packer-cn/builder/hyperv/vmcx/builder.go

//go:generate struct-markdown

package vmcx

import (
	"context"
	"errors"
	"fmt"
	"log"
	"os"
	"strings"

	hypervcommon "github.com/hashicorp/packer/builder/hyperv/common"
	"github.com/hashicorp/packer/common"
	"github.com/hashicorp/packer/common/bootcommand"
	powershell "github.com/hashicorp/packer/common/powershell"
	"github.com/hashicorp/packer/common/powershell/hyperv"
	"github.com/hashicorp/packer/common/shutdowncommand"
	"github.com/hashicorp/packer/helper/communicator"
	"github.com/hashicorp/packer/helper/config"
	"github.com/hashicorp/packer/helper/multistep"
	"github.com/hashicorp/packer/packer"
	"github.com/hashicorp/packer/template/interpolate"
)

const (
	DefaultRamSize                 = 1 * 1024    // 1GB
	MinRamSize                     = 32          // 32MB
	MaxRamSize                     = 1024 * 1024 // 1TB
	MinNestedVirtualizationRamSize = 4 * 1024    // 4GB

	LowRam = 256 // 256MB

	DefaultUsername = ""
	DefaultPassword = ""
)

// Builder implements packer.Builder and builds the actual Hyperv
// images.
type Builder struct {
	config Config
	runner multistep.Runner
}

type Config struct {
	common.PackerConfig            `mapstructure:",squash"`
	common.HTTPConfig              `mapstructure:",squash"`
	common.ISOConfig               `mapstructure:",squash"`
	common.FloppyConfig            `mapstructure:",squash"`
	bootcommand.BootConfig         `mapstructure:",squash"`
	hypervcommon.OutputConfig      `mapstructure:",squash"`
	hypervcommon.SSHConfig         `mapstructure:",squash"`
	shutdowncommand.ShutdownConfig `mapstructure:",squash"`
	// The amount, in megabytes, of RAM to assign to the
	// VM. By default, this is 1 GB.
	RamSize uint `mapstructure:"memory" required:"false"`
	// A list of ISO paths to
	// attach to a VM when it is booted. This is most useful for unattended
	// Windows installs, which look for an Autounattend.xml file on removable
	// media. By default, no secondary ISO will be attached.
	SecondaryDvdImages []string `mapstructure:"secondary_iso_images" required:"false"`
	// If set to attach then attach and
	// mount the ISO image specified in guest_additions_path. If set to
	// none then guest additions are not attached and mounted; This is the
	// default.
	GuestAdditionsMode string `mapstructure:"guest_additions_mode" required:"false"`
	// The path to the ISO image for guest
	// additions.
	GuestAdditionsPath string `mapstructure:"guest_additions_path" required:"false"`

	// This is the path to a directory containing an exported virtual machine.
	CloneFromVMCXPath string `mapstructure:"clone_from_vmcx_path"`

