Re: Need help with Tomcat MBean support
I sent this in over the weekend and didn't get a response so let me try this again a bit differently. The Sun JDK 5.0 JMX tutorial shows that it is possible and simple to create JMX client and JMX server in separate JVMs and have them talk to each other. The first article cited by Mr. Hall shows that it is possible and simple to create a JMX server running inside Tomcat and talk to it through tools such as MC4J and JManage. I need to combine the Server side approach recommended by the article (JMX server within Tomcat webapp) with the Client side approach recommended by Sun in their tutorial. So far my client-side app can connect to the MBean server inside of Tomcat and talk to it but it fails to create the MBean needed to interact with the server because of ClassLoader issues. Questions: 1. Is this even possible? It would seem to be so since MC4J and JManage know how to do it. 2. If so, how do I surmount these ClassLoader issues? Thank you very much. Steve Cohen wrote: Okay using approach of first article. The MBean server is correctly initialized and everything on the server side looks good. Now we come to the client side. The first article assumes you are just going to connect using a tool such as MC4J or JManage (monitoring tools). That is not my use case. I want to write a command-line client that can talk to the MBean (which is inside of Tomcat) and invoke an operation on the MBean. I use the Client.java sample from the Sun tutorial as a starting point. I am able to connect to the server, and get a list of MBeans, but I fail when trying to call createMBean(). I am using the simple two-parameter version of createMBean() and it always fails with javax.management.ReflectionException: The MBean class could not be loaded by the default loader repository It seems pretty clear that my client needs to use one of the other versions of createMBean(), one that specifies some other Class Loader but I have no clue what I should be using for that. H. Hall wrote: Steve Cohen wrote: Let me ask my question a little more directly: Does the presence of a descriptor cause instantiation of an instance of an MBean or do I have to write code to create a server-side instance of my MBean and if so, where should this code reside or is there some configuration artifact that causes this instantiation to happen? Why don't you take a look at these two articles: http://today.java.net/pub/a/today/2005/11/15/using-jmx-to-manage-web-applications.html?page=1 http://marxsoftware.blogspot.com/2008/07/jmx-model-mbeans-with-apache-commons.html If you use the NetBeans IDE you might be interested in the JMX plugin for NB. Here is a link to a tutorial Getting Started with JMX Monitoring in NetBeans IDE 6.0 http://www.netbeans.org/kb/60/java/jmx-getstart.html cheers, HH - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Need help with Tomcat MBean support - SOLVED
Finally figured out how to do what I wanted to do. Turns out I had no need at all of creating an MBean in my client. Duh! I never understood why I needed to do that but that is what the sample did. All I needed to do was call the MBeanServerConnection.invoke() method with a suitable object name and other params to invoke the operation on the MBean I had ALREADY instantiated on my server. That's what you get for slavishly following example code instead of thinking. By the way I found this out by staring at the Ant examples on http://tomcat.apache.org/tomcat-6.0-doc/monitoring.html. I finally realized that if Ant can invoke an operation, so could a non-Ant executable. From there a simple peek at the jmx ant task source code showed me what I needed to do. Voila! Gotta love open source - once you figure out where to look. Thank you to all who helped. Steve Cohen wrote: I sent this in over the weekend and didn't get a response so let me try this again a bit differently. The Sun JDK 5.0 JMX tutorial shows that it is possible and simple to create JMX client and JMX server in separate JVMs and have them talk to each other. The first article cited by Mr. Hall shows that it is possible and simple to create a JMX server running inside Tomcat and talk to it through tools such as MC4J and JManage. I need to combine the Server side approach recommended by the article (JMX server within Tomcat webapp) with the Client side approach recommended by Sun in their tutorial. So far my client-side app can connect to the MBean server inside of Tomcat and talk to it but it fails to create the MBean needed to interact with the server because of ClassLoader issues. Questions: 1. Is this even possible? It would seem to be so since MC4J and JManage know how to do it. 2. If so, how do I surmount these ClassLoader issues? Thank you very much. Steve Cohen wrote: Okay using approach of first article. The MBean server is correctly initialized and everything on the server side looks good. Now we come to the client side. The first article assumes you are just going to connect using a tool such as MC4J or JManage (monitoring tools). That is not my use case. I want to write a command-line client that can talk to the MBean (which is inside of Tomcat) and invoke an operation on the MBean. I use the Client.java sample from the Sun tutorial as a starting point. I am able to connect to the server, and get a list of MBeans, but I fail when trying to call createMBean(). I am using the simple two-parameter version of createMBean() and it always fails with javax.management.ReflectionException: The MBean class could not be loaded by the default loader repository It seems pretty clear that my client needs to use one of the other versions of createMBean(), one that specifies