Windows Server 2025 “Preview” deployment with Packer

As Windows Server 2025 Preview is officially released, I wanted to test a  automated build of the Windows Server 2025 Preview release. So that I can deploy this in my home lab and going to test the new features if I can find the time….

About Hashicorp Packer

Hashicorp Packer is a self-contained executable producing quick and easy operating system builds across multiple platforms. Using Packer and a couple of HCL2 files, you can quickly create fully automated template(s) with latest Windows Updates en VMware Tools. When you schedule a fresh builds after patch Tuesday  you have always an up-to-date and fully secured template.

When using VMware customization tools. You can spin up vm’s in minutes.

Automated Windows Server 2025 “Preview” Build

Files you need?
The files and versions I am using at the time of this writing are as follows:

Outside of downloading both Packer and Windows Server 2022 Preview build, you will need the following files:

  • windowsserver2025.auto.pkrvars.hcl – houses the variable values you want to define.
  • windows2025.json.pkr.hcl – the Packer build file
  • Answer file – Generated with Windows System Image Manager (SIM) you can download the file below
  • Custom script file(s) – optional

Other considerations and tasks you will need to complete:

  • Copy the Windows Server 2025 ISO file to a vSphere datastore

Windows Server 2025 unattend Answer file for the automated Packer Build

Like other automated approaches to installing Windows Server, the automated Windows Server 2025 Packer build requires an answer file to provide answers to the GUI automatically and other installation prompts that you normally see in a manual installation of Windows Server.

You will find the scripts here: https://github.com/WardVissers/Packer-Win2025

The only problem that I had was: Switching from Nic from Public to Private

# Set network connections profile to Private mode.

Write-Output ‘Setting the network connection profiles to Private…’

do {

    $connectionProfile = Get-NetConnectionProfile

    Start-Sleep -Seconds 10

} while ($connectionProfile.Name -eq ‘Identifying…’)

Set-NetConnectionProfile -Name $connectionProfile.Name -NetworkCategory Private

Deploy Windows Core Server 2022 with Server Core App Compatibility Feature on Demand with Packer

I while ago I started with parker to create simple templates for use in my homelab.

It take some time to find the rights scripts and learning en understanding the HCL2 coding

But in related to Security reasons I want to use a Windows Core Server the smaller footprint.

What is Server Core App Compatibility Feature on Demand: https://learn.microsoft.com/en-us/windows-server/get-started/server-core-app-compatibility-feature-on-demand

Installing Features on Demand through Powerschell contains a bug. You may see “failure to download files”, “cannot download”, or errors like “0x800F0954” or file not found.

To Solve that I created I powerschell script to run the install twice: featuresondemand.ps1

You can find al the needed files on my Public Github Packer repository: https://github.com/WardVissers/Packer-Public

When running is showing like this:

A blue screen with white squares

Description automatically generated

It works for now, but there is one thing that would the hole thing a quiet nicer.
Passwords encrypted in a separate file.

Packer – Vmware Tools + Windows Server + VMTools service not installing correctly

I had a frustrating issue with Packer, specifically with VMware Tools installation.

During the Packer install, I load up a script and have VMware Tools 12.1.5 installed. It seems to install successfully, But I noticed that the VMTools service is not running. I have to re-run setup64.exe via the GUI and do a repair, then I see the service exist and runs, and Packer can discover the IP address of the VM to finish it.

The Solution

I used a older autounattend.xml which i never checked the time zone.
Setting the correcting time zone the trick:

<TimeZone>W. Europe Standard Time</TimeZone>

Deploy Multi VM’s based on Windows Template

I love powershell. I created a little script to deploy multi VM based on a Windows Template throug CSV file.

It’s create a computer account at the specfified ou. He greates also a Domain Local Group for management. (It used in the customization not specified here)

TempVMlist.csv

server,cpu,memory,DestinationCluster,OSCustomizationSpec,VMtemplate,adgroup

WARDTEST01,2,8,CLUSTER01,W2012R2_Demo,TPL_W2012R2_STD,ServerAdmin

MultiVM.ps1

#Filename: MultiVM.ps1

#Author: W. Vissers

#Source:

#Version: 1.1

#Date: 08-05-2018

#ChangeLog:

