return podMap
+			},
+			expected: []controlPlaneComponent{
+				{name: "kube-apiserver", url: fmt.Sprintf("https://[fd00:1::]:1111/%s", endpointLivez)},
+				{name: "kube-controller-manager", url: fmt.Sprintf("https://127.0.0.1:2222/%s", endpointHealthz)},
+				{name: "kube-scheduler", url: fmt.Sprintf("https://127.0.0.1:3333/%s", endpointLivez)},
+			},
+		},
+		{
+			name: "valid: default ports and addresses",
+			setup: func() map[string]*v1.Pod {
+				var (
+					pod    *v1.Pod
+					podMap = map[string]*v1.Pod{}
+				)
+				pod = getTestPod([]string{
+					constants.KubeAPIServer,
+				})
+				podMap[constants.KubeAPIServer] = pod
+				pod = getTestPod([]string{
+					constants.KubeControllerManager,
+				})
+				podMap[constants.KubeControllerManager] = pod
+				pod = getTestPod([]string{
+					constants.KubeScheduler,
+				})
+				podMap[constants.KubeScheduler] = pod
+				return podMap
+			},
 			expected: []controlPlaneComponent{
 				{name: "kube-apiserver", url: fmt.Sprintf("https://192.168.0.1:6443/%s", endpointLivez)},
 				{name: "kube-controller-manager", url: fmt.Sprintf("https://127.0.0.1:10257/%s", endpointHealthz)},
 				{name: "kube-scheduler", url: fmt.Sprintf("https://127.0.0.1:10259/%s", endpointLivez)},
 			},
 		},
+		{
+			name: "invalid: nil Pods in map",
+			setup: func() map[string]*v1.Pod {
+				return map[string]*v1.Pod{}
+			},
+			expectedError: `[got nil Pod for component "kube-apiserver", ` +
+				`got nil Pod for component "kube-controller-manager", ` +
+				`got nil Pod for component "kube-scheduler"]`,
+		},
+		{
+			name: "invalid: empty commands in containers",
+			setup: func() map[string]*v1.Pod {
+				podMap := map[string]*v1.Pod{}
+				podMap[constants.KubeAPIServer] = getTestPod([]string{})
+				podMap[constants.KubeControllerManager] = getTestPod([]string{})
+				podMap[constants.KubeScheduler] = getTestPod([]string{})
+				return podMap
+			},
+			expectedError: `[the Pod has no container command starting with "kube-apiserver", ` +
+				`the Pod has no container command starting with "kube-controller-manager", ` +
+				`the Pod has no container command starting with "kube-scheduler"]`,
+		},
+		{
+			name: "invalid: missing commands in containers",
+			setup: func() map[string]*v1.Pod {
+				var (
+					pod    = getTestPod([]string{""})
+					podMap = map[string]*v1.Pod{}
+				)
+				podMap[constants.KubeAPIServer] = pod
+				podMap[constants.KubeControllerManager] = pod
+				podMap[constants.KubeScheduler] = pod
+				return podMap
+			},
+			expectedError: `[the Pod has no container command starting with "kube-apiserver", ` +
+				`the Pod has no container command starting with "kube-controller-manager", ` +
+				`the Pod has no container command starting with "kube-scheduler"]`,
+		},
 	}
 
-	for _, tc := range testcases {
+	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
-			actual := getControlPlaneComponents(tc.cfg, "192.168.0.1")
+			m := tc.setup()
+			actual, err := getControlPlaneComponents(m, "192.168.0.1")
+			if err != nil {
+				if err.Error() != tc.expectedError {
+					t.Fatalf("expected error:\n%v\ngot:\n%v",
+						tc.expectedError, err)
+				}
+			}
 			if !reflect.DeepEqual(tc.expected, actual) {
 				t.Fatalf("expected result: %+v, got: %+v", tc.expected, actual)
 			}

cmd/kubeadm/app/util/dryrun/dryrun.go

@@ -23,10 +23,10 @@ import (
 	"path/filepath"
 	"time"
 
+	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	errorsutil "k8s.io/apimachinery/pkg/util/errors"
 
-	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
 	kubeadmconstants "k8s.io/kubernetes/cmd/kubeadm/app/constants"
 	"k8s.io/kubernetes/cmd/kubeadm/app/util/apiclient"
 )
@@ -90,7 +90,7 @@ func NewWaiter() apiclient.Waiter {
 }
 
 // WaitForControlPlaneComponents just returns a dummy nil, to indicate that the program should just proceed
-func (w *Waiter) WaitForControlPlaneComponents(cfg *kubeadmapi.ClusterConfiguration, apiServerAddress string) error {
+func (w *Waiter) WaitForControlPlaneComponents(podsMap map[string]*v1.Pod, apiServerAddress string) error {
 	return nil
 }
 

cmd/kubeadm/app/util/staticpod/utils.go

@@ -31,6 +31,7 @@ import (
 
 	"github.com/pkg/errors"
 	"github.com/pmezard/go-difflib/difflib"
+	utilerrors "k8s.io/apimachinery/pkg/util/errors"
 
