Merge pull request #52251 from sbezverk/kubeadm_lint_cleanup

Automatic merge from submit-queue (batch tested with PRs 52251, 52540). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>..

kubeadm golint clean up

Cleaning up golint discovered issue for kubeadm

Fixes: https://github.com/kubernetes/kubeadm/issues/375

cmd/kubeadm/app/apis/kubeadm/doc.go

@@ -14,6 +14,10 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+// Package kubeadm is the package that contains the libraries that drive the kubeadm binary.
+// kubeadm is responsible for handling a Kubernetes cluster's lifecycle.
+
 // +k8s:deepcopy-gen=package,register
 // +groupName=kubeadm.k8s.io
+
 package kubeadm // import "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"

cmd/kubeadm/app/apis/kubeadm/register.go

@@ -28,7 +28,9 @@ const GroupName = "kubeadm.k8s.io"
 var SchemeGroupVersion = schema.GroupVersion{Group: GroupName, Version: runtime.APIVersionInternal}
 
 var (
+	// SchemeBuilder points to a list of functions added to Scheme.
 	SchemeBuilder = runtime.NewSchemeBuilder(addKnownTypes)
+	// AddToScheme applies all the stored functions to the scheme.
 	AddToScheme = SchemeBuilder.AddToScheme
 )
 

cmd/kubeadm/app/apis/kubeadm/types.go

@@ -22,6 +22,8 @@ import (
 
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
 
+// MasterConfiguration contains a list of elements which make up master's
+// configuration object.
 type MasterConfiguration struct {
 	metav1.TypeMeta
 
@@ -59,6 +61,7 @@ type MasterConfiguration struct {
 	FeatureGates map[string]bool
 }
 
+// API struct contains elements of API server address.
 type API struct {
 	// AdvertiseAddress sets the address for the API server to advertise.
 	AdvertiseAddress string
@@ -66,18 +69,21 @@ type API struct {
 	BindPort int32
 }
 
+// TokenDiscovery contains elements needed for token discovery
 type TokenDiscovery struct {
 	ID        string
 	Secret    string
 	Addresses []string
 }
 
+// Networking contains elements describing cluster's networking configuration
 type Networking struct {
 	ServiceSubnet string
 	PodSubnet     string
 	DNSDomain     string
 }
 
+// Etcd contains elements describing Etcd configuration
 type Etcd struct {
 	Endpoints []string
 	CAFile    string
@@ -91,6 +97,7 @@ type Etcd struct {
 
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
 
+// NodeConfiguration contains elements describing a particular node
 type NodeConfiguration struct {
 	metav1.TypeMeta
 

cmd/kubeadm/app/apis/kubeadm/v1alpha1/defaults.go

@@ -26,14 +26,23 @@ import (
 )
 
 const (
+	// DefaultServiceDNSDomain defines default cluster-internal domain name for Services and Pods
 	DefaultServiceDNSDomain = "cluster.local"
+	// DefaultServicesSubnet defines default service subnet range
 	DefaultServicesSubnet = "10.96.0.0/12"
+	// DefaultKubernetesVersion defines default kubernetes version
 	DefaultKubernetesVersion = "stable-1.8"
+	// DefaultAPIBindPort defines default API port
 	DefaultAPIBindPort = 6443
+	// DefaultAuthorizationModes defines default authorization modes
 	DefaultAuthorizationModes = "Node,RBAC"
+	// DefaultCACertPath defines default location of CA certificate
 	DefaultCACertPath = "/etc/kubernetes/pki/ca.crt"
+	// DefaultCertificatesDir defines default certificate directory
 	DefaultCertificatesDir = "/etc/kubernetes/pki"
+	// DefaultEtcdDataDir defines default location of etcd
 	DefaultEtcdDataDir = "/var/lib/etcd"
+	// DefaultImageRepository defines default image registry
 	DefaultImageRepository = "gcr.io/google_containers"
 )
 
@@ -41,6 +50,7 @@ func addDefaultingFuncs(scheme *runtime.Scheme) error {
 	return RegisterDefaults(scheme)
 }
 
+// SetDefaults_MasterConfiguration assigns default values to Master node
 func SetDefaults_MasterConfiguration(obj *MasterConfiguration) {
 	if obj.KubernetesVersion == "" {
 		obj.KubernetesVersion = DefaultKubernetesVersion
@@ -81,6 +91,7 @@ func SetDefaults_MasterConfiguration(obj *MasterConfiguration) {
 	}
 }
 
+// SetDefaults_NodeConfiguration assigns default values to a regular node
 func SetDefaults_NodeConfiguration(obj *NodeConfiguration) {
 	if obj.CACertPath == "" {
 		obj.CACertPath = DefaultCACertPath

cmd/kubeadm/app/apis/kubeadm/v1alpha1/doc.go

@@ -14,6 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+// Package v1alpha1 is the package that contains the libraries that drive the kubeadm binary.
 // +k8s:defaulter-gen=TypeMeta
 // +groupName=kubeadm.k8s.io
 // +k8s:deepcopy-gen=package

cmd/kubeadm/app/apis/kubeadm/v1alpha1/register.go

@@ -31,8 +31,11 @@ var SchemeGroupVersion = schema.GroupVersion{Group: GroupName, Version: "v1alpha
 var (
 	// TODO: move SchemeBuilder with zz_generated.deepcopy.go to k8s.io/api.
 	// localSchemeBuilder and AddToScheme will stay in k8s.io/kubernetes.
+
+	// SchemeBuilder points to a list of functions added to Scheme.
 	SchemeBuilder      runtime.SchemeBuilder
 	localSchemeBuilder = &SchemeBuilder
+	// AddToScheme applies all the stored functions to the scheme.
 	AddToScheme = localSchemeBuilder.AddToScheme
 )
 

cmd/kubeadm/app/apis/kubeadm/v1alpha1/types.go

@@ -22,6 +22,8 @@ import (
 
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
 
+// MasterConfiguration contains a list of elements which make up master's
+// configuration object.
 type MasterConfiguration struct {
 	metav1.TypeMeta `json:",inline"`
 
@@ -54,6 +56,7 @@ type MasterConfiguration struct {
 	FeatureGates map[string]bool `json:"featureGates,omitempty"`
 }
 
+// API struct contains elements of API server address.
 type API struct {
 	// AdvertiseAddress sets the address for the API server to advertise.
 	AdvertiseAddress string `json:"advertiseAddress"`
@@ -61,18 +64,21 @@ type API struct {
 	BindPort int32 `json:"bindPort"`
 }
 
+// TokenDiscovery contains elements needed for token discovery
 type TokenDiscovery struct {
 	ID        string   `json:"id"`
 	Secret    string   `json:"secret"`
 	Addresses []string `json:"addresses"`
 }
 
+// Networking contains elements describing cluster's networking configuration
 type Networking struct {
 	ServiceSubnet string `json:"serviceSubnet"`
 	PodSubnet     string `json:"podSubnet"`
 	DNSDomain     string `json:"dnsDomain"`
 }
 
+// Etcd contains elements describing Etcd configuration
 type Etcd struct {
 	Endpoints []string          `json:"endpoints"`
 	CAFile    string            `json:"caFile"`
@@ -86,6 +92,7 @@ type Etcd struct {
 
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
 
+// NodeConfiguration contains elements describing a particular node
 type NodeConfiguration struct {
 	metav1.TypeMeta `json:",inline"`
 

cmd/kubeadm/app/apis/kubeadm/validation/validation.go

@@ -58,6 +58,7 @@ var requiredAuthzModes = []string{
 	authzmodes.ModeNode,
 }
 
+// ValidateMasterConfiguration validates master configuration and collects all encountered errors
 func ValidateMasterConfiguration(c *kubeadm.MasterConfiguration) field.ErrorList {
 	allErrs := field.ErrorList{}
 	allErrs = append(allErrs, ValidateCloudProvider(c.CloudProvider, field.NewPath("cloudprovider"))...)
@@ -72,6 +73,7 @@ func ValidateMasterConfiguration(c *kubeadm.MasterConfiguration) field.ErrorList
 	return allErrs
 }
 
