Explanation/Reference:
Explanation:
Because domain controllers provide a distributed environment, you could not safely clone an Active Directory domain controller in the past.
Before, if you cloned any server, the server would end up with the same domainor forest, which is unsupported with the same domain or forest. You would then have to run sysprep, which would remove the unique security information before cloning and then promote a domain controller manually. When you clone a domain controller, you perform safe cloning, which a cloned domain controller automatically runs a subset of the sysprep process and promotes the server to a domain controller automatically.
The four primary steps to deploy a cloned virtualized domain controller are as follows:
Grant the source virtualized domain controller the permission to be cloned by adding the source

virtualized domain controller to the Cloneable Domain Controllers group.
Run Get-ADDCCloningExcludedApplicationList cmdlet in Windows PowerShell to determine which

services and applications on the domain controller are not compatible with the cloning.
Run New-ADDCCloneConfigFile to create the clone configuration file, which is stored in the C:

\Windows\NTDS.
In Hyper-V, export and then import the virtual machine of the source domain controller.

Run Get-ADDCCloningExcludedApplicationList cmdlet In this procedure, run the Get- ADDCCloningExcludedApplicationList cmdlet on the source virtualized domain controller to identify any programs or services that are not evaluated for cloning. You need to run the Get- ADDCCloningExcludedApplicationList cmdlet before the New- ADDCCloneConfigFile cmdlet because if the New-ADDCCloneConfigFile cmdlet detects an excluded application, it will not create a DCCloneConfig.xml file. To identify applications or services that run on a source domain controller which have not been evaluated for cloning Get-ADDCCloningExcludedApplicationList Get-ADDCCloningExcludedApplicationList -GenerateXml The clone domain controller will be located in the same site as the source domain controller unless a different site is specified in the DCCloneConfig.xml file.
Note:
The Get-ADDCCloningExcludedApplicationList cmdlet searches the local domain controller for programs and services in the installed programs database, the services control manager that are not specified in the default and user defined inclusion list. The applications in the resulting list can be added to the user defined exclusion list if they are determined to support cloning. If the applications are not cloneable, they should be removed from the source domain controller before the clone media is created. Any application that appears in cmdlet output and is not included in the user defined inclusion list will force cloning to fail.
The Get-ADDCCloningExcludedApplicationList cmdlet needs to be run before the New- ADDCCloneConfigFile cmdlet is used because if the New-ADDCCloneConfigFile cmdlet detects an excluded application, it will not create a DCCloneConfig.xml file.
DCCloneConfig.xml is an XML configuration file that contains all of thesettings the cloned DC will take when it boots. This includes network settings, DNS, WINS, AD site name, new DC name and more. This file can be generated in a few different ways.
The New-ADDCCloneConfig cmdlet in PowerShell
By hand with an XML editor
By editing an existing config file, again with an XML editor (Notepad is not an XML editor.)



You can populate the XML file. . . . . doesn't need to be empty. . . . .


References:
https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/introduction-to-active-directory-domain- services-ad-ds-virtualization-level-100
http://blogs.dirteam.com/blogs/sanderberkouwer/archive/2012/09/10/new-features-in-active-directory- domain-services-in-windows-server-2012-part-13-domain-controller-cloning.aspx