Implement kubeadm reset

cmd/kubeadm/app/cmd/cmd.go

@@ -80,6 +80,7 @@ func NewKubeadmCommand(f cmdutil.Factory, in io.Reader, out, err io.Writer) *cob
 
 	cmds.AddCommand(NewCmdInit(out))
 	cmds.AddCommand(NewCmdJoin(out))
+	cmds.AddCommand(NewCmdReset(out))
 	cmds.AddCommand(NewCmdVersion(out))
 
 	return cmds

cmd/kubeadm/app/cmd/reset.go

@@ -0,0 +1,97 @@
+/*
+Copyright 2014 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 cmd
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+
+	"github.com/spf13/cobra"
+
+	"k8s.io/kubernetes/cmd/kubeadm/app/preflight"
+	cmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util"
+	"k8s.io/kubernetes/pkg/util/initsystem"
+)
+
+func NewCmdReset(out io.Writer) *cobra.Command {
+	var skipPreFlight bool
+	cmd := &cobra.Command{
+		Use:   "reset",
+		Short: "Revert the actions kubeadm init or join made to the machine",
+		Run: func(cmd *cobra.Command, args []string) {
+			err := RunReset(out, cmd, skipPreFlight)
+			cmdutil.CheckErr(err)
+		},
+	}
+
+	cmd.PersistentFlags().BoolVar(
+		&skipPreFlight, "skip-preflight-checks", false,
+		"skip preflight checks normally run before modifying the system",
+	)
+
+	return cmd
+}
+
+func RunReset(out io.Writer, cmd *cobra.Command, skipPreFlight bool) error {
+
+	if !skipPreFlight {
+		fmt.Println("Running pre-flight checks")
+		err := preflight.RunResetCheck()
+		if err != nil {
+			return err
+		}
+	} else {
+		fmt.Println("Skipping pre-flight checks")
+	}
+
+	serviceToStop := "kubelet"
+	initSystem, err := initsystem.GetInitSystem()
+	if err != nil {
+		fmt.Printf("%v", err)
+	} else {
+		fmt.Printf("Stopping the %s service...\n", serviceToStop)
+		initSystem.ServiceStop(serviceToStop)
+	}
+
+	fmt.Printf("Unmounting directories in /var/lib/kubelet...\n")
+	// Don't check for errors here, since umount will return a non-zero exit code if there is no directories to umount
+	exec.Command("sh", "-c", "cat /proc/mounts | awk '{print $2}' | grep '/var/lib/kubelet' | xargs umount").Run()
+
+	dirsToRemove := []string{"/var/lib/kubelet", "/var/lib/etcd", "/etc/kubernetes"}
+	fmt.Printf("Deleting the stateful directories: %v\n", dirsToRemove)
+	for _, dir := range dirsToRemove {
+		err := os.RemoveAll(dir)
+		if err != nil {
+			fmt.Printf("failed to remove directory: [%v]", err)
+		}
+	}
+
+	dockerCheck := preflight.ServiceCheck{Service: "docker"}
+	if warnings, errors := dockerCheck.Check(); len(warnings) == 0 && len(errors) == 0 {
+
+		fmt.Printf("Stopping all running docker containers...")
+		if err := exec.Command("sh", "-c", "docker ps | grep 'k8s_' | awk '{print $1}' | xargs docker rm --force --volumes").Run(); err != nil {
+			fmt.Printf("failed to stop the running containers")
+		}
+	} else {
+		fmt.Printf("docker doesn't seem to be running, skipping the removal of kubernetes containers")
+	}
+
+	return nil
+}

cmd/kubeadm/app/preflight/checks.go

@@ -45,32 +45,32 @@ type PreFlightCheck interface {
 // detect a supported init system however, all checks are skipped and a warning is
 // returned.
 type ServiceCheck struct {
-	service string
+	Service string
 }
 
 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
+	initSystem, err := initsystem.GetInitSystem()
+	if err != nil {
+		return []error{err}, nil
 	}
 
 	warnings = []error{}
 
-	if !initSystem.ServiceExists(sc.service) {
-		warnings = append(warnings, fmt.Errorf("%s service does not exist", sc.service))
+	if !initSystem.ServiceExists(sc.Service) {
+		warnings = append(warnings, fmt.Errorf("%s service does not exist", sc.Service))
 		return warnings, nil
 	}
 