+// ValidateNodeConfiguration validates node configuration and collects all encountered errors
 func ValidateNodeConfiguration(c *kubeadm.NodeConfiguration) field.ErrorList {
 	allErrs := field.ErrorList{}
 	allErrs = append(allErrs, ValidateDiscovery(c, field.NewPath("discovery"))...)
@@ -82,10 +84,10 @@ func ValidateNodeConfiguration(c *kubeadm.NodeConfiguration) field.ErrorList {
 	return allErrs
 }
 
+// ValidateAuthorizationModes  validates authorization modes and collects all encountered errors
 func ValidateAuthorizationModes(authzModes []string, fldPath *field.Path) field.ErrorList {
 	allErrs := field.ErrorList{}
 	found := map[string]bool{}
-
 	for _, authzMode := range authzModes {
 		if !authzmodes.IsValidAuthorizationMode(authzMode) {
 			allErrs = append(allErrs, field.Invalid(fldPath, authzMode, "invalid authorization mode"))
@@ -105,6 +107,7 @@ func ValidateAuthorizationModes(authzModes []string, fldPath *field.Path) field.
 	return allErrs
 }
 
+// ValidateDiscovery validates discovery related configuration and collects all encountered errors
 func ValidateDiscovery(c *kubeadm.NodeConfiguration, fldPath *field.Path) field.ErrorList {
 	allErrs := field.ErrorList{}
 	if len(c.DiscoveryToken) != 0 {
@@ -123,10 +126,10 @@ func ValidateDiscovery(c *kubeadm.NodeConfiguration, fldPath *field.Path) field.
 	if len(c.DiscoveryFile) != 0 {
 		allErrs = append(allErrs, ValidateDiscoveryFile(c.DiscoveryFile, fldPath)...)
 	}
-
 	return allErrs
 }
 
+// ValidateArgSelection validates discovery related configuration and collects all encountered errors
 func ValidateArgSelection(cfg *kubeadm.NodeConfiguration, fldPath *field.Path) field.ErrorList {
 	allErrs := field.ErrorList{}
 	if len(cfg.DiscoveryToken) != 0 && len(cfg.DiscoveryFile) != 0 {
@@ -156,6 +159,7 @@ func ValidateArgSelection(cfg *kubeadm.NodeConfiguration, fldPath *field.Path) f
 	return allErrs
 }
 
+// ValidateJoinDiscoveryTokenAPIServer validates discovery token for API server
 func ValidateJoinDiscoveryTokenAPIServer(c *kubeadm.NodeConfiguration, fldPath *field.Path) field.ErrorList {
 	allErrs := field.ErrorList{}
 	for _, m := range c.DiscoveryTokenAPIServers {
@@ -167,6 +171,7 @@ func ValidateJoinDiscoveryTokenAPIServer(c *kubeadm.NodeConfiguration, fldPath *
 	return allErrs
 }
 
+// ValidateDiscoveryFile validates location of a discovery file
 func ValidateDiscoveryFile(discoveryFile string, fldPath *field.Path) field.ErrorList {
 	allErrs := field.ErrorList{}
 	u, err := url.Parse(discoveryFile)
@@ -189,6 +194,7 @@ func ValidateDiscoveryFile(discoveryFile string, fldPath *field.Path) field.Erro
 	return allErrs
 }
 
+// ValidateToken validates token
 func ValidateToken(t string, fldPath *field.Path) field.ErrorList {
 	allErrs := field.ErrorList{}
 
@@ -203,6 +209,7 @@ func ValidateToken(t string, fldPath *field.Path) field.ErrorList {
 	return allErrs
 }
 
+// ValidateAPIServerCertSANs validates alternative names
 func ValidateAPIServerCertSANs(altnames []string, fldPath *field.Path) field.ErrorList {
 	allErrs := field.ErrorList{}
 	for _, altname := range altnames {
@@ -213,6 +220,7 @@ func ValidateAPIServerCertSANs(altnames []string, fldPath *field.Path) field.Err
 	return allErrs
 }
 
+// ValidateIPFromString validates ip address
 func ValidateIPFromString(ipaddr string, fldPath *field.Path) field.ErrorList {
 	allErrs := field.ErrorList{}
 	if net.ParseIP(ipaddr) == nil {
@@ -221,6 +229,7 @@ func ValidateIPFromString(ipaddr string, fldPath *field.Path) field.ErrorList {
 	return allErrs
 }
 
+// ValidateIPNetFromString validates network portion of ip address
 func ValidateIPNetFromString(subnet string, minAddrs int64, fldPath *field.Path) field.ErrorList {
 	allErrs := field.ErrorList{}
 	_, svcSubnet, err := net.ParseCIDR(subnet)
@@ -235,6 +244,7 @@ func ValidateIPNetFromString(subnet string, minAddrs int64, fldPath *field.Path)
 	return allErrs
 }
 
+// ValidateNetworking validates networking configuration
 func ValidateNetworking(c *kubeadm.Networking, fldPath *field.Path) field.ErrorList {
 	allErrs := field.ErrorList{}
 	allErrs = append(allErrs, apivalidation.ValidateDNS1123Subdomain(c.DNSDomain, field.NewPath("dns-domain"))...)
@@ -245,6 +255,7 @@ func ValidateNetworking(c *kubeadm.Networking, fldPath *field.Path) field.ErrorL
 	return allErrs
 }
 
+// ValidateAbsolutePath validates whether provided path is absolute or not
 func ValidateAbsolutePath(path string, fldPath *field.Path) field.ErrorList {
 	allErrs := field.ErrorList{}
 	if !filepath.IsAbs(path) {
@@ -253,6 +264,7 @@ func ValidateAbsolutePath(path string, fldPath *field.Path) field.ErrorList {
 	return allErrs
 }
 
+// ValidateNodeName validates the name of a node
 func ValidateNodeName(nodename string, fldPath *field.Path) field.ErrorList {
 	allErrs := field.ErrorList{}
 	if node.GetHostname(nodename) != nodename {
@@ -261,6 +273,7 @@ func ValidateNodeName(nodename string, fldPath *field.Path) field.ErrorList {
 	return allErrs
 }
 
+// ValidateCloudProvider validates if cloud provider is supported
 func ValidateCloudProvider(provider string, fldPath *field.Path) field.ErrorList {
 	allErrs := field.ErrorList{}
 	if len(provider) == 0 {
@@ -275,6 +288,7 @@ func ValidateCloudProvider(provider string, fldPath *field.Path) field.ErrorList
 	return allErrs
 }
 
+// ValidateMixedArguments validates passed arguments
 func ValidateMixedArguments(flag *pflag.FlagSet) error {
 	// If --config isn't set, we have nothing to validate
 	if !flag.Changed("config") {
@@ -296,6 +310,7 @@ func ValidateMixedArguments(flag *pflag.FlagSet) error {
 	return nil
 }
 
+// ValidateFeatureGates validates provided feature gates
 func ValidateFeatureGates(featureGates map[string]bool, fldPath *field.Path) field.ErrorList {
 	allErrs := field.ErrorList{}
 	validFeatures := features.Keys(features.InitFeatureGates)
@@ -311,6 +326,7 @@ func ValidateFeatureGates(featureGates map[string]bool, fldPath *field.Path) fie
 	return allErrs
 }
 
+// ValidateAPIEndpoint validates API server's endpoint
 func ValidateAPIEndpoint(c *kubeadm.MasterConfiguration, fldPath *field.Path) field.ErrorList {
 	allErrs := field.ErrorList{}
 

cmd/kubeadm/app/apis/kubeadm/validation/validation_test.go

@@ -410,7 +410,6 @@ func TestValidateMixedArguments(t *testing.T) {
 	}
 
 	var cfgPath string
-
 	for _, rt := range tests {
 		f := pflag.NewFlagSet("test", pflag.ContinueOnError)
 		if f.Parsed() {

cmd/kubeadm/app/cmd/cmd.go

@@ -27,6 +27,7 @@ import (
 	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/upgrade"
 )
 
