Add-AHVMDisk.ps1

function Add-AHVMDisk {
    <#
    .SYNOPSIS
    Adds a new vhdx to Hyper-V VM
  
    .DESCRIPTION
    Creates a new VHDX in VM's default disk location with given size (VHDSize). Attaches to a VM.
  
    .PARAMETER ComputerName
    ComputerName of a HyperV Computer where VM is.
  
    .PARAMETER VMName
    VMName to which attach a new VHDX
  
    .PARAMETER VHDSize
    Size of the VHDX file to create.
  
    .PARAMETER VHDType
    Type of VHDX file. Currently only Dynamic is supported
  
    .PARAMETER Credential
    Alternate credentials to use to connect to ComputerName
  
    .EXAMPLE
    Add-AHVMDisk -ComputerName OBJPLWHV1 -VMName OBJPLWCON0 -VHDSize 100GB -VHDType Dynamic -Credential (Get-Credential)
  
    #>
  
    [Diagnostics.CodeAnalysis.SuppressMessageAttribute('PSAvoidUsingPlainTextForPassword', '')]
    [CmdletBinding()]
    Param(
        [Parameter(Mandatory = $True,
            ValueFromPipelineByPropertyName = $True)]
        [string]
        $ComputerName,
  
        [Parameter(Mandatory = $True,
            ValueFromPipelineByPropertyName = $True)]
        [string]
        $VMName,
  
        [Parameter(Mandatory = $True,
            ValueFromPipelineByPropertyName = $True)]
        [uint64]
        $VHDSize,
  
        [Parameter(Mandatory = $True,
            ValueFromPipelineByPropertyName = $True)]
        [ValidateSet('Dynamic')]
        [string]
        $VHDType,
  
        [Parameter(Mandatory = $false,
            ValueFromPipelineByPropertyName = $True)]
        [string]
        $VHDName,
  
        [Parameter(Mandatory = $false,
            ValueFromPipelineByPropertyName = $True)]
        [System.Management.Automation.CredentialAttribute()]
        $Credential  
    )
  
  
    Process {
        $invokeProps = @{
            ComputerName = $ComputerName
        }
        if ($PSBoundParameters.ContainsKey('Credential')) {
            Write-Verbose -Message "Credential {$($Credential.UserName)} will be used to connect to Computer {$ComputerName}"
            $invokeProps.Credential = $Credential
        }
        else {
            Write-Verbose -Message "Processing Computer {$ComputerName} with default credentials of user {$($env:USERNAME)}"
        }
  
        Write-Verbose -Message "Processing adding new VHDX Disk to VM {$VMName} on Computer {$ComputerName}"
  
        $vhdProps = @{
            Path         = ''
            SizeBytes    = $VHDSize
            ComputerName = $ComputerName
        }
  
        Write-Verbose -Message "Getting VM {$VMName} properties from Computer {$ComputerName} to set Path for new VHDX"
        $VMCurrentHDD = Invoke-command @invokeProps -ScriptBlock { Get-VMHardDiskDrive -VMName $USING:VMName }
        $VMBaseHDDPath = $VMCurrentHDD[0].Path
        $VMCurrentVHDCount = ($VMCurrentHDD | Measure-Object ).Count
        $VMParentPath = Split-Path $VMBaseHDDPath -Parent
  
        if ($PSBoundParameters.ContainsKey('VHDName')) {
            $VHDFileName = $VHDName
        }
        else {
            $VHDFileName = "{0}_disk{1}.vhdx" -f $VMName, $VMCurrentVHDCount
        }
  
        $VHDPath = Join-Path $VMParentPath -ChildPath $VHDFileName
  
        $vhdProps.Path = $VHDPath
  
        Write-Verbose -Message "Setting disk type to {$VHDType} for {$VMName} on Computer {$ComputerName}"
        if ($VHDType -eq 'Dynamic') {
            $vhdProps.Dynamic = $true
        }
  
        Write-Verbose -Message "Creating new VHDX in {$($vhdProps.Path)} for {$VMName} on Computer {$ComputerName}"
  
        Invoke-Command @invokeProps -ScriptBlock {
            $vhdProps = $USING:vhdProps
            New-VHD @vhdProps
        }
  
        Write-Verbose -Message "Attaching new VHD for {$VMName} on Computer {$ComputerName}"
  
        Invoke-Command @invokeProps -ScriptBlock {
            Add-VMHardDiskDrive -VMName $USING:VMName -Path $USING:VHDPath
        }
  
        Write-Verbose -Message "Attached new VHD for {$VMName} on Computer {$ComputerName}"
    }
}