For virtual machines that are configured as domain controllers, it is recommended that you disable time synchronization between the host system and guest operating system acting as a domain controller. This enables your guest domain controller to synchronize time from the domain hierarchy.
This guidance has been recently updated to reflect the current recommendation to synchronize time for the guest domain controller from only the domain hierarchy, rather than the previous recommendation to partially disable time synchronization between the host system and guest domain controller.
Instead of partially disabling the Hyper-V time sync, the now recommended approach is to leave it enabled on the host, but disabled in the VM. Run the following command on the virtual DC, which stops W32Time from using the Hyper-V time synchronization integration service for moment-to-moment synchronisation:
reg add HKLM\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\VMICTimeProvider /v Enabled /t reg_dword /d 0
Then you can tell Windows to go and look for the best time source in the domain hierarchy:
w32tm /config /syncfromflags:DOMHIER /update net stop w32time & net start w32time w32tm /resync /force w32tm /query /source
For more info on setting up time sync on the PDC, see Hyper-V