+// NewKubeadmCommand return cobra.Command to run kubeadm command
 func NewKubeadmCommand(_ io.Reader, out, err io.Writer) *cobra.Command {
 	cmds := &cobra.Command{
 		Use:   "kubeadm",

cmd/kubeadm/app/cmd/completion.go

@@ -45,7 +45,7 @@ const defaultBoilerPlate = `
 `
 
 var (
-	completion_long = dedent.Dedent(`
+	completionLong = dedent.Dedent(`
 		Output shell completion code for the specified shell (bash or zsh).
 		The shell code must be evalutated to provide interactive
 		completion of kubeadm commands.  This can be done by sourcing it from
@@ -63,7 +63,7 @@ var (
 
 		Note for zsh users: [1] zsh completions are only supported in versions of zsh >= 5.2`)
 
-	completion_example = dedent.Dedent(`
+	completionExample = dedent.Dedent(`
 		# Install bash completion on a Mac using homebrew
 		brew install bash-completion
 		printf "\n# Bash completion support\nsource $(brew --prefix)/etc/bash_completion\n" >> $HOME/.bash_profile
@@ -82,23 +82,24 @@ var (
 )
 
 var (
-	completion_shells = map[string]func(out io.Writer, cmd *cobra.Command) error{
+	completionShells = map[string]func(out io.Writer, cmd *cobra.Command) error{
 		"bash": runCompletionBash,
 		"zsh":  runCompletionZsh,
 	}
 )
 
+// NewCmdCompletion return command for executing "kubeadm completion" command
 func NewCmdCompletion(out io.Writer, boilerPlate string) *cobra.Command {
 	shells := []string{}
-	for s := range completion_shells {
+	for s := range completionShells {
 		shells = append(shells, s)
 	}
 
 	cmd := &cobra.Command{
 		Use:     "completion SHELL",
 		Short:   i18n.T("Output shell completion code for the specified shell (bash or zsh)"),
-		Long:    completion_long,
+		Long:    completionLong,
-		Example: completion_example,
+		Example: completionExample,
 		Run: func(cmd *cobra.Command, args []string) {
 			err := RunCompletion(out, boilerPlate, cmd, args)
 			kubeadmutil.CheckErr(err)
@@ -109,16 +110,17 @@ func NewCmdCompletion(out io.Writer, boilerPlate string) *cobra.Command {
 	return cmd
 }
 
+// RunCompletion checks given arguments and executes command
 func RunCompletion(out io.Writer, boilerPlate string, cmd *cobra.Command, args []string) error {
 	if len(args) == 0 {
-		return fmt.Errorf("shell not specified.")
+		return fmt.Errorf("shell not specified")
 	}
 	if len(args) > 1 {
-		return fmt.Errorf("too many arguments. expected only the shell type.")
+		return fmt.Errorf("too many arguments. expected only the shell type")
 	}
-	run, found := completion_shells[args[0]]
+	run, found := completionShells[args[0]]
 	if !found {
-		return fmt.Errorf("unsupported shell type %q.", args[0])
+		return fmt.Errorf("unsupported shell type %q", args[0])
 	}
 
 	if len(boilerPlate) == 0 {
@@ -135,7 +137,7 @@ func runCompletionBash(out io.Writer, kubeadm *cobra.Command) error {
 }
 
 func runCompletionZsh(out io.Writer, kubeadm *cobra.Command) error {
-	zsh_initialization := `
+	zshInitialization := `
 __kubeadm_bash_source() {
 	alias shopt=':'
 	alias _expand=_bash_expand
@@ -276,18 +278,18 @@ __kubeadm_convert_bash_to_zsh() {
 	-e "s/\\\$(type${RWORD}/\$(__kubeadm_type/g" \
 	<<'BASH_COMPLETION_EOF'
 `
-	out.Write([]byte(zsh_initialization))
+	out.Write([]byte(zshInitialization))
 
 	buf := new(bytes.Buffer)
 	kubeadm.GenBashCompletion(buf)
 	out.Write(buf.Bytes())
 
-	zsh_tail := `
+	zshTail := `
 BASH_COMPLETION_EOF
 }
 
 __kubeadm_bash_source <(__kubeadm_convert_bash_to_zsh)
 `
-	out.Write([]byte(zsh_tail))
+	out.Write([]byte(zshTail))
 	return nil
 }

cmd/kubeadm/app/cmd/config.go

@@ -36,6 +36,7 @@ import (
 	"k8s.io/kubernetes/pkg/api"
 )
 
+// NewCmdConfig returns cobra.Command for "kubeadm config" command
 func NewCmdConfig(out io.Writer) *cobra.Command {
 
 	var kubeConfigFile string
@@ -64,6 +65,7 @@ func NewCmdConfig(out io.Writer) *cobra.Command {
 	return cmd
 }
 
+// NewCmdConfigUpload returs cobra.Command for "kubeadm config upload" command
 func NewCmdConfigUpload(out io.Writer, kubeConfigFile *string) *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "upload",
@@ -76,6 +78,7 @@ func NewCmdConfigUpload(out io.Writer, kubeConfigFile *string) *cobra.Command {
 	return cmd
 }
 
+// NewCmdConfigView returs cobra.Command for "kubeadm config view" command
 func NewCmdConfigView(out io.Writer, kubeConfigFile *string) *cobra.Command {
 	return &cobra.Command{
 		Use:   "view",
@@ -95,6 +98,8 @@ func NewCmdConfigView(out io.Writer, kubeConfigFile *string) *cobra.Command {
 	}
 }
 
+// NewCmdConfigUploadFromFile verifies given kubernetes config file and returs cobra.Command for
+// "kubeadm config upload from-file" command
 func NewCmdConfigUploadFromFile(out io.Writer, kubeConfigFile *string) *cobra.Command {
 	var cfgPath string
 	cmd := &cobra.Command{
@@ -126,6 +131,7 @@ func NewCmdConfigUploadFromFile(out io.Writer, kubeConfigFile *string) *cobra.Co
 	return cmd
 }
 
+// NewCmdConfigUploadFromFlags returs cobra.Command for "kubeadm config upload from-flags" command
 func NewCmdConfigUploadFromFlags(out io.Writer, kubeConfigFile *string) *cobra.Command {
 	cfg := &kubeadmapiext.MasterConfiguration{}
 	api.Scheme.Default(cfg)

cmd/kubeadm/app/cmd/init.go

@@ -211,6 +211,7 @@ func AddInitOtherFlags(flagSet *flag.FlagSet, cfgPath *string, skipPreFlight, sk
 	)
 }
 
+// NewInit validates given arguments and instantiates Init struct with provided information.
 func NewInit(cfgPath string, cfg *kubeadmapi.MasterConfiguration, skipPreFlight, skipTokenPrint, dryRun bool) (*Init, error) {
 
 	fmt.Println("[kubeadm] WARNING: kubeadm is in beta, please do not use it for production clusters.")
@@ -256,6 +257,7 @@ func NewInit(cfgPath string, cfg *kubeadmapi.MasterConfiguration, skipPreFlight,
 	return &Init{cfg: cfg, skipTokenPrint: skipTokenPrint, dryRun: dryRun}, nil
 }
 
+// Init defines struct used by "kubeadm init" command
 type Init struct {
 	cfg            *kubeadmapi.MasterConfiguration
 	skipTokenPrint bool

cmd/kubeadm/app/cmd/join.go

@@ -154,10 +154,12 @@ func NewCmdJoin(out io.Writer) *cobra.Command {
 	return cmd
 }
 
+// Join defines struct used by kubeadm join command
 type Join struct {
 	cfg *kubeadmapi.NodeConfiguration
 }
 
+// NewJoin instantiates Join struct with given arguments
 func NewJoin(cfgPath string, args []string, cfg *kubeadmapi.NodeConfiguration, skipPreFlight bool) (*Join, error) {
 	fmt.Println("[kubeadm] WARNING: kubeadm is in beta, please do not use it for production clusters.")
 
