How to use SNMP4J-AgentJMX with existing MBeans?

Last modified by Frank Fock on 2024/05/25 10:58

 

SNMP4J-AgentJMX is an API that works on top of SNMP4J-Agent and SNMP4J to provide support for mapping content of an MBean server to a SNMP4J-Agent based SNMP agent.

To map MBeans of a server to SNMP, the following steps are necessary:

  1. Define or download a MIB. If you need to create one, use MIB Designer because you will have to redesign your MIB often in an iterative process. Using a visual tool which is capable of undo/redo and moving/refactoring MIB nodes saves many hours of work and bug search.
  2. Create the SNMP4J-Agent object initialization for MOTables & MOScalars to hold the MIB structure. This step is called "creating the MIB stubs". This can be done automated for SNMP4J-Agent by AgenPro (code generation from the MIB).

  3. Create a your own MOFactory (myJmxMoFactory) based on JMXDefaultMOFactory that actually creates SNMP4J-AgentJMX based ManagedObjects (MOScalarJMX and MOTableJMX).
    Subclass the Mib class generated by AgenPro from the MIB and call (see also the addJvmManagementMibInstrumentaton method of the sample MIB instrumentation class JvmManagementMibInst):

    JMXDefaultMOFactory jmxFactory = new JMXDefaultMOFactory(server, scalarSupport);
    // create MOs with factory
    createMO(jmxFactory);

  4. Statically map the OIDs  of the MIB (generated in the Mib class by AgenPro) to the MBean names of the MBean server:

      private static final Object[][] SCALAR_MBEANS_JVM_RUNTIME = {
         { JvmManagementMib.oidJvmRTName,         "Name",          String.class },
         { JvmManagementMib.oidJvmRTVMName,       "VmName",        String.class },
         { JvmManagementMib.oidJvmRTVMVendor,     "VmVendor",      String.class },
         { JvmManagementMib.oidJvmRTVMVersion,    "VmVersion",     String.class },
         { JvmManagementMib.oidJvmRTSpecName,     "SpecName",      String.class },
         { JvmManagementMib.oidJvmRTSpecVendor,   "SpecVendor",    String.class },
         { JvmManagementMib.oidJvmRTSpecVersion,  "SpecVersion",   String.class },
         { JvmManagementMib.oidJvmRTManagementSpecVersion, "ManagementSpecVersion",
        String.class },
         { JvmManagementMib.oidJvmRTBootClassPathSupport,
          new InverseBooleanType("BootClassPathSupported") },
         { JvmManagementMib.oidJvmRTInputArgsCount,"InputArguments", Long.class },
         { JvmManagementMib.oidJvmRTUptimeMs,     "Uptime", Long.class },
         { JvmManagementMib.oidJvmRTStartTimeMs,  "StartTime", Long.class }

      };

  5. Bind the mapping to an MBean:

        final MBeanServerConnection server =
            ManagementFactory.getPlatformMBeanServer();

       final MBeanAttributeMOTableSupport tableSupport =
           new MBeanAttributeMOTableSupport(server);
       final MBeanAttributeMOScalarSupport scalarSupport =
           new MBeanAttributeMOScalarSupport(server);

        ObjectName onameJvmRT =
           new ObjectName(ManagementFactory.RUNTIME_MXBEAN_NAME);

        scalarSupport.addAll(onameJvmRT, SCALAR_MBEANS_JVM_RUNTIME);

  6. That's all for scalars. For tables there is more to do. Of course, you also need to setup the SNMP agent with its securtiy, listen ports, etc. See the JMXTestAgent for a simple example of that.