Fix errors and improve output in kubeadm pre-flight checks.

Add skip-preflight-checks to known flags.
Fix bug with preflight checks not returning system is-active as errors.
Fix error handling to use correct function.

cmd/kubeadm/app/cmd/init.go

@@ -27,11 +27,11 @@ import (
 	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
 	kubemaster "k8s.io/kubernetes/cmd/kubeadm/app/master"
 	"k8s.io/kubernetes/cmd/kubeadm/app/preflight"
+	cmdutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
 	kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
 	"k8s.io/kubernetes/pkg/api"
 	"k8s.io/kubernetes/pkg/cloudprovider"
 	_ "k8s.io/kubernetes/pkg/cloudprovider/providers"
-	cmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util"
 	"k8s.io/kubernetes/pkg/runtime"
 	netutil "k8s.io/kubernetes/pkg/util/net"
 )
@@ -150,7 +150,7 @@ func NewInit(cfgPath string, cfg *kubeadmapi.MasterConfiguration, skipPreFlight
 	}
 
 	if !skipPreFlight {
-		fmt.Println("Running pre-flight checks")
+		fmt.Println("<cmd/init> Running pre-flight checks")
 		err := preflight.RunInitMasterChecks()
 		if err != nil {
 			return nil, err

cmd/kubeadm/app/preflight/checks.go

@@ -49,7 +49,6 @@ type ServiceCheck struct {
 }
 
 func (sc ServiceCheck) Check() (warnings, errors []error) {
-
 	initSystem := initsystem.GetInitSystem()
 	if initSystem == nil {
 		return []error{fmt.Errorf("no supported init system detected, skipping service checks for %s", sc.service)}, nil
@@ -74,7 +73,7 @@ func (sc ServiceCheck) Check() (warnings, errors []error) {
 				sc.service, sc.service))
 	}
 
-	return warnings, nil
+	return warnings, errors
 }
 
 // PortOpenCheck ensures the given port is available for use.
@@ -219,7 +218,7 @@ func runChecks(checks []PreFlightCheck) error {
 	for _, c := range checks {
 		warnings, errors := c.Check()
 		for _, w := range warnings {
-			fmt.Printf("WARNING: %s\n", w)
+			fmt.Printf("<preflight/checks> WARNING: %s\n", w)
 		}
 		for _, e := range errors {
 			found = append(found, e)

hack/verify-flags/known-flags.txt

@@ -512,6 +512,7 @@ since-seconds
 since-time
 skip-generated-rewrite
 skip-munges
+skip-preflight-checks
 sort-by
 source-file
 ssh-env

pkg/util/initsystem/initsystem.go

@@ -17,13 +17,11 @@ limitations under the License.
 package initsystem
 
 import (
-	"fmt"
 	"os/exec"
 	"strings"
 )
 
 type InitSystem interface {
-
 	// ServiceExists ensures the service is defined for this init system.
 	ServiceExists(service string) bool
 
@@ -50,7 +48,6 @@ func (sysd SystemdInitSystem) ServiceIsEnabled(service string) bool {
 	args := []string{"is-enabled", service}
 	_, err := exec.Command("systemctl", args...).Output()
 	if err != nil {
-		fmt.Println(err)
 		return false
 	}
 	return true