@@ -192,6 +194,7 @@ func NewJoin(cfgPath string, args []string, cfg *kubeadmapi.NodeConfiguration, s
 	return &Join{cfg: cfg}, nil
 }
 
+// Validate validates mixed arguments passed to cobra.Command
 func (j *Join) Validate(cmd *cobra.Command) error {
 	if err := validation.ValidateMixedArguments(cmd.PersistentFlags()); err != nil {
 		return err
@@ -206,7 +209,7 @@ func (j *Join) Run(out io.Writer) error {
 		return err
 	}
 
-	client, err := kubeconfigutil.KubeConfigToClientSet(cfg)
+	client, err := kubeconfigutil.ToClientSet(cfg)
 	if err != nil {
 		return err
 	}

cmd/kubeadm/app/cmd/phases/bootstraptoken.go

@@ -110,7 +110,7 @@ func NewSubCmdNodeBootstrapTokenPostCSRs(kubeConfigFile *string) *cobra.Command
 	return cmd
 }
 
-// NewSubCmdNodeBootstrapToken returns the Cobra command for running the allow-auto-approve sub-phase
+// NewSubCmdNodeBootstrapTokenAutoApprove returns the Cobra command for running the allow-auto-approve sub-phase
 func NewSubCmdNodeBootstrapTokenAutoApprove(kubeConfigFile *string) *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "allow-auto-approve",

cmd/kubeadm/app/cmd/phases/preflight.go

@@ -24,6 +24,7 @@ import (
 	"k8s.io/kubernetes/cmd/kubeadm/app/preflight"
 )
 
+// NewCmdPreFlight calls cobra.Command for preflight checks
 func NewCmdPreFlight() *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "preflight",
@@ -36,6 +37,7 @@ func NewCmdPreFlight() *cobra.Command {
 	return cmd
 }
 
+// NewCmdPreFlightMaster calls cobra.Command for master preflight checks
 func NewCmdPreFlightMaster() *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "master",
@@ -49,6 +51,7 @@ func NewCmdPreFlightMaster() *cobra.Command {
 	return cmd
 }
 
+// NewCmdPreFlightNode calls cobra.Command for node preflight checks
 func NewCmdPreFlightNode() *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "node",

cmd/kubeadm/app/cmd/reset.go

@@ -59,10 +59,12 @@ func NewCmdReset(out io.Writer) *cobra.Command {
 	return cmd
 }
 
+// Reset defines struct used for kubeadm reset command
 type Reset struct {
 	certsDir string
 }
 
+// NewReset instantiate Reset struct
 func NewReset(skipPreFlight bool, certsDir string) (*Reset, error) {
 	if !skipPreFlight {
 		fmt.Println("[preflight] Running pre-flight checks")

cmd/kubeadm/app/cmd/token.go

@@ -46,6 +46,7 @@ import (
 	"k8s.io/kubernetes/pkg/printers"
 )
 
+// NewCmdToken returns cobra.Command for token management
 func NewCmdToken(out io.Writer, errW io.Writer) *cobra.Command {
 
 	var kubeConfigFile string
@@ -168,6 +169,7 @@ func NewCmdToken(out io.Writer, errW io.Writer) *cobra.Command {
 	return tokenCmd
 }
 
+// NewCmdTokenGenerate returns cobra.Command to generate new token
 func NewCmdTokenGenerate(out io.Writer) *cobra.Command {
 	return &cobra.Command{
 		Use:   "generate",
@@ -260,14 +262,14 @@ func RunListTokens(out io.Writer, errW io.Writer, client clientset.Interface) er
 	w := tabwriter.NewWriter(out, 10, 4, 3, ' ', 0)
 	fmt.Fprintln(w, "TOKEN\tTTL\tEXPIRES\tUSAGES\tDESCRIPTION\tEXTRA GROUPS")
 	for _, secret := range secrets.Items {
-		tokenId := getSecretString(&secret, bootstrapapi.BootstrapTokenIDKey)
+		tokenID := getSecretString(&secret, bootstrapapi.BootstrapTokenIDKey)
-		if len(tokenId) == 0 {
+		if len(tokenID) == 0 {
 			fmt.Fprintf(errW, "bootstrap token has no token-id data: %s\n", secret.Name)
 			continue
 		}
 
 		// enforce the right naming convention
-		if secret.Name != fmt.Sprintf("%s%s", bootstrapapi.BootstrapTokenSecretPrefix, tokenId) {
+		if secret.Name != fmt.Sprintf("%s%s", bootstrapapi.BootstrapTokenSecretPrefix, tokenID) {
 			fmt.Fprintf(errW, "bootstrap token name is not of the form '%s(token-id)': %s\n", bootstrapapi.BootstrapTokenSecretPrefix, secret.Name)
 			continue
 		}
@@ -277,7 +279,7 @@ func RunListTokens(out io.Writer, errW io.Writer, client clientset.Interface) er
 			fmt.Fprintf(errW, "bootstrap token has no token-secret data: %s\n", secret.Name)
 			continue
 		}
-		td := &kubeadmapi.TokenDiscovery{ID: tokenId, Secret: tokenSecret}
+		td := &kubeadmapi.TokenDiscovery{ID: tokenID, Secret: tokenSecret}
 
 		// Expiration time is optional, if not specified this implies the token
 		// never expires.
@@ -328,20 +330,20 @@ func RunListTokens(out io.Writer, errW io.Writer, client clientset.Interface) er
 }
 
 // RunDeleteToken removes a bootstrap token from the server.
-func RunDeleteToken(out io.Writer, client clientset.Interface, tokenIdOrToken string) error {
+func RunDeleteToken(out io.Writer, client clientset.Interface, tokenIDOrToken string) error {
 	// Assume the given first argument is a token id and try to parse it
-	tokenId := tokenIdOrToken
+	tokenID := tokenIDOrToken
-	if err := tokenutil.ParseTokenID(tokenIdOrToken); err != nil {
+	if err := tokenutil.ParseTokenID(tokenIDOrToken); err != nil {
-		if tokenId, _, err = tokenutil.ParseToken(tokenIdOrToken); err != nil {
+		if tokenID, _, err = tokenutil.ParseToken(tokenIDOrToken); err != nil {
-			return fmt.Errorf("given token or token id %q didn't match pattern [%q] or [%q]", tokenIdOrToken, tokenutil.TokenIDRegexpString, tokenutil.TokenRegexpString)
+			return fmt.Errorf("given token or token id %q didn't match pattern [%q] or [%q]", tokenIDOrToken, tokenutil.TokenIDRegexpString, tokenutil.TokenRegexpString)
 		}
 	}
 
-	tokenSecretName := fmt.Sprintf("%s%s", bootstrapapi.BootstrapTokenSecretPrefix, tokenId)
+	tokenSecretName := fmt.Sprintf("%s%s", bootstrapapi.BootstrapTokenSecretPrefix, tokenID)
 	if err := client.CoreV1().Secrets(metav1.NamespaceSystem).Delete(tokenSecretName, nil); err != nil {
 		return fmt.Errorf("failed to delete bootstrap token [%v]", err)
 	}
-	fmt.Fprintf(out, "bootstrap token with id %q deleted\n", tokenId)
+	fmt.Fprintf(out, "bootstrap token with id %q deleted\n", tokenID)
 	return nil
 }
 

cmd/kubeadm/app/cmd/version.go

@@ -36,6 +36,7 @@ type Version struct {
 	ClientVersion *apimachineryversion.Info `json:"clientVersion"`
 }
 
+// NewCmdVersion provides the version information of kubeadm.
 func NewCmdVersion(out io.Writer) *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "version",
@@ -49,6 +50,8 @@ func NewCmdVersion(out io.Writer) *cobra.Command {
 	return cmd
 }
 
+// RunVersion provides the version information of kubeadm in format depending on an arguments
+// specified in cobra.Command.
 func RunVersion(out io.Writer, cmd *cobra.Command) error {
 	clientVersion := version.Get()
 	v := Version{

cmd/kubeadm/app/constants/constants.go

@@ -32,48 +32,87 @@ import (
 var KubernetesDir = "/etc/kubernetes"
 
 const (
+	// ManifestsSubDirName defines directory name to store manifests
 	ManifestsSubDirName = "manifests"
+	// TempDirForKubeadm defines temporary directory for kubeadm
 	TempDirForKubeadm = "/etc/kubernetes/tmp"
 
