Automating Windows VM Provisioning on Hyper-V with PowerShell

<# 

Author: Yahia Hamza

Description: This script creates a virtual machine, attaches a virtual switch, 
              and attaches a VHD for Windows installation.
              It uses Convert-WindowsImage to install Windows on the VHD.

Date: 2024-12-25
 
Note: This script uses the Convert-WindowsImage.ps1 script to create a VHD and 
       install Windows from an ISO. Ensure that Convert-WindowsImage.ps1 is available 
       in the script's directory for the installation process.
#>

param(
    [Parameter(Mandatory)]
    [string]$vSName,  # Virtual Switch Name
    
    [Parameter(Mandatory)]
    [string]$VMName,  # Virtual Machine Name
    
    [Parameter(Mandatory)]
    [string]$DirectoryPath,  # Path to store VM (e.g., "D:\Hyper-V\VMs")
    
    [Parameter(Mandatory)]
    [int]$StartupMemory,  # Startup memory in GB (as integer, e.g., "4")
    
    [Parameter(Mandatory)]
    [int]$Gen,  # VM Generation (1 or 2)
    
    [Parameter(Mandatory)]
    [string]$vhdDirectory,  # Path for VHD storage (e.g., "D:\Hyper-V\VHDs")
    
    [Parameter(Mandatory)]
    [int]$CPUCount,  # Number of CPU cores (as integer, e.g., "2")
    
    [Parameter(Mandatory)]
    [string]$ISOPath,  # Path to the Windows Server ISO
    
    [Parameter(Mandatory)]
    [string]$Edition,  # Windows Edition to install (e.g., "Windows Server 2019 Datacenter (Desktop Experience)")
    
    [Parameter(Mandatory)]
    [string]$DiskLayout,  # Disk layout (UEFI or MBR)
    
    [Parameter(Mandatory)]
    [int]$vhdSizeGB  # Size of the VHD in GB (as integer, e.g., "90")
)

# Convert memory size to bytes
function Convert-SizeToBytes {
    param(
        [int]$SizeInGB
    )
    return $SizeInGB * 1GB  # Convert GB to bytes
}

$ConvertedStartupMemory = Convert-SizeToBytes -SizeInGB $StartupMemory
$vhdSizeBytes = Convert-SizeToBytes -SizeInGB $vhdSizeGB

# Function to attach a virtual switch to a VM
function Attach-vSwitchToVM {
    param(
        [string]$VMName,
        [string]$vSwitchName
    )

    if (Get-VMSwitch -Name $vSwitchName -ErrorAction SilentlyContinue) {
        Connect-VMNetworkAdapter -VMName $VMName -SwitchName $vSwitchName | Out-Null
        Write-Output "VM '$VMName' connected to switch '$vSwitchName'."
    } else {
        Write-Warning "Switch '$vSwitchName' not found. VM '$VMName' will not be connected to any network."
    }
}

# Function to create a new virtual machine
function Create-NewVirtualMachine {
    param(
        [string]$VMName,
        [string]$DirectoryPath,
        [int64]$StartupMemory,
        [int]$Gen,
        [int]$CPUCount
    )

    if (-not (Get-VM -Name $VMName -ErrorAction SilentlyContinue)) {
        New-VM -Name $VMName -Path $DirectoryPath -MemoryStartupBytes $StartupMemory -Generation $Gen | Out-Null
        Set-VMProcessor -VMName $VMName -Count $CPUCount | Out-Null
        Write-Output "Virtual Machine '$VMName' created successfully."
    } else {
        Write-Output "Virtual Machine '$VMName' already exists."
    }
}

# Function to create a VHDX using Convert-WindowsImage
function Create-VHDX {
    param(
        [string]$ISOPath,
        [string]$Edition,
        [string]$DiskLayout,
        [int64]$SizeBytes,
        [string]$vhdPath
    )

    if (-not (Test-Path -Path $ISOPath)) {
        Write-Error "ISO file '$ISOPath' does not exist."
        return
    }

    # Import Convert-WindowsImage.ps1 dynamically from the script's current directory
    $modulePath = Join-Path -Path $PSScriptRoot -ChildPath "Convert-WindowsImage.ps1"

    if (-not (Test-Path -Path $modulePath)) {
    Write-Error "Convert-WindowsImage.ps1 not found in the current directory: $PSScriptRoot"
    exit 1
    }

    . $modulePath  # Dot-source the script to load its functions
    Write-Output "Convert-WindowsImage.ps1 loaded successfully from $PSScriptRoot"

    Convert-WindowsImage -SourcePath $ISOPath -Edition $Edition -SizeBytes $SizeBytes -DiskLayout $DiskLayout -VHDFormat "VHDX" -VHDPath $vhdPath -ErrorAction Stop
    Write-Output "VHDX created successfully at '$vhdPath'."
}

# Function to attach an existing VHDX
function Attach-ExistingVHD {
    param(
        [string]$VMName,
        [string]$vhdPath
    )

    if (Test-Path -Path $vhdPath) {
        # Detach any existing VHDs to ensure the new one is attached
        Get-VMHardDiskDrive -VMName $VMName | Remove-VMHardDiskDrive -ErrorAction SilentlyContinue | Out-Null

        # Attach the new VHD
        Add-VMHardDiskDrive -VMName $VMName -Path $vhdPath | Out-Null
        Write-Output "VHD '$vhdPath' attached to VM '$VMName'."

        # Ensure boot order is set correctly
        if ((Get-VM -Name $VMName).Generation -eq 2) {
            Set-VMFirmware -VMName $VMName -FirstBootDevice (Get-VMHardDiskDrive -VMName $VMName) | Out-Null
            Write-Output "Boot order updated for Generation 2 VM '$VMName'."
        }
    } else {
        Write-Error "The VHD file '$vhdPath' does not exist."
    }
}

# Main execution logic
$vhdPath = Join-Path -Path $vhdDirectory -ChildPath "$VMName\$VMName.vhdx"

# Create VHDX
Create-VHDX -ISOPath $ISOPath -Edition $Edition -DiskLayout $DiskLayout -SizeBytes $vhdSizeBytes -vhdPath $vhdPath

# Create VM
Create-NewVirtualMachine -VMName $VMName -DirectoryPath $DirectoryPath -StartupMemory $ConvertedStartupMemory -Gen $Gen -CPUCount $CPUCount

# Attach vSwitch
Attach-vSwitchToVM -VMName $VMName -vSwitchName $vSName

# Attach VHDX
Attach-ExistingVHD -VMName $VMName -vhdPath $vhdPath