	// This is the name of the virtual machine to clone from.
	CloneFromVMName string `mapstructure:"clone_from_vm_name"`
	// The name of a snapshot in the
	// source machine to use as a starting point for the clone. If the value
	// given is an empty string, the last snapshot present in the source will
	// be chosen as the starting point for the new VM.
	CloneFromSnapshotName string `mapstructure:"clone_from_snapshot_name" required:"false"`
	// If set to true all snapshots
	// present in the source machine will be copied when the machine is
	// cloned. The final result of the build will be an exported virtual
	// machine that contains all the snapshots of the parent.
	CloneAllSnapshots bool `mapstructure:"clone_all_snapshots" required:"false"`
	// This is the name of the new virtual machine,
	// without the file extension. By default this is "packer-BUILDNAME",
	// where "BUILDNAME" is the name of the build.
	VMName string `mapstructure:"vm_name" required:"false"`
	// If true enables differencing disks. Only
	// the changes will be written to the new disk. This is especially useful if
	// your source is a VHD/VHDX. This defaults to false.
	DifferencingDisk bool `mapstructure:"differencing_disk" required:"false"`
	// The name of the switch to connect the virtual
	// machine to. By default, leaving this value unset will cause Packer to
	// try and determine the switch to use by looking for an external switch
	// that is up and running.
	SwitchName string `mapstructure:"switch_name" required:"false"`
	// When cloning a vm to build from, we run a powershell
	// Compare-VM command, which, depending on your version of Windows, may need
	// the "Copy" flag to be set to true or false. Defaults to "false". Command:
	CompareCopy bool `mapstructure:"copy_in_compare" required:"false"`
	// This is the VLAN of the virtual switch's
	// network card. By default none is set. If none is set then a VLAN is not
	// set on the switch's network card. If this value is set it should match
	// the VLAN specified in by vlan_id.
	SwitchVlanId string `mapstructure:"switch_vlan_id" required:"false"`
	// This allows a specific MAC address to be used on
	// the default virtual network card. The MAC address must be a string with
	// no delimiters, for example "0000deadbeef".
	MacAddress string `mapstructure:"mac_address" required:"false"`
	// This is the VLAN of the virtual machine's network
	// card for the new virtual machine. By default none is set. If none is set
	// then VLANs are not set on the virtual machine's network card.
	VlanId string `mapstructure:"vlan_id" required:"false"`
	// The number of CPUs the virtual machine should use. If
	// this isn't specified, the default is 1 CPU.
	Cpu uint `mapstructure:"cpus" required:"false"`
	// The Hyper-V generation for the virtual machine. By
	// default, this is 1. Generation 2 Hyper-V virtual machines do not support
	// floppy drives. In this scenario use secondary_iso_images instead. Hard
	// drives and DVD drives will also be SCSI and not IDE.
	Generation uint `mapstructure:"generation" required:"false"`
	// If true enable MAC address spoofing
	// for the virtual machine. This defaults to false.
	EnableMacSpoofing bool `mapstructure:"enable_mac_spoofing" required:"false"`
	// If true enable dynamic memory for
	// the virtual machine. This defaults to false.
	EnableDynamicMemory bool `mapstructure:"enable_dynamic_memory" required:"false"`
	// If true enable secure boot for the
	// virtual machine. This defaults to false. See secure_boot_template
	// below for additional settings.
	EnableSecureBoot bool `mapstructure:"enable_secure_boot" required:"false"`
	// The secure boot template to be
	// configured. Valid values are "MicrosoftWindows" (Windows) or
	// "MicrosoftUEFICertificateAuthority" (Linux). This only takes effect if
	// enable_secure_boot is set to "true". This defaults to "MicrosoftWindows".
	SecureBootTemplate string `mapstructure:"secure_boot_template" required:"false"`
	// If true enable
	// virtualization extensions for the virtual machine. This defaults to
	// false. For nested virtualization you need to enable MAC spoofing,
	// disable dynamic memory and have at least 4GB of RAM assigned to the
	// virtual machine.
	EnableVirtualizationExtensions bool `mapstructure:"enable_virtualization_extensions" required:"false"`
	// The location under which Packer will create a
	// directory to house all the VM files and folders during the build.
	// By default %TEMP% is used which, for most systems, will evaluate to
	// %USERPROFILE%/AppData/Local/Temp.
	TempPath string `mapstructure:"temp_path" required:"false"`
	// This allows you to set the vm version when
	//  calling New-VM to generate the vm.
	Version string `mapstructure:"configuration_version" required:"false"`
	// If "true", Packer will not delete the VM from
	// The Hyper-V manager.
	KeepRegistered bool `mapstructure:"keep_registered" required:"false"`

