11 Replies Latest reply on Jul 19, 2005 4:21 AM by dimitris

Using the platform MBeanServer in jdk5 environments

dimitris Mar 22, 2005 5:07 PM

Would it make sense for our ServerImpl class to instantiate and re-use as its main MBeanServer, the one returned by a call to ManagementFactory.getPlatformMBeanServer(), when running under a java 5 runtime?

This would make the "standard" MXBeans appearing in the jmx-console, for example.

1. Re: Using the platform MBeanServer in jdk5 environments

adrian.brock Mar 22, 2005 5:28 PM (in response to dimitris)

No, because the RI does not understand our classloading.

It might work if you defined the MBeanServerBuilder class as a system
property before starting the jvm.

But then you would have to change the logic in
org.jboss.mx.util.MBeanServerLocator.locateJBoss();
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2. Re: Using the platform MBeanServer in jdk5 environments

dimitris Mar 22, 2005 7:37 PM (in response to dimitris)

It works :-)

JMImplementation
 name=Default,service=LoaderRepository
 type=MBeanRegistry
 type=MBeanServerDelegate

java.lang
 name=Code Cache,type=MemoryPool
 name=CodeCacheManager,type=MemoryManager
 name=Copy,type=GarbageCollector
 name=Eden Space,type=MemoryPool
 name=MarkSweepCompact,type=GarbageCollector
 name=Perm Gen,type=MemoryPool
 name=Survivor Space,type=MemoryPool
 name=Tenured Gen,type=MemoryPool
 type=ClassLoading
 type=Compilation
 type=Memory
 type=OperatingSystem
 type=Runtime
 type=Threading

java.util.logging
 type=Logging

jboss
 database=localDB,service=Hypersonic
 name=PropertyEditorManager,type=Service
 ...

3. Re: Using the platform MBeanServer in jdk5 environments

juha Mar 23, 2005 6:05 AM (in response to dimitris)

And you will want to check the performance of that thing.
That was the main reason for having to rewrite it.
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4. Re: Using the platform MBeanServer in jdk5 environments

dimitris Mar 23, 2005 6:48 AM (in response to dimitris)

You mean the MBeanServer? We use our MX implementation so there is no issue there.

Now, what overhead those MXBeans impose that I don't know, but they must be integrated with the underlying JVM in a native way probably.

A couple of glitches I noticed:

To activate/integrate with this, you need to let them (ManagementFactory.getPlatformMBeanServer()) create the MBeanServer (they'll use the initial 'builder' setting so we still get our own JMX impl), and then we use this as our main MBeanServer.

It doesn't work the other way around i.e. provide them with an existing MBeanServer to use (which is stupid). Also, while the docs say it'll use "DefaultDomain" for this MBeanServer, apparently 'null' is used as the default domain (this must be a bug). Again, this should be settable.

So we loose "jboss" being the default domain, but that's not too bad, with a little twiking of the MBeanServerLocator.locateJBoss() (as Adrian noted) we can locate the main jboss MBeanServer not necessarily by name (well, we could look for 'null') but instead store a reference to it at instantiation time, which is probably more correct, since we could have many "jboss" MBeanServers...

Another strange thing, although it instantiates you own JMX MBeanServer implementation, it hijacks the javax.management.MBeanServerDelegate to show 'Sun' as being the ImplementationVendor, generating it's own MBeanServerId (did we have some code that depended on the id format/uniqueness???)

But wait! I just checked, this happens anyway it you run under jdk5, I hadn't noticed it before...

In any case, it looks pretty cool on the jmx-console to get all this metrics about the garbage collector, etc. and it opens up new possibilities for setting up all sorts of monitors.

I think I'll commit this to head so you can have look (the change is pretty minor), so when jboss starts under jdk5 it'll instantiate those MXBeans, and I'll use also a system property to turn off this, if needed (or the ther way round? :)
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5. Re: Using the platform MBeanServer in jdk5 environments

iwadasn Jun 20, 2005 4:17 PM (in response to dimitris)

Was this ever put in? Does it exist in 4.0.2?

If so, how do you turn this on. I would like to see the standard java JMX beans in the jmx-console.
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6. Re: Using the platform MBeanServer in jdk5 environments

adrian.brock Jun 20, 2005 4:29 PM (in response to dimitris)

This is the design forums. If you want to ask for help, use the user forums!!!!
If you want to know what is in a release, use the release notes.

The JBoss forums are not a mechanism whereby you can get every frivilous
question answered without doing some research for yourself.
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7. Re: Using the platform MBeanServer in jdk5 environments

adrian.brock Jul 15, 2005 1:10 PM (in response to dimitris)

Following up on http://jira.jboss.com/jira/browse/JBAS-1610

The issue is that to start the agent for jconsole "-Dcom.sun.management.jmxremote"
we must have JBossJMX in the CLASSPATH rather than having ServerImpl
setup the system properties and classloader.

We cannot use Sun's MBeanServer because
1) We cannot plugin our UnifiedLoaderRepository
2) It does not do MBean context classloading
3) It is slow for Standard/ModelMBean (see the performance tests in the jmx module)
In fact when we did use Sun's MBeanServer in 2.4.x we had to implement performance
critical mbeans like the EJBContainer using DynamicMBeans.

Other alternatives:
1) Write a listener for MBeanRegistration events that creates proxies from
the platform mbean server to the JBoss MBeanServer (a poor man's cascading MBeanServer)
2) Deploy a jmx remote connector in JBoss's MBeanServer and use the remote tab
to connect to it from jconsole (including adding the platform XMBeans to JBoss's MBeanServer).
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8. Re: Using the platform MBeanServer in jdk5 environments

adrian.brock Jul 15, 2005 1:18 PM (in response to dimitris)

Or Scott's alternative LazyMBeanServer.
http://wiki.jboss.org/wiki/Wiki.jsp?page=JBossMBeansInJConsole
that delegates to JBoss's MBeanServer (when it is available) for non platform XMBeans.
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9. Re: Using the platform MBeanServer in jdk5 environments

starksm64 Jul 15, 2005 1:41 PM (in response to dimitris)

I think a new jmx remote connector is what we really need, because even with the current workaround, there are still the problems of accessing objects that are not really designed for remote access.

We need a flexible connector that can be configured for remote class loading and even custom serialization/object replacement of non-remotable objects. I would have looked at this first but I was not sure how far Tom has gotten with the current implementation.
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10. Re: Using the platform MBeanServer in jdk5 environments

adrian.brock Jul 15, 2005 2:08 PM (in response to dimitris)

We might be able to do something with the extension points

http://java.sun.com/j2se/1.5.0/docs/api/javax/management/remote/JMXConnectorServer.html#setMBeanServerForwarder(javax.management.remote.MBeanServerForwarder)

or jmx.remote.protocol.provider.class.loader
http://java.sun.com/j2se/1.5.0/docs/api/javax/management/remote/JMXConnectorServerFactory.html

I'm not that familiar with JSR160
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11. Re: Using the platform MBeanServer in jdk5 environments

dimitris Jul 19, 2005 4:21 AM (in response to dimitris)

Another workaround I was using, is to explicitly set the jboss classpath and the mbeanserver builder in a batch file (like what Main and ServerLoader would do), so only one mbeanserver gets created (the platform one).

I've added that as a subtask to the case:

http://jira.jboss.com/jira/browse/JBAS-2028
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