Extend-VmWareWindowsDisk

[cmdletbinding()]
param (
    # vCenter Name
    [Parameter(Mandatory)]
    [ValidateScript({Test-NetConnection -ComputerName $_ -Port 443})]
    [string]
    $vCenterName,

    # vCenter Credentials
    [Parameter(Mandatory)]
    [pscredential]
    $Credential,

    # VM Name Filter
    [Parameter(Mandatory=$false)]
    [string]
    $VMNameFilter = "^ff2-(bo|ab).*",

    # New Disk Size
    [Parameter(Mandatory)]
    [ValidateRange(64,256)]
    [int]$NewSizeGB,

    # Log File Path
    [Parameter(Mandatory=$false)]
    [String]$LogFilePath = $env:TEMP
)

begin {
    try {
        Import-Module VMware.PowerCLI -errorAction Stop
        Import-Module LogStream
    }
    catch [System.Management.Automation.ActionPreferenceStopException] {
        Write-Error "Go fix your PowerCLI Installation: $($error[0].Exception.Message)"
    }
    $logFile = Join-Path $LogFilePath -ChildPath "Extend-VMDisk_$(Get-Date -Format yyyyMMdd).log"
    Start-Log -LogFilePath $logFile
    Set-PowerCLIConfiguration -InvalidCertificateAction Ignore -ParticipateInCeip $false -confirm:$false
    $null = Connect-VIServer -Server $vCenterName -credential $Credential
    Write-VerboseLog -LogFilePath $logFile -Message "Connected VCenter $vCenterName with Credentials $($cred.UserName)"
}

process{
    $vmArr = Get-VM | Where-Object {$_.Name -match $VMNameFilter -and $_.GuestId -match "^Windows.*"}
    Write-VerboseLog -LogFilePath $logFile -Message  "Found $($vmArr.Length) matching Virtual Machines"
    $vmArr | ForEach-Object {
        $tmpVm = $_
        Write-VerboseLog -LogFilePath $logFile -Message  "Processing Virtual Machine: $($tmpVm.Name)"
        $primaryDisk = ($_ | Get-HardDisk)[0]
        Write-VerboseLog -LogFilePath $logFile -Message  "Current Primary Disk Size: $($primaryDisk.CapacityGB)"
        if ($primaryDisk.CapacityGB -ge $NewSizeGB) {
            Write-WarningLog -LogFilePath $logFile -Message "Current Disk Size already greater or equal...skipping"
        }
        else {
            try {
                Write-VerboseLog -LogFilePath $logFile -Message  "Increasing Disk Size for Virtual Machine"
                $primaryDisk | Set-HardDisk -Confirm:$false -CapacityGB $NewSizeGB
                Write-VerboseLog -LogFilePath $logFile -Message  "Increasing Disk Size in Operating System"
                invoke-command -ComputerName $tmpVm.Name -scriptBlock {
                    $maxSize = (Get-PartitionSupportedSize -DriveLetter C).Sizemax
                    Resize-Partition -DriveLetter C -Size $maxSize
                }
                Write-VerboseLog -LogFilePath $logFile -Message  "Successfully updated Virtual Machine"
            }
            catch {
                write-ErrorLog -LogFilePath $logFile -Message "Could not increase Disk Size: $($error[0].exception.Message)"
            }
        }
    }
}

end {
    Stop-Log -LogFilePath $logFile
    Disconnect-VIServer -Server $vCenterName -confirm:$false
}