	Communicator string `mapstructure:"communicator"`
	// If true skip compacting the hard disk for
	// the virtual machine when exporting. This defaults to false.
	SkipCompaction bool `mapstructure:"skip_compaction" required:"false"`
	// If true Packer will skip the export of the VM.
	// If you are interested only in the VHD/VHDX files, you can enable this
	// option. The resulting VHD/VHDX file will be output to
	// <output_directory>/Virtual Hard Disks. By default this option is false
	// and Packer will export the VM to output_directory.
	SkipExport bool `mapstructure:"skip_export" required:"false"`
	// Packer defaults to building Hyper-V virtual
	// machines by launching a GUI that shows the console of the machine being
	// built. When this value is set to true, the machine will start without a
	// console.
	Headless bool `mapstructure:"headless" required:"false"`

	ctx interpolate.Context
}

// Prepare processes the build configuration parameters.
func (b *Builder) Prepare(raws ...interface{}) ([]string, error) {
	err := config.Decode(&b.config, &config.DecodeOpts{
		Interpolate:        true,
		InterpolateContext: &b.config.ctx,
		InterpolateFilter: &interpolate.RenderFilter{
			Exclude: []string{
				"boot_command",
			},
		},
	}, raws...)
	if err != nil {
		return nil, err
	}

	// Accumulate any errors and warnings
	var errs *packer.MultiError
	warnings := make([]string, 0)

	if b.config.RawSingleISOUrl != "" || len(b.config.ISOUrls) > 0 {
		isoWarnings, isoErrs := b.config.ISOConfig.Prepare(&b.config.ctx)
		warnings = append(warnings, isoWarnings...)
		errs = packer.MultiErrorAppend(errs, isoErrs...)
	}

	errs = packer.MultiErrorAppend(errs, b.config.BootConfig.Prepare(&b.config.ctx)...)
	errs = packer.MultiErrorAppend(errs, b.config.FloppyConfig.Prepare(&b.config.ctx)...)
	errs = packer.MultiErrorAppend(errs, b.config.HTTPConfig.Prepare(&b.config.ctx)...)
	errs = packer.MultiErrorAppend(errs, b.config.OutputConfig.Prepare(&b.config.ctx, &b.config.PackerConfig)...)
	errs = packer.MultiErrorAppend(errs, b.config.SSHConfig.Prepare(&b.config.ctx)...)
	errs = packer.MultiErrorAppend(errs, b.config.ShutdownConfig.Prepare(&b.config.ctx)...)

	err = b.checkRamSize()
	if err != nil {
		errs = packer.MultiErrorAppend(errs, err)
	}

	if b.config.VMName == "" {
		b.config.VMName = fmt.Sprintf("packer-%s", b.config.PackerBuildName)
	}

	log.Println(fmt.Sprintf("%s: %v", "VMName", b.config.VMName))

	if b.config.SwitchName == "" {
		b.config.SwitchName = b.detectSwitchName()
	}

	if b.config.Cpu < 1 {
		b.config.Cpu = 1
	}

	if b.config.CloneFromVMName == "" {
		if b.config.CloneFromVMCXPath == "" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("The clone_from_vm_name must be specified if "+
				"clone_from_vmcx_path is not specified."))
		}
	} else {
		virtualMachineExists, err := powershell.DoesVirtualMachineExist(b.config.CloneFromVMName)
		if err != nil {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("Failed detecting if virtual machine to clone "+
				"from exists: %s", err))
		} else {
			if !virtualMachineExists {
				errs = packer.MultiErrorAppend(errs, fmt.Errorf("Virtual machine '%s' to clone from does not "+
					"exist.", b.config.CloneFromVMName))
			} else {
				b.config.Generation, err = powershell.GetVirtualMachineGeneration(b.config.CloneFromVMName)
				if err != nil {
					errs = packer.MultiErrorAppend(errs, fmt.Errorf("Failed detecting virtual machine to clone "+
						"from generation: %s", err))
				}

				if b.config.CloneFromSnapshotName != "" {
					virtualMachineSnapshotExists, err := powershell.DoesVirtualMachineSnapshotExist(
						b.config.CloneFromVMName, b.config.CloneFromSnapshotName)
					if err != nil {
						errs = packer.MultiErrorAppend(errs, fmt.Errorf("Failed detecting if virtual machine "+
							"snapshot to clone from exists: %s", err))
					} else {
						if !virtualMachineSnapshotExists {
							errs = packer.MultiErrorAppend(errs, fmt.Errorf("Virtual machine snapshot '%s' on "+
								"virtual machine '%s' to clone from does not exist.",
								b.config.CloneFromSnapshotName, b.config.CloneFromVMName))
						}
					}
				}