some other Class Loader but I have no clue what I should be using for that. H. Hall wrote: Steve Cohen wrote: Let me ask my question a little more directly: Does the presence of a descriptor cause instantiation of an instance of an MBean or do I have to write code to create a server-side instance of my MBean and if so, where should this code reside or is there some configuration artifact that causes this instantiation to happen? Why don't you take a look at these two articles: http://today.java.net/pub/a/today/2005/11/15/using-jmx-to-manage-web-applications.html?page=1 http://marxsoftware.blogspot.com/2008/07/jmx-model-mbeans-with-apache-commons.html If you use the NetBeans IDE you might be interested in the JMX plugin for NB. Here is a link to a tutorial Getting Started with JMX Monitoring in NetBeans IDE 6.0 http://www.netbeans.org/kb/60/java/jmx-getstart.html cheers, HH - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Need help with Tomcat MBean support
Okay using approach of first article. The MBean server is correctly initialized and everything on the server side looks good. Now we come to the client side. The first article assumes you are just going to connect using a tool such as MC4J or JManage (monitoring tools). That is not my use case. I want to write a command-line client that can talk to the MBean (which is inside of Tomcat) and invoke an operation on the MBean. I use the Client.java sample from the Sun tutorial as a starting point. I am able to connect to the server, and get a list of MBeans, but I fail when trying to call createMBean(). I am using the simple two-parameter version of createMBean() and it always fails with javax.management.ReflectionException: The MBean class could not be loaded by the default loader repository It seems pretty clear that my client needs to use one of the other versions of createMBean(), one that specifies some other Class Loader but I have no clue what I should be using for that. H. Hall wrote: Steve Cohen wrote: Let me ask my question a little more directly: Does the presence of a descriptor cause instantiation of an instance of an MBean or do I have to write code to create a server-side instance of my MBean and if so, where should this code reside or is there some configuration artifact that causes this instantiation to happen? Why don't you take a look at these two articles: http://today.java.net/pub/a/today/2005/11/15/using-jmx-to-manage-web-applications.html?page=1 http://marxsoftware.blogspot.com/2008/07/jmx-model-mbeans-with-apache-commons.html If you use the NetBeans IDE you might be interested in the JMX plugin for NB. Here is a link to a tutorial Getting Started with JMX Monitoring in NetBeans IDE 6.0 http://www.netbeans.org/kb/60/java/jmx-getstart.html cheers, HH - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Need help with Tomcat MBean support
Steve Cohen wrote: Let me ask my question a little more directly: Does the presence of a descriptor cause instantiation of an instance of an MBean or do I have to write code to create a server-side instance of my MBean and if so, where should this code reside or is there some configuration artifact that causes this instantiation to happen? Why don't you take a look at these two articles: http://today.java.net/pub/a/today/2005/11/15/using-jmx-to-manage-web-applications.html?page=1 http://marxsoftware.blogspot.com/2008/07/jmx-model-mbeans-with-apache-commons.html If you use the NetBeans IDE you might be interested in the JMX plugin for NB. Here is a link to a tutorial Getting Started with JMX Monitoring in NetBeans IDE 6.0 http://www.netbeans.org/kb/60/java/jmx-getstart.html cheers, HH Steve Cohen wrote: H. Hall wrote: Okay, thanks again. This got me off square one. Now on to square two. :-) 1. I compose a legal mbeans-descriptor.xml file configuring my MBean according to DTD. I place it in the domain Catalina. Don't know if this is right. Also tried my own domain name. 2. I launch Tomcat with parameters sufficient to launch JMX, define a port etc. This works. 3. I modify the simple Client.java from the Sun tutorial modifying the url to talk to my port and the jmxrmi context. This succeeds to the point of letting me iterate the list of available domain names. 4, When I use the version of the descriptor with a custom Domain name, this domain name does not even appear in the list and the Client app fails with a ClassNotFoundException. 5. When I use the version of the descriptor that places my mbean in the Catalina domain, my bean is not found within that Domain and the Client app also fails - with a ClassNotFoundException. Is there a preexisting domain within Tomcat to which I should attach my mbean? If not, what must I do to get my mbean found. Steve Cohen wrote: I am trying to write a custom MBean to put a particular function of our application under management control This application is currently deployed under Tomcat 6.0. I do not need remote monitoring/management. Local management will do. I am perfectly happy to invoke my management function through a shell script invoking a java jmx client to perform the action required. I find the Tomcat documentation on this subject confusing and sparse. The howto page here: http://tomcat.apache.org/tomcat-6.0-doc/mbeans-descriptor-howto.html simply shows a sample configuration file without explaining which elements on it are required, which pertain to the specific example, etc. Is there a standard syntax for these mbean descriptor files with a true explanation of each field? I believe it's based on the Apache Commons Modeler. Here is a link to the DTD for the Model MBeans Configuration File: http://jakarta.apache.org/commons/dtds/mbeans-descriptors.dtd Here is a link for the java doc for package org.apache.tomcat.util.modeler. Scroll down to description: http://tomcat.apache.org/tomcat-6.0-doc/api/org/apache/tomcat/util/modeler/package-summary.html cheers, HH Also, compared to the standard Sun JMX tutorial - which elements does Tomcat provide - server, agent ? Thanks. - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] -- H. Hall ReedyRiver Group LLC http://www.reedyriver.com - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Need help with Tomcat MBean support
