[Xymon] PID file for XYMOND_ALERT

[J.C. Cleaver]

On Tue, December 1, 2015 12:06 pm, John Thurston wrote:
> So that I can kill off my errant process and keep xymon alerts flowing,
> I need to identify that process. It seems like it would be simple to get
> the right PID. I have xymon_history writing a pid file when it is
> launched with the following line in my tasks.cfg
>
>> CMD xymond_channel --channel=stachg --log=$XYMONSERVERLOGS/h.log
>> xymond_history --pidfile=$XYMONSERVERLOGS/x_h.pid
>
> But I am unable to get xymon_alert to create this pid file. It isn't a
> documented option on the man-page, but I had hoped the capability was
> buried in the there anyway. It doesn't appear to be so :(
>
> So I thought maybe I could get the pid of the parent by specifying
> --pidfile on that instance of xymond_channel with:
>
>> CMD xymond_channel --channel=page  --log=$XYMONSERVERLOGS/a.log
>> --pidfile=$XYMONSERVERLOGS/x_a.pid xymond_alert --debug
>> --checkpoint-file=$XYMONTMP/a.chk --checkpoint-interval=600
>
> but this doesn't seem to work either.


Unfortunately, this isn't an option with xymond_alert as-is, although it
will be with 4.4 (since the --pid-file option will be in a standard
library), and 4.4 (and the Terabithia RPMs) have a 'PIDFILE' option in
tasks.cfg for controlling this at the xymonlaunch level too.

The idea to have xymond_channel write out pid files too is an interesting
one -- something I hadn't considered -- and might be able to be added in
some form in 4.4. (How it could interact with --multilocal would be
interesting, though...)

> The only way I can think to
> identify the process is to
>    pgrep -f "xymond_channel --channel=page"
> which seems like a long way around the barn, but I can make it work.
>
> Should I be able to get a pidfile written for this worker process, or it
> simply impossible?
>

This is probably the easiest in this case. Really, the xymond_channel
process can substitute for xymond_alert in this case since xymond_channel
will kill the worker(s) when it terminates itself (under normal
circumstances).

HTH,
-jc