RD Session Host templates are designed specifically to give you the ability to replicate RD Session Hosts running in virtual machines. Hosts created from an RD Session Host template are treated by Parallels RAS almost like regular RD Session Hosts. The main difference is, you can create as many hosts from a single template as you require, thus automating RD Session Host provisioning according to your needs.
RD Session Host templates are supported on the following VDI platforms:
Microsoft Hyper-V
Microsoft Hyper-V Failover Cluster
VMware VCenter
VMware ESXi
SC//HyperCore
Nutanix AHV (AOS)
Microsoft Azure
Amazon Web Services
RD Session Host templates support Windows Server 2008 R2 up to Windows Server 2022 as a guest OS. Compared to regular RD Session Hosts, servers created from an RD Session Host template do not support earlier versions of Windows Server. The reason is, these servers run in VMs and require the RAS Guest Agent installed in them, so the guest OS requirements are limited by Windows Server versions supported by RAS Guest Agent.
Please note that the following standard RAS VDI features are not available when using RD Session Host templates:
Pool management
Persistent hosts
Session management
Publishing from a specific Template
Some other strictly RAS VDI specific features.
For the information on how to provision RD Session Hosts created from a template, see Manage host pools (RD Session Hosts).
To view the list of RD Session Hosts based on a specific template:
Go to Farm > <Site> > RD Session Hosts > Templates.
Select a template and click Tasks > Show servers.
RD Session Hosts based on a template inherit the template settings. To view the settings, note on which template an RD Session Host is based and then view properties of that template, specifically the Settings and Security tabs. For more information, see . Note that you a template can inherit Site default settings or you can specify your own custom settings for it.
A guest RD Session Hosts based on a template must have RAS Guest Agent installed and the agent must match the Parallels RAS version. The agent is installed by default when an RD Session Host is created from a template. If the RD Session Host was created using the native hypervisor tools, it may not have the agent installed in it. In such a case, the RD Session Host will be able to serve only the remote desktop. To enable it to server applications or documents, you'll need to install the agent yourself.
To check if the RAS Guest Agent is installed and up to date:
Go to Farm > <Site> > RD Session Hosts > RD Session Hosts.
Continue as described in subsection "Checking the RAS Guest Agent status".
The RD Session Host template must also have the RAS RD Session Host Agent installed.
To check if the RAS RD Session Host Agent is installed and up to date:
Go to Farm > <Site> > RD Session Hosts > Templates.
Select a template in the list and then click Tasks > Troubleshooting > Check agent.
If something happens to a RD Session Hosts based on a template and it becomes unusable, you don't have to delete it and create a new one. Instead, you can recreate it keeping its name, MAC address, and other properties. This way none of the other Site settings, which may rely on a broken RD Session Host, will be affected. Another reason for recreating an RD Session Host is to apply changes made to the template (when you exit from maintenance without executing the Recreate command).
Please note that recreated RD Session Hosts can keep the the following properties:
MAC address is kept on ESXi, vCenter, Hyper-v, Hyper-v Failover Cluster, Nutanix AHV (AOS), and SC//HyperCore.
BIOS UUID is kept on ESXi and vCenter.
DRS groups are kept on vCenter.
Note: If an RD Session Host based on a template was already assigned to an RD Session Host host pool, it cannot be recreated.
To recreate one or more guest RD Session Host:
In the Parallels RAS Console, navigate to Farm > <Site> > RD Session Hosts > Templates.
To recreate all deployed RD Session Host, click the Tasks drop-down list and choose Recreate all servers.
To recreate a specific host (or multiple hosts), click Tasks > Show servers. This will open the dialog which will list RD Session Hosts. Select one or more RD Session Hosts and then click the Tasks > Recreate.
When you recreate a RD Session Host based on a template:
The procedure deletes the RD Session Host and creates a new one from the same template.
The new RD Session Host retains the same computer name as the one it replaces.
If an RD Session Host is running, all unsaved data in its memory will be lost. For this reason, an important data should be saved to an external storage.
See , subsection "Deleting a host".
See , subsection "Managing hosts that failed preparation". Notice than in case of RD Session Hosts, you have to go to Farm > <Site> > RD Session Hosts > RD Session Hosts and click Tasks > Site defaults to see Site Defaults.
When you create RD Session Host host pools, you can assign a template to a host pool. This can be done when you create or modify a host pool, or it can be done from the Templates tab.
To assign a template to a host pool:
Go to Farm > Site > RD Session Hosts > Templates tab.
On the Templates tab, select a template.
Click Tasks > Assign to host pool.
Select the template version in the Version dialog.
A dialog opens listing existing RD Session Host host pools. Host pools that already have a template assigned are not shown in this list by default. To display them, select the Show host pools with assigned template option. The template that they are currently using is displayed in the Template column.
Select one or more host pools and click OK.
To remove a template from a host pool or host pool:
Select a template and click Tasks > Remove from host pool.
A dialog opens listing all host pools to which this template is assigned.
Select the host pools to remove the template from and click OK.
Note that if a host pool has hosts created from the template that you are removing, they will be removed as well. A message is displayed where you need to confirm the removal.
To complete the tasks described in this section, the following requirements must be met:
Requirements described in the "Requirements" subsection of Creating a VM template.
Network Discovery UDP port 137 must be enabled for a domain firewall profile in the guest OS. This can be done via domain group policies or manually in the guest OS.
Normally, you will push install the necessary agent software in a source VM right from the Parallels RAS console. However, you can also install the software manually by running the Parallels RAS installer in Windows in the VM. When doing so, use the Custom installation option and select the following agent components RAS Guest Agent and RAS RD Session Host Agent to be installed in the source VM.
To create an RD Session Host template:
Add one of the supported provides, as described in Add a Provider.
Go to Farm > Site > RD Session Hosts > Templates tab.
In the Tasks drop-down menu, click Add (or click the [+] icon).
In the dialog that opens, select a host from which you would like to create a template and click OK.
The Create Parallels Template Wizard opens. Each wizard page is described below in the order they appear on the screen.
Verify that the Agent is installed and install it manually if needed as described in Step 1: Check and install the Agent. This step only appears if an on-premises Provider is used.
Configure the template as described in Step 2: Configure the template.