				virtualMachineOn, err := powershell.IsVirtualMachineOn(b.config.CloneFromVMName)
				if err != nil {
					errs = packer.MultiErrorAppend(errs, fmt.Errorf("Failed detecting if virtual machine to "+
						"clone is running: %s", err))
				} else {
					if virtualMachineOn {
						warning := fmt.Sprintf("Cloning from a virtual machine that is running.")
						warnings = appendWarnings(warnings, warning)
					}
				}
			}
		}
	}

	if b.config.CloneFromVMCXPath == "" {
		if b.config.CloneFromVMName == "" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("The clone_from_vmcx_path be specified if "+
				"clone_from_vm_name must is not specified."))
		}
	} else {
		if _, err := os.Stat(b.config.CloneFromVMCXPath); os.IsNotExist(err) {
			if err != nil {
				errs = packer.MultiErrorAppend(
					errs, fmt.Errorf("CloneFromVMCXPath does not exist: %s", err))
			}
		}
		if strings.HasSuffix(strings.ToLower(b.config.CloneFromVMCXPath), ".vmcx") {
			// User has provided the vmcx file itself rather than the containing
			// folder.
			if strings.Contains(b.config.CloneFromVMCXPath, "Virtual Machines") {
				keep := strings.Split(b.config.CloneFromVMCXPath, "Virtual Machines")
				b.config.CloneFromVMCXPath = keep[0]
			} else {
				errs = packer.MultiErrorAppend(errs, fmt.Errorf("Unable to "+
					"parse the clone_from_vmcx_path to find the vm directory. "+
					"Please provide the path to the folder containing the "+
					"vmcx file, not the file itself. Example: instead of "+
					"C:\\path\\to\\output-hyperv-iso\\Virtual Machines\\filename.vmcx"+
					", provide C:\\path\\to\\output-hyperv-iso\\."))
			}
		}
	}

	if b.config.Generation < 1 || b.config.Generation > 2 {
		b.config.Generation = 1
	}

	if b.config.Generation == 2 {
		if len(b.config.FloppyFiles) > 0 || len(b.config.FloppyDirectories) > 0 {
			err = errors.New("Generation 2 vms don't support floppy drives. Use ISO image instead.")
			errs = packer.MultiErrorAppend(errs, err)
		}
	}

	log.Println(fmt.Sprintf("Using switch %s", b.config.SwitchName))
	log.Println(fmt.Sprintf("%s: %v", "SwitchName", b.config.SwitchName))

	// Errors
	if b.config.GuestAdditionsMode == "" {
		if b.config.GuestAdditionsPath != "" {
			b.config.GuestAdditionsMode = "attach"
		} else {
			b.config.GuestAdditionsPath = os.Getenv("WINDIR") + "\\system32\\vmguest.iso"

			if _, err := os.Stat(b.config.GuestAdditionsPath); os.IsNotExist(err) {
				if err != nil {
					b.config.GuestAdditionsPath = ""
					b.config.GuestAdditionsMode = "none"
				} else {
					b.config.GuestAdditionsMode = "attach"
				}
			}
		}
	}

	if b.config.GuestAdditionsPath == "" && b.config.GuestAdditionsMode == "attach" {
		b.config.GuestAdditionsPath = os.Getenv("WINDIR") + "\\system32\\vmguest.iso"

		if _, err := os.Stat(b.config.GuestAdditionsPath); os.IsNotExist(err) {
			if err != nil {
				b.config.GuestAdditionsPath = ""
			}
		}
	}

	for _, isoPath := range b.config.SecondaryDvdImages {
		if _, err := os.Stat(isoPath); os.IsNotExist(err) {
			if err != nil {
				errs = packer.MultiErrorAppend(
					errs, fmt.Errorf("Secondary Dvd image does not exist: %s", err))
			}
		}
	}

	numberOfIsos := len(b.config.SecondaryDvdImages)

