Prior to the release of System Center 2012 R2 Virtual Machine Manager, administrators used the Virtual Machine Servicing Tool (VMST) to apply software updates to offline VMM virtual machines. Since the release of System Center 2012 R2 Virtual Machine Manager, the recommended method of updating offline virtual machines is to use a service management automation runbook that is available on Microsoft’s website. The service management automation runbook performs the following tasks:
1. Locate all images stored in the VMM library.
2. Mount each virtual machine hard disk image on the VMM server.
3. Locate updates that are made available through WSUS.
4. Perform a check to determine if the update is applicable.
5. Perform a check to determine whether the update has been applied.
6. Apply updates to the mounted virtual hard disk image.
7. Commit the changes to the virtual hard disk and dismount.
