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h1. Introduction

Nagios is a complete infrastructure monitoring solution.


[Get more details about Nagios.|http://www.nagios.org/]


The integration of Petals ESB and Nagios is based on getting information about the JVM. This is done using SNMP probes.
{info}Following examples are based on a Petals ESB topology composed of two nodes on the same host.{info}

h2. Nagios screenshots extract samples

!petals-esb-overview.jpg|align=center!

!petals-esb-services-overview.jpg|align=center!
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h1. Installation


h2. Nagios installation

The Nagios integration was experienced on a Linux distribution "Ubuntu Maverick Meerkat (10.10)".

Nagios 3 is available through the default Ubuntu repository. So, just install the package "nagios3" using the standard way.

h2. Enabling the SNMP agents of the Petals ESB JVMs

{include:Enabling the SNMP agent of a Petals ESB JVM}

h1. Nagios configuration


h2. JVM host template

A best practice to monitor Java application is to create a template 'JVM host'.

According to our environment defined above, create the file 'jvm-host-nagios2.cfg' in the directory '/etc/nagios3/conf.d' with the following content:

{code}
define host{
     use                 generic-host
        name                            jvm-host    ; The name of this host template
        notifications_enabled           1       ; Host notifications are enabled
        event_handler_enabled           1       ; Host event handler is enabled
        flap_detection_enabled          1       ; Flap detection is enabled
        failure_prediction_enabled      1       ; Failure prediction is enabled
        process_perf_data               1       ; Process performance data
        retain_status_information       1       ; Retain status information across program restarts
        retain_nonstatus_information    1       ; Retain non-status information across program restarts
        check_command                   check-host-alive
        max_check_attempts              10
        notification_interval           0
        notification_period             24x7
        notification_options            d,u,r
        contact_groups                  admins

h2. Nagios commands definition to interact with a SNMP agent

We recommand to define specific Nagios command to interact with the Java virtual machine MIB.

Interresting commands will be:

* jvm_heapused: to get the real heap memory used by the Petals ESB node,
* jvm_heapmaxused: to get the current allocated (commited) heap size. This value should be check against the heap max size at the JVM level to generate alarms.

According to our environment defined above, create the file 'jvm.cfg' in the directory '/etc/nagios-plugins/config' with the following content:

{code}
# 'jvm_heapused' command definition
define command{
    command_name    jvm_heapused
    command_line    /usr/lib/nagios/plugins/check_snmp -H '$HOSTADDRESS$' -p '$_HOSTSNMPPORT$' -C '$ARG1$' -P '$ARG2$' -o 1.3.6.1.4.1.42.2.145.3.163.1.1.2.11.0 -w :'$ARG3$' -c :'$ARG4$' -l load
    }

# 'jvm_heapmaxused' command definition
define command{
    command_name    jvm_heapmaxused
    command_line    /usr/lib/nagios/plugins/check_snmp -H '$HOSTADDRESS$' -p '$_HOSTSNMPPORT$' -C '$ARG1$' -P '$ARG2$' -o 1.3.6.1.4.1.42.2.145.3.163.1.1.2.12.0 -w :'$ARG3$' -c :'$ARG4$' -l load
    }
{code}

h2. Petals ESB host template

A best practice to monitor Petals ESB nodes is to create a template 'Petals ESB host' that inherites from the 'JVM host'.

According to our environment defined above, create the file 'petals-esb-host-nagios2.cfg' in the directory '/etc/nagios3/conf.d' with the following content:

{code}
define host{
        use                             jvm-host
        name                            petals-esb-host    ; The name of this host template
        notifications_enabled           1       ; Host notifications are enabled
        event_handler_enabled           1       ; Host event handler is enabled
        flap_detection_enabled          1       ; Flap detection is enabled
        failure_prediction_enabled      1       ; Failure prediction is enabled
        process_perf_data               1       ; Process performance data
        retain_status_information       1       ; Retain status information across program restarts
        retain_nonstatus_information    1       ; Retain non-status information across program restarts
        check_command                   check-host-alive
        max_check_attempts              10
        notification_interval           0
        notification_period             24x7
        notification_options            d,u,r
        contact_groups                  admins
        register                        0       ; DONT REGISTER THIS DEFINITION - ITS NOT A REAL HOST, JUST A TEMPLATE!

h2. Defining your Petals ESB hosts

For each Petals ESB node of your Petals ESB topology, create an instance of the template 'petals-esb-host'.

According to our environment defined above, create the file 'petals-esb-host-node1.cfg' in the directory '/etc/nagios3/conf.d' with the following content:
{code}
define host{
        use                     petals-esb-host            ; Name of host template to use
        host_name               petals-esb-node-1
        alias                   Petals ESB Node 1
        address                 127.0.0.1
        _snmpport               16161 ; This value should be set with the SNMP
; agent listener port of your Petals ESB node.
        }
{code}
and create the file 'petals-esb-host-node2.cfg' in the directory '/etc/nagios3/conf.d' with the following content:
{code}
define host{
        use                     petals-esb-host            ; Name of host template to use
        host_name               petals-esb-node-2
        alias                   Petals ESB Node 2
        address                 127.0.0.1
        _snmpport               16162 ; This value should be set with the SNMP
; agent listener port of your Petals ESB node.
        }
{code}

h2. Defining your Petals ESB topology as a Petals ESB host group

The Petals ESB topology can be considered as a Nagios host group composed of your Petals ESB nodes.

So, according to our environment defined above, create the file 'petals-esb-hostgroup.cfg' in the directory '/etc/nagios3/conf.d' with the following content:

{code}
define hostgroup {
        hostgroup_name petals-esb
        alias           Petals ESB
        members         petals-esb-node-1, petals-esb-node-2
        }
{code}

h2. Petals ESB host services

A best practice to monitor Petals ESB nodes is to create a template of services to associate to each Petals ESB nodes.

According to our environement defined above, create the file 'petals-esb-services.cfg' in the directory '/etc/nagios3/conf.d' with the following content:

{code}
# Define a service to check the disk space of the root partition# Define a service to check the disk space of the root partition
# on the local machine. Warning if < 20% free, critical if
# < 10% free space on partition.
define service{
use generic-service
hostgroup_name petals-esb
service_description Disk Space
check_command check_all_disks!20%!10%
}

# Define a service to check the load on the local machine.
define service{
use generic-service
hostgroup_name petals-esb
service_description Current Load
check_command check_load!5.0!4.0!3.0!10.0!6.0!4.0
}

# Define a service to check the heap memory used by Petals ESB node.
# Warning if > 85% configured max heap size, critical if 95% configured
# max heap size.
# Note: The value returned by the SNMP Get is a byte value. So, for
# a max heap size of 1Go:
# 85% => 912680550 bytes,
# and 95% => 1020054733 bytes
define service{
use generic-service
hostgroup_name petals-esb
service_description Current heap memory
check_command jvm_heapused!public!2c!912680550!1020054732
}

# Define a service to check the max (commited) heap memory used by Petals ESB node.
# Warning if > Warning if > 85% configured max heap size, critical if 95% configured
# max heap size.
# Note: The value returned by the SNMP Get is a byte value. So, for
# a max heap size of 1Go:
# 85% => 912680550 bytes,
# and 95% => 1020054733 bytes
define service{
use generic-service
hostgroup_name petals-esb
service_description Current commited heap memory size
check_command jvm_heapmaxused!public!2c!912680550!1020054732
}
{code}

h2. Restart Nagios

Restart your Nagios service to take into account the configuration.
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