# V1.0 – Module Active Directory

#      – Module VMware PowerCli

#      – Active Directory Computer Account, Group

#      – Host Selected from Cluster with Least Memory

#      – Storage selection based on volume with most free space

# V1.1 – Added Harddisk 1&2

#      – Changed porte group other vlan

#

<#

.SYNOPSIS

Script to create a virtual machine from template

.DESCRIPTION

Script to create a virtual machine from template

.EXAMPLE

MultiVM.ps1

#>

################################## INIT #################################################

# LoadModule Active Directory

if (!(Get-Module “activedirectory”)) {Import-module activedirectory}

Else {Write-Host “Module Active Directory is al ready loaded”}

# LoadModule VMware PowerCLI

# if (!(Get-Module “VMware.PowerCLI”)) {

#    Find-Module VMware.PowerCLI

#    Install-Module -Name VMware.PowerCLI -Scope CurrentUser

#}

#Else

# {

# Write-Host “Module PowerCLI is al ready loaded”

# }

#Config

$ouservers=”OU=Servers,DC=wardvissers.nl,DC=nl”

$ougroup=”OU=GroepObjecten,DC=wardvissers,DC=nl”

$folder=”Applicatie Servers”

$DestinationVC =”vcenter01.wardvissers.nl

#Username

if (!$username ) { $username = Read-Host “Give vCenter username ‘wardvissers\admin'”}

#Password

if ( -NOT $Password ) {

$PasswordSec = Read-Host “Give vCenter password” -AsSecureString

$Password = [Runtime.InteropServices.Marshal]::PtrToStringAuto([Runtime.InteropServices.Marshal]::SecureStringToBSTR($PasswordSec))

}

#Connect vCenter

$ConnectVC = Connect-VIServer $DestinationVC -Username $Username -Password $Password -AllLinked

$AllVMs = @()

$AllVMs = Import-Csv “D:\TempVMlist.csv”

foreach ($vm in $AllVMs) {

#Haal De Gegevens op

$server=$($vm.server)

$memory=$($vm.memory)

$cpu=$($vm.cpu)

$DestinationCluster=$($vm.DestinationCluster)

$OSSpec=”$($vm.OSCustomizationSpec)”

$VMtemplate=$($vm.VMtemplate)

$group=$($vm.adgroup)

$harddisk1=$($vm.harddisk1)

$harddisk2=$($vm.harddisk2)

Write-Host “$server heeft $memory GB memory en $cpu cpu(‘s)”

if ($server.length -gt 15) {

Write-Output “Hostname cannot contain more than 15 characters.”

$server = Read-Host “Re-enter hostname for host $server”}

Else

{

Write-Host “Server is umc server”

#Maak AD Groep aan en Computer Account

New-ADComputer -Name $server -Path $ouservers -Enabled $true

New-ADGroup -Name “DLG.$server” -SamAccountName “DLG.$server” -GroupCategory Security -GroupScope DomainLocal -DisplayName “DLG.$server” -Path $ougroup

Add-ADGroupMember -Identity “DLG.$server” -Members $group

}

# Rol server uit van Template

# Select the host with the less used memory

$DestinationHost = Get-Cluster –Name $DestinationCluster –Server $DestinationVC | Get-VMhost -State Connected | Sort-Object -Property MemoryUsageGB | Select-Object -First1

# Select DataStore with the most free space and not in maintance

$destinationDatastore = Get-Cluster $DestinationCluster | Get-Datastore | Where {$_.State -ne “Maintenance”} | Sort-Object -Property FreeSpaceGB -Descending | Select-Object -First 1

# Finally, I deploy my VM with the New-VM cmdlet using my template and OS specs. I place the VM on the ESXi host and store the VM on the datastore.

New-VM -Name $server -Template $VMTemplate -OSCustomizationSpec $OSSpec -VMHost $DestinationHOST -Datastore $DestinationDatastore -Location $folder

Get-VM $server | Set-VM -NumCpu $cpu -MemoryGB $memory -Confirm:$false

if ($harddisk1 -gt 60){Get-HardDisk -vm $server | Where {$_.Name -eq “Hard disk 1”} | Set-HardDisk -CapacityGB $harddisk1 -Confirm:$false}

if ($harddisk2 -gt 20) {Get-HardDisk -vm $server | Where {$_.Name -eq “Hard disk 2”} | Set-HardDisk -CapacityGB $harddisk2 -Confirm:$false}

Get-VM $server | Start-VM -Confirm:$false

Get-VM $Server | Get-NetworkAdapter | Set-NetworkAdapter -Connected $true -Confirm:$false

}

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