Thanks again. These articles are very clear and simple. They do raise a couple questions, though. In the first article, no mention is made of an mbeans-descriptor.xml file. It's all done programatically in the first article - which might be fine for my needs. The Tomcat documentation does make it sound as though you can drop the xml file into your MBean package directory and something provided by Tomcat picks it up and makes the MBean accessible, but it now seems that this is not the case. The second article shows code to read these XML files ( CommonsModelMBeanDemonstrator.applyCommonsModeler() ) which leads me to ask whether Tomcat comes with commons-modeler support built-in or whether this must be added manually as in this sample. Anyway, it appears that there are two approaches here 1 - do everything programatically, in which case the .xml file isn't needed 2 - use the commons-modeler xml-file approach (question remains what support, if any, Tomcat provides for this). Do I have this right? H. Hall wrote: Steve Cohen wrote: Let me ask my question a little more directly: Does the presence of a descriptor cause instantiation of an instance of an MBean or do I have to write code to create a server-side instance of my MBean and if so, where should this code reside or is there some configuration artifact that causes this instantiation to happen? Why don't you take a look at these two articles: http://today.java.net/pub/a/today/2005/11/15/using-jmx-to-manage-web-applications.html?page=1 http://marxsoftware.blogspot.com/2008/07/jmx-model-mbeans-with-apache-commons.html If you use the NetBeans IDE you might be interested in the JMX plugin for NB. Here is a link to a tutorial Getting Started with JMX Monitoring in NetBeans IDE 6.0 http://www.netbeans.org/kb/60/java/jmx-getstart.html cheers, HH - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Need help with Tomcat MBean support
Steve Cohen wrote: I am trying to write a custom MBean to put a particular function of our application under management control This application is currently deployed under Tomcat 6.0. I do not need remote monitoring/management. Local management will do. I am perfectly happy to invoke my management function through a shell script invoking a java jmx client to perform the action required. I find the Tomcat documentation on this subject confusing and sparse. The howto page here: http://tomcat.apache.org/tomcat-6.0-doc/mbeans-descriptor-howto.html simply shows a sample configuration file without explaining which elements on it are required, which pertain to the specific example, etc. Is there a standard syntax for these mbean descriptor files with a true explanation of each field? I believe it's based on the Apache Commons Modeler. Here is a link to the DTD for the Model MBeans Configuration File: http://jakarta.apache.org/commons/dtds/mbeans-descriptors.dtd Here is a link for the java doc for package org.apache.tomcat.util.modeler. Scroll down to description: http://tomcat.apache.org/tomcat-6.0-doc/api/org/apache/tomcat/util/modeler/package-summary.html cheers, HH Also, compared to the standard Sun JMX tutorial - which elements does Tomcat provide - server, agent ? Thanks. -- H. Hall ReedyRiver Group LLC http://www.reedyriver.com - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Need help with Tomcat MBean support
Thank you very much - this is exactly what I was looking for. And a word to the Tomcat team - Documentation would be much improved by simply mentioning the two links provided by Mr. Hall. H. Hall wrote: Steve Cohen wrote: I am trying to write a custom MBean to put a particular function of our application under management control This application is currently deployed under Tomcat 6.0. I do not need remote monitoring/management. Local management will do. I am perfectly happy to invoke my management function through a shell script invoking a java jmx client to perform the action required. I find the Tomcat documentation on this subject confusing and sparse. The howto page here: http://tomcat.apache.org/tomcat-6.0-doc/mbeans-descriptor-howto.html simply shows a sample configuration file without explaining which elements on it are required, which pertain to the specific example, etc. Is there a standard syntax for these mbean descriptor files with a true explanation of each field? I believe it's based on the Apache Commons Modeler. Here is a link to the DTD for the Model MBeans Configuration File: http://jakarta.apache.org/commons/dtds/mbeans-descriptors.dtd Here is a link for the java doc for package org.apache.tomcat.util.modeler. Scroll down to description: http://tomcat.apache.org/tomcat-6.0-doc/api/org/apache/tomcat/util/modeler/package-summary.html cheers, HH Also, compared to the standard Sun JMX tutorial - which elements does Tomcat provide - server, agent ? Thanks. - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Need help with Tomcat MBean support
Steve Cohen wrote: Thank you very much - this is exactly what I was looking for. And a word to the Tomcat team - Documentation would be much improved by simply mentioning the two links provided by Mr. Hall. Patches are always welcome. Mark - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Need help with Tomcat MBean support
