One of the most difficult things about managing a virtual desktop environment is the fact that virtual desktops are anything but static. Because they're so dynamic, it is important to have a change management strategy in place.
Change management helps keep track of desktop apps and system details, as well as which upgrades and patches are needed. A good strategy also means you implement changes with little effect on end users, and you have a way of reversing changes if things go wrong.
Virtual desktops must routinely be patched in order to remain secure. Never mind the fact that virtual desktop images periodically need application upgrades and configuration changes. Imagine for a moment that a virtual desktop image contains a configuration error. That single error could affect every user who is working from a virtual desktop that was created from the image. A change management strategy makes it much easier to determine what went wrong and revert back to a previous virtual desktop image if necessary.
What change management can do for you
So, what's the best way to implement a change management strategy? There are a variety of workable methods. Some organizations track change management manually, and others use dedicated change management software. There are also organizations that integrate change management functionality into the image creation software. Regardless of which method you choose, change management needs to accomplish two things.
First, your change management system should allow you to keep track of what changes were made and when. For example, if a patch were applied to the virtual desktop image, then your change log should list the patch that was applied, when it was applied and what the patch does. Similarly, if you make a configuration change, your change management log should specify exactly what change was made, why the change was made and by whom.
The second major thing that your change management strategy should do is provide you with a way to revert desktops to a previous image in the event that there are problems with the existing image. Image problems can affect a lot of users, so taking the time to fix a problem with an image may be unacceptable. It is usually better to revert to a known good image and then correct the problem with the new image later, in an isolated environment.
Implementing a change management schedule
Devising an effective change management strategy is important, but the way in which you go about implementing the necessary changes is equally important. No matter how you keep track of changes or what your image rollback plan consists of, the changes that you make have a very real impact on your end users. As such, your change management policies should provide a schedule for updates.
Putting together a change management schedule involves a little bit of work on your part because some changes are more important than others, and some changes are potentially more disruptive than others. It's often a good idea to prioritize image updates based on the type of change that is being made.
For example, suppose that Microsoft released a patch to address a critical operating system vulnerability or a patch that is directly related to a problem that your organization has been experiencing. You would want to apply those changes almost immediately. On the other hand, more routine patches can be deployed less frequently, giving you more time to test those patches. You might choose to deploy noncritical patches monthly or quarterly.
Major configuration changes or application updates tend to be a lot more noticeable to end users than routine patches. So, you should apply these types of changes only after thorough testing and any necessary end-user training has been completed. Remember, one of the key goals of change management is to minimize the impact of a change.
That brings up another point. You should apply revisions to VDI images at a time when they will be minimally disruptive. Even if a new image contains only minor changes, it is still a good idea to deploy the image late at night or on a weekend. You don't want to be replacing VDI images during periods of peak activity.
Ultimately, the key to developing an effective change management strategy for your VDI environment is to use common sense. Changes should be made during minimally disruptive times, and the changes should always be logged. Most importantly, always leave yourself with a way of reversing the change.