NRPE and the $USER1$ variable

I could write Puppet templates for all the variants but I would much prefer to manage this through a native method.

$USERn$ is a standard macro for Nagios. They are defined in the resource.cfg file:

# Sets $USER1$ to be the path to the plugins
$USER1$=/usr/local/nagios/libexec

# Sets $USER2$ to be the path to event handlers
#$USER2$=/usr/local/nagios/libexec/eventhandlers

and this file is included in the main configuration:

# This is an optional resource file that contains $USERx$ macro
# definitions. Multiple resource files can be specified by using
# multiple resource_file definitions.  The CGIs will not attempt to
# read the contents of resource files, so information that is
resource_file=/usr/local/nagios/etc/resource.cfg

AFAIK, you cannot use it on the remote host, with NRPE.

I put together a custom Fact that addresses my needs. I also tried a small switch that would apply the arch but it wasn't cross platform.

lib/facter/nrpe.rb

file = File.open("/etc/nagios/resource.cfg" , "r" )
while ( line = file.gets )
  if  /^\$USER1\$=(.*)/ =~ line
    matched="#{$1}"
  end
end
file.close
Facter.add("nrpe") do
  setcode do
    matched
  end
end

Here are some of the custom facts, and manifest code we use for handling nrpe. Be sure that puppet ensures the service is setup to start at boot, and is running. Since we run Fedora 15, with an older version of puppet, be aware that some versions of puppet can't handle Fedora 15's systemd.

nrpe_plugin_directory.rb

Facter.add("nrpe_plugin_directory") do
    setcode do
            %x{dirs="/usr/lib/nagios/plugins /usr/lib64/nagios/plugins /usr/local/nagios/libexec"; for dir in $dirs; do [[ -e $dir ]] && [[ ! -L $dir ]] && { echo $dir; exit; }; done}.chomp
    end
end

nrpe_cfg_file.rb

Facter.add("nrpe_cfg_file") do
    setcode do
            %x{files="/etc/nagios/nrpe.cfg /usr/local/nagios/etc/nrpe.cfg /usr/local/nagios/nrpe.cfg"; for file in $files; do [[ -f $file ]] && { echo $file; exit; }; done}.chomp
    end
end

Manifest code:

                    file{"/nagios/plugins":
                            ensure => "symlink",
                            target => "${nrpe_plugin_directory}",
                            force => 'true',
                            }

                    file{"$nrpe_plugin_directory":
                            source => "/..../plugins",
                            ensure => "directory",
                            recurse => "true",
                            ignore => ".svn",
                            }
                    case $nrpe_cfg_file {
                            undef: { }
                            default:{
                                    file{"/nagios/nrpe.cfg":
                                            ensure => "symlink",
                                            target => "${nrpe_cfg_file}",
                                            require => File["/nagios"],
                                            }
                                    file{"$nrpe_cfg_file":
                                            source => "/..../nrpe.cfg",
                                            }
            # ..............
                            }

In modules/nagios/target/params.pp:

class nagios::target::params {
  case $operatingsystem {
    redhat,centos: {
          $nagios_plugin_dir = $architecture ? {
            x86_64 => "/usr/lib64/nagios/plugins/",
            i386   => "/usr/lib/nagios/plugins/",
          }
    }
    solaris: {
          $nagios_plugin_dir           = '/opt/csw/libexec/nagios-plugins/'
    }
  }
}

In modules/nagios/templates/custom-checks.cfg

...
command[check_ram]=<%= scope.lookupvar('nagios::target::params::nagios_plugin_dir') %>check_mem.pl -C -w<%= ramwarn %> -c<%= ramcrit %> -f 
command[check_puppet]=<%= scope.lookupvar('nagios::target::params::nagios_plugin_dir') %>check_puppet.rb -w 1800 -c 3600
...

In modules/nagios/target.pp:

include nagios::target::params
file { "/etc/nrpe.d/50-custom-checks.cfg":
  ensure  => present,
  notify  => Service["nrpe"],
  require => Package['nrpe'],
  content => template("${module_name}/custom-checks.cfg.erb"),
}