Windows Server 2012 HYPER-V has a great feature that to be honest until few months ago i didn't know it. The feature is the Domain Controller Clone. As IT Pro you must know that to restore a Domain Controller it's not so simple. It's not only a Restore from a Backup. You must have prepare a plan with specific tests to Restore successful a failed Domain Controller.
With a simple words everything else as restore , copy , snapshot except rebuilding from scratch it has the potential to create more problems in the directory.
To be honest i don't have say with lot of details because i don't have use it so many times to monitoring behaviors and results. But of course i have to say lot of things how can start to clone.
Before start to Clone the Domain Controller must meet the following requirements to take advantage:
- Hypervisor must support VM-GenerationID. It's a new feature on Windows Server 2012 HYPER-V.
- The source server must run Windows Server 2012.
- The PDC Remulator Role must be online and available to the cloned DC and mus be running Windows Server 2012.
Unsupported Application and Service for Clone
Here you can find all the unsupported Applications from Microsoft that you should remove it if decide to Clone the DC
- Dynamic Host Configuration Protocol (DHCP)
- Active Directory Certificate Services (AD CS)
- Active Directory Lightweight Directory Services (AD LDS)
If you have install any 3rd application in the Domain Controller then you must verify with the vendor of the Application if support Cloning.
Prepare the Source Domain Controller for Cloning
If you meet all the Requirements that you can start to Clone Domain Controller.
Let's explain the scenario.
In my Lab i have one Domain Controller and i plan to build 2 more Domain Controllers.
The source Domain Controller is the DC1
The Clone Domain Controllers will be DC2 and DC3.
First Step before start is to add the Source Domain Controller in the Clonable Domain Controllers Group. It's a new group in Windows Server 2012 DC.
- Open Server Manager.
- Click in Tools and select Active Directory Administrative Center
- Find the Clonable Domain Controllers Group in the Users Container and add the Source Domain Controller which is the DC1.
- The specific Group has some permissions set on the domain head that should not be removed. If try to remove these permissions then it's sure that the cloning will be fail.
It's time to use Powershell to create the DCClobeConfig.xml. This xml file contains all the settings that you want to give in cloned DC as ip address,gateway , domain name and more and will be used when cloned DC will boot for the first time.
This file is one of the big difference between cloneable DC and DC that is being restored.
- Open Powershell in source Domain controller as Administrator
- Type the following command
New-ADDCCloneConfigFile -CloneComputerName “Name_of_New_DC” -SiteName “Name_of_AD_Site” -Static -IPv4Address “IP_Address_of_New_DC” -IPv4SubnetMask “Subnet_Mask_for_New_DC” -IPv4DefaultGateway “Gateway_For_New_DC” -IPv4DNSResolver “IP_Address_of_DNS_Server”
The command will be do few things
- Verify that the PDC is available and running Windows Server 2012 and later
- Verify if the source Domain Controller is member of Clonable Domain Controllers Group
- Check if any application or service are detected which is not support cloning like DHCP Server.
In the specific scenario i don't have any Warning for the Application List but i will proceed with the next step which describe how can use the ExcludeApplicationList to identify any application or service that installed in the Domain Controller which not support cloning and must be remove it.
After Creation of the file DCCloneConfig.xml type the following command to identify if you have any unsupported application or service to clone.
If appear any line with a program or service then must be uninstall before proceed with the cloning.
In my scenario i don't have any unspported application or service.
So i will proceed with the following step.
Export-Import Source Domain Controller
The last step is to export the source domain controller and import as new VM in the same HYPER-V host or another one.
First shutdown the source domain controller and find the detail instruction how can Export and Import VM from HYPER-V.
Be careful that when import the VM must use only the Copy the virtual machine (create a new unique ID)
After Import the new VM the only thing that you must do is the fire up the new VM and watch the Cloning of the new Domain Controller.
After finish the Installation you will see a new DC in Domain Controller OU.
Take some time to monitoring the Replication and verify that NTDS and SYSVOL are working properly.
If verify that all works without problem then you have successful cloned the Virtual Domain.