Easily Maintain a Hyper-V Template Image

Q: How can I easily maintain a virtual machine image that I can patch without having to do offline patching and using other tools for Hyper-V?

A: In a virtual environment, it's always desirable to have a template virtual machine (VM) image that can be deployed to newly created VMs. Initially this VM template will be created by installing the OS into a VM, patching it, customizing it and then running SYSPREP to enable the VM to be duplicated.

A month later, however, you will likely want to patch that template rather than deploying the VM template, and then have to apply 200MBs of patches. I've previously written FAQs about how to offline patch VM VHD and WIM files with the major one available at Windows IT Pro.  I also created a video walking through the process.

People were still asking if there is a way to just maintain a VM live, which can then be used as an updated template.

The typical problem is that to use a VM as a template, you have to run SYSPREP--and you can only run SYSPREP three times typically (although there are rearm processes to extend this).

But we don't want to SYSPREP an image, then a month later start the image, patch it, then SYSPREP it again, and so on. It's very messy and won't work for very long.

Instead, there is actually a fairly simple process which I've outlined below. I also created a video that walks you through the entire process.

Your VM  template VM is now ready to be patched again in a month's time, as that SYSPREP operation essentially never happened. In a month's time you would repeat steps 2 to 13 and they would be repeated every time you make any change to the template. This way you save all the updates you make but never maintain that SYSPREP operation.