Registering MBean in Dispatcher node

Question

Hi All,
  I am trying to figure out a way to register a
customized StandardMBean in all cluster nodes.
Unfortunately I don't manage to register my mbean in
dispatcher MBeanServer as it doesn't have the MBean classloader.
Currently I am registering the MBeans from a servlet so
the server classloader is aware of the MBean (it is
deployed together with the servlet in the EAR file), but
the dispatcher node isn't.
I am using javax.management.MBeanServerConnection to
obtain connection to the remote MBean server.
Then I am using the createMBean(..) method to istantiate
and register the MBean in the remote MBeanServer.
Could someone give me a hint how to add my MBean to the
dispatcher classloader.   Any alternatives will be also
appreciated.
This is the exception I get when trying to register the
MBean in the dispatcher MBeanServer:
com.sap.engine.services.jmx.exception.JmxConnectorException:
Unable to de-serialize request parameters, message [ JMX request
(java) v1.0 len: 323 | src: cluster target-node: 505798100 req:
createMBean(S,ON,ON) params-number: 3 params-bytes: 0 | com.abc.jmx.MyMBean :name=MyName,j2eeType=ABC_MyType,SAP_J2EEClusterNode=505798100,SAP_J2EECluster=""
:name="abc.com/MyLoader",j2eeType=SAP_J2EEClassLoader,SAP_J2EEClusterNode="",SAP_J2EECluster="" ] at
com.sap.engine.services.jmx.RequestMessage.readParams(RequestMessage.java:526) at
com.sap.engine.services.jmx.RequestMessage.getParams(RequestMessage.java:575) at
com.sap.engine.services.jmx.MBeanServerInvoker.invokeMbs(MBeanServerInvoker.java:106) at
com.sap.engine.services.jmx.JmxServiceConnectorServer.receiveWait(JmxServiceConnectorServer.java:173) at com.sap.engine.core.service630.context.cluster.message.MessageListenerWrapper.process(MessageListenerWrapper.java:81) at
com.sap.engine.core.cluster.impl6.ms.MSListenerThread.run(MSListenerThread.java:47) at
com.sap.engine.frame.core.thread.Task.run(Task.java:60)
at com.sap.engine.core.thread.impl6.SingleThread.execute(SingleThread.java:72) at
com.sap.engine.core.thread.impl6.SingleThread.run(SingleThread.java:142) <b>Caused by:
javax.management.InstanceNotFoundException: ClassLoader with name :name="abc.com/MyLoader",j2eeType=SAP_J2EEClassLoader,SAP_J2EEClusterNode="",SAP_J2EECluster="" not found in repository at com.sap.engine.services.jmx.CompletionInterceptor.getClassLoader(CompletionInterceptor.java:556)</b> at com.sap.engine.services.jmx.RedirectInterceptor.getClassLoader(RedirectInterceptor.java:493) at
com.sap.pj.jmx.server.interceptor.MBeanServerInterceptorChain.getClassLoader(MBeanServerInterceptorChain.java:435) at com.sap.engine.services.jmx.RequestMessage.readParams
(RequestMessage.java:515) ... 8 more -
predecessor system -
com.sap.engine.services.jmx.exception.JmxConnectorException: Unable to de-serialize request parameters, message
[ JMX request (java) v1.0 len: 323 | src: cluster target-node: 505798100 req: createMBean(S,ON,ON)
params-number: 3 params-bytes: 0 | com.abc.jmx.MyMBean :name=MyName,j2eeType=ABC_MyType,SAP_J2EEClusterNode=505798100,SAP_J2EECluster=""
:name="abc.com/MyLoader",j2eeType=SAP_J2EEClassLoader,SAP_J2EEClusterNode="",SAP_J2EECluster="" ] at com.sap.engine.services.jmx.MBeanServerConnectionImpl.invokeMbsInternal(MBeanServerConnectionImpl.java:677) at com.sap.engine.services.jmx.MBeanServerConnectionImpl.createMBean(MBeanServerConnectionImpl.java:105) at
com.sap.engine.services.jmx.MBeanServerConnectionSecurityWrapper.createMBean(MBeanServerConnectionSecurityWrapper.java:95) at ...
Dan
Message was edited by: Dan Sobol

Answer 1

I don’t think SAP has intended customers to register custom mbeans in the dispatcher node. This is probably the reason that there is no documentation in regard.  Anyway with some common sense and creativeness I found the way.
<b>1)</b>     
First think you want to deploy your mbean so a class loader of your mbean class is available in all the cluster nodes including dispatcher nodes.  In order to accomplish this you’ll have to:
<b>a.</b> Implement your mbean and archive it in a jar file.
<b>b.</b> Create a Library J2EE Server component.   File ---> new --> other --> J2EE Server Component --> Library
<b>c.</b> Use the privder.xml wizard to add your jar created in (a) to the library project.
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE provider-descriptor SYSTEM "library.provider.dtd">
<provider-descriptor>
  <display-name>XxxLib</display-name>
  <component-name>XxxLib</component-name>
  <major-version>6</major-version>
  <minor-version>40</minor-version>
  <micro-version>0</micro-version>
  <provider-name>xxx.com</provider-name>
  <references>
    <reference provider-name="sap.com" strength="weak" type="library">tc/jmx</reference>
    <reference provider-name="sap.com" strength="weak" type="library">com.sap.tc.Logging</reference>
    <reference provider-name="sap.com" strength="weak" type="library">core_lib</reference>
  </references>
  <jars>
    <jar-name>mbeanjar.jar</jar-name>
  </jars>
</provider-descriptor>
<b>d.</b> Now the tricky part: 
The current library project structure as created by the Netweaver IDE is
ProjectName
     META-INF
          sda-dd.xml
     server
          provider.xml
In order to deploy the mbean to the dispatcher node you need to create another folder named dispatcher and copy the provider.xml to it.
ProjectName
     META-INF
          sda-dd.xml
     server
          provider.xml
     dispatcher
          provider.xml
<b>e.</b> Create a deployable .sda archive from the library project.
<b>f.</b> Deploy the sda archive.
<b>g.</b> Check if the mbean class loader has been added to all cluster nodes.   Go to visual admin Services --> Class Loader Viewer --> Libraries and check if the mbean class loader exists e.g. library:com.xxx~libname.
<b>2)</b>     
Once a class loader of your mbean implementation exists in all nodes it is straightforward how to actually register the mbean.
<b>…</b>
MBeanServer mbs = (MBeanServer) initCtx.lookup("jmx");
mbs.createMBean(<i>mbeanClassName</i>, <i>objectName</i>, <i>classLoaderObjectName</i>);
<b>Where:</b>
mbeanClassName is the mbean class full qualified name e.g. com.xxx.mbean.ClassName
objectName is the mbean object name.  You may create it by using ObjectNameFactory.getNameForServerChildPerNode(<i>j2eeType</i>, <i>name</i>, <i>nodeId</i>, null);
classLoaderObjectName is the mbean's class loader object name: You may create it using ObjectNameFactory.getNameForClassLoader(<i>libraryName</i>, null, null);
Hopefully I didn’t miss anything substantial.
Have fun