[Samba] accidentally upgraded DC to 4.17.3 ... didn't work

[Michael Tokarev]

24.11.2022 14:41, Stefan G. Weichinger via samba wrote:
> Am 24.11.22 um 12:10 schrieb Stefan G. Weichinger via samba:
>> Am 24.11.22 um 11:12 schrieb Stefan G. Weichinger via samba:
> 
>> somehow the 2 DCs can't talk to each other?
> 
> I assume that somehow the adc1 comes with a wrong "identity" somehow.
> 
> "samba-tool dbcheck --cross-nc --fix" on adc2 works ok.
> 
> But there is some mismatch:
> 
> [2022/11/24 12:37:11.755128,  1] ../../source4/dsdb/common/util.c:4978(dsdb_validate_dsa_guid)
>    ../../source4/dsdb/common/util.c:4978: Failed to find DSA objectGUID afe62553-1846-4d35-96c1-1b939cec36f2 for sid 
> S-1-5-21-2777655458-4002997014-749295002-5650

Unfortunately I don't know that far.
Don't even know what a DSA objectGUID is.

What do you have now in the end?  Do you
have at least one working DC?

If yes, it should be easy to recreate the
other DCs from scratch, - removing all old
data in them after demotion and rejoining.
Including smb.conf, - it gets recreated by
samba-tool domain join DC command, you can
make some adjustments later from old smb.conf.

This is a way without understanding what's happening.
It'd be very good if we're able to find the actual
reason why it is failing and fix that one instead
of going the reinstall (in this case: rejoin)
route.  Thankfully rejoin procedure is easy to
do, at least.

But for this, someone with more knowlege in this
area is needed, who knows what does these error
messages mean.

If you go the actual rejoin route, I suggest you
to clear 5 places: /var/lib/samba/* (recreating private/
there), /var/cache/samba/* /var/log/samba/log.*,
/etc/samba/smb.conf and /run/samba. there's nothing
in /var/lib/samba/ which might be needed before
rejoin as a DC - samba-tool domain join foo DC will
create everything in there (except of the private/
subdir itself), with all the info populated from
the AD (from active DCs).

If I follow you right, samba-tool domain join works,
but when you start samba it fails to do the work, -
it suggest either some configuration (in smb.conf?)
which is not used by samba-tool join but is used
when you start samba, or some cache or other "later"
state file in one of the mentioned places.

Again, it'd be very interesting to find out what
it is, but here we go.

/mjt