+	// CACertAndKeyBaseName defines certificate authority base name
 	CACertAndKeyBaseName = "ca"
+	// CACertName defines certificate name
 	CACertName = "ca.crt"
+	// CAKeyName defines certificate name
 	CAKeyName = "ca.key"
 
+	// APIServerCertAndKeyBaseName defines API's server certificate and key base name
 	APIServerCertAndKeyBaseName = "apiserver"
+	// APIServerCertName defines API's server certificate name
 	APIServerCertName = "apiserver.crt"
+	// APIServerKeyName defines API's server key name
 	APIServerKeyName = "apiserver.key"
-	APIServerCertCommonName     = "kube-apiserver" //used as subject.commonname attribute (CN)
+	// APIServerCertCommonName defines API's server certificate common name (CN)
+	APIServerCertCommonName = "kube-apiserver"
 
+	// APIServerKubeletClientCertAndKeyBaseName defines kubelet client certificate and key base name
 	APIServerKubeletClientCertAndKeyBaseName = "apiserver-kubelet-client"
+	// APIServerKubeletClientCertName defines kubelet client certificate name
 	APIServerKubeletClientCertName = "apiserver-kubelet-client.crt"
+	// APIServerKubeletClientKeyName defines kubelet client key name
 	APIServerKubeletClientKeyName = "apiserver-kubelet-client.key"
-	APIServerKubeletClientCertCommonName     = "kube-apiserver-kubelet-client" //used as subject.commonname attribute (CN)
+	// APIServerKubeletClientCertCommonName defines kubelet client certificate common name (CN)
+	APIServerKubeletClientCertCommonName = "kube-apiserver-kubelet-client"
 
+	// ServiceAccountKeyBaseName defines SA key base name
 	ServiceAccountKeyBaseName = "sa"
+	// ServiceAccountPublicKeyName defines SA public key base name
 	ServiceAccountPublicKeyName = "sa.pub"
+	// ServiceAccountPrivateKeyName defines SA private key base name
 	ServiceAccountPrivateKeyName = "sa.key"
 
+	// FrontProxyCACertAndKeyBaseName defines front proxy CA certificate and key base name
 	FrontProxyCACertAndKeyBaseName = "front-proxy-ca"
+	// FrontProxyCACertName defines front proxy CA certificate name
 	FrontProxyCACertName = "front-proxy-ca.crt"
+	// FrontProxyCAKeyName defaines front proxy CA key name
 	FrontProxyCAKeyName = "front-proxy-ca.key"
 
+	// FrontProxyClientCertAndKeyBaseName defines front proxy certificate and key base name
 	FrontProxyClientCertAndKeyBaseName = "front-proxy-client"
+	// FrontProxyClientCertName defines front proxy certificate name
 	FrontProxyClientCertName = "front-proxy-client.crt"
+	// FrontProxyClientKeyName defines front proxy key name
 	FrontProxyClientKeyName = "front-proxy-client.key"
+	// FrontProxyClientCertCommonName defines front proxy certificate common name
 	FrontProxyClientCertCommonName = "front-proxy-client" //used as subject.commonname attribute (CN)
 
+	// AdminKubeConfigFileName defines name for the KubeConfig aimed to be used by the superuser/admin of the cluster
 	AdminKubeConfigFileName = "admin.conf"
+	// KubeletBootstrapKubeConfigFileName defines the file name for the KubeConfig that the kubelet will use to do
+	// the TLS bootstrap to get itself an unique credential
 	KubeletBootstrapKubeConfigFileName = "bootstrap-kubelet.conf"
+
+	// KubeletKubeConfigFileName defines the file name for the KubeConfig that the master kubelet will use for talking
+	// to the API server
 	KubeletKubeConfigFileName = "kubelet.conf"
+	// ControllerManagerKubeConfigFileName defines the file name for the controller manager's KubeConfig file
 	ControllerManagerKubeConfigFileName = "controller-manager.conf"
+	// SchedulerKubeConfigFileName defines the file name for the scheduler's KubeConfig file
 	SchedulerKubeConfigFileName = "scheduler.conf"
 
 	// Some well-known users and groups in the core Kubernetes authorization system
 
+	// ControllerManagerUser defines the well-known user the controller-manager should be authenticated as
 	ControllerManagerUser = "system:kube-controller-manager"
+	// SchedulerUser defines the well-known user the scheduler should be authenticated as
 	SchedulerUser = "system:kube-scheduler"
+	// MastersGroup defines the well-known group for the apiservers. This group is also superuser by default
+	// (i.e. bound to the cluster-admin ClusterRole)
 	MastersGroup = "system:masters"
+	// NodesGroup defines the well-known group for all nodes.
 	NodesGroup = "system:nodes"
+	// NodesClusterRoleBinding defines the well-known ClusterRoleBinding which binds the too permissive system:node
+	// ClusterRole to the system:nodes group. Since kubeadm is using the Node Authorizer, this ClusterRoleBinding's
+	// system:nodes group subject is removed if present.
 	NodesClusterRoleBinding = "system:node"
 
 	// APICallRetryInterval defines how long kubeadm should wait before retrying a failed API operation
@@ -83,7 +122,7 @@ const (
 	// MarkMasterTimeout specifies how long kubeadm should wait for applying the label and taint on the master before timing out
 	MarkMasterTimeout = 2 * time.Minute
 
-	// Minimum amount of nodes the Service subnet should allow.
+	// MinimumAddressesInServiceSubnet defines minimum amount of nodes the Service subnet should allow.
 	// We need at least ten, because the DNS service is always at the tenth cluster clusterIP
 	MinimumAddressesInServiceSubnet = 10
 
@@ -107,10 +146,15 @@ const (
 	// DefaultEtcdVersion indicates the default etcd version that kubeadm uses
 	DefaultEtcdVersion = "3.0.17"
 
+	// Etcd defines variable used internally when referring to etcd component
 	Etcd = "etcd"
+	// KubeAPIServer defines variable used internally when referring to kube-apiserver component
 	KubeAPIServer = "kube-apiserver"
+	// KubeControllerManager defines variable used internally when referring to kube-controller-manager component
 	KubeControllerManager = "kube-controller-manager"
+	// KubeScheduler defines variable used internally when referring to kube-scheduler component
 	KubeScheduler = "kube-scheduler"
+	// KubeProxy defines variable used internally when referring to kube-proxy component
 	KubeProxy = "kube-proxy"
 
 	// SelfHostingPrefix describes the prefix workloads that are self-hosted by kubeadm has
@@ -146,7 +190,9 @@ var (
 		Effect: v1.TaintEffectNoSchedule,
 	}
 
+	// AuthorizationPolicyPath defines the supported location of authorization policy file
 	AuthorizationPolicyPath = filepath.Join(KubernetesDir, "abac_policy.json")
+	// AuthorizationWebhookConfigPath defines the supported location of webhook config file
 	AuthorizationWebhookConfigPath = filepath.Join(KubernetesDir, "webhook_authz.conf")
 
 	// DefaultTokenUsages specifies the default functions a token will get

cmd/kubeadm/app/discovery/discovery.go

@@ -28,6 +28,7 @@ import (
 	kubeconfigutil "k8s.io/kubernetes/cmd/kubeadm/app/util/kubeconfig"
 )
 
+// TokenUser defines token user
 const TokenUser = "tls-bootstrap-token-user"
 
 // For returns a KubeConfig object that can be used for doing the TLS Bootstrap with the right credentials
@@ -60,7 +61,7 @@ func GetValidatedClusterInfoObject(cfg *kubeadmapi.NodeConfiguration) (*clientcm
 	case len(cfg.DiscoveryToken) != 0:
 		return token.RetrieveValidatedClusterInfo(cfg.DiscoveryToken, cfg.DiscoveryTokenAPIServers, cfg.DiscoveryTokenCACertHashes)
 	default:
-		return nil, fmt.Errorf("couldn't find a valid discovery configuration.")
+		return nil, fmt.Errorf("couldn't find a valid discovery configuration")
 	}
 }
 

cmd/kubeadm/app/discovery/file/file.go

@@ -62,7 +62,7 @@ func ValidateClusterInfo(clusterinfo *clientcmdapi.Config) (*clientcmdapi.Cluste
 		defaultCluster.CertificateAuthorityData,
 	)
 
