Using Packer and Vagrant to build Windows images automatically
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This repo is a collection of tools and scripts that can be used to automatically build a Windows image from start to finish in a virtual machine, and was written for imaging Windows onto labs of Mac computers. By default it will build the image in a format compatible with Winclone or DeployStudio. Winclone Pro also supports installing these images via a self-extracting bundle-style macOS installer package, which this tool can also produce.

It can also output the image in WIM format, using wimlib tools to build the image. Winclone 6, released after this tool was originally written, now also uses the WIM format to store the image. This tool hasn't yet been tested with Winclone 6 - WIM support should be possible but it's likely going to need some minor changes to be compatible with how Winclone 6 expects the image bundle to be laid out.

This particular image is used in dual-boot labs managed by this project's maintainer. It is a fully up-to-date Windows 10 LTSB installation including Office 2016, Sophos and the BootCamp drivers. LTSB isn't strictly required, but it's what we're using currently.

The particular sequence of steps to build the image is quite site-specific and I've tried where possible to leave the scripts intact but to remove any links to internal locations and credentials. You may choose to omit some of these steps (for example installing your own custom Office) and just comment them out. If the image build and capture process used in this project were better documented, it would be easier to know exactly how to remove these steps or further customize the image, but for now this project assumes a familiarity with Windows OSD deployment, Sysprep, PowerShell, etc.

The Windows Packer template and several scripts (mainly win-updates.ps1) are mostly borrowed from the excellent joefitzgerald/packer-windows and dylanmei/packer-windows-templates repos, with some additions. These templates and scripts were borrowed from these repos around spring 2016, so there may be newer changes in their source repos.


All tasks are driven by a simple Python script,, which supports different "steps." The following is a rough outline of the steps this project can perform. See the "More Details" section further down for more on each step.


Builds a Windows VM using Packer. The VM will install Windows, Office 2016, run updates and then self-sysprep using the unattend_capture.xml answer file.


Uses Vagrant to attach the virtual disk that was built in the previous step to an Ubuntu VM, then uses either ntfsprogs and pigz (parallel gzip) to make an image file compatible with Winclone's command-line tools, or wimlib to make a WIM image restorable using other standard Windows imaging tools.


Copies a list of resources out of /Applications/Winclone so as to make a self-extracting Winclone bundle. This bundle can be restored using Winclone or DeployStudio (or your own tools).


Wraps this bundle in a payload-free package template derived from the one included in Winclone Pro, and with an option to use a modified postflight script.


Wrap the bundle-style package in a read-only DMG. Wrapping in a UDZO (gzip-compressed) DMG saves almost no space, as the Windows image itself is already gzip-compressed, so read-only (not compressed) is used.


Import the DMG into Munki, setting custom metadata and scripts for the pkginfo. These custom scripts are somewhat site-specific and can be found in the munki. They shouldn't be absolutely required for the image to install, but it may be helpful to see what we've done for handling removal of the image, for example.


The following components are required. In parentheses are the currently tested versions of all the tools:

  • Packer (0.12.1)
  • Vagrant (1.9.1)
  • puphpet/ubuntu1404-x64 Vagrant box version 20151201 (this box supports both vmware-desktop and virtualbox providers)
  • VirtualBox (5.1.12)
  • Winclone Pro (5.7.6)
  • Windows 10 Enterprise LTSB ISO (2015 or 2016)
  • optional: Munki tools installed on the build system, for munkiimport, if using the munki step
  • optional: VMware Fusion (7 or 8) and the (paid) HashiCorp Vagrant Fusion provider, if you prefer to use VMware Fusion over VirtualBox (--platform vmware)

You'll need to download Winclone Pro and copy the .app to /Applications, and make sure it's licensed (and that your license for Winclone Pro permits deploying the package to the given number of machines).


  1. Clone this repo and install all the requirements above.
  2. Copy the Windows 10 LTSB ISO into the iso directory, or use a custom http URL with your desired ISO.
  3. Open answer_files/10/Autounattend.xml and put the plaintext local admin password where you see PLAINTEXT_ADMIN_PASSWORD. Yes, it has to be plaintext in this one location, as far as I've been able to determine. You'll also need the base64-encoded password in several places where you see ENCODED_ADMIN_PASSWORD.
  4. If you want to import the final built package into Munki, you'll need to install Munki tools and run munkiimport --configure, and mount the repo prior to running the build (it will check this up front and fail otherwise)
  5. Finally, run the build with all the steps (you can also use --platform vmware if you have VMware Fusion and the HashiCorp vagrant-vmware-fusion plugin installed):

./ --step all --template windows_10.json

More details on steps


With Packer, normally one would build an image and let Packer finish the build by sending the VM a shutdown command via a communicator: SSH or WinRM. The wrapper script actually sends SIGKILL to Packer's build process once it detects that the VM build is done, monitoring the process table to know when it's safe to do so. This is done so as to avoid requiring any SSH or WinRM configuration or communication to the VM.

