2
0
mirror of https://github.com/munin-monitoring/contrib.git synced 2018-11-08 00:59:34 +01:00
contrib-munin/plugins/network/dns/dnsresponse_

186 lines
3.8 KiB
Perl
Executable File

#!/usr/bin/perl -w
=head1 NAME
dnsresponse - Plugin to monitor DNS resolution times.
"Poor man's smokeping" :)
=head1 APPLICABLE SYSTEMS
Any unix system.
=head1 CONFIGURATION
The following shows the default configuration.
[dnsresponse_*]
env.site www.google.com
env.times 20
=head1 INTERPRETATION
The plugin shows the average and median times taken to resolve a site.
=head1 MAGIC MARKERS
#%# family=auto
#%# capabilities=autoconf,suggest
=head1 BUGS
None known.
=head1 VERSION
$Id: dnsresponse_ 61 2009-04-14 09:11:00Z stsimb $
=head1 AUTHOR
Copyright (c) 2009 by Sotiris Tsimbonis.
=head1 LICENSE
GPLv2
=cut
#%# family=auto
#%# capabilities=autoconf suggest
use strict;
use warnings;
my $DEBUG=0;
my $site = exists $ENV{'site'} ? $ENV{'site'} : "www.google.com";
my $times = exists $ENV{'times'} ? $ENV{'times'} : "20";
my $resconf="/etc/resolv.conf";
use File::Basename;
my $basename=basename($0);
my $scriptname;
my $dnsip;
($scriptname, $dnsip) = split("_", $basename);
print "DBG: target dns ip $dnsip\n" if ($DEBUG>0);
if ( defined $ARGV[0] and $ARGV[0] eq "config" ) {
print "graph_title $dnsip DNS response time\n";
print "graph_vlabel milliseconds\n";
print "graph_scale no\n";
print "graph_category dns\n";
print "graph_info Time taken by $dnsip to resolve $site $times times.\n";
#my @val = ("min", "avg", "median", "max");
my @val = ("avg", "median", "stddev");
my $value;
foreach $value ( @val ) {
if ($value eq "stddev") {
print "$value.info Standard deviation (variance).\n";
} else {
print "$value.info $value time taken by $dnsip to resolve $site $times times.\n";
}
print "$value.label $value\n";
# print "$value.type DERIVE\n";
# print "$value.min 0\n";
# print "$value.warning 100\n";
# print "$value.critical 600\n";
}
exit 0;
}
if ( defined $ARGV[0] and $ARGV[0] eq "autoconf" ) {
my $ret;
if (! eval "require Net::DNS;") { $ret .= "Net::DNS not found. "; }
if (! eval "require Time::HiRes;") { $ret .= "Time::HiRes not found. "; }
if (! -s $resconf) { $ret .= "$resconf not found. "; }
if ($ret) {
print "no ($ret)\n";
exit 1;
} else {
print "yes\n";
exit 0;
}
}
if ( defined $ARGV[0] and $ARGV[0] eq "suggest" ) {
if (-s $resconf) {
open (FILE, "< $resconf") || die "Could not open $resconf: $!\n";
my $line;
while ($line = <FILE>) {
if ($line =~ /^nameserver/) {
my $ns; my $ip;
($ns, $ip) = split(" ", $line);
print "$ip\n";
}
}
exit 0;
} else {
print "ERROR reading $resconf\n";
exit 1;
}
}
use Time::HiRes qw ( gettimeofday tv_interval );
use Net::DNS;
my $res = Net::DNS::Resolver->new(
nameservers => [$dnsip],
recurse => 1,
debug => $DEBUG,
);
my $i;
my @restimes;
for ($i=1; $i<=$times; $i++) {
my $t0 = [gettimeofday];
my $answer = $res->send($site);
my $elapsed = tv_interval ($t0);
push(@restimes, $elapsed);
print "DBG: count $i elapsed $elapsed\n" if ($DEBUG>0);
}
@restimes=sort(@restimes);
#my $min=$restimes[0]*1000;
my $average=mean(@restimes)*1000;
my $median=median(@restimes)*1000;
my $stddev=std_dev_ref_sum(@restimes)*1000;
#my $max=$restimes[$times-1]*1000;
#print "min.value $min\n";
print "avg.value $average\n";
print "median.value $median\n";
print "stddev.value $stddev\n";
#print "max.value $max\n";
sub mean {
my $result;
foreach (@_) { $result += $_ }
return $result / @_;
}
sub median {
my @ar = @_;
my $elements = scalar(@ar);
return $ar[(int($elements-1)/2)];
# if ($elements % 2) {
# return $ar[($elements-1)/2];
# } else {
# return ($ar[($elements-1)/2-0.5]+$ar[($elements-1)/2+0.5])/2;
# }
}
# Standard Deviance function from http://www.linuxjournal.com/article/6540
sub std_dev_ref_sum {
my @ar = @_;
my $elements = scalar @ar;
my $sum = 0;
my $sumsq = 0;
foreach (@ar) {
$sum += $_;
$sumsq += ($_ **2);
}
return sqrt( $sumsq/$elements - (($sum/$elements) ** 2));
}