[Samba] not quite demoted, yet

Andrew Bartlett abartlet at samba.org
Sun Oct 16 09:16:46 UTC 2016

On Thu, 2016-10-13 at 19:00 -0500, Bob of Donelson Trophy via samba
> A few days ago I demoted my first DC (a v4.2.14, I think) and thought
> the demote had gone well. Now, when I run "samba-tool dnsupdate
> --verbose" I can see references to the first DC that remain.
> Unfortunately, that DC no longer exists so I simply cannot demote it
> again. 
> Following the instructions on the "Demote a Samba AD DC" page
> "Verifying
> The Demotion" section, I can see references to the original AD DC in
> the
> ADUC, ADSS and the MMC Console. So, I need to fix this. 
> Currently I am running a Samba 4.3.11 version AD DC. I see that it is
> suggested that I use v4.4.0 or newer to "Demote an Offline Domain
> Controller." 
> I have a second v4.5.0 AD DC waiting to join the existing v4.3.11 AD
> DC.
> The idea is to join the v4.5.0, get it working and demote the v4.3.11
> AD
> DC to rebuild it (the v4.3.11) as the then second AD DC running
> v4.5.0.
> The end result being I will have two AD DC running v4.5.0. 
> Now, the question, do I ignore the dns issue, for now, and move
> forward
> with the second (v4.5.0) AD DC join, demote the v4.3.11 DC and then
> "remove-the-other-dead-server" with the v4.5.0 DC? Is there any issue
> I
> may be overlooking? 

That seems reasonable.  However it is better to upgrade servers then to
demote/join if you can.  If you don't need to do the underlying OS,
Samba actually works better when you just upgrade in place, rather than
try and do what seems tidy, because as you have seen, a DC is very hard
to totally remove from the state. 

In particular (a bug) moving the RID manager FSMO around is causing
folks pain right now.

Andrew Bartlett

Andrew Bartlett                       http://samba.org/~abartlet/
Authentication Developer, Samba Team  http://samba.org
Samba Developer, Catalyst IT          http://catalyst.net.nz/services/samba

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