== Creating a nagios monitor ==
This page explains how to create a nagios monitor configuration in [wiki:how-to/puppet puppet].  You will need to make changes to get the correct configuration for the specific type of monitoring needed.  

=== Set up an executable ===
These files are stored in puppet/modules/mayfirst/files/monitor-utils/ you can
find examples of different versions of monitoring scripts there.

=== Set up a cronjob ===
projects/puppet/modules/mayfirst/templates/monitor-utils/cron.d/mf-monitor

You'll need to add your script to this directory.

=== Add to utils.pp ===
puppet/modules/mayfirst/manifests/utils.pp

The code should look something like this, with the correct file from the executable specified.:

{{{
  file { "/usr/local/sbin/mf-monitor-mailq":
    source => "puppet:///modules/mayfirst/monitor-utils/mf-monitor-mailq",
    ensure => present,
    mode => 755,
    owner => "root",
    group => "root"
  }
}}}

=== Define hostgroup ===
projects/puppet/modules/mayfirst/files/nagios/nagios3/conf.d/

This code section should look something like this:

{{{
define hostgroup {
  hostgroup_name  mailq-servers
  alias           Mail Check Servers
}
}}}

=== Define nagios command ===
puppet/modules/mayfirst/files/nagios/nagios3/commands.cfg

Should look like this:

{{{
define command{
  command_name    check-upgrade
  command_line    /usr/local/share/nagios/plugins/mf-nagios-check-upgrade '$HOSTNAME$'
}
}}}
=== Create parsing script ===
You will also need to create a script that parses the output of the monitoring
files.

'''puppet/modules/mayfirst/files/nagios/nagios-plugins/plugins/mf-SCRIPT-NAME'''

You can model scripts that already exist to check this.

=== Add the check as a service ===
The service part of the infrastructure is the display component for nagios.

'''puppet/modules/mayfirst/files/nagios/nagios3/conf.d/services_nagios2.cfg'''

Copy a pre-existing stanza and make the necessary changes.  It will look something like this:

{{{
define service{
        hostgroup_name                  upgrade-servers
        service_description             Upgrade 
        check_command                   check-upgrade
        notification_interval           0
        use                             generic-service
}
}}}

=== Finally add the hostgroup to nagios manifest ===
This is not a mandatory step.  If the monitor should be run on all servers, then add the hostgroup/service here.  Otherwise leave it out, but be sure to include in the monitor script a line that specifies under what context the script should be run.  For example (from mf-monitor-fcgid):

{{{
# Only run if fcgid is installed 
[ ! -e "/etc/apache2/mods-enabled/fcgid.conf" ] && exit 0
}}}

'''projects/puppet/modules/mayfirst/manifests/nagios.pp'''

One example for standard_hostgroups is:
{{{
  if ( $include_standard_hostgroups == true ) {
    $standard_hostgroups = [ 'df-servers', 'upgrade-servers', 'mailq-servers' ]
    $assigned_hostgroups = concat($hostgroups, $standard_hostgroups)
  } else {
    $assigned_hostgroups = $hostgroups
    
  }
}}}

This is from 'define m_nagios_host'.

'''Make sure all executable scripts have execute permissions'''