-	client, err := kubeconfigutil.KubeConfigToClientSet(configFromClusterInfo)
+	client, err := kubeconfigutil.ToClientSet(configFromClusterInfo)
 	if err != nil {
 		return nil, err
 	}
@@ -79,11 +79,10 @@ func ValidateClusterInfo(clusterinfo *clientcmdapi.Config) (*clientcmdapi.Cluste
 				// In that case, trust the cluster admin and do not refresh the cluster-info credentials
 				fmt.Printf("[discovery] Could not access the %s ConfigMap for refreshing the cluster-info information, but the TLS cert is valid so proceeding...\n", bootstrapapi.ConfigMapClusterInfo)
 				return true, nil
-			} else {
+			}
 			fmt.Printf("[discovery] Failed to validate the API Server's identity, will try again: [%v]\n", err)
 			return false, nil
 		}
-		}
 		return true, nil
 	})
 

cmd/kubeadm/app/discovery/token/token.go

@@ -36,13 +36,14 @@ import (
 	"k8s.io/kubernetes/pkg/controller/bootstrap"
 )
 
+// BootstrapUser defines bootstrap user name
 const BootstrapUser = "token-bootstrap-client"
 
 // RetrieveValidatedClusterInfo connects to the API Server and tries to fetch the cluster-info ConfigMap
 // It then makes sure it can trust the API Server by looking at the JWS-signed tokens and (if rootCAPubKeys is not empty)
 // validating the cluster CA against a set of pinned public keys
 func RetrieveValidatedClusterInfo(discoveryToken string, tokenAPIServers, rootCAPubKeys []string) (*clientcmdapi.Cluster, error) {
-	tokenId, tokenSecret, err := tokenutil.ParseToken(discoveryToken)
+	tokenID, tokenSecret, err := tokenutil.ParseToken(discoveryToken)
 	if err != nil {
 		return nil, err
 	}
@@ -61,7 +62,7 @@ func RetrieveValidatedClusterInfo(discoveryToken string, tokenAPIServers, rootCA
 		insecureBootstrapConfig := buildInsecureBootstrapKubeConfig(endpoint)
 		clusterName := insecureBootstrapConfig.Contexts[insecureBootstrapConfig.CurrentContext].Cluster
 
-		insecureClient, err := kubeconfigutil.KubeConfigToClientSet(insecureBootstrapConfig)
+		insecureClient, err := kubeconfigutil.ToClientSet(insecureBootstrapConfig)
 		if err != nil {
 			return nil, err
 		}
@@ -85,11 +86,11 @@ func RetrieveValidatedClusterInfo(discoveryToken string, tokenAPIServers, rootCA
 		if !ok || len(insecureKubeconfigString) == 0 {
 			return nil, fmt.Errorf("there is no %s key in the %s ConfigMap. This API Server isn't set up for token bootstrapping, can't connect", bootstrapapi.KubeConfigKey, bootstrapapi.ConfigMapClusterInfo)
 		}
-		detachedJWSToken, ok := insecureClusterInfo.Data[bootstrapapi.JWSSignatureKeyPrefix+tokenId]
+		detachedJWSToken, ok := insecureClusterInfo.Data[bootstrapapi.JWSSignatureKeyPrefix+tokenID]
 		if !ok || len(detachedJWSToken) == 0 {
-			return nil, fmt.Errorf("there is no JWS signed token in the %s ConfigMap. This token id %q is invalid for this cluster, can't connect", bootstrapapi.ConfigMapClusterInfo, tokenId)
+			return nil, fmt.Errorf("there is no JWS signed token in the %s ConfigMap. This token id %q is invalid for this cluster, can't connect", bootstrapapi.ConfigMapClusterInfo, tokenID)
 		}
-		if !bootstrap.DetachedTokenIsValid(detachedJWSToken, insecureKubeconfigString, tokenId, tokenSecret) {
+		if !bootstrap.DetachedTokenIsValid(detachedJWSToken, insecureKubeconfigString, tokenID, tokenSecret) {
 			return nil, fmt.Errorf("failed to verify JWS signature of received cluster info object, can't trust this API Server")
 		}
 		insecureKubeconfigBytes := []byte(insecureKubeconfigString)
@@ -126,7 +127,7 @@ func RetrieveValidatedClusterInfo(discoveryToken string, tokenAPIServers, rootCA
 
 		// Now that we know the proported cluster CA, connect back a second time validating with that CA
 		secureBootstrapConfig := buildSecureBootstrapKubeConfig(endpoint, clusterCABytes)
-		secureClient, err := kubeconfigutil.KubeConfigToClientSet(secureBootstrapConfig)
+		secureClient, err := kubeconfigutil.ToClientSet(secureBootstrapConfig)
 		if err != nil {
 			return nil, err
 		}

cmd/kubeadm/app/images/images.go

@@ -24,6 +24,7 @@ import (
 	kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
 )
 
+// GetCoreImage generates and returns the image for the core Kubernetes components or returns overrideImage if specified
 func GetCoreImage(image, repoPrefix, k8sVersion, overrideImage string) string {
 	if overrideImage != "" {
 		return overrideImage

cmd/kubeadm/app/kubeadm.go

@@ -25,6 +25,7 @@ import (
 	"k8s.io/kubernetes/cmd/kubeadm/app/cmd"
 )
 
+// Run creates and executes new kubeadm command
 func Run() error {
 	// We do not want these flags to show up in --help
 	pflag.CommandLine.MarkHidden("google-json-key")

cmd/kubeadm/app/node/csr.go

@@ -31,7 +31,7 @@ const CSRContextAndUser = "kubelet-csr"
 
 // PerformTLSBootstrap executes a node certificate signing request.
 func PerformTLSBootstrap(cfg *clientcmdapi.Config, hostName string) error {
-	client, err := kubeconfigutil.KubeConfigToClientSet(cfg)
+	client, err := kubeconfigutil.ToClientSet(cfg)
 	if err != nil {
 		return err
 	}

cmd/kubeadm/app/phases/certs/pkiutil/pki_helpers.go

@@ -27,6 +27,7 @@ import (
 	certutil "k8s.io/client-go/util/cert"
 )
 
+// NewCertificateAuthority creates new certificate and private key for the certificate authority
 func NewCertificateAuthority() (*x509.Certificate, *rsa.PrivateKey, error) {
 	key, err := certutil.NewPrivateKey()
 	if err != nil {
@@ -44,6 +45,7 @@ func NewCertificateAuthority() (*x509.Certificate, *rsa.PrivateKey, error) {
 	return cert, key, nil
 }
 
+// NewCertAndKey creates new certificate and key by passing the certificate authority certificate and key
 func NewCertAndKey(caCert *x509.Certificate, caKey *rsa.PrivateKey, config certutil.Config) (*x509.Certificate, *rsa.PrivateKey, error) {
 	key, err := certutil.NewPrivateKey()
 	if err != nil {
@@ -68,6 +70,7 @@ func HasServerAuth(cert *x509.Certificate) bool {
 	return false
 }
 
+// WriteCertAndKey stores certificate and key at the specified location
 func WriteCertAndKey(pkiPath string, name string, cert *x509.Certificate, key *rsa.PrivateKey) error {
 	if err := WriteKey(pkiPath, name, key); err != nil {
 		return err
@@ -80,6 +83,7 @@ func WriteCertAndKey(pkiPath string, name string, cert *x509.Certificate, key *r
 	return nil
 }
 
+// WriteCert stores the given certificate at the given location
 func WriteCert(pkiPath, name string, cert *x509.Certificate) error {
 	if cert == nil {
 		return fmt.Errorf("certificate cannot be nil when writing to file")
@@ -93,6 +97,7 @@ func WriteCert(pkiPath, name string, cert *x509.Certificate) error {
 	return nil
 }
 
