[Samba] How to best configure DNS for upgrading samba AD DC?

[Jonathan Kreider]

https://wiki.samba.org/index.php/Updating_Samba says we should shut down
all the samba processes before we upgrade. However, if I do that, then I
don't have DNS b/c samba _is_ my DNS on the AD DC. I configured it per
https://wiki.samba.org/index.php/Setting_up_Samba_as_an_Active_Directory_Domain_Controller

Am I missing something? Do I have something misconfigured? Is there a way
to configure a fall-back DNS service so I can still run apt-get when samba
is not running? Or do I need to manually reconfigure DNS after shutting
samba down?

OS = Ubuntu 18.04
Samba = 4.10.2 (the latest & greatest - big thanks to Louis) BTW, the
4.7-4.9 upgrade bug is listed as fixed in 4.10 and my upgrade from
4.7.6-ubuntu to Louis' 4.10.2 had no issues.

Obviously I managed to upgrade without shutting down samba (I did take a
snapshot), despite the recommendations and as of a day later, I'm unaware
of any problems.

But, for the future, I'd prefer to do this the "right" way.

Thanks,
Jonathan Kreider