vCloud Director lets you specify a guest OS customization script on each virtual machine. The custom script runs on the virtual machine upon deployment, after the general Sysprep and hardware customization have taken place. This is similar to the RunOnce commands of a Windows Sysprep operation. Using vCenter Orchestrator, you can establish variables in this customization script to be substituted at workflow run time. An example of this is demonstrated in section 5.5.3.4, Add Specified Domain\User to Local Administrators Group. For relevant scripting, see the VM Customization scriptable task of the sample workflow.