Soon as I get out of this time crunch I will try to do so. Mark Thomas wrote: Steve Cohen wrote: Thank you very much - this is exactly what I was looking for. And a word to the Tomcat team - Documentation would be much improved by simply mentioning the two links provided by Mr. Hall. Patches are always welcome. Mark - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Need help with Tomcat MBean support
H. Hall wrote: Okay, thanks again. This got me off square one. Now on to square two. :-) 1. I compose a legal mbeans-descriptor.xml file configuring my MBean according to DTD. I place it in the domain Catalina. Don't know if this is right. Also tried my own domain name. 2. I launch Tomcat with parameters sufficient to launch JMX, define a port etc. This works. 3. I modify the simple Client.java from the Sun tutorial modifying the url to talk to my port and the jmxrmi context. This succeeds to the point of letting me iterate the list of available domain names. 4, When I use the version of the descriptor with a custom Domain name, this domain name does not even appear in the list and the Client app fails with a ClassNotFoundException. 5. When I use the version of the descriptor that places my mbean in the Catalina domain, my bean is not found within that Domain and the Client app also fails - with a ClassNotFoundException. Is there a preexisting domain within Tomcat to which I should attach my mbean? If not, what must I do to get my mbean found. Steve Cohen wrote: I am trying to write a custom MBean to put a particular function of our application under management control This application is currently deployed under Tomcat 6.0. I do not need remote monitoring/management. Local management will do. I am perfectly happy to invoke my management function through a shell script invoking a java jmx client to perform the action required. I find the Tomcat documentation on this subject confusing and sparse. The howto page here: http://tomcat.apache.org/tomcat-6.0-doc/mbeans-descriptor-howto.html simply shows a sample configuration file without explaining which elements on it are required, which pertain to the specific example, etc. Is there a standard syntax for these mbean descriptor files with a true explanation of each field? I believe it's based on the Apache Commons Modeler. Here is a link to the DTD for the Model MBeans Configuration File: http://jakarta.apache.org/commons/dtds/mbeans-descriptors.dtd Here is a link for the java doc for package org.apache.tomcat.util.modeler. Scroll down to description: http://tomcat.apache.org/tomcat-6.0-doc/api/org/apache/tomcat/util/modeler/package-summary.html cheers, HH Also, compared to the standard Sun JMX tutorial - which elements does Tomcat provide - server, agent ? Thanks. - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Need help with Tomcat MBean support
Let me ask my question a little more directly: Does the presence of a descriptor cause instantiation of an instance of an MBean or do I have to write code to create a server-side instance of my MBean and if so, where should this code reside or is there some configuration artifact that causes this instantiation to happen? Steve Cohen wrote: H. Hall wrote: Okay, thanks again. This got me off square one. Now on to square two. :-) 1. I compose a legal mbeans-descriptor.xml file configuring my MBean according to DTD. I place it in the domain Catalina. Don't know if this is right. Also tried my own domain name. 2. I launch Tomcat with parameters sufficient to launch JMX, define a port etc. This works. 3. I modify the simple Client.java from the Sun tutorial modifying the url to talk to my port and the jmxrmi context. This succeeds to the point of letting me iterate the list of available domain names. 4, When I use the version of the descriptor with a custom Domain name, this domain name does not even appear in the list and the Client app fails with a ClassNotFoundException. 5. When I use the version of the descriptor that places my mbean in the Catalina domain, my bean is not found within that Domain and the Client app also fails - with a ClassNotFoundException. Is there a preexisting domain within Tomcat to which I should attach my mbean? If not, what must I do to get my mbean found. Steve Cohen wrote: I am trying to write a custom MBean to put a particular function of our application under management control This application is currently deployed under Tomcat 6.0. I do not need remote monitoring/management. Local management will do. I am perfectly happy to invoke my management function through a shell script invoking a java jmx client to perform the action required. I find the Tomcat documentation on this subject confusing and sparse. The howto page here: http://tomcat.apache.org/tomcat-6.0-doc/mbeans-descriptor-howto.html simply shows a sample configuration file without explaining which elements on it are required, which pertain to the specific example, etc. Is there a standard syntax for these mbean descriptor files with a true explanation of each field? I believe it's based on the Apache Commons Modeler. Here is a link to the DTD for the Model MBeans Configuration File: http://jakarta.apache.org/commons/dtds/mbeans-descriptors.dtd Here is a link for the java doc for package org.apache.tomcat.util.modeler. Scroll down to description: http://tomcat.apache.org/tomcat-6.0-doc/api/org/apache/tomcat/util/modeler/package-summary.html cheers, HH Also, compared to the standard Sun JMX tutorial - which elements does Tomcat provide - server, agent ? Thanks. - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