 	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/resource"
@@ -229,6 +230,28 @@ func ReadStaticPodFromDisk(manifestPath string) (*v1.Pod, error) {
 	return pod, nil
 }
 
+// ReadMultipleStaticPodsFromDisk reads multiple known component static Pods from manifestDir
+// and returns a list of Pods objects.
+func ReadMultipleStaticPodsFromDisk(manifestDir string, components ...string) (map[string]*v1.Pod, error) {
+	var (
+		podMap = map[string]*v1.Pod{}
+		errs   []error
+	)
+	for _, c := range components {
+		path := kubeadmconstants.GetStaticPodFilepath(c, manifestDir)
+		pod, err := ReadStaticPodFromDisk(path)
+		if err != nil {
+			errs = append(errs, err)
+			continue
+		}
+		podMap[c] = pod
+	}
+	if len(errs) > 0 {
+		return nil, utilerrors.NewAggregate(errs)
+	}
+	return podMap, nil
+}
+
 // LivenessProbe creates a Probe object with a HTTPGet handler
 func LivenessProbe(host, path string, port int32, scheme v1.URIScheme) *v1.Probe {
 	// sets initialDelaySeconds same as periodSeconds to skip one period before running a check

cmd/kubeadm/app/util/staticpod/utils_test.go

@@ -21,10 +21,13 @@ import (
 	"os"
 	"path/filepath"
 	"reflect"
+	"sort"
 	"strconv"
 	"strings"
 	"testing"
 
+	"github.com/google/go-cmp/cmp"
+
 	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 
@@ -692,6 +695,88 @@ func TestReadStaticPodFromDisk(t *testing.T) {
 	}
 }
 
+func TestReadMultipleStaticPodsFromDisk(t *testing.T) {
+	getTestPod := func(name string) *v1.Pod {
+		return &v1.Pod{
+			TypeMeta: metav1.TypeMeta{
+				Kind:       "Pod",
+				APIVersion: "v1",
+			},
+			ObjectMeta: metav1.ObjectMeta{
+				Name: name,
+			},
+		}
+	}
+
+	testCases := []struct {
+		name                  string
+		setup                 func(dir string)
+		components            []string
+		expected              []*v1.Pod
+		expectedErrorContains []string
+	}{
+		{
+			name: "valid: all pods are written and read",
+			setup: func(dir string) {
+				var pod *v1.Pod
+				pod = getTestPod("a")
+				_ = WriteStaticPodToDisk(kubeadmconstants.KubeAPIServer, dir, *pod)
+				pod = getTestPod("b")
+				_ = WriteStaticPodToDisk(kubeadmconstants.KubeControllerManager, dir, *pod)
+				pod = getTestPod("c")
+				_ = WriteStaticPodToDisk(kubeadmconstants.KubeScheduler, dir, *pod)
+			},
+			components: kubeadmconstants.ControlPlaneComponents,
+			expected: []*v1.Pod{
+				getTestPod("a"),
+				getTestPod("b"),
+				getTestPod("c"),
+			},
+		},
+		{
+			name:       "invalid: all pods returned errors",
+			setup:      func(dir string) {},
+			components: kubeadmconstants.ControlPlaneComponents,
+			expectedErrorContains: []string{
+				"kube-apiserver.yaml: no such file or directory",
+				"kube-controller-manager.yaml: no such file or directory",
+				"kube-scheduler.yaml: no such file or directory",
+			},
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			dir := t.TempDir()
+			tc.setup(dir)
+			m, err := ReadMultipleStaticPodsFromDisk(dir, tc.components...)
+			if err != nil {
+				for _, ec := range tc.expectedErrorContains {
+					if !strings.Contains(err.Error(), ec) {
+						t.Fatalf("expected error to contain string: %s\nerror:\n%v", ec, err)
+					}
+				}
+			}
+
+			// Compare sorted result to expected result.
+			var actual []*v1.Pod
+			for _, v := range m {
+				actual = append(actual, v)
+			}
+			sort.Slice(actual, func(a, b int) bool {
+				return actual[a].Name < actual[b].Name
+			})
+			sort.Slice(tc.expected, func(a, b int) bool {
+				return actual[a].Name < actual[b].Name
+			})
+
+			if diff := cmp.Diff(tc.expected, actual); diff != "" {
+				t.Fatalf("unexpected difference (-want,+got):\n%s", diff)
+			}
+		})
+	}
+}
+
 func TestManifestFilesAreEqual(t *testing.T) {
 	var tests = []struct {
 		description    string