Introduction
This how-to will show how to monitor an installation of Jboss with OP5 Monitor and the plugin check_jmx.
Java Management Extensions (JMX) is a Java technology that supplies tools for managing and monitoring applications, system objects, devices (e. g. printers) and service oriented networks. Those resources are represented by objects called MBeans (for Managed Bean).*
JMX exposes a set of 'Managed bean' (MBean) which represents a resource running in the Java Virtual Machine.
The JMX implementation of a java application server typically exposes resource usage statistics (memory, threads used, etc.) and lots of other statistics/metrics. Apart from generic information the application server vendor also provides MBeans specific for the application server in question.
Standard JMX using RMI is no longer available in JBoss as of version 7.1
Functionality
The check_jmx plugin enables you to monitor the values of any MBean attribute made available through JMX.
Prerequisites
The JMX agent needs to be enabled on the application server that is being monitored. The agent must be configured to allow remote connections over RMI ((Java) Remote Method Invocation). Refer to the application server documentation for details on how to set this up.
It is also possible to run the checks in this how-to with a username and password to increase security, this how-to will not cover that. Please refer to your application servers manual on how to set that up.
Installation
The check_jmx plugin is included in the op5-plugins package and is located in /opt/plugins. Metadata/checkcommand information is installed in /opt/plugins/metadata/check_jmx.metadata.
You will also need java installed in your OP5 Monitor instance, you can install java via yum from our repositories: yum install java-1.7.0-openjdk
More information regarding Java installation and it's versions can be found through the CentOS community: http://wiki.centos.org/HowTos/JavaOnCentOS.
Please note, beginning in OP5 Monitor version 9.x, the check_jmx plugin is no longer included but can be imported as a custom plugin.
Usage
The plugin consist of a shell script wrapper (check_jmx) and a java jar file (check_jmx.jar). When running the plugin the shell script should be invoked, the jar file should not be used directly.
./check_jmx -U -O
Examples
You can test the different checks from the command-line to verify that they work before you implement them into OP5 Monitor. Check the 'used' key of attribute 'HeapMemoryUsage' in the object: 'java.lang:type=Memory'
cd /opt/plugins ./check_jmx -U service:jmx:rmi:///jndi/rmi://'app-server':'1090'/jmxrmi -O java.lang:type=Memory -A HeapMemoryUsage -K "used"
Check the 'ThreadCount' attribute in the object 'java.lang:type=Threading'
./check_jmx -U service:jmx:rmi:///jndi/rmi://'app-server':'1090'/jmxrmi -O java.lang:type=Threading -A ThreadCount -K ""
Check available connections in the connection-pool in the object 'jboss.jca:name=JmsXA,service=ManagedConnectionPool' with the attribute 'AvailableConnectionCount'
./check_jmx -U service:jmx:rmi:///jndi/rmi://'app-server':'1090'/jmxrmi -O jboss.jca:name=JmsXA,service=ManagedConnectionPool -A AvailableConnectionCount
Check Commands
Add the required check-commands, if they don't already exist in your configuration ('Configure' -> 'Commands' -> 'Check Command Import'):
| command_name | command_line |
| check_jmx_current_threadcount | $USER1$/check_jmx -U service:jmx:rmi:///jndi/rmi://'$HOSTADDRESS$':'$ARG1$'/jmxrmi -O java.lang:type=Threading -A ThreadCount -K "" -w $ARG2$ -c $ARG3$ |
| check_jmx_garbage_collection_timing | $USER1$/check_jmx -U service:jmx:rmi:///jndi/rmi://'$HOSTADDRESS$':'$ARG1$'/jmxrmi -O "java.lang:type=GarbageCollector,name=PS MarkSweep" -A LastGcInfo -K duration -w $ARG2$ -c $ARG3$ -u ms |
| check_jmx_heapmem_used | $USER1$/check_jmx -U service:jmx:rmi:///jndi/rmi://'$HOSTADDRESS$':'$ARG1$'/jmxrmi -O java.lang:type=Memory -A HeapMemoryUsage -K used -w $ARG2$ -c $ARG3$ -u B |
| check_jmx_long_running_threads | $USER1$/check_jmx -U service:jmx:rmi:///jndi/rmi://'$HOSTADDRESS$':'$ARG1$'/jmxrmi -O jboss.threads:name=LongRunningTasksThreadPool,type=queuelessThreadPool -A CurrentThreadCount -K "" -w $ARG2$ -c $ARG3$ |
| check_jmx_nonheap_mem_used | $USER1$/check_jmx -U service:jmx:rmi:///jndi/rmi://'$HOSTADDRESS$':'$ARG1$'/jmxrmi -O java.lang:type=Memory -A NonHeapMemoryUsage -K used -w $ARG2$ -c $ARG3$ -u B |
| check_jmx_availible_connections_in_pool | $USER1$/check_jmx -U service:jmx:rmi:///jndi/rmi://'$HOSTADDRESS$':'$ARG1$'/jmxrmi -O jboss.jca:name=JmsXA,service=ManagedConnectionPool -A AvailableConnectionCount -K "" -w $ARG2$ -c $ARG3$ |
Adding Services
Add the required services, ('Configure' -> 'Host: ' -> 'Go' -> 'Services for host ' -> 'Add new service' -> 'Go'):
Add the following services (Arguments are just examples, you need to adjust them to suite your environment).
| service_description | check_command | check_command_args |
| Current Threadcount | check_jmx_current_threadcount | 1090!100!120 |
| Garbage Collection Timing | check_jmx_garbage_collection_timing | 1090!3500!4000 |
| HeapMem Usage | check_jmx_heapmem_used | 1090!140000000!150000000 |
| Check Long Running Threads | check_jmx_long_running_threads | 1090!3!5 |
| NonHeap Memory Usage | check_jmx_nonheap_mem_used | 1090!100000000!120000000 |
| Availible Connections in pool | check_jmx_availible_connections_in_pool | 1090!20!25 |
Other
This is just an example of some parameters that you can monitor with check_jmx, for more detailed information, please refer to the developers site. We recommend that you also monitor the server that is running JBoss at a lower level, i.e. on operating system level with for example NRPE to get more detailed information about the underlying operating system. More information: Additional server and software setup.
Read more
The developers site: http://snippets.syabru.ch/nagios-jmx-plugin/
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