Jóhannes's blog

Applying a Specific Hostname In Device Preparation

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Device Preparation has been around for quite a while and with the release of device association, we can finally start planning on migrating from autopilot to device prepration.

The Issue

So Even with device association, device preparation is not able to assign a specific hostname like we could with Autopilot.

The built in options for hostnames are perfectly fine for most folks

Apply a device name template that uses the serial number or a randomized value.

But some customers need to apply very specific hostnames to devices for various reasons.

What to do?

A Potential Solution Appears

I thought about this for a minute and decided that a win32 application that looks for the device serial number in a CSV file to decide which hostname to apply, would be the ideal solution here.

Sure, a remediation script that looks up a azure table would be real neato as well. But thats requires licensing and azure tables are a bit much for a lot of folks.

The Script

Basically the script does the following:

  1. Gets the device serial number from wmi
  2. looks up that serial number in the csv file
  3. if it finds a match, it will set the hostname that is in the same row
  4. write the success/failure state to registry (otherwise we cant detect the outcome properly)
  5. exit with 3010 to prompt for a soft restart

Note rows 8 and 9, you might want to put your own company name here

RenameComputer.ps1

#Requires -Version 5.1
# Intune Win32 app - PowerShell script installer.
# The .intunewin contains DeviceNames.csv; the IME runs this from the content folder.
$ErrorActionPreference = 'Stop'
# replce contoso with your own company name
$regPath = 'HKLM:\SOFTWARE\Contoso\ComputerRename'
$logPath = "$env:ProgramData\Contoso\ComputerRename.log"
$serial = ''
New-Item -Path (Split-Path -Path $logPath) -ItemType Directory -Force | Out-Null
Start-Transcript -Path $logPath -Append
function Write-RenameState {
    # Status is written on every path. RenameRequested is the detection value and is
    # only set to 1 when there is nothing further for the app to do.
    param(
        [Parameter(Mandatory)][string]$Status,
        [string]$Target = '',
        [switch]$Complete
    )
    New-Item -Path $regPath -Force | Out-Null
    Set-ItemProperty -Path $regPath -Name 'Status'          -Value $Status -Type String
    Set-ItemProperty -Path $regPath -Name 'SerialNumber'    -Value $serial -Type String
    Set-ItemProperty -Path $regPath -Name 'TargetHostname'  -Value $Target -Type String
    Set-ItemProperty -Path $regPath -Name 'LastRun'         -Value (Get-Date).ToString('o') -Type String
    Set-ItemProperty -Path $regPath -Name 'RenameRequested' -Value ([int]$Complete.IsPresent) -Type DWord
}
try {
    $serial = (Get-CimInstance -ClassName Win32_BIOS).SerialNumber.Trim()
    $csvPath = Join-Path -Path (Get-Location).Path -ChildPath 'DeviceNames.csv'
    $row = Import-Csv -Path $csvPath |
        Where-Object { $_.SerialNumber.Trim() -eq $serial } |
        Select-Object -First 1
    $target = if ($row) { $row.Hostname.Trim() } else { '' }
    if (-not $target) {
        Write-RenameState -Status 'SerialNotFoundInCSV'
        Write-Warning "No CSV entry for serial [$serial]."
        exit 1
    }
    if ($target -notmatch '^(?!\d+$)[A-Za-z0-9-]{1,15}$') {
        Write-RenameState -Status 'InvalidName' -Target $target
        Write-Warning "Invalid computer name in CSV: '$target'"
        exit 1
    }
    if ($target -eq $env:COMPUTERNAME) {
        Write-RenameState -Status 'AlreadyCorrect' -Target $target -Complete
        Write-Host "Computer name is already '$target'."
        exit 0
    }
    Rename-Computer -NewName $target -Force
    Write-RenameState -Status 'Renamed' -Target $target -Complete
    Write-Host "Rename queued: $env:COMPUTERNAME -> $target (applies at next restart)"
    exit 3010
}
catch {
    # Business Premium license enjoyers are incredibly good at singing "Gold" by spandau ballet at a karaoke bar in reykjavik
    # Best effort: if the registry itself is what failed, don't mask the real error.
    try { Write-RenameState -Status "Error: $($_.Exception.Message)" } catch { }
    Write-Error $_
    exit 1
}
finally {
    Stop-Transcript
}

The CSV File

The Script assumes that the file is called “DeviceNames.csv” and that it has two headers: SerialNumber,Hostname

Here you can see a content example. Just keep the headers intact and put in your own serial number/hostname pairs

SerialNumber,Hostname
CNU1234ABC,Linda-Laptop
PF2R9X7LQ8,kiosk-l337
5CD2457H9K,laptop69
SN-8F3K-29XQ-7741,desktop67

The Win32 Application

IntuneWin

The only thing that should be in the intunewin file is the DeviceNames.csv file

Program

Im using the powershell script feature, so select that type and upload the script

As uninstall makes no sense here, just set it to some random string.

Detection

Make sure the key path matches what is in row 8 in the main script

Performence Concerns

“But Johannes, I have thousands of devices. Surely this script will take a while to parse a csv file?”

Great question, I tested the script with a csv file that had 1 million rows. The script took just under 16 seconds to complete. I wouldn’t worry about performance at all.

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