VDI in the Time of Frequent Windows 10 Upgrades

The longevity of Windows 7, and Windows XP before that, has spoiled many customers and enterprises.  It provided IT organizations with a stable base to build their end-user computing infrastructures and applications on, and users were provided with a consistent experience.  The update model was fairly well known – a major service pack with all updates and feature enhancements would come out after about one year.

Whether this stability was good for organizations is debatable.  It certainly came with trade-offs, security of the endpoint being the primary one.

The introduction of Windows 10 has changed that model, and Microsoft is continuing to refine that model.  Microsoft is now releasing two major “feature updates” for Windows 10 each year, and these updates will only be supported for about 18 months each.  Microsoft calls this the “Windows as a Service” model, and it consists of two production-ready semi-annual release channels – a targeted deployment that is used to pilot users to test applications, and a broad deployment that replaces the “Current Branch for Business” option for enterprises.

Gone are the days where the end user’s desktop will have the same operating system for it’s entire life cycle.

(Note: While there is still a long-term servicing branch, Microsoft has repeatedly stated that this branch is suited for appliances and “machinery” that should not receive frequent feature updates such as ATMs and medical equipment.)

In order to facilitate this new delivery model, Microsoft has refined their in-place operating system upgrade technology.  While it has been possible to do this for years with previous versions of Windows, it was often flaky.  Settings wouldn’t port over properly, applications would refuse to run, and other weird errors would crop up.  That’s mostly a thing of the past when working with physical Windows 10 endpoints.

Virtual desktops, however, don’t seem to handle in-place upgrades well.  Virtual desktops often utilize various additional agents to deliver desktops remotely to users, and the in-place upgrade process can break these agents or cause otherwise unexpected behavior.  They also have a tendancy to reinstall Windows Modern Applications that have been removed or reset settings (although Microsoft is supposed to be working on those items).

If Windows 10 feature release upgrades can break, or at least require significant rework of, existing VDI images, what is the best method for handling them in a VDI environment?

I see two main options.  The first is to manually uninstall the VDI agents from the parent VMs, take a snapshot, and then do an in-place upgrade.  After the upgrade is complete, the VDI agents would need to be reinstalled on the machine.  In my opinion, this option has a couple of drawbacks.

First, it requires a significant amount of time.  While there are a number of steps that could be automated, validating the image after the upgrade would still require an administrator.  Someone would have to log in to validate that all settings were carried over properly and that Modern Applications were not reinstalled.  This may become a significant time sink if I have multiple parent desktop images.

Second, this process wouldn’t scale well.  If I have a large number of parent images, or a large estate of persistent desktops, I have to build a workflow to remove agents, upgrade Windows, and reinstall agents after the upgrade.  Not only do I have to test this workflow significantly, but I still have to test my desktops to ensure that the upgrade didn’t break any applications.

The second option, in my view, is to rebuild the desktop image when each new version of Windows 10 is released.  This ensures that you have a clean OS and application installation with every new release, and it would require less testing to validate because I don’t have to check to see what broke during the upgrade process.

One of the main drawbacks to this approach is that image building is a time consuming process.  This is where automated deployments can be helpful.  Tools like Microsoft Deployment Toolkit can help administrators build their parent images, including any agents and required applications, automatically as part of a task sequence.  With this type of toolkit, and administrator can automate their build process so that when a new version of Windows 10 is released, or a core desktop component like the Horizon or XenDesktop agent is updated, the image will have the latest software the next time a new build is started.

(Note: MDT is not the only tool in this category.  It is, however, the one I’m most familiar with.  It’s also the tool that Trond Haavarstein, @XenAppBlog, used for his Automation Framework Tool.)

Let’s take this one step further.  As an administrator, I would be doing a new Windows 10 build every 6 months to a year to ensure that my virtual desktop images remain on a supported version of Windows.  At some point, I’ll want to do more than just automate the Windows installation so that my end result, a fully configured virtual desktop that is deployment ready, is available at the push of a button.  This can include things like bringing it into Citrix Provisioning Services or shutting it down and taking a snapshot for VMware Horizon.

Virtualization has allowed for significant automation in the data center.  Tools like VMware PowerCLI and the Nutanix REST API make it easy for administrators to deploy and manage virtual machines using a few lines of PowerShell.   Using these same tools, I can also take details from this virtual machine shell, such as the name and MAC address, and inject them into my MDT database along with a Task Sequence and role.  When I power the VM on, it will automatically boot to MDT and start the task sequence that has been defined.

This is bringing “Infrastructure as Code” concepts to end-user computing, and the results should make it easier for administrators to test and deploy the latest versions of Windows 10 while reducing their management overhead.

I’m in the process of working through the last bits to automate the VM creation and integration with MDT, and I hope to have something to show in the next couple of weeks.

 

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  1. Pingback: Newsletter: January 27, 2018 – Notes from MWhite

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