[Kea-users] Log rotation - SIGHUP?

MRob mrobti at insiberia.net
Mon Nov 14 22:44:39 UTC 2016


On 2016-11-14 05:22, Thomas Markwalder wrote:
> On 11/14/16 12:44 AM, MRob wrote:
>> After rotating Kea logs, is a SIGHUP sufficient to get each of the Kea
>> servers to start using their new log files?
>> _______________________________________________
>> Kea-users mailing list
>> Kea-users at lists.isc.org
>> https://lists.isc.org/mailman/listinfo/kea-users
> 
> Hello:
> 
> 
> It should be. Ultimately it depends on how you've configured your
> logging and how you are rotating the log the files.  Sending SIGHUP 
> will
> cause Kea servers to reload their configuration, which in turn will
> cause it to reconfigured its loggers.  If you have configured your
> logger(s) to write to explicit files, the files will be closed and 
> reopened.
> 
> If the only reason you're issuing the SIGHUP is to rotate the files,
> there are ways to do it without causing the server to reload its
> configuration.  The most obvious way would be to use the "syslog" log
> destination and configure syslog (or rsyslog depending on your OS) to 
> do
> the log rotation for you.
> 
> If you prefer using explicitly named files and managing the log 
> rotation
> on your own, then you could simply copy the Kea log file to the
> appropriate rotate name, cat /dev/null to the Kea log file, and you're
> done,  no  SIGHUP necessary.   For example, if your logger config were 
> this:
> 
> "Logging":
> {
>   "loggers": [
>     {
>       "name": "kea-dhcp4",
>       "output_options": [
>           {
>             "output": "/tmp/kea.log"
>           }
>       ],
>       "severity": "DEBUG",
>       "debuglevel":99
>     }
>   ]
> }
> 
> Then as root, you could do something like this:
> 
> 
> # cp /tmp/kea.log /tmp.kea.log.1
> 
> # cat /dev/null > /tmp/kea.log
> 
> This works fine for me under Centos.
> 
> Hope that helps.

Thank you. I'm adding a kea entry to the logrotate system - although I 
can make logrotate do as you suggest ("copytruncate" option), I prefer 
more atomic action of move old file.

Is SIGHUP extremely disruptive to Kea?



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