Updating Windows VM Templates on VMWare is quite essential in order to deploy new virtual machines in VMWare.

It is necessary to keep it up-to-date at least once a month.

To deploy new virtual machines in VMWare, VM templates are typically used. A VMWare VM template is a reference virtual machine copy with the configured settings, installed software and security updates. 

An administrator needs to regularly update the VM template to keep it up-to-date: install new Windows security updates (at least once a month), update system and application apps, update antivirus definitions, and so on.

Here at Ibmi Media, as part of our Server Management Services, we regularly help our Customers to resolve Windows related queries.

In this context, we shall look into how to update Windows VM Templates on VMWare with PowerShell.

How to update Windows VM Templates on VMWare ?

To update the Windows VM templates on VMWare, follow the steps given below:

1. Converting a template from the Content Library to a virtual machine.;

2. An administrator logs on after starting it and installs approved Windows updates using WSUS. Then he updates the required software;

3. After installing the updates, the VM is restarted, then turned off and converted back to the template.

Now we shall how to install Windows updates to a VMWare virtual machine template automatically without doing anything manually.

We can make use of PowerCLI to install updates to a Windows virtual machine. Here we are considering that the PowerShell version 4 (or newer), and the PSWindowsUpdate module are installed in the virtual machine template. Running PowerShell scripts must be allowed in the guest OS by the script execution policy.

We make use of the below PowerCLI script to automatically convert a VMWare template into a VM and install security updates from WSUS:

# Import the PowerCLI module
Import-Module VMware.VimAutomation.Core -ErrorAction SilentlyContinue
# Connect to vCenter
connect-viserver de-vcenter1
$TeplateVMName="Win2016StdTemplate"
# Convert a template to a VM
Set-Template -Template $TeplateVMName -ToVM -Confirm:$false –RunAsync
# Make a 60 seconds delay
Start-sleep -s 60
# Start the virtual machine
Start-VM -VM $TeplateVMName | Get-VMQuestion | Set-VMQuestion -DefaultOption -Confirm:$false
Start-sleep -s 120
# Get an administrator credentials from an encrypted file (if you do not want to keep the password in the PS script in clear text)
$adminname = "administrator"
$Pwd = Get-Content c:\Scripts\VMWare\vm_admin_passfile.txt | ConvertTo-SecureString $
cred = new-object -typename System.Management.Automation.PSCredential -argumentlist $adminname, $Pwd
# Run the command to install all available updates in the guest OS using VMWare Tools (the update installation log is saved to a file: C:\temp\Update.log)
Invoke-VMScript -ScriptType PowerShell -ScriptText "Install-WindowsUpdate -MicrosoftUpdate -AcceptAll -AutoReboot" -VM $TeplateVMName -GuestCredential $Cred | Out-file -Filepath C:\temp\Update.log -Append
Start-sleep -s 1800
# Update VMTools version
Update-Tools -VM $TeplateVMName -NoReboot
# Clean up the WinSxS component store and optimize the image with DISM
Invoke-VMScript -ScriptType PowerShell -ScriptText "Dism.exe /Online /Cleanup-Image /StartComponentCleanup /ResetBase" -VM $TeplateVMName -GuestCredential $Cred
Start-sleep -s 1800
# Force restart the VM
Restart-VMGuest -VM $TeplateVMName -Confirm:$false
# Shut the VM down and convert it back to the template
Shutdown-VMGuest –VM $TeplateVMName -Confirm:$false –RunAsync
Start-sleep -s 180
Set-VM –VM $TeplateVMName -ToTemplate -Confirm:$false

Also, we can add this PowerShell script to the Task Scheduler to automatically install updates to the template once a month. 

Then if you deploy a new virtual machine from a VMWare template, you may be sure that the latest Microsoft security updates are installed in it.

[Still not able to update Windows VM Templates on VMWare? – We are here to help you. ]