On 05/09/2011 05:15 PM, David A. Webster wrote:

>I thought the LocalVMTypeDescriptor conn type was for when the managed
JMX server was inside the same process as the RHQ plugin container, at
least that seems to be what the code in
InternalJMXServerDiscoveryComponent suggests.


I believe this is so for the Agent to discover it's own JVM.  But with JON 2.4 the agent will not discover any JVM running on the same node that is not using JMX Remoting....  The code is a bit confusing, but it appears to discover "itself" using the Attach API or some similar Sun API, but not for discovering other JVM processes running on the same node under the same Agent. 


Yep, that's my impression too. I'm pretty sure we currently don't have any once in there for discovering and managing external JVMs that don't have JMX Remoting enabled (aside from JBoss AS JVMs as discussed below).

I will attach code in Bug tracking system later showing what we did and you guys can determine if that something is already there in 4.0 that accomplishes this, and I have just not found it yet.

Bottom line is the agent should be able to see every JVM running on the node under the same account, regardless of whether or not JMX remoting is enabled, attach


I'm not familiar with the Attach API. Is it only possible to attach to processes owned by the same user? Also, what would you use as the JVM Resource's key for a JVM discovered via Attach? You wouldn't want to use the PID right, since it would change if the JVM was restarted. Perhaps the java.home dir?
to its MBean server and expose every registered MBean, its attributes and operations, found there on each JVM, and report it all back to the JON server for inventory management.  

Same should go for Tomcat.  Shouldn't need to have jmx remoting enabled to see Tomcat instances.  Oddly, it appears JBoss EAP/EWP doesn't need jmx remoting for those to be discovered....wondering if they use the Attach API or something similar in those plugins?


For the AS4 and AS5 plugins, we actually use the the JBoss JNP protocol for obtaining the reference to the remote MBeanServer, so JMX Remoting isn't required, but it is required that JBoss is configured to expose its MBeanServer remotely via JNP. What happens is the PROCESS_FILTERS code in JMXDiscoveryComponent prevents JBoss JVMs from being discovered by that discovery component, so they can instead be discovered by EmbeddedJMXServerDiscoveryComponent, which essentially piggybacks on the JMX connection that was discovered by the AS4 or AS5 plugin.