	if b.config.GuestAdditionsMode == "attach" {
		if _, err := os.Stat(b.config.GuestAdditionsPath); os.IsNotExist(err) {
			if err != nil {
				errs = packer.MultiErrorAppend(
					errs, fmt.Errorf("Guest additions iso does not exist: %s", err))
			}
		}

		numberOfIsos = numberOfIsos + 1
	}

	if b.config.Generation < 2 && numberOfIsos > 2 {
		if b.config.GuestAdditionsMode == "attach" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("There are only 2 ide controllers available, so "+
				"we can't support guest additions and these secondary dvds: %s",
				strings.Join(b.config.SecondaryDvdImages, ", ")))
		} else {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("There are only 2 ide controllers available, so "+
				"we can't support these secondary dvds: %s",
				strings.Join(b.config.SecondaryDvdImages, ", ")))
		}
	} else if b.config.Generation > 1 && len(b.config.SecondaryDvdImages) > 16 {
		if b.config.GuestAdditionsMode == "attach" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("There are not enough drive letters available for "+
				"scsi (limited to 16), so we can't support guest additions and these secondary dvds: %s",
				strings.Join(b.config.SecondaryDvdImages, ", ")))
		} else {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("There are not enough drive letters available for "+
				"scsi (limited to 16), so we can't support these secondary dvds: %s",
				strings.Join(b.config.SecondaryDvdImages, ", ")))
		}
	}

	if b.config.EnableVirtualizationExtensions {
		hasVirtualMachineVirtualizationExtensions, err := powershell.HasVirtualMachineVirtualizationExtensions()
		if err != nil {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("Failed detecting virtual machine virtualization "+
				"extensions support: %s", err))
		} else {
			if !hasVirtualMachineVirtualizationExtensions {
				errs = packer.MultiErrorAppend(errs, fmt.Errorf("This version of Hyper-V does not support "+
					"virtual machine virtualization extension. Please use Windows 10 or Windows Server 2016 "+
					"or newer."))
			}
		}
	}

	// Warnings

	if b.config.ShutdownCommand == "" {
		warnings = appendWarnings(warnings,
			"A shutdown_command was not specified. Without a shutdown command, Packer\n"+
				"will forcibly halt the virtual machine, which may result in data loss.")
	}

	warning := b.checkHostAvailableMemory()
	if warning != "" {
		warnings = appendWarnings(warnings, warning)
	}

	if b.config.EnableVirtualizationExtensions {
		if b.config.EnableDynamicMemory {
			warning = fmt.Sprintf("For nested virtualization, when virtualization extension is enabled, " +
				"dynamic memory should not be allowed.")
			warnings = appendWarnings(warnings, warning)
		}

		if !b.config.EnableMacSpoofing {
			warning = fmt.Sprintf("For nested virtualization, when virtualization extension is enabled, " +
				"mac spoofing should be allowed.")
			warnings = appendWarnings(warnings, warning)
		}

		if b.config.RamSize < MinNestedVirtualizationRamSize {
			warning = fmt.Sprintf("For nested virtualization, when virtualization extension is enabled, " +
				"there should be 4GB or more memory set for the vm, otherwise Hyper-V may fail to start " +
				"any nested VMs.")
			warnings = appendWarnings(warnings, warning)
		}
	}

	if b.config.SwitchVlanId != "" {
		if b.config.SwitchVlanId != b.config.VlanId {
			warning = fmt.Sprintf("Switch network adaptor vlan should match virtual machine network adaptor " +
				"vlan. The switch will not be able to see traffic from the VM.")
			warnings = appendWarnings(warnings, warning)
		}
	}

	if errs != nil && len(errs.Errors) > 0 {
		return warnings, errs
	}

	return warnings, nil
}

// Run executes a Packer build and returns a packer.Artifact representing
// a Hyperv appliance.
func (b *Builder) Run(ctx context.Context, ui packer.Ui, hook packer.Hook) (packer.Artifact, error) {
	// Create the driver that we'll use to communicate with Hyperv
	driver, err := hypervcommon.NewHypervPS4Driver()
	if err != nil {
		return nil, fmt.Errorf("Failed creating Hyper-V driver: %s", err)
	}