WinRM generally works, but requires a bunch of configuration I didn't want to have to later undo, and I've also experienced reliability issues with doing sysprep shutdowns over WinRM. Usually hacky workarounds involving sleep and reboots have been required, and there've been a history of open issues on this in both mitchellh/packer (and its predecessor WinRM support in packer-community/packer-windows-plugins) and joefitzgerald/packer-windows related to expected exit codes, etc. and they have been frustrating to diagnose in that they are done at the end of a lengthy build process. Here's one, for example.

In the end, I found it much simpler to just avoid WinRM configuration altogether in this particular case, and just do what's needed all within AutoUnattend.xml, which includes the sysprep shutdown at the end of its run.

Here are steps explaining the actual Windows image creation. See "Image Restoration" later for more details on what automation steps happen after

  1. Packer creates and boots the VM, copying various scripts and files to an attached floppy device.
  2. The installer environment loads Autounattend.xml, which instructs it to format the virtual disk and runs the installation.
  3. UAC is disabled because there will later be configurations (or installations) that will take place within the oobeSystem phase which are problematic to be automated if UAC is still enabled. It will be re-enabled later during the build.
  4. The Autounattend oobeSystem defines the creation of our local admin user, skips a few OOBE dialogs, sets an autologon for this new user, then sets a number of scripts to run to on this first login. These include copying files over from the floppy which will be needed within the final image for post-imaging installations like BootCamp drivers and Sophos. This also includes installing a custom Office 2016 package. The final step is a win-updates.ps1 script, which will check and install Microsoft updates and reboot on a loop until there are no updates left. The script will call a Finish function which does a few remaining steps as part of the build:
  5. UAD is re-enabled, extraneous files are cleaned up, the Windows update service is restarted.
  6. Sysprep is called, passing it the unattend_capture.xml answer file.
  7. Because sysprep itself will shutdown the VM instead of the conventional Packer remote command, waits to see the VM process go away and kills the Packer parent process.
  8. A new Ubuntu Vagrant box is set up, and the VM disk that was just finished is attached to it.
  9. The box is booted and a single shell provisioner runs, capturing and compressing the image in a format compatible with Winclone Pro's ntfsprogs-based self-extracting tools. There is also an option in (--image-format) to instead capture this image in WIM format as opposed to Winclone.


This step will copy over Winclone Pro's PackageSkel resource dir into a new directory called winclone_resources. If you place a custom postflight installer script at winclone_resources/custom/postflight (make sure it is executable), this script will copy this custom postflight script into the final image self-extracting bundle, overwriting the one included with Winclone Pro.

One thing you may wish to do in such a custom postflight script is to pre-set the computer name in a sysprep unattend XML using a script similar to what DeployStudio's NTFS restore task does.

It is also worth noting that the installer package produced by this step will be set to create the Windows partition. In the GUI, Winclone offers the option to have the installer package create the partition or to rely on an existing one, and in this case it's going to pick the first option.

Currently the disk size for the Windows volume is 80GB, and its package identifier is com.github.winclone-image-builder.Windows10 - hardcoded in The package version will be of the format YYYY.MM.DD.


THe options for the munki step are all configured as options passed to munkiimport, which are currently all hardcoded in These include several additional scripts, which I don't recommend for general use, but rather that you audit them and decide whether they're appropriate or if you have improvements to make. They make certain assumptions about the environment in which they're being installed. I also don't like that they parse standard diskutil output rather than parsing -plist output and would not consider that safe for general use.

Image Restoration

See answer_files/10/unattend_capture.xml for all the details on the Sysprep configured for restore (this includes binding to AD, creating another local user). You would want to customize this for your needs.

Eventually, when the image is restored to a client machine, the oobeSystem pass in Sysprep will do an automatic login as the admin user, install BootCamp drivers for this model automatically via BootCamp.ps1 using Brigadier, install our custom Sophos package, and reboot. The BackToMyMac.cmd is a script we used to run in order to permanently set the boot volume to the OS X volume by invoking the BootCamp.exe -StartupDisk command. We don't do this during the Sysprep phase anymore, so this script has those commands commented out and simply reboots the machine. One of the steps in BootCamp.ps1 sets the BootCamp.exe -StartupDisk command to run as a scheduled task at startup.

The BootCamp.exe tool still seems to work (in our testing) in order to configure the boot volume, but according to my sources it is not officially supported by Apple as a CLI utility for doing this.

Notes on SIP

The postflight script included in this repo assumes that it will be able to write to the MBR, and for this, SIP must be disabled if deploying on 10.11 or later. There are tricks to getting around this by partitioning the boot volume yourself with a stub partition so that OS X will automatically create a guard MBR (rather than a legacy MBR) - see Twocanoes's blog post on the topic, but I've not tested whether performing these steps ahead of time will result in a successful restore by Winclone. If you handle the partitioning yourself prior to installing this image (using the method above or via a Netboot environment, for example), then you shouldn't need SIP disabled to restore this image on a regular booted OS.