Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP
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@jaredbusch said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
Keeping the same name and IP is a recipe for disaster.
Agreed, take this as a time to fix this rather than doing extra work now to maintain it. Clean up two things at once.
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@dashrender said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
Is renaming a DC allowed? I didn’t think windows allowed this.
It really does not like it, that's for sure.
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@dave247 said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
@jaredbusch said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
Keeping the same name and IP is a recipe for disaster.
I've asked around numerous times in the past and have had mixed input. Some say it's bad to do and others say it's fine. Can you give me the reasons why you're saying it's a recipe for disaster?
It's bad to do, but can be done.
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@scottalanmiller said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
@jaredbusch said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
Keeping the same name and IP is a recipe for disaster.
Agreed, take this as a time to fix this rather than doing extra work now to maintain it. Clean up two things at once.
How would you go about fixing it?
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@scottalanmiller said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
@dave247 said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
@jaredbusch said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
Keeping the same name and IP is a recipe for disaster.
I've asked around numerous times in the past and have had mixed input. Some say it's bad to do and others say it's fine. Can you give me the reasons why you're saying it's a recipe for disaster?
It's bad to do, but can be done.
And what about if I were to completely de-commission DC1, then remove it from the domain the right way, then set up the new 2016 to be the same as DC1 was. In that way, wouldn't it be like setting up a new DC since there wouldn't be a trace of the old one?
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How I'd handle it....
Well, I'd not do it if possible and fix things pointing to something that they shouldn't here. That's the root level fix.
To go after a proximate fix...
- Set up the new DC. Do NOT use the old IP or hostname.
- Get it all working with the old machines in place.
- Create a CNAME to point the old name to the new server's A record. Remove the old machine.
- If you must, change the new IP to the old IP.
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@dave247 said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
@scottalanmiller said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
@dave247 said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
@jaredbusch said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
Keeping the same name and IP is a recipe for disaster.
I've asked around numerous times in the past and have had mixed input. Some say it's bad to do and others say it's fine. Can you give me the reasons why you're saying it's a recipe for disaster?
It's bad to do, but can be done.
And what about if I were to completely de-commission DC1, then remove it from the domain the right way, then set up the new 2016 to be the same as DC1 was. In that way, wouldn't it be like setting up a new DC since there wouldn't be a trace of the old one?
Except, you know, the keys
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@scottalanmiller said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
@dave247 said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
@scottalanmiller said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
@dave247 said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
@jaredbusch said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
Keeping the same name and IP is a recipe for disaster.
I've asked around numerous times in the past and have had mixed input. Some say it's bad to do and others say it's fine. Can you give me the reasons why you're saying it's a recipe for disaster?
It's bad to do, but can be done.
And what about if I were to completely de-commission DC1, then remove it from the domain the right way, then set up the new 2016 to be the same as DC1 was. In that way, wouldn't it be like setting up a new DC since there wouldn't be a trace of the old one?
Except, you know, the keys
What do you mean the keys? Registry keys?? Wouldn't they be cleaned up during proper decommission?
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@jaredbusch said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
Keeping the same name and IP is a recipe for disaster.
Exactly. Never do that. Just add a new one, demote the old.
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Changing the IP on a DC as the very last step is fine. It'll change everything automagically, such as the DNS records and such.
It's always better not to do it, but if you MUST, then it should be fine.
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@dave247 said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
@scottalanmiller said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
@dave247 said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
@scottalanmiller said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
@dave247 said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
@jaredbusch said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
Keeping the same name and IP is a recipe for disaster.
I've asked around numerous times in the past and have had mixed input. Some say it's bad to do and others say it's fine. Can you give me the reasons why you're saying it's a recipe for disaster?
It's bad to do, but can be done.
And what about if I were to completely de-commission DC1, then remove it from the domain the right way, then set up the new 2016 to be the same as DC1 was. In that way, wouldn't it be like setting up a new DC since there wouldn't be a trace of the old one?
Except, you know, the keys
What do you mean the keys? Registry keys?? Wouldn't they be cleaned up during proper decommission?
Identity keys. And no, it's not the same machine. The issue here is that you are trying to have one key masquerade as if it is another when it is not.
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What do you have that's relying upon AD? other than windows logon and Exchange? You can change Exchange to use another GC as it's catalog.
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@scottalanmiller said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
How I'd handle it....
Well, I'd not do it if possible and fix things pointing to something that they shouldn't here. That's the root level fix.
To go after a proximate fix...
- Set up the new DC. Do NOT use the old IP or hostname.
- Get it all working with the old machines in place.
- Create a CNAME to point the old name to the new server's A record. Remove the old machine.
- If you must, change the new IP to the old IP.
Ok, let's scratch everything I mentioned. If I were to do this the best practice way, would I simply:
- Set up the new 3rd domain controller new name (DC3) and IP address
- Pass the roles from DC1 to DC3
- Finally, go through and point all "primary DNS" entries on Exchange and EVERYTHING else to the new DC3
If I perform the above steps, I am assuming no systems will have issues authenticating since they will all be reaching out to one of the three DCs, right? Therefore, I can gradually point systems to the new DC as needed.
Otherwise, please help me understand what I should do. I am going to spend my day tomorrow researching this stuff so I'm better educated on what I'm doing and can come up with an action plan.
Thank you
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@dave247 said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
@scottalanmiller said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
How I'd handle it....
Well, I'd not do it if possible and fix things pointing to something that they shouldn't here. That's the root level fix.
