kubeadm: add mandatory configuration to "phase preflight"

Add the:
- mandatory flag "--config" to the preflight phase
and parse the specified config file for either "master" or "node".
- flag "--ignore-preflight-errors" to the preflight phase to
allow skipping errors.
- the function AddIgnorePreflightErrorsFlag()
to "options/generic.go", because the flag is used in multiple commands.

cmd/kubeadm/app/cmd/options/generic.go

@@ -27,3 +27,11 @@ func AddKubeConfigFlag(fs *pflag.FlagSet, kubeConfigFile *string) {
 func AddConfigFlag(fs *pflag.FlagSet, cfgPath *string) {
 	fs.StringVar(cfgPath, "config", *cfgPath, "Path to kubeadm config file (WARNING: Usage of a configuration file is experimental)")
 }
+
+// AddIgnorePreflightErrorsFlag adds the --ignore-preflight-errors flag to the given flagset
+func AddIgnorePreflightErrorsFlag(fs *pflag.FlagSet, ignorePreflightErrors *[]string) {
+	fs.StringSliceVar(
+		ignorePreflightErrors, "ignore-preflight-errors", *ignorePreflightErrors,
+		"A list of checks whose errors will be shown as warnings. Example: 'IsPrivilegedUser,Swap'. Value 'all' ignores errors from all checks.",
+	)
+}

cmd/kubeadm/app/cmd/phases/BUILD

@@ -49,7 +49,6 @@ go_library(
         "//pkg/util/normalizer:go_default_library",
         "//pkg/util/version:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
-        "//staging/src/k8s.io/apimachinery/pkg/util/sets:go_default_library",
         "//staging/src/k8s.io/apiserver/pkg/util/flag:go_default_library",
         "//staging/src/k8s.io/client-go/kubernetes:go_default_library",
         "//staging/src/k8s.io/client-go/tools/bootstrap/token/api:go_default_library",

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

@@ -17,13 +17,19 @@ limitations under the License.
 package phases
 
 import (
+	"errors"
+	"fmt"
+
 	"github.com/spf13/cobra"
 
-	"k8s.io/apimachinery/pkg/util/sets"
+	kubeadmscheme "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/scheme"
-	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
+	kubeadmapiv1alpha3 "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1alpha3"
+	"k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/validation"
+	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/options"
 	cmdutil "k8s.io/kubernetes/cmd/kubeadm/app/cmd/util"
 	"k8s.io/kubernetes/cmd/kubeadm/app/preflight"
 	kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
+	configutil "k8s.io/kubernetes/cmd/kubeadm/app/util/config"
 	"k8s.io/kubernetes/pkg/util/normalizer"
 	utilsexec "k8s.io/utils/exec"
 )
@@ -46,32 +52,59 @@ var (
 		# Run node pre-flight checks.
 		kubeadm alpha phase preflight node
 	`)
+
+	errorMissingConfigFlag = errors.New("the --config flag is mandatory")
 )
 
 // NewCmdPreFlight calls cobra.Command for preflight checks
 func NewCmdPreFlight() *cobra.Command {
+	var cfgPath string
+	var ignorePreflightErrors []string
+
 	cmd := &cobra.Command{
 		Use:   "preflight",
 		Short: "Run pre-flight checks",
 		Long:  cmdutil.MacroCommandLongDescription,
 	}
 
-	cmd.AddCommand(NewCmdPreFlightMaster())
+	options.AddConfigFlag(cmd.PersistentFlags(), &cfgPath)
-	cmd.AddCommand(NewCmdPreFlightNode())
+	options.AddIgnorePreflightErrorsFlag(cmd.PersistentFlags(), &ignorePreflightErrors)
+
+	cmd.AddCommand(NewCmdPreFlightMaster(&cfgPath, &ignorePreflightErrors))
+	cmd.AddCommand(NewCmdPreFlightNode(&cfgPath, &ignorePreflightErrors))
+
 	return cmd
 }
 
 // NewCmdPreFlightMaster calls cobra.Command for master preflight checks
-func NewCmdPreFlightMaster() *cobra.Command {
+func NewCmdPreFlightMaster(cfgPath *string, ignorePreflightErrors *[]string) *cobra.Command {
+
 	cmd := &cobra.Command{
 		Use:     "master",
 		Short:   "Run master pre-flight checks",
 		Long:    masterPreflightLongDesc,
 		Example: masterPreflightExample,
 		Run: func(cmd *cobra.Command, args []string) {
-			cfg := &kubeadmapi.InitConfiguration{}
+			if len(*cfgPath) == 0 {
-			err := preflight.RunInitMasterChecks(utilsexec.New(), cfg, sets.NewString())
+				kubeadmutil.CheckErr(errorMissingConfigFlag)
+			}
+			ignorePreflightErrorsSet, err := validation.ValidateIgnorePreflightErrors(*ignorePreflightErrors)
 			kubeadmutil.CheckErr(err)
+
+			cfg := &kubeadmapiv1alpha3.InitConfiguration{}
+			kubeadmscheme.Scheme.Default(cfg)
+
+			internalcfg, err := configutil.ConfigFileAndDefaultsToInternalConfig(*cfgPath, cfg)
+			kubeadmutil.CheckErr(err)
+			err = configutil.VerifyAPIServerBindAddress(internalcfg.APIEndpoint.AdvertiseAddress)
+			kubeadmutil.CheckErr(err)
+
+			fmt.Println("[preflight] running pre-flight checks")
+
+			err = preflight.RunInitMasterChecks(utilsexec.New(), internalcfg, ignorePreflightErrorsSet)
+			kubeadmutil.CheckErr(err)
+
+			fmt.Println("[preflight] pre-flight checks passed")
 		},
 	}
 
