Add Packer Template for Building supported Windows client and server images

[lukasfazik]

OpenNebula forum thread discussing these changes

Changes include

Packer template files

• There is a core packer build template windows.pkr.hcl like in other distributions.
  • This template uses a separate file variables.pkr.hcl file for variables, but unlike other distributions, the installation files are not directly referenced here. Only the type of installation media for a given Windows edition is referenced here.
• variables.auto.pkrvars.hcl references paths for the Windows ISO files. As discussed here. I will try to make an example file out of this one in a later commit.
• Next there is a template for Autounattend.xml file used for automation of Windows installation process. The placeholder values for edition names and language are substituted during the build process.
• Lastly, there is a template for the OOBEUnattend.xml file which is used to automate the OOBE (Out of box experience)

Powershell scripts

The scripts are in scripts folder with exception of Run-Scripts.ps1. The Run-Scripts.ps1 script is called from unattended (automated) Windows installation multiple times during each phase of online installation (not Windows PE phase). This script executes scripts in alphabetical order and passes the return values to the unattended installation, so reboots are possible and don't break the unattended installation.

The scripts are divided into:

• specialize
  • Runs during the first reboot after Windows PE finishes offline installation (deployment of fresh Windows image to disk)
• audit
  • Runs after the second reboot when on normal installation OOBE would be present. In our case, we boot into audit mode to make changes and Sysprep the image
• oobe
  • Runs when the finished Windows image is used (after Sysprep).

The Install-Updates.ps1 script is dependent on PSWindowsUpdate module which is included in cd_files directory. This is an external module, but it's also on the official PowerShell Gallery webpage. It is licensed under MIT License, and therefore, it should be usable in our project. Correct me if I am wrong.

Empty iso directory

This directory is used when searching for ISO files. Also, the virtio-win.iso drivers file must be included here. the ISO files could be obtained from official Microsoft sources:

• Windows 10 (Change the browser user agent to non-Windows one to see direct ISO download like in Windows 11)
• Windows 11
• Azure Dev Tools for Teaching
• Visual Studio Subscriptions
• Microsoft 365 admin center

For testing purposes, the hash values for the ISO files could be omitted by replacing them with none keyword.

[lukasfazik]

I have noticed a file header in the context-windows/src/context.ps1 contains information about the author and copyright. Should I include something like this in my files?

[lukasfazik]

I have added support for Windows LTSC editions. But Windows 10 Enterprise 2015 LTSB is broken in following ways:

• Virtio drivers refuse to install because the OS is not Windows 10 :)
• PSWindowsUpdate module does not support Powershell 5.0 (requires 5.1 and above)

Virttio installation error

Possible future solutions:

• Report issue to virtio-win
• Install drivers manually using pnputil
• Update Windows using Windows Update Agent API

Also, the support for Windows 10 Enterprise 2015 LTSB is ending on 14.10.2025, so maybe it's not worth spending the time to make it work.

I have decided to keep it in since other people can build on top of this work or customize it for their needs.

[lukasfazik]

The last commit revert fixes Windows Server editions, but Windows 10 Enterprise 2015 LTSB is broken instead.