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Cloning virtual domain controllers
Step 5 of 6 in Deploying domain controllers · video 9:28
What you will learn
- Requirements: generation identifier, Windows Server 2012 or later guests, PDC emulator
- Preparing the source DC and its DCCloneConfig.xml file
- How clone names and IP settings are chosen automatically
- What a clone checks when it starts for the first time
About this lesson
Since Windows Server 2012, a virtualised domain controller can be cloned instead of built from scratch, which helps when adding DCs quickly, recovering from a disaster, scaling a private cloud, building test labs or supplying branch offices. Cloning needs a hypervisor that supports the virtual machine generation identifier, such as Hyper-V from Windows Server 2012, guest DCs on Windows Server 2012 or later, and a PDC emulator on 2012 or later that is online, with a global catalog server, when clones first start. Both a domain admin and a Hyper-V admin are involved. The source DC is added to the Cloneable Domain Controllers group, its software is checked with Get-ADDCCloningExcludedApplicationList (with -GenerateXml to build CustomDCCloneAllowList.xml), DCCloneConfig.xml is created with New-ADDCCloneConfigFile, and the VM is exported and imported as copies. The lesson also covers automatic clone names, offline configuration of mounted VHDX files, and how the generation identifier decides between a normal start, cloning and DSRM.
New-ADDCCloneConfigFile with Get-Help New-ADDCCloneConfigFile before you run the example.Check yourself
1. Which group must the source domain controller belong to before it can be cloned?
The Cloneable Domain Controllers group. Adding it there is how an AD DS administrator authorises that DC to be cloned.
2. What does Get-ADDCCloningExcludedApplicationList tell you, and what do you do with the result?
It lists apps and services on the source DC that are not known to support cloning. You remove them, or test them and, if they work after cloning, add them to CustomDCCloneAllowList.xml.
3. What happens if DCCloneConfig.xml specifies no computer name and no IP settings?
The clone gets an automatic name built from the first eight characters of the source name plus a CLnnnn suffix, and dynamic IP settings, so a DHCP server is needed and the clone stays in the source DC's site.
4. A clone with a DCCloneConfig.xml file starts on a hypervisor that provides no virtual machine generation identifier. What happens?
Cloning cannot be done safely, so the machine renames DCCloneConfig.xml and restarts in Directory Services Restore Mode as a safeguard until an administrator fixes the problem.
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This lesson comes from the course below - with the full set of lessons, demonstrations and practice.