Introduction

I’ll show you the quickest way to move an existing public advertising DNS deployment on Windows Server 2012R2, generation 1 virtual machines (1 primary DNS server and 1 or more secondary DNS Servers) to Windows 2016 RTM generation 2 VMs. On top of this we will preserve the sever names and the IP addresses. This makes the migration easier and it doesn’t burden anyone with updating IP addresses or FQDN of services pointing to the existing public advertising DNS service. Basically the result is the best possible for everyone involved.

Step by Step

We start by preparing a sysprepped VHDX of Windows 2016 with all the updates installed and any tools that are sysprep compatible and that you want or need on your VMs. This will allow us to make the move fast. As we want our new DNS VMs to be generation 2 VMS, make sure you use a generation 2 VM to create the syprepped OS VHDX.

The process we describe below is the same for each of the involved DNS servers. You start with the secondary VMs and end with the primary VM. This is just a form risk reduction, it’s smart to start with the secondary as it’s less critical than the primary where you make the changes.

Log on to the old, source VM and do the following

Create a Folder to store the migration data and Info, i.e. C:\DNSMigrateServer01
Open an elevated command prompt
Run Ipconfig /all > C:\DNSMigrateServer01\Server01TCPIPinfo.txt this gives you the IP info you need for future reference.
Run reg export HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\DNS\Parameters C:\DNSMigrateServer01\Dns-Service.REG
Run reg export HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\DNS Server” C:\DNSMigrateServer01\Dns-Software.REG
In some cases, rarely for most deployments, you’ll need to also copy all files under each custom database directory on the old DNS server by manually reading from the registry at the following path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DNS\Parameters\DatabaseDirectory If you have these also copy the directory to C:\DNSMigrateServer01. Normally when you have custom DNS database locations this is not by accident and should be well documented.
Run xcopy %windir%\system32\dns C:\DNSMigrateServer01 /s This copies the content of your DNS folder (normally C:\Windows\System32\dns) to your migration folder. Note that you don’t need to copy the samples sub folder. Even the backup folder is not really needed. Just create a new backup when needed on the news DNS servers.
Copy the C:\DNSMigrateServer01 from your old DNS Server to your desktop or some file share for safe keeping. You’ll need to copy this into the new DNS Server later. Note it contains your IP information, your registry exports and your DNS files.

You now have everything you need form the old DNS Server. So now we’ll decommission it, but before we do so we’ll make sure we have the options to recover it if needed.

Make sure you have a backup or have made on recently (you do trust your ability to restore, right?)
Shut down the VM and for good measure and fast recovery you might want to export the VM for quick import.
Remove the VM from Failover Clustering if it’s clustered.
Now remove the VM from Hyper-V Manager. Note this doesn’t delete the virtual disk files.
Remove the old VHDX (you have an export and a backup) and replace it with your sysprepped W2K16RTM VHDX that has all the updates already. Rename that VHDX to something sensible like server01disk01.vhdx.
Create a new generation 2 VM with the same name as the old one, select the required memory settings, choose to use an existing VHDX and point it to your sysprepped VHDX.
Start the VM
Go through the mini wizard and log in to it.
Configure the NIC with the same setting as your old DNS Server
Rename the VM to the old DNS VM name and join the domain.
Restart the VM
Login to the new DNS VM
Install DNS
Copy the C:\DNSMigrateServer01 you saved from your old DNS Server into the new one
Open an elevated command prompt and run
- Stop the DNS Server service by running net stop “DNS Server”
- Double click the Dns-Service.REG and merge them into the registry

Double click the Dns-Software.REG files and merge them into the registry.

Copy all the files under C:\DNSMigrateServer01 to %windir%\System32\DNS
Start the DNS Server service by running net start “DNS Server”

Congratulations, you now have a new generation 2 VM running DNS on Windows Server 2016 with the same name and IP configuration as the old one. You now want to validate it’s working. To do so on the primary DNS server update the serial number in the start of authority (SOA) tab of the zone properties. I normally use YearMonthDayXX.

