[collectd] generic JMX plugin

[matthew sporleder]

On Wed, Aug 5, 2009 at 12:18 PM, Florian Forster<octo at verplant.org> wrote:
> Hi Matthew,
>
> On Tue, Aug 04, 2009 at 11:47:59AM -0400, matthew sporleder wrote:
>> Also to report- this plugin keeps the collectd daemon from shutting
>> down cleanly.  I have to kill -9 it every time.
>>
>> [2009-08-04 11:38:14] Exiting normally.
>> [2009-08-04 11:38:14] collectd: Stopping 5 read threads.
>
> I can confirm that there is some sort of problem. I get some weird
> behavior with (Sun) Java 1.5 and 1.6 on Debian Etch and Lenny/Squeeze. I
> have only observed problems when letting collectd fork to the background
> - when running with `-f' the daemon works just fine.
>
> The problems I have observed appear to be just one problem, though:
>
>  - When run in the background, the daemon (or rather, the Java plugin)
>    appears to get stuck shortly after starting.
>  - Shutdown does not work as expected. The daemon is hanging with a
>    couple of threads calling `pthread_cond_timedwait'. This looks a lot
>    like a deadlock.
>
> I have just realized, though, that I usually kill collectd with SIGTERM
> but when it's running in the foreground I simply use ^C (i. e. SIGINT).
> Since libjvm appears to install a lot of signal handlers, the shutdown
> problem might be related to that. I'll give that a try tomorrow.
>


I would also like to add that running in the foreground (collectd -f)
successfully created an output directory for my <Connection> and
<MBeans>.  So it looks like the deadlock may actually happen at
startup.