samba - Mar 2021 - samba 4.9.7 - DC online backup error - "uncaught exception - 'TarFile' object has no attribute '__exit__'"

Hi,

I've been running two DC:s (DC1 and DC2) in a pure samba AD domain since
2015 on Centos 6. Starting with version 4.1.14 I have upgraded my way to version
4.9.7. It seems I have now reached the limit for possible upgrades of these DC:s
since it is no longer possible to upgrade to 4.10 on Centos 6.

I'm now preparing to deploy a DC3 on a Centos 8 vm with samba 4.14.0. Before
joining it to the domain I have tried to make an online backup of the AD on the
two existing DC:s following the guide at
https://wiki.samba.org/index.php/Back_up_and_Restoring_a_Samba_AD_DC.

When I run the command (as root) "samba-tool domain backup online
--targetdir=/root/samba-backup/ --server=DC2 -UAdministrator" I get the
following error:

ERROR(<type 'exceptions.AttributeError'>): uncaught exception -
'TarFile' object has no attribute '__exit__'
  File
"/usr/local/samba/lib64/python2.6/site-packages/samba/netcmd/__init__.py",
line 178, in _run
    return self.run(*args, **kwargs)
  File
"/usr/local/samba/lib64/python2.6/site-packages/samba/netcmd/domain_backup.py",
line 243, in run
    backup_online(smb_conn, sysvol_tar, remote_sam.get_domain_sid())
  File
"/usr/local/samba/lib64/python2.6/site-packages/samba/ntacls.py", line
502, in backup_online
    with tarfile.open(name=dest_tarfile_path, mode='w:gz') as tar:
[root at dc2 samba-backup]#

Does anybody know if this can be fixed? It looks like the problem is python 2.6?

I would be very grateful for all the help I can get since it would feel
fantastic to be able to perform a backup before I start to join new DC:s and
make changes to the existing setup.

Best regards,
Carlos

On 18/03/2021 19:27, Carlos Gardel via samba wrote:
> Hi,
>
> I've been running two DC:s (DC1 and DC2) in a pure samba AD domain
since 2015 on Centos 6. Starting with version 4.1.14 I have upgraded my way to
version 4.9.7. It seems I have now reached the limit for possible upgrades of
these DC:s since it is no longer possible to upgrade to 4.10 on Centos 6.
>
> I'm now preparing to deploy a DC3 on a Centos 8 vm with samba 4.14.0.
Before joining it to the domain I have tried to make an online backup of the AD
on the two existing DC:s following the guide at
https://wiki.samba.org/index.php/Back_up_and_Restoring_a_Samba_AD_DC.
>
> When I run the command (as root) "samba-tool domain backup online
--targetdir=/root/samba-backup/ --server=DC2 -UAdministrator" I get the
following error:
>
> ERROR(<type 'exceptions.AttributeError'>): uncaught exception
- 'TarFile' object has no attribute '__exit__'
>    File
"/usr/local/samba/lib64/python2.6/site-packages/samba/netcmd/__init__.py",
line 178, in _run
>      return self.run(*args, **kwargs)
>    File
"/usr/local/samba/lib64/python2.6/site-packages/samba/netcmd/domain_backup.py",
line 243, in run
>      backup_online(smb_conn, sysvol_tar, remote_sam.get_domain_sid())
>    File
"/usr/local/samba/lib64/python2.6/site-packages/samba/ntacls.py", line
502, in backup_online
>      with tarfile.open(name=dest_tarfile_path, mode='w:gz') as tar:
> [root at dc2 samba-backup]#
>
> Does anybody know if this can be fixed? It looks like the problem is python
2.6?
>
> I would be very grateful for all the help I can get since it would feel
fantastic to be able to perform a backup before I start to join new DC:s and
make changes to the existing setup.
>
> Best regards,
> Carlos
>
You need python 2.7 at least, not being a Centos user, is it possible to 
upgrade Python ?

Rowland

On Thu, 2021-03-18 at 19:27 +0000, Carlos Gardel via samba
wrote:
> Hi,
> 
> I've been running two DC:s (DC1 and DC2) in a pure samba AD domain
> since 2015 on Centos 6. Starting with version 4.1.14 I have upgraded
> my way to version 4.9.7. It seems I have now reached the limit for
> possible upgrades of these DC:s since it is no longer possible to
> upgrade to 4.10 on Centos 6.
> 
> I'm now preparing to deploy a DC3 on a Centos 8 vm with samba 4.14.0.
> Before joining it to the domain I have tried to make an online backup
> of the AD on the two existing DC:s following the guide at 
> https://wiki.samba.org/index.php/Back_up_and_Restoring_a_Samba_AD_DC.
> 
> When I run the command (as root) "samba-tool domain backup online --
> targetdir=/root/samba-backup/ --server=DC2 -UAdministrator" I get the
> following error:
> I would be very grateful for all the help I can get since it would
> feel fantastic to be able to perform a backup before I start to join
> new DC:s and make changes to the existing setup.
The backup is taken over the network, so just start he backup on a new
modern Samba version, rather than with the old one.  

Python 2.6 was poorly tested with Samba - every release we would have a
bug filed about some issue or other - which is one of the reasons we
raised the minimum version recently to 3.5 and 3.6 - it was becoming
foolish to pretend to support versions that we didn't run CI on.

Andrew Bartlett
> Best regards,
> Carlos
> 
-- 
Andrew Bartlett (he/him)       https://samba.org/~abartlet/
Samba Team Member (since 2001) https://samba.org
Samba Team Lead, Catalyst IT   https://catalyst.net.nz/services/samba

Samba Development and Support, Catalyst IT - Expert Open Source
Solutions