We help IT Professionals succeed at work.

Migrating DHCP & DNS first or DCPROMO first from 2008R2 to 2012 R2 ?

471 Views
Last Modified: 2017-04-23
People,

I've got two 2008 R2 AD Domain Controller that is running also as Global Catalog in one of my AD site.
It doesn't run any of the FSMO roles, but it is currently serving as AD integrated DNS server and also DHCP server for the subnet.

I have deployed 2x Win 2012 R2 VMs but now I'm confused myself. Should I:

#1 Migrate both DNS and DHCP (I will setup DHCP resiliency in the two new 2012R2) first, then DCPROMO after
#2 DCPROMO the two new 2012 R2 VMs as DC/GC and then migrate both DHCP & DNS server

Which one is better or the most recommended way ?
Comment
Watch Question

Patrick BogersDatacenter platform engineer Lindows
CERTIFIED EXPERT
Commented:
This problem has been solved!
(Unlock this solution with a 7-day Free Trial)
UNLOCK SOLUTION
Systems Administrator
CERTIFIED EXPERT
Top Expert 2016
Commented:
This problem has been solved!
(Unlock this solution with a 7-day Free Trial)
UNLOCK SOLUTION
Senior IT System EngineerSenior Systems Engineer
CERTIFIED EXPERT

Author

Commented:
Thanks Todd,

So in this case, the two Powershell lines must be executed from the new Win 2012 R2 that has already installed DHCP role ?
or do I have to run it from each respective server ?

Patrick & Todd, this is just the deployment in one of the AD site, while in the main Data Center AD site, I already got one Physical machine running all FSMO roles.
Todd NelsonSystems Administrator
CERTIFIED EXPERT
Top Expert 2016
Commented:
This problem has been solved!
(Unlock this solution with a 7-day Free Trial)
UNLOCK SOLUTION
Senior IT System EngineerSenior Systems Engineer
CERTIFIED EXPERT

Author

Commented:
Hi Todd,

If I promote the two new servers as Domain Controllers + DNS AD Integrated during the business hours, would there be any outage or interruptions to the existing environment ?
Todd NelsonSystems Administrator
CERTIFIED EXPERT
Top Expert 2016

Commented:
There shouldn't be with those specific tasks.
Senior IT System EngineerSenior Systems Engineer
CERTIFIED EXPERT

Author

Commented:
OK, and lastly,

Do I need to reduce the DHCP lease to just 1 hour the day before the migration to make sure the cutover is quicker from the old server to the new server?
Todd NelsonSystems Administrator
CERTIFIED EXPERT
Top Expert 2016

Commented:
No.  The purpose of migrating dhcp is so you don't need to do that.
Senior IT System EngineerSenior Systems Engineer
CERTIFIED EXPERT

Author

Commented:
Ah I see,

So during the DHCP address lease, the IP is still working on the client, so by the time the lease is expired, the client would look for new IP and hopefully the Active-DHCP server will be answering the IP address request.

Is that correct ?
Todd NelsonSystems Administrator
CERTIFIED EXPERT
Top Expert 2016

Commented:
Correct.
Todd NelsonSystems Administrator
CERTIFIED EXPERT
Top Expert 2016

Commented:
Please reassign majority of the points to Todd for more thorough solution and responses to requester's follow up questions.