Need urgent help with samba4 DC re-join

Andreas Oster aoster at novanetwork.de
Wed Jun 27 23:26:04 MDT 2012


Am 28.06.2012 00:00, schrieb Andrew Bartlett:
> On Wed, 2012-06-27 at 19:27 +0200, Andreas Oster wrote:
>> Am 27.06.2012 15:43, schrieb Andreas Oster:
>>> Am 27.06.2012 15:35, schrieb Andrew Bartlett:
>>>> On Wed, 2012-06-27 at 15:28 +0200, Andreas Oster wrote:
>>>>> Am 27.06.2012 15:21, schrieb Andrew Bartlett:
>>>>>> On Wed, 2012-06-27 at 15:09 +0200, Andreas Oster wrote:
>>>>>>> Hello Andrew,
>>>>>>>
>>>>>>> i think the only differences when doing a "ldbsearch -H sam.ldb -s base
>>>>>>> -b DC=DomainDnsZones,DC=novanetwork,DC=loc" are:
>>>>>>>
>>>>>>> objectClass: domain
>>>>>>> objectClass: domainDNS
>>>>>>>
>>>>>>> and
>>>>>>>
>>>>>>> objectCategory: CN=Top,CN=Schema,CN=Configuration,DC=novanetwork,DC=loc
>>>>>>>
>>>>>>>
>>>>>>> I do not know if this was correct before demoting the second DC.
>>>>>>> It did not come into my mind to check for errors because everything
>>>>>>> worked like a charm and I was/am really happy with samba4.
>>>>>>>
>>>>>>> here the output of:
>>>>>>>
>>>>>>> ../bin/ldbsearch -H sam.ldb -s base -b
>>>>>>> dc=domaindnszones,DC=novanetwork,DC=loc --reveal --show-binary
>>>>>>> replPropertyMetaData
>>>>>>
>>>>>> Thanks.  This gives us a very good clue as to what has gone on:
>>>>>>
>>>>>> I'm assuming that 61f36cfd-ba7d-4702-87d3-7e861bb32cfe is PDC and
>>>>>> fd9ca123-ed33-483a-a735-ff41940789a2 was the BDC?
>>>>>>
>>>>>> The key attributes changed that you mention are objectClass and
>>>>>> objectCategory.  Both need to be fixed.  The incorrect values seem to
>>>>>> have been written at Sun Apr 22 16:07:06 2012 CEST compared with Sun Apr
>>>>>> 22 16:03:41 2012 CEST for the good ones.
>>>>>>
>>>>>> My guess is that in attempting to replicate the DNS to the slave with
>>>>>> the samba-tool drs commands, and running samba_upgradedns on that
>>>>>> server, have somehow sent back a corrupted version of the same object.
>>>>>>
>>>>>> Andrew Bartlett
>>>>>>
>>>>
>>>>> Hello Andrew,
>>>>>
>>>>> this is absolute possible. In a prior try to replicate the
>>>>> DomainDnsZones and ForestDnsZones I used the samba-tool drs command but
>>>>> this did not succeed and, if I do remember correct, quit with an error
>>>>> message. As everything kept on working as before, it did not come to my
>>>>> mind that it might have broken anything.
>>>>>
>>>>> Do you have an idea how to fix this ?
>>>>
>>>> ldbedit -H sam.ldb -s base -b dc=domaindnszones,DC=novanetwork,DC=loc
>>>>
>>>> Then set:
>>>>
>>>> objectClass: domainDNS 
>>>> objectCategory:
>>>> CN=Domain-DNS,CN=Schema,CN=Configuration,DC=novanetwork,DC=loc
>>>>
>>>> That should fix it (I hope).
>>>>
>>>> This is the end for me for tonight, but I'll follow up tomorrow.
>>>> Hopefully others here can help you with any remaining details. 
>>>>
>>>> KEEP GOOD BACKUPS.
>>>>
>>>> Thanks,
>>>>
>>>> Andrew Bartlett
>>>>
>>> Hello Andrew,
>>>
>>> thank you very much for your help. I appreciate very much that you use
>>> your limited time to help guys like me.
>>>
>>> I will create a backup and do the proposed changes with ldbedit. I will
>>> report here if joining works again afterwards.
>>>
>>> best regards
>>>
>>> Andreas
>>>
>>>
>> Hello Andrew,
>>
>> unfortunately, I have been unable to modify/add the settings via
>> ldbedit. I got the following error message when committing the
>> modifications:
>>
>> ../bin/ldbedit -H sam.ldb -s base -b dc=domaindnszones,DC=novanetwork,DC=loc
>> failed to modify DC=DomainDnsZones,DC=novanetwork,DC=loc - cannot change
>> replicated attribute on partial replica at
>> ../source4/dsdb/samdb/ldb_modules/repl_meta_data.c:1408
>>
>> Any idea what could be causing it ?
> 
> When Amitay first wrote samba_dnsupgrade, he misunderstood about the
> difference between a partial and a full replica.  A partition does not
> start as one, and then become another.  We will need to correct your
> database to record the DNS partition as being a full replica. 
> 
>> Luckily, I did a vmware snapshot before demoting the second DC, I was so
>> upset that I forget about that. I have now reverted back to the old
>> snapshots and second DC is functional again.
>> I have done the tests with ldbsearch on the DomainDnsZones and
>> ForestDnsZones and realized, that the faulty entries already existed
>> before demoting. So I guess before I can demote the second DC again I
>> will have to fix those errors.
> 
> It will also be required before any modifications can be made.  This may
> explain why DNS entries appear to be 'stuck' - Samba is refusing to
> change anything in that partition, because it wrongly believes that
> someone else is the master for that data. 
> 
> Andrew Bartlett
> 
Hello Andrew,

do you have an idea what needs to be changed ? Is it only the
DomainDnsZones and ForestDnsZones part or are there other places where
changes need to be made ? Yesterday I have tried to change the
DomainDnsZones stuff but got an error message when trying to commit the
modifications.

I will be out of office this morning and can only check this thread from
time to time. Please excuse any delays in answering your comments.

best regards

Andreas





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