+// WriteKey stores the given key at the given location
 func WriteKey(pkiPath, name string, key *rsa.PrivateKey) error {
 	if key == nil {
 		return fmt.Errorf("private key cannot be nil when writing to file")
@@ -106,6 +111,7 @@ func WriteKey(pkiPath, name string, key *rsa.PrivateKey) error {
 	return nil
 }
 
+// WritePublicKey stores the given public key at the given location
 func WritePublicKey(pkiPath, name string, key *rsa.PublicKey) error {
 	if key == nil {
 		return fmt.Errorf("public key cannot be nil when writing to file")

cmd/kubeadm/app/preflight/checks.go

@@ -64,6 +64,7 @@ var (
 	minExternalEtcdVersion = semver.MustParse(kubeadmconstants.MinExternalEtcdVersion)
 )
 
+// Error defines struct for communicating error messages generated by preflight checks
 type Error struct {
 	Msg string
 }
@@ -86,6 +87,7 @@ type ServiceCheck struct {
 	CheckIfActive bool
 }
 
+// Check validates if the service is enabled and active.
 func (sc ServiceCheck) Check() (warnings, errors []error) {
 	initSystem, err := initsystem.GetInitSystem()
 	if err != nil {
@@ -114,11 +116,13 @@ func (sc ServiceCheck) Check() (warnings, errors []error) {
 	return warnings, errors
 }
 
-// FirewalldCheck checks if firewalld is enabled or active, and if so outputs a warning.
+// FirewalldCheck checks if firewalld is enabled or active. If it is, warn the user that there may be problems
+// if no actions are taken.
 type FirewalldCheck struct {
 	ports []int
 }
 
+// Check validates if the firewall is enabled and active.
 func (fc FirewalldCheck) Check() (warnings, errors []error) {
 	initSystem, err := initsystem.GetInitSystem()
 	if err != nil {
@@ -145,6 +149,7 @@ type PortOpenCheck struct {
 	port int
 }
 
+// Check validates if the particular port is available.
 func (poc PortOpenCheck) Check() (warnings, errors []error) {
 	errors = []error{}
 	ln, err := net.Listen("tcp", fmt.Sprintf(":%d", poc.port))
@@ -161,6 +166,7 @@ func (poc PortOpenCheck) Check() (warnings, errors []error) {
 // IsRootCheck verifies user is root
 type IsRootCheck struct{}
 
+// Check validates if an user has root privileges.
 func (irc IsRootCheck) Check() (warnings, errors []error) {
 	errors = []error{}
 	if os.Getuid() != 0 {
@@ -175,6 +181,7 @@ type DirAvailableCheck struct {
 	Path string
 }
 
+// Check validates if a directory does not exist or empty.
 func (dac DirAvailableCheck) Check() (warnings, errors []error) {
 	errors = []error{}
 	// If it doesn't exist we are good:
@@ -202,6 +209,7 @@ type FileAvailableCheck struct {
 	Path string
 }
 
+// Check validates if the given file does not already exist.
 func (fac FileAvailableCheck) Check() (warnings, errors []error) {
 	errors = []error{}
 	if _, err := os.Stat(fac.Path); err == nil {
@@ -215,6 +223,7 @@ type FileExistingCheck struct {
 	Path string
 }
 
+// Check validates if the given file already exists.
 func (fac FileExistingCheck) Check() (warnings, errors []error) {
 	errors = []error{}
 	if _, err := os.Stat(fac.Path); err != nil {
@@ -229,6 +238,7 @@ type FileContentCheck struct {
 	Content []byte
 }
 
+// Check validates if the given file contains the given content.
 func (fcc FileContentCheck) Check() (warnings, errors []error) {
 	f, err := os.Open(fcc.Path)
 	if err != nil {
@@ -251,12 +261,13 @@ func (fcc FileContentCheck) Check() (warnings, errors []error) {
 
 }
 
-// InPathCheck checks if the given executable is present in the path
+// InPathCheck checks if the given executable is present in $PATH
 type InPathCheck struct {
 	executable string
 	mandatory  bool
 }
 
+// Check validates if the given executable is present in the path.
 func (ipc InPathCheck) Check() (warnings, errors []error) {
 	_, err := exec.LookPath(ipc.executable)
 	if err != nil {
@@ -276,6 +287,7 @@ type HostnameCheck struct {
 	nodeName string
 }
 
+// Check validates if hostname match dns sub domain regex.
 func (hc HostnameCheck) Check() (warnings, errors []error) {
 	errors = []error{}
 	warnings = []error{}
@@ -300,6 +312,7 @@ type HTTPProxyCheck struct {
 	Port  int
 }
 
+// Check validates http connectivity type, direct or via proxy.
 func (hst HTTPProxyCheck) Check() (warnings, errors []error) {
 
 	url := fmt.Sprintf("%s://%s:%d", hst.Proto, hst.Host, hst.Port)
@@ -326,6 +339,7 @@ type ExtraArgsCheck struct {
 	SchedulerExtraArgs         map[string]string
 }
 
+// Check validates additional arguments of the control plane components.
 func (eac ExtraArgsCheck) Check() (warnings, errors []error) {
 	argsCheck := func(name string, args map[string]string, f *pflag.FlagSet) []error {
 		errs := []error{}
@@ -359,8 +373,10 @@ func (eac ExtraArgsCheck) Check() (warnings, errors []error) {
 	return warnings, nil
 }
 
+// SystemVerificationCheck defines struct used for for running the system verification node check in test/e2e_node/system
 type SystemVerificationCheck struct{}
 
+// Check runs all individual checks
 func (sysver SystemVerificationCheck) Check() (warnings, errors []error) {
 	// Create a buffered writer and choose a quite large value (1M) and suppose the output from the system verification test won't exceed the limit
 	// Run the system verification check, but write to out buffered writer instead of stdout
@@ -397,11 +413,13 @@ func (sysver SystemVerificationCheck) Check() (warnings, errors []error) {
 	return warns, nil
 }
 
+// KubernetesVersionCheck validates kubernetes and kubeadm versions
 type KubernetesVersionCheck struct {
 	KubeadmVersion    string
 	KubernetesVersion string
 }
 
+// Check validates kubernetes and kubeadm versions
 func (kubever KubernetesVersionCheck) Check() (warnings, errors []error) {
 
 	// Skip this check for "super-custom builds", where apimachinery/the overall codebase version is not set.
@@ -434,6 +452,7 @@ func (kubever KubernetesVersionCheck) Check() (warnings, errors []error) {
 // SwapCheck warns if swap is enabled
 type SwapCheck struct{}
 
+// Check validates whether swap is enabled or not
 func (swc SwapCheck) Check() (warnings, errors []error) {
 	f, err := os.Open("/proc/swaps")
 	if err != nil {
@@ -451,7 +470,7 @@ func (swc SwapCheck) Check() (warnings, errors []error) {
 	}
 
 	if len(buf) > 1 {
-		return []error{fmt.Errorf("Running with swap on is not supported. Please disable swap or set kubelet's --fail-swap-on flag to false.")}, nil
+		return []error{fmt.Errorf("running with swap on is not supported. Please disable swap or set kubelet's --fail-swap-on flag to false")}, nil
 	}
 
 	return nil, nil
@@ -467,6 +486,7 @@ type ExternalEtcdVersionCheck struct {
 	Etcd kubeadmapi.Etcd
 }
 
