[Kea-users] Log rotation - SIGHUP?

Thomas Markwalder tmark at isc.org
Mon Nov 14 13:22:46 UTC 2016

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?
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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:

  "loggers": [
      "name": "kea-dhcp4",
      "output_options": [
            "output": "/tmp/kea.log"
      "severity": "DEBUG",

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.

Thomas Markwalder

ISC Software Engineering

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