[Samba] restarting samba using a cron job on Debian

[Lars Hanke]

 > Why bother with all the above, just use samba-ad-dc instead.

Yes, I streamlined the script somewhat. Let's see what happens when 
replication fails next time.

 > You are going to have to supply more info, is there anything in the logs
 > when replication fails?
 > If not, try raising the log level until you do get something.

Anything specific I should look for? As said it happens at unpredictable 
intervals, usually after many days. An of course I cannot leave the 
system in that state for long. So I have to get as many information at 
once. Any recommendation for settings?

Am 30.11.2015 um 14:24 schrieb Rowland Penny:
> On 30/11/15 12:35, Lars Hanke wrote:
>> Thanks Rowland, for the thoughts.
>>
>> > If you are running Samba4 as an AD DC, you should never start the nmbd
>> > deamon, you should also never start smbd manually.
>>
>> Yes, I could optimize to use /etc/init.d/samba-ad-dc immediately,but
>> in fact this is what /etc/init.d/samba does. The messages with "AD DC
>> daemon" are generated by that script, and it is the failing one.
>
> Yes, you are correct running /etc/init.d/samba does run samba-ad-dc, but
> I still wouldn't run it, this is part of that script:
>
> case $1 in
>      start)
>          /etc/init.d/nmbd start
>          /etc/init.d/smbd start
>          /etc/init.d/samba-ad-dc start
>          ;;
>
> So, it checks if it should start nmbd, exits because it shouldn't,
> checks if it should start smbd, exits because it shouldn't, it then
> checks if it should start samba and because it should, it does.
>
> Why bother with all the above, just use samba-ad-dc instead.
>
>>
>> > What you are trying to do is, in my opinion, the wrong way to go about
>> > fixing the problem, you really should try to ascertain why you are
>> > losing sync.
>>
>> Agreed. But I've no idea how to troubleshoot that issue. Any help on
>> fixing the cause is also appreciated.
>>
>>
>
> You are going to have to supply more info, is there anything in the logs
> when replication fails?
> If not, try raising the log level until you do get something.
>
> Rowland
>
>> Am 30.11.2015 um 12:13 schrieb Rowland Penny:
>>> On 30/11/15 10:01, Lars Hanke wrote:
>>>> For some reason my secondary DC loses sync every once in a while. It
>>>> looks like this in samba-tool drs showrepl:
>>>>
>>>> Last attempt @ Thu Nov 19 13:53:09 2015 CET failed, result 5
>>>> (WERR_ACCESS_DENIED)
>>>> 229 consecutive failure(s).
>>>> Last success @ Wed Nov 18 18:48:07 2015 CET
>>>>
>>>> Restarting samba fixes the issue for an unpredictable time. Sometimes
>>>> hours, sometimes many weeks. So I wrote a script to restart samba in
>>>> this case:
>>>>
>>>> #!/bin/bash
>>>> #
>>>> # Check if samba replication broke down and restart samba in this case
>>>> #
>>>> SAMBA_TOOL=/usr/bin/samba-tool
>>>> SED=/bin/sed
>>>> MAIL=/usr/bin/mail
>>>> RM=/bin/rm
>>>> MKTMP=/bin/mktemp
>>>>
>>>> FAIL=`$SAMBA_TOOL drs showrepl | $SED -n "/^\s*[1-9][0-9]* consecutive
>>>> failure(s)\.$/p"`
>>>>
>>>> if [[ -n "$FAIL" ]]; then
>>>>   TMP=$($MKTMP)
>>>>   $SAMBA_TOOL drs showrepl > "$TMP"
>>>>   echo "Restart ..." >> "$TMP"
>>>>   /etc/init.d/samba restart >> "$TMP"
>>>>   echo "... done!" >> "$TMP"
>>>>   $MAIL -s 'DC2 restart' sysop at example.com < "$TMP"
>>>>   $RM -f "$TMP"
>>>> fi
>>>>
>>>> And it works perfectly, if I run it manually. However, the idea is to
>>>> run it by cron every 5 minutes. But when it's run from cron restarting
>>>> samba fails:
>>>>
>>>> Restart ...
>>>> Stopping NetBIOS name server: nmbd.
>>>> Stopping SMB/CIFS daemon: smbd.
>>>> Stopping Samba AD DC daemon: samba.
>>>> Starting Samba AD DC daemon: samba failed!
>>>> ... done!
>>>
>>> I think you may be using the wrong start/stop/restart init script. On
>>> Debian there are usually 4 samba init scripts:
>>>
>>> nmbd
>>> smbd
>>> samba
>>> samba-ad-dc
>>>
>>> There is also the winbind init script, but this will only be installed
>>> if you are using winbind i.e. on a domain member
>>>
>>> The nmbd & smbd init scripts are there to start and stop the individual
>>> deamons, the samba init script runs both of the nmbd & smbd init
>>> scripts, samba-ad-dc starts/stops the samba deamon, which will then
>>> start the smbd deamon.
>>>
>>> If you are running Samba4 as an AD DC, you should never start the nmbd
>>> deamon, you should also never start smbd manually.
>>>
>>> What you are trying to do is, in my opinion, the wrong way to go about
>>> fixing the problem, you really should try to ascertain why you are
>>> losing sync.
>>>
>>> Rowland
>>>
>>>>
>>>> Running the same script manually from a root shell works however fine.
>>>>
>>>> The system is Debian Jessie using samba 4.1.17-Debian. I start the
>>>> script using the following entry in root's crontab:
>>>>
>>>> */5 * * * * /root/samba-restart.sh
>>>>
>>>> Any ideas what I'm doing wrong?
>>>>
>>>> Thanks for your help,
>>>>  - lars.
>>>>
>>>
>>>
>>
>>
>
>