	// Set up the state.
	state := new(multistep.BasicStateBag)
	state.Put("config", &b.config)
	state.Put("debug", b.config.PackerDebug)
	state.Put("driver", driver)
	state.Put("hook", hook)
	state.Put("ui", ui)

	steps := []multistep.Step{
		&hypervcommon.StepCreateBuildDir{
			TempPath: b.config.TempPath,
		},
		&common.StepOutputDir{
			Force: b.config.PackerForce,
			Path:  b.config.OutputDir,
		},
	}

	if b.config.RawSingleISOUrl != "" || len(b.config.ISOUrls) > 0 {
		steps = append(steps,
			&common.StepDownload{
				Checksum:     b.config.ISOChecksum,
				ChecksumType: b.config.ISOChecksumType,
				Description:  "ISO",
				ResultKey:    "iso_path",
				Url:          b.config.ISOUrls,
				Extension:    b.config.TargetExtension,
				TargetPath:   b.config.TargetPath,
			},
		)
	}

	steps = append(steps,
		&common.StepCreateFloppy{
			Files:       b.config.FloppyFiles,
			Directories: b.config.FloppyConfig.FloppyDirectories,
			Label:       b.config.FloppyConfig.FloppyLabel,
		},
		&common.StepHTTPServer{
			HTTPDir:     b.config.HTTPDir,
			HTTPPortMin: b.config.HTTPPortMin,
			HTTPPortMax: b.config.HTTPPortMax,
		},
		&hypervcommon.StepCreateSwitch{
			SwitchName: b.config.SwitchName,
		},
		&hypervcommon.StepCloneVM{
			CloneFromVMCXPath:              b.config.CloneFromVMCXPath,
			CloneFromVMName:                b.config.CloneFromVMName,
			CloneFromSnapshotName:          b.config.CloneFromSnapshotName,
			CloneAllSnapshots:              b.config.CloneAllSnapshots,
			VMName:                         b.config.VMName,
			SwitchName:                     b.config.SwitchName,
			CompareCopy:                    b.config.CompareCopy,
			RamSize:                        b.config.RamSize,
			Cpu:                            b.config.Cpu,
			EnableMacSpoofing:              b.config.EnableMacSpoofing,
			EnableDynamicMemory:            b.config.EnableDynamicMemory,
			EnableSecureBoot:               b.config.EnableSecureBoot,
			SecureBootTemplate:             b.config.SecureBootTemplate,
			EnableVirtualizationExtensions: b.config.EnableVirtualizationExtensions,
			MacAddress:                     b.config.MacAddress,
			KeepRegistered:                 b.config.KeepRegistered,
		},

		&hypervcommon.StepEnableIntegrationService{},

		&hypervcommon.StepMountDvdDrive{
			Generation: b.config.Generation,
		},
		&hypervcommon.StepMountFloppydrive{
			Generation: b.config.Generation,
		},

		&hypervcommon.StepMountGuestAdditions{
			GuestAdditionsMode: b.config.GuestAdditionsMode,
			GuestAdditionsPath: b.config.GuestAdditionsPath,
			Generation:         b.config.Generation,
		},

		&hypervcommon.StepMountSecondaryDvdImages{
			IsoPaths:   b.config.SecondaryDvdImages,
			Generation: b.config.Generation,
		},

		&hypervcommon.StepConfigureVlan{
			VlanId:       b.config.VlanId,
			SwitchVlanId: b.config.SwitchVlanId,
		},

		&hypervcommon.StepRun{
			Headless:   b.config.Headless,
			SwitchName: b.config.SwitchName,
		},

		&hypervcommon.StepTypeBootCommand{
			BootCommand:   b.config.FlatBootCommand(),
			BootWait:      b.config.BootWait,
			SwitchName:    b.config.SwitchName,
			Ctx:           b.config.ctx,
			GroupInterval: b.config.BootConfig.BootGroupInterval,
		},

