Re: Behaviour change request.

[Jan-Henrik Haukeland]

Eetu Rantanen <address@hidden> writes:

>       Last night we got flooded with some 200 mails stating that one
>       of the processes monit was watching had become an zombie. I tried
>       looking into the config but could not find a switch or an option
>       that would make monit restart the program. The "zombie" was a
>       java-process and I managed to kill without having to use -9.
> 
>       Therefore I am requesting an option to the configuration file such
>       as "zombie (alert|kill|restart)".

The problem with a "real" zombie process is that it's (usually) not
killable. When monit starts a process it forks twice so the parent of
the process is going to be the init process. If such a process later
becomes a zombie process you would actually have to restart the system
to get rid of the zombie. Therefor it's better for monit to raise an
alert when a process has become a zombie, so you as a sys. adm. can
figure out what to do. When monit check for zombies it reads info
directly from the kernel so if it says a process is a zombie it's a
zombie, isn't that right Christian? 

I'm not sure why you was able to actually kill this Java process.
Maybe it wasn't started from within monit in the first place and it
was a light-weight process (thread) in the JVM that become a zombie
(not unusual) and when you killed (without -9) the JVM gracefully
waited for all of it's threads and thereby removed the zombie from the
system?

-- 
Jan-Henrik Haukeland