To go after a proximate fix...
- Set up the new DC. Do NOT use the old IP or hostname.
- Get it all working with the old machines in place.
- Create a CNAME to point the old name to the new server's A record. Remove the old machine.
- If you must, change the new IP to the old IP.
Ok, let's scratch everything I mentioned. If I were to do this the best practice way, would I simply:
- Set up the new 3rd domain controller new name (DC3) and IP address
- Pass the roles from DC1 to DC3
- Finally, go through and point all "primary DNS" entries on Exchange and EVERYTHING else to the new DC3
If I perform the above steps, I am assuming no systems will have issues authenticating since they will all be reaching out to one of the three DCs, right? Therefore, I can gradually point systems to the new DC as needed.
Otherwise, please help me understand what I should do. I am going to spend my day tomorrow researching this stuff so I'm better educated on what I'm doing and can come up with an action plan.
Thank you
The above is the correct way to handle it. You can export your DHCP and import it on the new DC. The same goes for the print server settings, they can be exported and imported. DNS self replicates.
It is also why you never use static IP addressing in a Windows AD network, IMO. I mean I never use it on any type of network, but in the AD world, this makes shit a pain in the ass.
Everything, except the DC and router get DHCP reservations. When Exchange was on site, I would give that a static IP also, just because Microsoft.
This means you only need to modify your DHCP scope to hand out the new info and you are done once everything renews.
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@jaredbusch said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
This means you only need to modify your DHCP scope to hand out the new info and you are done once everything renews.
To expedite your endpoints getting the new information, change the DHCP renewal time to something like 8 hours or even less, depending on your needs. Beats waiting the normal 8 days ( really the half life - 4 days).
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@dashrender said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
@jaredbusch said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
This means you only need to modify your DHCP scope to hand out the new info and you are done once everything renews.
To expedite your endpoints getting the new information, change the DHCP renewal time to something like 8 hours or even less, depending on your needs. Beats waiting the normal 8 days ( really the half life - 4 days).
That is a different issue. I also never leave that at such a stupid default value. Production LAN networks are set to 24 hours.
Guest networks are set to 4 or 8 hours. -
@jaredbusch said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
@dave247 said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
@scottalanmiller said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
How I'd handle it....
Well, I'd not do it if possible and fix things pointing to something that they shouldn't here. That's the root level fix.
To go after a proximate fix...
- Set up the new DC. Do NOT use the old IP or hostname.
- Get it all working with the old machines in place.
- Create a CNAME to point the old name to the new server's A record. Remove the old machine.
- If you must, change the new IP to the old IP.
Ok, let's scratch everything I mentioned. If I were to do this the best practice way, would I simply:
- Set up the new 3rd domain controller new name (DC3) and IP address
- Pass the roles from DC1 to DC3
- Finally, go through and point all "primary DNS" entries on Exchange and EVERYTHING else to the new DC3
If I perform the above steps, I am assuming no systems will have issues authenticating since they will all be reaching out to one of the three DCs, right? Therefore, I can gradually point systems to the new DC as needed.
Otherwise, please help me understand what I should do. I am going to spend my day tomorrow researching this stuff so I'm better educated on what I'm doing and can come up with an action plan.
Thank you
The above is the correct way to handle it. You can export your DHCP and import it on the new DC. The same goes for the print server settings, they can be exported and imported. DNS self replicates.
It is also why you never use static IP addressing in a Windows AD network, IMO. I mean I never use it on any type of network, but in the AD world, this makes shit a pain in the ass.
Everything, except the DC and router get DHCP reservations. When Exchange was on site, I would give that a static IP also, just because Microsoft.
This means you only need to modify your DHCP scope to hand out the new info and you are done once everything renews.
omg yes, that makes total sense!! That would make updating the DNS entries SO MUCH EASIER... I'm actually pissed I didn't realize this earlier. We currently have all our static addresses set on the host side, not via reservation. This was done by previous administrators. When I came on board I suggested reservations (as I had been reading up on DHCP stuff). We never implemented it and I just forgot about it, but I'm going to now that I see what you're saying makes total sense.
Thanks JB
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@dashrender said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
@jaredbusch said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
This means you only need to modify your DHCP scope to hand out the new info and you are done once everything renews.
To expedite your endpoints getting the new information, change the DHCP renewal time to something like 8 hours or even less, depending on your needs. Beats waiting the normal 8 days ( really the half life - 4 days).
Sounds like another good idea. I currently have it set to 3 days, but I'll change that to every 24 hours as JB mentioned.
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@dave247 said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
@dashrender said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
@jaredbusch said in Need some guidance - replacing physical 2008 R2 DC with a virtual 2016 DC - keeping same name and IP:
This means you only need to modify your DHCP scope to hand out the new info and you are done once everything renews.
To expedite your endpoints getting the new information, change the DHCP renewal time to something like 8 hours or even less, depending on your needs. Beats waiting the normal 8 days ( really the half life - 4 days).
Sounds like another good idea. I currently have it set to 3 days, but I'll change that to every 24 hours as JB mentioned.
I chose 24 hours intentionally.
If a user reboots their machine at 8am, it will not request a renew until 8pm. So nothing should impact a normal work day.
For the same reason, I chose to force weekly reboots of user computers at 4am on Mondays. Their DHCP renew should be at 4pm and very unlikely to impact their workday, but still an hour before end of business just in case. That way I get trouble reports at the end of the day and can work on it instead of en mass the next morning when everyone comes in.
