When a Desktop Displays App Volumes Error About Virtualization Disabled

Given a floating VDI desktop is based on a multi-pod image in which the App Volumes Agent is installed, and the end users who are entitled to the App Volumes applications log in to the desktop, they see an error message that contains the sentence "Virtualization is disabled".

Upon logging in to the floating VDI desktop, an error message displays that says something along the lines of "Connection Error. Unable to contact App Volumes Manager. Virtualization is disabled." or "Error from Manager (error code: 400) Virtualization is disabled."

Note: App Volumes used with Horizon Cloud on Microsoft Azure deployments is only supported for use with floating VDI desktops. Because dedicated VDI desktops are not currently supported for use with App Volumes with these Horizon Cloud pods, this documentation page describes the floating VDI desktops scenario.

This problem occurs in the following scenario.

• You have multiple Horizon Cloud on Microsoft Azure pods in your tenant's fleet.
• The floating VDI desktops were created using multi-pod images, using the publishing workflow in the console's Inventory > Images - Multi-Pod page.
• In the publishing workflow, the Install Horizon Agent toggle was switched off. That is, the option to have the Image Management Service install the agent during the publishing workflow was deselected.

By design in the first-generation Horizon Cloud, each pod has its own App Volumes Manager IP address.

In the publishing workflow of a multi-pod image, a copy is published to each destination pod.

Each pod's copy of the multi-pod image must know the specific App Volumes Manager IP for that pod.

The way that each copy gets to know the App Volumes Manager IP for its associated pod is when the Image Management Service (IMS) installs the Horizon agent.

Only when the Install Horizon Agent toggle is switched on for the Publish workflow will IMS perform its designed actions to configure each copy with its pod's specific App Volumes Manager IP.

If the Install Horizon Agent toggle is switched off in the Publish workflow, then IMS skips those actions, which then results in all of the copies ending up configured with the same App Volumes Manager IP, instead of the individual IPs specific to their pods.

Therefore, to avoid experiencing this problem, have IMS do the agent installation as part of its Publish workflow. Ensure that the Install Horizon Agent toggle is switched on in the Publish workflow.

Note: This problem also occurs when you have created the published image using the Move to Multi-Pod Images action which moves an imported image from the console's Imported VMs page to the Images - Multi-Pod page, then published the first image version and used that image in the desktop assignments. In the use case of the Move to Multi-Pod Images action, the console does not make the Install Horizon Agent toggle available to switch on because the image from the Imported VMs already has the agent installed. For a work around in this specific scenario, use the first solution below.

Results

• To fix this problem for existing desktops and published multi-pod images

  1. Locate the image on the console's Images - Multi-Pod page (Inventory > Images - Multi-Pod).

     

  2. Click the name of the image to navigate into the image versions UI page.

     Click the image's name as the green arrow illustrates in the previous screenshot.

     Then in that image versions page, click the radio button so that the New Version action becomes available.

     

  3. Click New Version to create a new version of the image.

     You will publish this new version with the option to install the Horizon Agent into this new image version.

     The following screenshot illustrates the UI after New Version is clicked and after filling out the information.

     Important: Remember to input a marker and click Enter to ensure the marker is displayed in the Markers field before submitting this window. If a marker doesn't exist for the version, you will not be able to successfully complete the final step of updating the floating VDI desktop assignment to use this new image version.

     

     Click Submit to complete creation of this new image version.

     The system will being deploying the underlying VM for the new image version.

  4. When the UI indicates the new image version is Deployment Complete on the image versions page, select that image version and click Publish.

     

  5. In the Publish workflow, ensure the Install Horizon Agent option is switched on.

     Attention: Ensuring the Install Horizon Agent option is switched on for this new image version is critical to ensuring the "Virtualization is disabled" issue does not occur when you complete these troubleshooting steps.

  6. Then update the floating VDI desktop assignment to use the new image version when the version is ready.

• To avoid this problem in brand new images

  Always use the Import Image workflow on the console's Images - Multi-Pod page and publish the images using the standard workflow, with Install Horizon Agent switched on.