-	if !initSystem.ServiceIsEnabled(sc.service) {
+	if !initSystem.ServiceIsEnabled(sc.Service) {
 		warnings = append(warnings,
 			fmt.Errorf("%s service is not enabled, please run 'systemctl enable %s.service'",
-				sc.service, sc.service))
+				sc.Service, sc.Service))
 	}
 
-	if !initSystem.ServiceIsActive(sc.service) {
+	if !initSystem.ServiceIsActive(sc.Service) {
 		errors = append(errors,
 			fmt.Errorf("%s service is not active, please run 'systemctl start %s.service'",
-				sc.service, sc.service))
+				sc.Service, sc.Service))
 	}
 
 	return warnings, errors
@@ -160,8 +160,8 @@ func RunInitMasterChecks() error {
 	// TODO: Some of these ports should come from kubeadm config eventually:
 	checks := []PreFlightCheck{
 		IsRootCheck{root: true},
-		ServiceCheck{service: "kubelet"},
-		ServiceCheck{service: "docker"},
+		ServiceCheck{Service: "kubelet"},
+		ServiceCheck{Service: "docker"},
 		PortOpenCheck{port: 443},
 		PortOpenCheck{port: 2379},
 		PortOpenCheck{port: 8080},
@@ -189,12 +189,9 @@ func RunJoinNodeChecks() error {
 	// TODO: Some of these ports should come from kubeadm config eventually:
 	checks := []PreFlightCheck{
 		IsRootCheck{root: true},
-		ServiceCheck{service: "docker"},
-		ServiceCheck{service: "kubelet"},
-		PortOpenCheck{port: 8080},
+		ServiceCheck{Service: "docker"},
+		ServiceCheck{Service: "kubelet"},
 		PortOpenCheck{port: 10250},
-		PortOpenCheck{port: 10251},
-		PortOpenCheck{port: 10252},
 		DirAvailableCheck{path: "/etc/kubernetes"},
 		DirAvailableCheck{path: "/var/lib/kubelet"},
 		InPathCheck{executable: "ebtables", mandatory: true},
@@ -211,6 +208,14 @@ func RunJoinNodeChecks() error {
 	return runChecks(checks)
 }
 
+func RunResetCheck() error {
+	checks := []PreFlightCheck{
+		IsRootCheck{root: true},
+	}
+
+	return runChecks(checks)
+}
+
 // runChecks runs each check, displays it's warnings/errors, and once all
 // are processed will exit if any errors occurred.
 func runChecks(checks []PreFlightCheck) error {

pkg/util/initsystem/initsystem.go

@@ -17,11 +17,18 @@ limitations under the License.
 package initsystem
 
 import (
+	"fmt"
 	"os/exec"
 	"strings"
 )
 
 type InitSystem interface {
+	// ServiceStart tries to start a specific service
+	ServiceStart(service string) error
+
+	// ServiceStop tries to stop a specific service
+	ServiceStop(service string) error
+
 	// ServiceExists ensures the service is defined for this init system.
 	ServiceExists(service string) bool
 
@@ -34,6 +41,18 @@ type InitSystem interface {
 
 type SystemdInitSystem struct{}
 
+func (sysd SystemdInitSystem) ServiceStart(service string) error {
+	args := []string{"start", service}
+	_, err := exec.Command("systemctl", args...).Output()
+	return err
+}
+
+func (sysd SystemdInitSystem) ServiceStop(service string) error {
+	args := []string{"stop", service}
+	_, err := exec.Command("systemctl", args...).Output()
+	return err
+}
+
 func (sysd SystemdInitSystem) ServiceExists(service string) bool {
 	args := []string{"status", service}
 	outBytes, _ := exec.Command("systemctl", args...).Output()
@@ -70,11 +89,11 @@ func (sysd SystemdInitSystem) ServiceIsActive(service string) bool {
 // getInitSystem returns an InitSystem for the current system, or nil
 // if we cannot detect a supported init system for pre-flight checks.
 // This indicates we will skip init system checks, not an error.
-func GetInitSystem() InitSystem {
+func GetInitSystem() (InitSystem, error) {
 	// Assume existence of systemctl in path implies this is a systemd system:
 	_, err := exec.LookPath("systemctl")
 	if err == nil {
-		return &SystemdInitSystem{}
+		return &SystemdInitSystem{}, nil
 	}
-	return nil
+	return nil, fmt.Errorf("no supported init system detected, skipping checking for services")
 }