#!/usr/bin/perl

# Nagios plugin for monitoring KSM usage

# Written by Adrian Bridgett (c) Bitcube Ltd. 2009
# Released under GPL v3 license

# For opsview
use lib '/usr/local/nagios/perl/lib', '/usr/local/nagios/lib';

use warnings;
use strict;
use Nagios::Plugin;

my $VERSION = "0.01";

my $np = Nagios::Plugin->new(
  usage   => "Usage: %s [-w warning] [-c critical]",
  version => $VERSION,
  blurb   => "Checks KSM usage",
);

$np->add_arg(
    spec => "warning|w=s",
    help => qq{-w, --warning=RANGE
       Warning if number of shared pages is outside this range},
    default => 0,
);

$np->add_arg(
    spec => "critical|c=s",
    help => qq{-c, --critical=RANGE
       Critical if number of shared pages is outside this range},
    default => 0,
);

$np->getopts;

open PAGES, "</sys/kernel/mm/ksm/pages_shared" or
  $np->nagios_exit(UNKNOWN, "Unable to read shared KSM pages");
my $ksm_shared = <PAGES>;
chomp $ksm_shared;
close PAGES;

open PAGES, "</sys/kernel/mm/ksm/pages_sharing" or
  $np->nagios_exit(UNKNOWN, "Unable to read sharing KSM pages");
my $ksm_sharing = <PAGES>;
chomp $ksm_sharing;
close PAGES;

open PAGES, "</sys/kernel/mm/ksm/pages_unshared" or
  $np->nagios_exit(UNKNOWN, "Unable to read unshared KSM pages");
my $ksm_unshared = <PAGES>;
chomp $ksm_unshared;
close PAGES;

open PAGES, "</sys/kernel/mm/ksm/pages_volatile" or
  $np->nagios_exit(UNKNOWN, "Unable to read volatile KSM pages");
my $ksm_volatile = <PAGES>;
chomp $ksm_volatile;
close PAGES;


$np->set_thresholds(warning => $np->opts->warning,
                    critical => $np->opts->critical);

$np->add_perfdata(label => "Shared KSM pages", value => $ksm_shared,
                  threshold => $np->threshold());
$np->add_perfdata(label => "Sharing KSM pages", value => $ksm_sharing);
$np->add_perfdata(label => "Unshared KSM pages", value => $ksm_unshared);
$np->add_perfdata(label => "Volatile KSM pages", value => $ksm_volatile);

$np->nagios_exit(return_code => $np->check_threshold($ksm_shared),
                 message => "$ksm_shared shared pages, $ksm_sharing sharing pages, $ksm_unshared unshared pages, $ksm_volatile volatile pages");