title: Check memory usage of Java application server via JMX and j4p.war
agents: linux
author: Mathias Kettner <mk@mathias-kettner.de>
license: GPL
distribution: check_mk
description:
 This checks uses the JSON HTTP service of j4p (from jmx4perl) to
 monitor the current memory usage of a Java application server like
 Tomcat or JBoss. You can define levels against the total memory
 usage of the Java machine (heap + non heap).

 In order for the check to work, you need to load the j4p.war into your
 application server. Furthermore you need the agent plugin {j4p_performance}
 in your Check_MK agent's plugins directory. If you do not use the
 default port 8080 for j4p - lets say {9090} - then you have to create
 a configuration file {j4p.conf} in the agents configuration directory
 (usually {/etc/check_mk/j4p.conf}) with the single line {port = 9090}.

 Note: No jmx4perl is needed - neither on the target host nor
 on the monitoring server. No Perl is needed, either.
 The agent connects to the application server always via {localhost}.

item:
 The instance name as configured in {j4p.conf} with the variable
 {instance}. If you do not specify an instance then the port number
 converted to a string is used.

 Please note that the current implementation of the agent plugin
 supports only one instance per host.

examples:
 # Set default levels for heap memory to 500 MB / 800 MB
 j4p_performance_mem_default_levels = (500, 800)

perfdata:
 Two variables: the heap memory usage and the non heap memory usage
 in MB.

inventory:
 One check is created for each JMX instance sent by the agent.
 The agent currently supports only one instance, but that might
 be changed in future.

[parameters]
warning (int): The warning level for used memory in MB
critical (int): The critical level for used memory in MB

[configuration]
j4p_performance_mem_default_levels (int, int): Default levels for memory usage in MB. This
    is preset to {(1000, 2000)}.