Merge pull request #47803 from gtirloni/kubeadm-phase-preflight

Automatic merge from submit-queue (batch tested with PRs 47694, 47772, 47783, 47803, 47673)

Add "alpha phase preflight" command

**What this PR does / why we need it:**

Adds "alpha phase preflight" command to kubeadm in order to run pre-flight checks independently of init phase.

**Which issue this PR fixes:** fixes kubernetes/kubeadm#314

/cc @luxas

cmd/kubeadm/app/cmd/init.go

@@ -167,12 +167,6 @@ func NewInit(cfgPath string, cfg *kubeadmapi.MasterConfiguration, skipPreFlight,
 	if !skipPreFlight {
 		fmt.Println("[preflight] Running pre-flight checks")
 
-		// First, check if we're root separately from the other preflight checks and fail fast
-		if err := preflight.RunRootCheckOnly(); err != nil {
-			return nil, err
-		}
-
-		// Then continue with the others...
 		if err := preflight.RunInitMasterChecks(cfg); err != nil {
 			return nil, err
 		}

cmd/kubeadm/app/cmd/join.go

@@ -147,11 +147,6 @@ func NewJoin(cfgPath string, args []string, cfg *kubeadmapi.NodeConfiguration, s
 	if !skipPreFlight {
 		fmt.Println("[preflight] Running pre-flight checks")
 
-		// First, check if we're root separately from the other preflight checks and fail fast
-		if err := preflight.RunRootCheckOnly(); err != nil {
-			return nil, err
-		}
-
 		// Then continue with the others...
 		if err := preflight.RunJoinNodeChecks(cfg); err != nil {
 			return nil, err

cmd/kubeadm/app/cmd/phases/BUILD

@@ -13,6 +13,7 @@ go_library(
         "certs.go",
         "kubeconfig.go",
         "phase.go",
+        "preflight.go",
         "validate.go",
     ],
     tags = ["automanaged"],
@@ -23,6 +24,7 @@ go_library(
         "//cmd/kubeadm/app/phases/certs:go_default_library",
         "//cmd/kubeadm/app/phases/kubeconfig:go_default_library",
         "//cmd/kubeadm/app/phases/validate:go_default_library",
+        "//cmd/kubeadm/app/preflight:go_default_library",
         "//cmd/kubeadm/app/util:go_default_library",
         "//pkg/api:go_default_library",
         "//vendor/github.com/spf13/cobra:go_default_library",

cmd/kubeadm/app/cmd/phases/phase.go

@@ -33,6 +33,7 @@ func NewCmdPhase(out io.Writer) *cobra.Command {
 	cmd.AddCommand(NewCmdKubeConfig(out))
 	cmd.AddCommand(NewCmdCerts())
 	cmd.AddCommand(NewCmdValidate())
+	cmd.AddCommand(NewCmdPreFlight())
 
 	return cmd
 }
@@ -46,8 +47,8 @@ func subCmdRunE(name string) func(*cobra.Command, []string) error {
 	return func(_ *cobra.Command, args []string) error {
 		if len(args) < 1 {
 			return fmt.Errorf("missing subcommand; %q is not meant to be run on its own", name)
-		} else {
-			return fmt.Errorf("invalid subcommand: %q", args[0])
 		}
+
+		return fmt.Errorf("invalid subcommand: %q", args[0])
 	}
 }

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

@@ -0,0 +1,62 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package phases
+
+import (
+	"github.com/spf13/cobra"
+
+	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
+	"k8s.io/kubernetes/cmd/kubeadm/app/preflight"
+)
+
+func NewCmdPreFlight() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "preflight",
+		Short: "Run pre-flight checks",
+		RunE:  subCmdRunE("preflight"),
+	}
+
+	cmd.AddCommand(NewCmdPreFlightMaster())
+	cmd.AddCommand(NewCmdPreFlightNode())
+	return cmd
+}
+
+func NewCmdPreFlightMaster() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "master",
+		Short: "Run master pre-flight checks",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			cfg := &kubeadmapi.MasterConfiguration{}
+			return preflight.RunInitMasterChecks(cfg)
+		},
+	}
+
+	return cmd
+}
+
+func NewCmdPreFlightNode() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "node",
+		Short: "Run node pre-flight checks",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			cfg := &kubeadmapi.NodeConfiguration{}
+			return preflight.RunJoinNodeChecks(cfg)
+		},
+	}
+
+	return cmd
+}

cmd/kubeadm/app/preflight/checks.go

@@ -485,6 +485,11 @@ func getEtcdVersionResponse(client *http.Client, url string, target interface{})
 	return err
 }
 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 {
+		return err
+	}
+
 	checks := []Checker{
 		SystemVerificationCheck{},
 		IsRootCheck{},
@@ -538,6 +543,11 @@ func RunInitMasterChecks(cfg *kubeadmapi.MasterConfiguration) error {
 }
 
 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 {
+		return err
+	}
+
 	checks := []Checker{
 		SystemVerificationCheck{},
 		IsRootCheck{},