		// configure the communicator ssh, winrm
		&communicator.StepConnect{
			Config:    &b.config.SSHConfig.Comm,
			Host:      hypervcommon.CommHost(b.config.SSHConfig.Comm.SSHHost),
			SSHConfig: b.config.SSHConfig.Comm.SSHConfigFunc(),
		},

		// provision requires communicator to be setup
		&common.StepProvision{},

		// Remove ephemeral SSH keys, if using
		&common.StepCleanupTempKeys{
			Comm: &b.config.SSHConfig.Comm,
		},

		&hypervcommon.StepShutdown{
			Command: b.config.ShutdownCommand,
			Timeout: b.config.ShutdownTimeout,
		},

		// wait for the vm to be powered off
		&hypervcommon.StepWaitForPowerOff{},

		// remove the secondary dvd images
		// after we power down
		&hypervcommon.StepUnmountSecondaryDvdImages{},
		&hypervcommon.StepUnmountGuestAdditions{},
		&hypervcommon.StepUnmountDvdDrive{},
		&hypervcommon.StepUnmountFloppyDrive{
			Generation: b.config.Generation,
		},
		&hypervcommon.StepCompactDisk{
			SkipCompaction: b.config.SkipCompaction,
		},
		&hypervcommon.StepExportVm{
			OutputDir:  b.config.OutputDir,
			SkipExport: b.config.SkipExport,
		},
		&hypervcommon.StepCollateArtifacts{
			OutputDir:  b.config.OutputDir,
			SkipExport: b.config.SkipExport,
		},

		// the clean up actions for each step will be executed reverse order
	)

	// Run the steps.
	b.runner = common.NewRunner(steps, b.config.PackerConfig, ui)
	b.runner.Run(ctx, state)

	// Report any errors.
	if rawErr, ok := state.GetOk("error"); ok {
		return nil, rawErr.(error)
	}

	// If we were interrupted or cancelled, then just exit.
	if _, ok := state.GetOk(multistep.StateCancelled); ok {
		return nil, errors.New("Build was cancelled.")
	}

	if _, ok := state.GetOk(multistep.StateHalted); ok {
		return nil, errors.New("Build was halted.")
	}

	return hypervcommon.NewArtifact(b.config.OutputDir)
}

// Cancel.

func appendWarnings(slice []string, data ...string) []string {
	m := len(slice)
	n := m + len(data)
	if n > cap(slice) { // if necessary, reallocate
		// allocate double what's needed, for future growth.
		newSlice := make([]string, (n+1)*2)
		copy(newSlice, slice)
		slice = newSlice
	}
	slice = slice[0:n]
	copy(slice[m:n], data)
	return slice
}

func (b *Builder) checkRamSize() error {
	if b.config.RamSize == 0 {
		b.config.RamSize = DefaultRamSize
	}

	log.Println(fmt.Sprintf("%s: %v", "RamSize", b.config.RamSize))

	if b.config.RamSize < MinRamSize {
		return fmt.Errorf("memory: Virtual machine requires memory size >= %v MB, but defined: %v",
			MinRamSize, b.config.RamSize)
	} else if b.config.RamSize > MaxRamSize {
		return fmt.Errorf("memory: Virtual machine requires memory size <= %v MB, but defined: %v",
			MaxRamSize, b.config.RamSize)
	}

	return nil
}

func (b *Builder) checkHostAvailableMemory() string {
	powershellAvailable, _, _ := powershell.IsPowershellAvailable()

	if powershellAvailable {
		freeMB := powershell.GetHostAvailableMemory()

		if (freeMB - float64(b.config.RamSize)) < LowRam {
			return fmt.Sprintf("Hyper-V might fail to create a VM if there is not enough free memory in the system.")
		}
	}

	return ""
}

func (b *Builder) detectSwitchName() string {
	powershellAvailable, _, _ := powershell.IsPowershellAvailable()

	if powershellAvailable {
		// no switch name, try to get one attached to a online network adapter
		onlineSwitchName, err := hyperv.GetExternalOnlineVirtualSwitch()
		if onlineSwitchName != "" && err == nil {
			return onlineSwitchName
		}
	}

	return fmt.Sprintf("packer-%s", b.config.PackerBuildName)
}