+// Check validates external etcd version
 func (evc ExternalEtcdVersionCheck) Check() (warnings, errors []error) {
 	var config *tls.Config
 	var err error
@@ -549,6 +569,7 @@ func (evc ExternalEtcdVersionCheck) configCertAndKey(config *tls.Config) (*tls.C
 	}
 	return config, nil
 }
+
 func (evc ExternalEtcdVersionCheck) getHTTPClient(config *tls.Config) *http.Client {
 	if config != nil {
 		transport := &http.Transport{
@@ -561,6 +582,7 @@ func (evc ExternalEtcdVersionCheck) getHTTPClient(config *tls.Config) *http.Clie
 	}
 	return &http.Client{Timeout: externalEtcdRequestTimeout}
 }
+
 func getEtcdVersionResponse(client *http.Client, url string, target interface{}) error {
 	loopCount := externalEtcdRequestRetries + 1
 	var err error
@@ -590,6 +612,8 @@ func getEtcdVersionResponse(client *http.Client, url string, target interface{})
 	}
 	return err
 }
+
+// RunInitMasterChecks executes all individual, applicable to Master node checks.
 func RunInitMasterChecks(cfg *kubeadmapi.MasterConfiguration) error {
 	// First, check if we're root separately from the other preflight checks and fail fast
 	if err := RunRootCheckOnly(); err != nil {
@@ -655,6 +679,7 @@ func RunInitMasterChecks(cfg *kubeadmapi.MasterConfiguration) error {
 	return RunChecks(checks, os.Stderr)
 }
 
+// RunJoinNodeChecks executes all individual, applicable to node checks.
 func RunJoinNodeChecks(cfg *kubeadmapi.NodeConfiguration) error {
 	// First, check if we're root separately from the other preflight checks and fail fast
 	if err := RunRootCheckOnly(); err != nil {
@@ -688,6 +713,7 @@ func RunJoinNodeChecks(cfg *kubeadmapi.NodeConfiguration) error {
 	return RunChecks(checks, os.Stderr)
 }
 
+// RunRootCheckOnly initializes cheks slice of structs and call RunChecks
 func RunRootCheckOnly() error {
 	checks := []Checker{
 		IsRootCheck{},
@@ -717,6 +743,7 @@ func RunChecks(checks []Checker, ww io.Writer) error {
 	return nil
 }
 
+// TryStartKubelet attempts to bring up kubelet service
 func TryStartKubelet() {
 	// If we notice that the kubelet service is inactive, try to start it
 	initSystem, err := initsystem.GetInitSystem()

cmd/kubeadm/app/util/config/masterconfig.go

@@ -34,6 +34,7 @@ import (
 	"k8s.io/kubernetes/pkg/util/version"
 )
 
+// SetInitDynamicDefaults checks and sets conifugration values for Master node
 func SetInitDynamicDefaults(cfg *kubeadmapi.MasterConfiguration) error {
 
 	// Choose the right address for the API Server to advertise. If the advertise address is localhost or 0.0.0.0, the default interface's IP address is used
@@ -48,7 +49,6 @@ func SetInitDynamicDefaults(cfg *kubeadmapi.MasterConfiguration) error {
 	if kubeadmutil.KubernetesIsCIVersion(cfg.KubernetesVersion) {
 		cfg.CIImageRepository = kubeadmconstants.DefaultCIImageRepository
 	}
-
 	// Validate version argument
 	ver, err := kubeadmutil.KubernetesReleaseVersion(cfg.KubernetesVersion)
 	if err != nil {
@@ -112,7 +112,6 @@ func ConfigFileAndDefaultsToInternalConfig(cfgPath string, defaultversionedcfg *
 	// static default values to cfg only for values not provided with flags
 	api.Scheme.Default(defaultversionedcfg)
 	api.Scheme.Convert(defaultversionedcfg, internalcfg, nil)
-
 	// Applies dynamic defaults to settings not provided with flags
 	if err := SetInitDynamicDefaults(internalcfg); err != nil {
 		return nil, err

cmd/kubeadm/app/util/error.go

@@ -26,8 +26,11 @@ import (
 )
 
 const (
+	// DefaultErrorExitCode defines exit the code for failed action generally
 	DefaultErrorExitCode = 1
+	// PreFlightExitCode defines exit the code for preflight checks
 	PreFlightExitCode = 2
+	// ValidationExitCode defines the exit code validation checks
 	ValidationExitCode = 3
 )
 

cmd/kubeadm/app/util/kubeconfig/kubeconfig.go

@@ -72,11 +72,11 @@ func ClientSetFromFile(path string) (*clientset.Clientset, error) {
 	if err != nil {
 		return nil, fmt.Errorf("failed to load admin kubeconfig [%v]", err)
 	}
-	return KubeConfigToClientSet(config)
+	return ToClientSet(config)
 }
 
-// KubeConfigToClientSet converts a KubeConfig object to a client
+// ToClientSet converts a KubeConfig object to a client
-func KubeConfigToClientSet(config *clientcmdapi.Config) (*clientset.Clientset, error) {
+func ToClientSet(config *clientcmdapi.Config) (*clientset.Clientset, error) {
 	clientConfig, err := clientcmd.NewDefaultClientConfig(*config, &clientcmd.ConfigOverrides{}).ClientConfig()
 	if err != nil {
 		return nil, fmt.Errorf("failed to create API client configuration from kubeconfig: %v", err)

cmd/kubeadm/app/util/template.go

@@ -22,6 +22,7 @@ import (
 	"text/template"
 )
 
+// ParseTemplate validates and parses passed as argument template
 func ParseTemplate(strtmpl string, obj interface{}) ([]byte, error) {
 	var buf bytes.Buffer
 	tmpl, err := template.New("template").Parse(strtmpl)

cmd/kubeadm/app/util/token/tokens.go

@@ -26,14 +26,20 @@ import (
 )
 
 const (
+	// TokenIDBytes defines a number of bytes used for a token id
 	TokenIDBytes = 3
+	// TokenSecretBytes defines a number of bytes used for a secret
 	TokenSecretBytes = 8
 )
 
 var (
+	// TokenIDRegexpString defines token's id regular expression pattern
 	TokenIDRegexpString = "^([a-z0-9]{6})$"
+	// TokenIDRegexp is a compiled regular expression of TokenIDRegexpString
 	TokenIDRegexp = regexp.MustCompile(TokenIDRegexpString)
+	// TokenRegexpString defines id.secret regular expression pattern
 	TokenRegexpString = "^([a-z0-9]{6})\\.([a-z0-9]{16})$"
+	// TokenRegexp is a compiled regular expression of TokenRegexpString
 	TokenRegexp = regexp.MustCompile(TokenRegexpString)
 )
 

cmd/kubeadm/app/util/version_test.go

@@ -187,7 +187,6 @@ func TestSplitVersion(t *testing.T) {
 		// unknown area, not valid input.
 		{"unknown/latest-1", "", "", false},
 	}
-
 	// kubeReleaseBucketURL can be overriden during network tests, thus ensure
 	// it will contain value corresponding to expected outcome for this unit test
 	kubeReleaseBucketURL = "https://dl.k8s.io"

cmd/kubeadm/test/cmd/util.go

@@ -27,6 +27,8 @@ import (
 
 // Forked from test/e2e/framework because the e2e framework is quite bloated
 // for our purposes here, and modified to remove undesired logging.
+
+// RunCmd is a utility function for kubeadm testing that executes a specified command
 func RunCmd(command string, args ...string) (string, string, error) {
 	var bout, berr bytes.Buffer
 	cmd := exec.Command(command, args...)

hack/.golint_failures

@@ -9,21 +9,6 @@ cmd/kube-proxy/app
 cmd/kubeadm/app
 cmd/kubeadm/app/apis/kubeadm
 cmd/kubeadm/app/apis/kubeadm/v1alpha1
-cmd/kubeadm/app/apis/kubeadm/validation
-cmd/kubeadm/app/cmd
-cmd/kubeadm/app/cmd/phases
-cmd/kubeadm/app/constants
-cmd/kubeadm/app/discovery
-cmd/kubeadm/app/discovery/file
-cmd/kubeadm/app/discovery/token
-cmd/kubeadm/app/images
-cmd/kubeadm/app/phases/certs/pkiutil
-cmd/kubeadm/app/preflight
-cmd/kubeadm/app/util
-cmd/kubeadm/app/util/config
-cmd/kubeadm/app/util/kubeconfig
-cmd/kubeadm/app/util/token
-cmd/kubeadm/test/cmd
 cmd/kubectl/app
 cmd/kubelet/app
 cmd/kubelet/app/options