[Samba] AD bind DNS broken after 4.7.3 -> 4.9.2 upgrade

[Král Gergely]

2018-12-31 20:50 időpontban L.P.H. van Belle via samba ezt írta:
> Can you try to upgrade to any 4.8 version then to 4.9.4?
> might work, atleast my guess this will have a better chance get passed 
> this bug.
> 

I can confirm that an upgrade to 4.7.3 to 4.8.5 works. But!


After upgrading the dnsupdate did not work, giving these log messages:

[2019/01/02 19:18:42.908955,  0] 
../source4/smbd/server.c:466(binary_smbd_main)
   samba version 4.8.5-Debian started.
   Copyright Andrew Tridgell and the Samba Team 1992-2018
[2019/01/02 19:18:56.468276,  0] 
../source4/smbd/server.c:638(binary_smbd_main)
   binary_smbd_main: samba: using 'standard' process model
[2019/01/02 19:19:00.030904,  0] 
../lib/util/util_runcmd.c:327(samba_runcmd_io_handler)
   /usr/sbin/samba_dnsupdate: ERROR(runtime): uncaught exception - (9711, 
'WERR_DNS_ERROR_RECORD_ALREADY_EXISTS')
[2019/01/02 19:19:00.031193,  0] 
../lib/util/util_runcmd.c:327(samba_runcmd_io_handler)
   /usr/sbin/samba_dnsupdate:   File 
"/usr/lib/python2.7/dist-packages/samba/netcmd/__init__.py", line 176, 
in _run
[2019/01/02 19:19:00.031286,  0] 
../lib/util/util_runcmd.c:327(samba_runcmd_io_handler)
   /usr/sbin/samba_dnsupdate:     return self.run(*args, **kwargs)
[2019/01/02 19:19:00.031360,  0] 
../lib/util/util_runcmd.c:327(samba_runcmd_io_handler)
   /usr/sbin/samba_dnsupdate:   File 
"/usr/lib/python2.7/dist-packages/samba/netcmd/dns.py", line 940, in run
[2019/01/02 19:19:00.031595,  0] 
../lib/util/util_runcmd.c:327(samba_runcmd_io_handler)
   /usr/sbin/samba_dnsupdate:     raise e
[2019/01/02 19:19:00.471859,  0] 
../lib/util/util_runcmd.c:327(samba_runcmd_io_handler)
   /usr/sbin/samba_dnsupdate: ERROR(runtime): uncaught exception - (9711, 
'WERR_DNS_ERROR_RECORD_ALREADY_EXISTS')
[2019/01/02 19:19:00.472011,  0] 
../lib/util/util_runcmd.c:327(samba_runcmd_io_handler)
   /usr/sbin/samba_dnsupdate:   File 
"/usr/lib/python2.7/dist-packages/samba/netcmd/__init__.py", line 176, 
in _run
[2019/01/02 19:19:00.472084,  0] 
../lib/util/util_runcmd.c:327(samba_runcmd_io_handler)
   /usr/sbin/samba_dnsupdate:     return self.run(*args, **kwargs)
[2019/01/02 19:19:00.472238,  0] 
../lib/util/util_runcmd.c:327(samba_runcmd_io_handler)
   /usr/sbin/samba_dnsupdate:   File 
"/usr/lib/python2.7/dist-packages/samba/netcmd/dns.py", line 940, in run
[2019/01/02 19:19:00.472301,  0] 
../lib/util/util_runcmd.c:327(samba_runcmd_io_handler)
   /usr/sbin/samba_dnsupdate:     raise e

and so on...

After downgrading from 4.9.2 back to 4.7.3 I experienced the same, and I 
could fix it by running "samba_upgradedns --dns-backend=BIND9_DLZ" (at 
least I guess this fixed it). The results of this command were basically 
the same as on the wiki page. But this time the result was exactly the 
same as with 4.9.2:

isa:~/# samba_upgradedns --dns-backend=BIND9_DLZ
Reading domain information
DNS accounts already exist
No zone file /var/lib/samba/bind-dns/dns/MYAD.DOMAIN.EU.zone
DNS records will be automatically created
DNS partitions already exist
dns-isa account already exists
Failed to create link /var/lib/samba/private/dns.keytab -> 
/var/lib/samba/bind-dns/dns.keytab: No such file or directory
Failed to chown /var/lib/samba/bind-dns to bind gid 107
Failed to chown /var/lib/samba/bind-dns/dns.keytab to bind gid 107
Traceback (most recent call last):
   File "/usr/sbin/samba_upgradedns", line 533, in <module>
     create_dns_dir(logger, paths)
   File "/usr/lib/python2.7/dist-packages/samba/provision/sambadns.py", 
line 697, in create_dns_dir
     os.mkdir(dns_dir, 0770)
OSError: [Errno 2] No such file or directory: 
'/var/lib/samba/bind-dns/dns'


I started to panic, but since I ran this with samba stopped, I restarted 
samba and the error messages are gone! The names are resolved and the 
clients are happily updating the records.


So to summarize, I do not know how it got fixed and why upgradedns does 
not work, but I believe the bug is already included somewhere in the 4.8 
branch. Even if it works.