Tuesday Nov 25, 2008

The Mystery Of Multiple MBeanServers

JConsole and VisualVM have made it very simple to access MBeans in a remote target VM. There's also a lot of blogs and documents that explain how to access remote MBeans programmatically.

But how do you access local MBeans registered in your own JVM?

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Tuesday Jul 29, 2008

Java 5, premain, RMI Connectors, Single Port, SSL, and Firewall.

... So many words I couldn't even put them all in the title...

I've been asked several times how to make my example of javaagent which starts a firewall friendly JMX RMI Connector work on JDK 5. Well, here is how. However, beware of the catch: if you use SSL and want to connect with JConsole then you need to use Java 6 JConsole on the client side.

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Friday Jul 11, 2008

OpenDS 1.0 is Released: A Java Open Source LDAP Server with JMX and SNMP monitoring

The first stable release of OpenDS is out! This LDAP Server written in Java can be monitored both through JMX and SNMP.

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Tuesday Jun 03, 2008

JavaScript and JMX 2.0 Namespaces

No, rest assured - I have not conjured up some kind of new unfathomable hybrid beast from Dante's Seventh Hell... More prosaically, I have simply put together a small JavaScript slide show from some JMX 2.0 Namespace slides presented by Eamonn at JavaOne 2008.

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Tuesday May 06, 2008

Mapping to OpenTypes: MXBean Complex Attribute Types

Although it might not be a very good idea to define your management model based on how it will be displayed by a given GUI, such as that provided by JConsole or VisualVM, I believe it is nonetheless interesting to explore the various ways in which a complex type such as a Map<String,Integer> could be modeled and exposed through an MXBean attribute.

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Friday Mar 07, 2008

Don't Do This! But Here Is a Way.

Recently I was asked how to do "registerMBean" in a remote JVM, from a remote JMX client. The MBeanServerConnection doesn't expose any registerMBean method, and for good reasons.

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Thursday Feb 14, 2008

Long time no blog...

... so I thought I'd drop a line. I have just uploaded a small set of slides of a high level presentation of project OpenDMK on the project's home page.

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Wednesday Jan 09, 2008

Building a Remotely Stoppable Connector Server

JMX is a wonderful tool to monitor and troubleshoot running applications. The new JDK 6 Attach API makes it very easy to attach to a running Java process, and start a JMX agent that will expose monitoring and configuration data to JMX consoles - like JConsole. However, there are some situations where you wish to start a JMX agent on demand, explore the monitoring data or diagnose the probable cause of an observed problem, and then close your JMX agent, leaving the application just how you found it.

In this post, I will discuss a means by which you can upload and start such a remotely stoppable JMX agent. Here is how.

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Monday Nov 12, 2007

Proxying a JMX Connection: Adapting To Another Protocol

This article exposes a proxying technique that can be used to adapt between two different protocols: one that is used on the server side, and one that we want to use on the client side. More to the point, this technique can be used to work around an annoying interoperation problem that can show up when exposing Model MBeans through an IIOP connector.

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Monday Oct 22, 2007

JMX: Connecting Through Firewalls Using RMI Over SSL And a Single Port (Part III)

This post explains how you can configure your Java application to export a single port using JMX RMI Connector Server over SSL. This is particularly useful when your application is located behind a firewall, because you will only need to let through a single port. However, using a single port when SSL is enabled requires a little care, because it can only work if the same RMI Socket Factories are used everywhere: indeed the same port cannot be shared by two different RMI Socket Factories. So at the risk of boring you, here is my third post on the subject.

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Wednesday Oct 17, 2007

Dmitri Maximovich: Monitoring JVM memory with MRTG

Dmitri Maximovich has written an excellent article about how to monitor JVM memory using MRTG.

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Wednesday Sep 12, 2007

More on premain and JMX Connectors

In my previous blog entry, I have talked about how to take advantage of java agents in order to start a custom JMX Connector in a Java application, without modifying the application. This is particularly useful when you need to monitor Java applications which are located behind a firewall. In that case, it makes it possible to write a java agent that will start a RMI connector configured in a firewall-friendly manner. However, there's a catch. This is what this entry is about.

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Wednesday Jul 25, 2007

Connecting Through Firewall Using JMX - Without modifying the server application

In a recent comment on my blog about Troubleshooting Connection Problems in JConsole I was asked the following question:

Can you simply explain how run jconsole on a client machine to connect to an unmodifiable applicaton that run on a server. One and only one port on the server is open though firewall for managing the application.

Here is how.

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Monday Jun 25, 2007

Java Real Time video (french) from Sun Tech Days Paris is online

As advertised by Alexis Moussine-Pouchkine the video of Bertrand Delsart, presenting Java Real Time is available online, among many others.

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Daniel Fuchs blogs on Scene Builder, JMX, SNMP, Java, etc...

The views expressed on this blog are those of the author and do not necessarily reflect the views of Oracle.


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