Updated: 12/15/2018

I stumbled upon an issue at work which allowed for an opportunity to build virtual machine (VM) templates within vCenter. I wanted to find a way to automate the process because there are lots of ways to screw up a VM template, and if you screw it up in the beginning, the issue(s) will be present through the lifecycle of the Server. No fun!

Here are the things required in order to automate the creation of a VM template:

Let’s start!

I begun by creating a repository with the following structure:

├── Setup
│   ├── Enable-WinRM.ps1
│   ├── vmtools.cmd
│   ├── autounattend.xml
├── Binaries
│   ├── packer.exe
│   ├── packer-builder-vsphere-clone.exe
│   ├── packer-builder-vsphere-iso.exe
├── README.md
├── Scripts
│   ├── Install-Boxstarter.ps1
│   ├── Install-Chocolatey.ps1
│   ├── Invoke-Cleanup.ps1
│   ├── Invoke-SystemCleanup.ps1
│   ├── Invoke-SystemUpdate.ps1
│   ├── Set-ChocolateySettings.ps1
│   ├── Set-Timezone.ps1
├── ConfigurationFiles
│   ├── server-2016.json

In a datastore of your choosing in vCenter, create a folder called ISO and upload the following:

  • Server 2016 ISO 14393.0.161119-1705.RS1_REFRESH_SERVER_EVAL_X64FRE_EN-US.ISO
  • VMware Tools ISO Windows.iso
  • Windows floppy image pvscsi-Windows8.flp

Once you’ve done that, create your autounattend.xml file and store in your git repository. You can use my customized autounattend.xml file as an example, as I’ve taken cues from several repositories and from JetBrain’s Repo, or build your own.

Once you’ve created the autounattend.xml file, uploaded the files neceessary to the vCenter Datastore, you’re finally ready to begin cusotmizing the Packer Template which are JSON files that configure the various components of Packer in order to create one or more machine images.

Here’s an example JSON file that I used with Server 2016. The latest version will be stored in my Github Repository.

Once you’ve created the JSON file, and have all parts in place, simply execute Packer.exe from your workstation. I have an example of doing it from Jenkins:

function Invoke-TemplateBuild {
    param (
        [Parameter(Mandatory = $true)]
        [Parameter(Mandatory = $true)]
        [Parameter(Mandatory = $true)]
        [Parameter(Mandatory = $true)]
    Executes Packer Template Build against a vCenter. This script is designed to run from Jenkins.
    PS C:\> Invoke-TemplateBuild.ps1 -vCenter vcenter.fqdn.com -TemplateFolder TemplateFolder -TemplateName Win2016 -ConfigurationFile Server2016.json
    Executes packer.exe, connects to a vCenter and moves the template to the correct folder.
    v1.0.0 - 7/9/18 - Jonathan Moss
    v1.0.1 - 7/11/18 - Remove existing template prior to deploying new one
    v1.0.2 - 10/22/18 - Added parameters to support targetting multiple vCenters

    Import-Module VMware.PowerCLI | Out-Null

    ## Define Jenkins parameters and pass through credentials stored in Jenkins using Credentials Binding plugin.
    $SecurePassword = $env:vCenterPassword | ConvertTo-SecureString -AsPlainText -Force
    $vCenterCred = New-Object System.Management.Automation.PSCredential -ArgumentList $env:vCenterAdmin, $SecurePassword

    Set-PowerCLIConfiguration -InvalidCertificateAction Ignore -Confirm:$false

    ## Connect to vCenter with stored credentials
    try {
        Connect-VIServer -Server $vCenterServer -Protocol https -Credential $vCenterCred -ErrorAction Stop
        Write-Output "Successfully connected to $vcenterServer! Continuing.."   
    catch {
        Write-Output "Could not connect to $vcenterserver"
        Write-Host $_.Exception.Message
        Write-Host $_.Exception.ItemName

    try {
        $VMTemplate = Get-Template -Name $TemplateName -ErrorAction STOP
        if ($VMTemplate) {
            try {
                Remove-Template -Template $VMTemplate -Confirm:$false -ErrorAction STOP
            catch {
                ## If template is found, yet can't be removed, exit the script.
                Write-Output "Could not delete, skipping..."
                Write-Output "Manually delete $VMTemplate from $vcenterServer"
    catch {
        Write-Host "No template found! Continuing.."
        Write-Host $_.Exception.Message
        Write-Host $_.Exception.ItemName

    $params = @{
        FilePath         = "$ENV:WORKSPACE\Binaries\packer.exe"
        ArgumentList     = "build -var `"password=$($env:vCenterPassword)`" -var `"winrm_password=$($env:LocalAdminPassword)`" `"$($ENV:WORKSPACE)\ConfigurationFiles\$ConfigurationFile`""
        WorkingDirectory = "$ENV:WORKSPACE\Packer"

    Start-Process @params -NoNewWindow -Wait

    ## Get existing folder where templates are stored

    $TemplateFolder = Get-Folder -Name $TemplateFolder

    ## Move template that was created from script to the destination template folder
    $a = Get-Template -Name $TemplateName
    $b = Get-Folder -Name $TemplateFolder
    Get-Template $a | Move-Template -Destination $b

    ## Disconnect from vCenter
    Disconnect-VIServer $vCenterServer -Confirm:$False

Once you do this, this will create a Server 2016 template and save it as Template_Win2016_Std_64bit_Prod within vCenter.

One of the extra things I did was take cues from DARKSURGEON with customizing the OS, but the world is your oyster when building out a customized server image.

Calling a Powershell script is done by using a Packer Provisioner, specifically the Powershell Provisioner.

By this point, you should have a completely automated method of deploying the latest Server 2016 image to vCenter, and convert it to a template using Packer and Powershell.

Feel free to check out the repository where I store all of this code.