This will allow you to check whether the zone transfers to your migrated DNS server work. Normally all is just fine. In case things went horribly wrong you can import the VMs you exported or restore the backups. If your VMs are domain members and as you have reused the VM name, you’ll need to reestablish its domain member ship but that’s easily done.

Now repeat the above process for all the reaming secondary DNS Server and finally for the primary DNS server. Until you’ve done them all.

Conclusion

You do this process for every DNS Server and finally for your primary DNS server. That’s it. You’re in business and you have achieved 2 goals. You’re DNS VMs have been move to generation 2 and are running on a clean install of Windows Server 2016. All this without having to reconfigure DNS zone and transfers and while maintaining your DNS server names and IP addresses. Life is good.

Most people who have been in IT for a while will know the Windows Sysinternals tools and most certainly the small but brilliant Disk2VHD tool we can use for Physical To Virtual (P2V) and Virtual to Virtual (V2V) conversions. It’s free, it’s good and it’s trustworthy as it’s made available by Microsoft.

For legacy systems, whether they are physical with IDE/SATA/SAS controllers or virtual with an IDE generation 1 VMS thing normally go smooth.

But sometimes you have hiccups. One of those is when you do a V2V of a generation 2 virtual machine using Disk2VHD. It’s a small issue, when you create a new generation 2 VM and point it to the OS vhdx it just won’t boot. That’s pretty annoying.

Why do a V2V in such a case you might ask. Well, sometimes is the only or fasted way to get out of pickle with a ton of phantom, non-removable checkpoints you’ve gotten yourself into.

But back to the real subject, how to fix this. What we need to do is repair the boot partition. Well recreate it actually as when you look at it after the conversion you’ll notice is RAW. That’s no good. So let’s walk through how to fix a vdhx that your created from a source generation 2 Hyper-V vm via Disk2VHD.

First of all create a new generation 2 VM that we’ll use with our new VHDX we created using Disk2VHD. Don’t create a new vdhx but select to use an existing one and point it to the one we just created with Disk2VHD. Rename it if needed to something more suitable.

Don’t boot the VM but add a DVD and attach the Windows Server ISO of the version your vhdx contains to the DVD.

Move the DVD to the top of the boot order I firmware.

The VM will boot to the DVD when you hit a key.

Select your language and keyboard layoout when asked and the don’t install or upgrade the OS but boot

Type diskpart and list the disks. Select the disk we need (the OS disk, the only one here) and list the volumes. You can see that volume 3 off 99MB is RAW. That’s not supposed to be that way. So let’s fix this by creating boot loader directory structure, repair the boot record by creating the boot sector & copy the needed boot files into it.

Type:

select volume 3

assign drive letter L:

FORMAT FS=FAT32 LABEL=”BOOT”

That’s it we can now us that 99MB volume to make our disk bootable to windows again. Type Exit to leave diskpart.

So now we have a formatted boot partition we can create the need folder structure and fix the boot record and configure our UEFI bootloader

Switch to the L: volume

create efi\microsoft\boot folder structure for the bootloader as show below with the md command(make directory)

Type: bootrec /fixboot to create the bootrecord

Type: bcdboot C:\Windows /l en-us /s l: /f ALL

This creates the BCD store & copies the boot files from the windows system directory

Just click Continue to exit and continue to Windows Server 2012R2

.. and voila, your new VM has now booted.

Now it’s a matter of cleaning up the remnants of the original VMs hardware such as the NIC and maybe some other devices. The NIC is very important as it will have any static TCP/IP configuration you might want to assign tied to it which mean you can’t reuse it for your new VM. So, the 1st thing to do is uninstall the old network adapters from device managers, you’ll see them when you select “show hidden devices” in the view menu.

Good luck!

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Tag Archives: Generation 2 VM

Easily migrating non-AD integrated DNS servers while preserving server names and IP addresses

Introduction

Step by Step

Conclusion

Disk2VHD on a Generation 2 VM results in an unbootable VHDX