Schedule Parallels RAS template updates with PowerShell

Automate the management and maintenance of templates.  

Administrators of Parallels RAS occasionally need to update templates to address system change requirements.  In this article, we’re going to show just how easy it is to use PowerShell to update RAS templates and use sample template scripts.   

What is a Parallels RAS template?  

A Parallels RAS template lets you capture the properties of an existing virtual machine (VM) to create guest VMs for publishing desktops, applications, documents, etc. Virtual desktop and Remote Desktop Session Host (RDSH) templates are essential to the Parallels RAS management features. In addition, templates provide a single place for administrators to update desktops, applications, and Windows Updates. 

What are template scripts for? 

Template scripts provide a way to schedule the release or update guest VMs after an administrator has updated the RDSH or virtual desktops template. This might be a task that the administrator wants to perform overnight or in a change window when users are not using the system. 

Here’s an example of how a script can work 

The main steps for using a script to update your template are: 

  1. Update your template by placing it into maintenance mode. 
  2. Exit maintenance mode when your updates are complete (don’t recreate it on exit). 
  3. Run the script at a scheduled time to update the guest VMs automatically. 

The template script follows these steps: 

  1. Finds any user sessions in the RDSH or VDI pool and logs them off. 
  2. Disables the RDSH Group. (RDSH servers are unregistered and removed from the RDSH Group. If it is a VDI template, the VMs are shut down.) 
  3. Enters maintenance mode. 
  4. Exits maintenance mode with updated guest VMs switch. 
  5. Recreates Guest VMs. 
  6. Enables RDSH Group. 
  7. Parallels RAS autoscaling adds RDSH servers back into the group and registers them in the Parallels RAS Console. 


Within the Parallels RAS Console, administrators can update virtual desktop, and remote desktop session host (RDSH) templates by first placing the template into maintenance mode (Fig 1). In maintenance mode, you can right-click the template and connect via RDP (Fig 2). 

Figure 1: Place the Parallels RAS template in Maintenance mode.

Figure 2: Right-click the template and choose Tools > Remote Desktop.

After you make the changes you want to your template, the next step is to exit maintenance mode.  

Note: When you are asked if you want to recreate the guest VMs, select No.
PRAS Powershell setup

IMPORTANT:  The RDSH group should have Autoscale enabled and a template assigned. 

The next step is to set up the script to run by scheduling it, checking that it is enabled, and ensuring that the next scheduled run is suitable. 


You will require the following: 

  1. Parallels RAS Farm. 
  2. RDSH or VDI pools with template. 
  3. Parallels RAS PowerShell module installed. 

Script Setup 

In order to set up the script for your Parallels RAS environment, find the #Variables section, as shown below, with username and password for an administrator service account.  This is a Windows account that has been given admin rights in the Parallels RAS Console. 

PRAS Powershell Variables

Enter the Parallels RAS connection broker hostname, Group ID, and template name. 

The log directory and file must also be set or created in the PS folder on the C:\ drive. 

You can find the Group ID in the Parallels RAS Console under Farm > RD. 

Please see GitHub for more information and sample scripts:  Two sample scripts are included: RDSH template script and VDI template script.

PRAS Powershell

Schedule the script(s) with Windows Task Scheduler 


  1. On one of your connection brokers, open the Windows Task Scheduler.
  2. Right-click the Task Scheduler Library and choose Create a Basic Task. 
  3. Type a name (for example, RAS – Update RDS Template), and click Next. 
  4. On the Trigger page, choose a trigger start type (for example, One time), and click Next. 
  5. Choose Start date and time, and click Next. 
  6. On the Action page, select Start a program, and click Next. 
  7. In the Program/script box, browse to or paste C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe. 
  8. In the Add arguments box, enter -File C:\PS\schedule-template-redeploy.ps1. (Change the path to match where you have saved and created your script.)
  9. Click Next. 
  10. Review the summary and click Finish.

Any questions or issues? Contact our support team!