JMX Connection - Cassandra

Larry O'Leary loleary at redhat.com
Fri Oct 26 02:39:41 UTC 2012


On Thu, 2012-10-25 at 17:07 -0400, Stefan Negrea wrote:
> Hello Everybody,
> 
> The new Cassandra plugin relies on the JMX plugin since most of the management is done via the exposed JMX interface. But I am running into a weird problem. After I restart the Cassandra node, all the JMX transactions from RHQ fail until the RHQ agent itself is restarted. I debugged the code and this is due to the fact the EMSConnection is no longer valid/connected after Cassandra is restarted. I looked at other plugins and there is no specific code do deal with this kind of situation. I also looked at the JMX plugin code and there is nothing that indicates a manual connection restart might be needed.
> 
> Restarting servers is a very common use case for JBoss AS servers; I am sure this detail was not overlooked so far.
> 
> Here is where I would need help:
> 1) What could be different with Cassandra and its JMX interface to cause this issue?
> 2) Did I miss something configuring the Cassandra plugin?
> 3) Should EMS take care of reconnecting to the server in case the underlying resource gets restarted?

I am certain we have run into this in the past and the plug-ins had to
be patched to work around the issue. I can't seem to locate any of the
BZs though. I remember specifically this issue affecting the AS4
plug-in. I agree that EMS should take care of this but I don't think it
does.
-- 
Larry O'Leary
https://plus.google.com/u/0/112645929986009801513



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