I had some discussion internally with my buddy today about this topic mainly due to some challenges been faced by the client as their current active DNS and Domain controller is hung once a while due to unknown issue. The  current domain controller are hosted on the Windows server 2005 which was not the matured product that came to market more than 5 years ago. They do have a new VMware vSphere 4 Infrastructure in place now.

The question posted by my buddy was;  how we could move or migrate the same state of the virtual machine to a physical or virtual without impact to the production environment?  My answer to him was big NO as this is Domain controller and not a normal application or database server migration.

We went through some due diligence and found that certain machines had been pointing to this DC for the DNS server preference IP. In this case, we may need to ensure Preferred DNS server IP on the client are require to change.

I would like to talk a little bits of the possibility we usually considered while come to p2v migration or v2v migration about the Domain controller.

As you may know, p2v a domain controller is strongly not recommended. I will usually setup a new DC on the VMware farm that I had, and perform the reconfiguration and role transfer as usual on the Domain controller level for the ease of migration. This mainly just follow the best practices from Microsoft for replacing a DC in the environment.

There may be some cases while users insist to maintain the same host name and IP of the DC, which you really want to perform a conversion from p2v or v2v, I will suggest to try on cold clone method. Which in this case, you will require to power down the domain controller.

Again, no right or wrong, on which method you prefer to do, but just be cautious as reminder that migrating a DC are not same as common application server as we do.