Template Maintenance

In addition to viewing and modifying configuration properties of a template, you can perform a number of maintenance tasks on it. These tasks are described below.

Updating RAS Guest Agent inside a template

A template must have the latest version of RAS Guest Agent installed in it. The agent is installed when you create a template. When a new version of RAS Guest Agent becomes available, it should be updated.

When the Parallels RAS Console is started, it may display a message box saying that agents need to be installed or updated. This happens when one or more servers or templates have no agent installed or when an agent is outdated. The message will ask if you want to update all agents. If you click Yes, you are presented with a dialog listing all servers and templates on which an agent needs to be updated. You can select or un-select a server/template to include it in the bulk update procedure or exclude it. Once you've made your selection, click OK to start the update. Follow the onscreen instructions and update the agents. Read the note below!

Full vs. linked clone templates: When you update RAS Guest Agent in a template, you also need to update Agents in guest VMs that were created from this template. This update is done differently for full and linked clone templates. Please read the instructions below for the explanation.

When you update the Agent in a linked clone template, you'll be asked if you want to recreate all guest VMs that were created from this template. You can click Yes and they will be automatically recreated to match the template.

When you update the Agent in a full clone template, full clone guest VMs are NOT recreated at this time. This is due to the fact that full clone VMs are complete machines (as opposed to linked clones which share the virtual hard disk with a snapshot of the template) and so recreating them would be a time consuming procedure. Therefore it is much faster and easier to update the Agent in these VMs by push-installing it from the RAS Console. This can be done by clicking Tasks > Upgrade all Agents while on the VDI > Desktops tab.

To manually check the RAS Guest Agent status inside a template, click Tasks > Check agent. If the agent is up to date, a message box will be displayed confirming this. If a newer version of RAS Guest Agent is available, you'll see a dialog asking if you want to update it. Click Yes to update the agent. If you click No, you can check the status again later and update the agent at that time. Please note that the difference in updating full and linked clone templates (as described above) applies to this scenario as well.

Using the template maintenance mode

The template maintenance mode is used to update software inside a template. For instance, if you want to install a Windows server pack or a software update, you need to use the maintenance mode.

Depending on whether a template is configured for full or linked clones, the maintenance mode is used slightly differently.

Full clones:

If your template is configured to create full clones, do the following:

1. Select a template and click Tasks > Maintenance. The template becomes disabled (grayed out), so all operations on it (including creating new guest VMs) are suspended.
2. Using native tools of the corresponding hypervisor, start the template as a normal virtual machine.
3. Install Windows updates or software as necessary.
4. When done, shut down the virtual machine.
5. Back in the RAS Console, select the template and click Tasks > Maintenance again to exit the maintenance mode.

Note: Please note that any updates applied to a full clone template in the maintenance mode will only affect future clones. Existing guest VMs that were created from this template as full clones will not be affected, so if you want these VMs to include these updates, you will have to recreate them.

Linked clones:

Since linked clones share the virtual hard disk with a snapshot of a template, you need to take additional steps compared to full clones.

First, you need to notify guest VM users to save their data and log off. This is necessary for existing guest VMs to include the updates that you will install in the template. Once all users are logged off, do the following:

1. Select the template and click Tasks > Maintenance. The template becomes disabled (grayed out), so all operations on it (including creating new guest VMs) are suspended.
2. Using native tools of the corresponding hypervisor, start the template as a normal virtual machine.
3. Install Windows updates or software as necessary.
4. When done, shut down the virtual machine.
5. Back in the RAS Console, select the template and click Tasks > Maintenance again to exit the maintenance mode. A dialog is displayed asking if you would like to recreate existing guest VMs. If you click No, then the dialog is closed and the existing guest VMs are left in their current state, which means that the updates that you installed will NOT appear in the existing VMs. If you click Yes, read on.
6. If you click Yes in the previous step, existing guest VMs will be examined for active connections. If an active connection is detected, another dialog opens asking if you want to proceed:
   • If you click Yes, all active sessions are forcibly logged off and existing guest VMs (linked clones), together with the corresponding snapshot, are deleted and a new snapshot and VMs are created from the updated template.
   • If you click No, the Template Guest VMs List dialog opens where you can view the current state of each available guest VM. The dialog gives you full control over a guest VM. You can send a message to the user and you can log the user off. Once all active sessions are logged off, click OK. The existing guest VMs and the corresponding snapshot are deleted and a new snapshot and VMs are created from the updated template.

When you are done configuring a template, click the Apply button on the main RAS Console window to commit the changes to Parallels RAS.

Please note that if you leave the maintenance mode without recreating linking clones, you will have to enter the maintenance mode again to apply the updates.

Maintaining RD Session Hosts based on a template

If you need to do a scheduled maintenance of RD Session Hosts that were created from a template, please follow these steps:

1. Create a schedule that fits your maintenance window to drain a desired RD Session Host group.
2. During maintenance (or right before it) switch the template into maintenance mode. Then apply the necessary changes.
3. The schedule disables groups provisioned by the template (while the maintenance window lasts) which leads to removing (unassigning) all guest VMs from them.
4. Release the template from maintenance and click Yes when asked whether to recreate all clones.
5. Enable groups which were disabled in step 3 (above). At this point, the groups will begin receiving guest VMs to comply with Keep Available Buffer setting
6. From this point forward, groups are provisioned with VMs on demand.