func (s *executor) Cleanup() {
	s.sshCommand.Cleanup()

	if s.vmName != "" {
		vbox.Kill(s.vmName)

		if s.Config.VirtualBox.DisableSnapshots || !s.provisioned {
			vbox.Delete(s.vmName)
		}
	}
}
func (s *executor) Prepare(globalConfig *common.Config, config *common.RunnerConfig, build *common.Build) error {
	err := s.AbstractExecutor.Prepare(globalConfig, config, build)
	if err != nil {
		return err
	}

	if s.BuildShell.PassFile {
		return errors.New("virtualbox doesn't support shells that require script file")
	}

	if s.Config.SSH == nil {
		return errors.New("Missing SSH config")
	}

	if s.Config.VirtualBox == nil {
		return errors.New("Missing VirtualBox configuration")
	}

	if s.Config.VirtualBox.BaseName == "" {
		return errors.New("Missing BaseName setting from VirtualBox configuration")
	}

	version, err := vbox.Version()
	if err != nil {
		return err
	}

	s.Println("Using VirtualBox version", version, "executor...")

	if s.Config.VirtualBox.DisableSnapshots {
		s.vmName = s.Config.VirtualBox.BaseName + "-" + s.Build.ProjectUniqueName()
		if vbox.Exist(s.vmName) {
			s.Debugln("Deleting old VM...")
			vbox.Stop(s.vmName)
			vbox.Delete(s.vmName)
			vbox.Unregister(s.vmName)
		}
	} else {
		s.vmName = fmt.Sprintf("%s-runner-%s-concurrent-%d",
			s.Config.VirtualBox.BaseName,
			s.Build.Runner.ShortDescription(),
			s.Build.RunnerID)
	}

	if vbox.Exist(s.vmName) {
		s.Println("Restoring VM from snapshot...")
		err := s.restoreFromSnapshot()
		if err != nil {
			s.Println("Previous VM failed. Deleting, because", err)
			vbox.Stop(s.vmName)
			vbox.Delete(s.vmName)
			vbox.Unregister(s.vmName)
		}
	}

	if !vbox.Exist(s.vmName) {
		s.Println("Creating new VM...")
		err := s.createVM(s.vmName)
		if err != nil {
			return err
		}

		if !s.Config.VirtualBox.DisableSnapshots {
			s.Println("Creating default snapshot...")
			err = vbox.CreateSnapshot(s.vmName, "Started")
			if err != nil {
				return err
			}
		}
	}

	s.Debugln("Checking VM status...")
	status, err := vbox.Status(s.vmName)
	if err != nil {
		return err
	}

	if !vbox.IsStatusOnlineOrTransient(status) {
		s.Println("Starting VM...")
		err := vbox.Start(s.vmName)
		if err != nil {
			return err
		}
	}

	if status != vbox.Running {
		s.Debugln("Waiting for VM to run...")
		err = vbox.WaitForStatus(s.vmName, vbox.Running, 60)
		if err != nil {
			return err
		}
	}

	s.Debugln("Identify SSH Port...")
	sshPort, err := vbox.FindSSHPort(s.vmName)
	s.sshPort = sshPort
	if err != nil {
		return err
	}

	s.Println("Waiting VM to become responsive...")
	err = s.verifyMachine(s.vmName, s.sshPort)
	if err != nil {
		return err
	}

	s.provisioned = true

	s.Println("Starting SSH command...")
	s.sshCommand = ssh.Client{
		Config: *s.Config.SSH,
		Stdout: s.BuildTrace,
		Stderr: s.BuildTrace,
	}
	s.sshCommand.Port = s.sshPort
	s.sshCommand.Host = "localhost"

	s.Debugln("Connecting to SSH server...")
	err = s.sshCommand.Connect()
	if err != nil {
		return err
	}
	return nil
}