@@ -79,16 +112,33 @@ func NewCmdPreFlightMaster() *cobra.Command {
 }
 
 // NewCmdPreFlightNode calls cobra.Command for node preflight checks
-func NewCmdPreFlightNode() *cobra.Command {
+func NewCmdPreFlightNode(cfgPath *string, ignorePreflightErrors *[]string) *cobra.Command {
 	cmd := &cobra.Command{
 		Use:     "node",
 		Short:   "Run node pre-flight checks",
 		Long:    nodePreflightLongDesc,
 		Example: nodePreflightExample,
 		Run: func(cmd *cobra.Command, args []string) {
-			cfg := &kubeadmapi.JoinConfiguration{}
+			if len(*cfgPath) == 0 {
-			err := preflight.RunJoinNodeChecks(utilsexec.New(), cfg, sets.NewString())
+				kubeadmutil.CheckErr(errorMissingConfigFlag)
+			}
+			ignorePreflightErrorsSet, err := validation.ValidateIgnorePreflightErrors(*ignorePreflightErrors)
 			kubeadmutil.CheckErr(err)
+
+			cfg := &kubeadmapiv1alpha3.JoinConfiguration{}
+			kubeadmscheme.Scheme.Default(cfg)
+
+			internalcfg, err := configutil.NodeConfigFileAndDefaultsToInternalConfig(*cfgPath, cfg)
+			kubeadmutil.CheckErr(err)
+			err = configutil.VerifyAPIServerBindAddress(internalcfg.APIEndpoint.AdvertiseAddress)
+			kubeadmutil.CheckErr(err)
+
+			fmt.Println("[preflight] running pre-flight checks")
+
+			err = preflight.RunJoinNodeChecks(utilsexec.New(), internalcfg, ignorePreflightErrorsSet)
+			kubeadmutil.CheckErr(err)
+
+			fmt.Println("[preflight] pre-flight checks passed")
 		},
 	}
 

cmd/kubeadm/app/cmd/reset.go

@@ -32,6 +32,7 @@ import (
 	"k8s.io/apimachinery/pkg/util/sets"
 	kubeadmapiv1alpha3 "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1alpha3"
 	"k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/validation"
+	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/options"
 	kubeadmconstants "k8s.io/kubernetes/cmd/kubeadm/app/constants"
 	"k8s.io/kubernetes/cmd/kubeadm/app/preflight"
 	kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
@@ -60,10 +61,7 @@ func NewCmdReset(in io.Reader, out io.Writer) *cobra.Command {
 		},
 	}
 
-	cmd.PersistentFlags().StringSliceVar(
+	options.AddIgnorePreflightErrorsFlag(cmd.PersistentFlags(), &ignorePreflightErrors)
-		&ignorePreflightErrors, "ignore-preflight-errors", ignorePreflightErrors,
-		"A list of checks whose errors will be shown as warnings. Example: 'IsPrivilegedUser,Swap'. Value 'all' ignores errors from all checks.",
-	)
 
 	cmd.PersistentFlags().StringVar(
 		&certsDir, "cert-dir", kubeadmapiv1alpha3.DefaultCertificatesDir,

cmd/kubeadm/app/cmd/upgrade/upgrade.go

@@ -77,8 +77,8 @@ func addApplyPlanFlags(fs *pflag.FlagSet, flags *applyPlanFlags) {
 	fs.BoolVar(&flags.allowExperimentalUpgrades, "allow-experimental-upgrades", flags.allowExperimentalUpgrades, "Show unstable versions of Kubernetes as an upgrade alternative and allow upgrading to an alpha/beta/release candidate versions of Kubernetes.")
 	fs.BoolVar(&flags.allowRCUpgrades, "allow-release-candidate-upgrades", flags.allowRCUpgrades, "Show release candidate versions of Kubernetes as an upgrade alternative and allow upgrading to a release candidate versions of Kubernetes.")
 	fs.BoolVar(&flags.printConfig, "print-config", flags.printConfig, "Specifies whether the configuration file that will be used in the upgrade should be printed or not.")
-	fs.StringSliceVar(&flags.ignorePreflightErrors, "ignore-preflight-errors", flags.ignorePreflightErrors, "A list of checks whose errors will be shown as warnings. Example: 'IsPrivilegedUser,Swap'. Value 'all' ignores errors from all checks.")
 	fs.MarkDeprecated("skip-preflight-checks", "it is now equivalent to --ignore-preflight-errors=all")
 	fs.StringVar(&flags.featureGatesString, "feature-gates", flags.featureGatesString, "A set of key=value pairs that describe feature gates for various features. "+
 		"Options are:\n"+strings.Join(features.KnownFeatures(&features.InitFeatureGates), "\n"))
+	options.AddIgnorePreflightErrorsFlag(fs, &flags.ignorePreflightErrors)
 }