Munin contributed plugins

#!/usr/bin/perl -w

# -*- perl -*-

=head1 NAME

docker_cpu - Munin plugin to monitor docker container CPU usage.

=head1 APPLICABLE SYSTEMS

Should work on any Linux system that has docker support.

=head1 CONFIGURATION

Root privilege required to execute docker command.

1. Create a new file named "docker" inside the folder /etc/munin/plugin-conf.d/

2. Docker file content:

 [docker_cpu]

 user root

=head1 MAGIC MARKERS

 #%# family=auto

 #%# capabilities=autoconf

=head1 VERSION

 v.0.1

=head1 AUTHOR

Copyright (C) 2015 Samuel Cantero <scanterog at gmail dot com>

=head1 LICENSE

GPLv3

=cut

my $docker=`which docker`;

if ( defined $ARGV[0] and $ARGV[0] eq "autoconf" ) {

   if ($docker) {

      print "yes\n";

      exit 0;

   }

   else{

      print "no (Docker has not been found)\n";

      exit 0;

   }

}

$docker =~ s/\s+$//;

my @containers = split "\n" , `$docker ps --no-trunc=true`;

my $result;

for my $i (1 .. $#containers)

{

   my @fields = split / +/, $containers[$i];

   my $id = $fields[0];

   my $name = $fields[$#fields];

   my $label = $name;

   # manage container name containing arithmetic operators and dots. E.g, my-container.

   $name =~ s/[-\+*\/\.]/_/g;

   # truncate container name with "," character.

   $name =~ s/,.*//g;

   # prefix if container starts with 0-9

   $name =~ s/^([0-9])/c$1/;

   if (open(my $file, '<', "/sys/fs/cgroup/cpuacct/docker/$id/cpuacct.usage"))

   {

      my $total_cpu_ns = <$file>;

      $total_cpu_ns =~ s/\s+$//;

      close $file;

      if (open($file, '<', "/sys/fs/cgroup/cpuacct/docker/$id/cpuacct.usage_percpu"))

      {

         my @ncpu = split / /, <$file>;

         close $file;

         push @result, {'name'=>$name, 'label'=>$label, 'total_cpu_ns'=>$total_cpu_ns, 'ncpu'=>$#ncpu};

      }

   }

}

if (defined $ARGV[0] and $ARGV[0] eq "config")

{

   my $nanoSecondsInSecond=1000000000;

   my $graphlimit = 1;

   foreach(@result){

      if ($$_{'ncpu'} || 1 > $graphlimit){

         $graphlimit = $$_{'ncpu'};

      }

   }

   $graphlimit = $graphlimit * 100;

   print "graph_title Docker container CPU usage\n";

   print "graph_args --base 1000 -r --lower-limit 0 --upper-limit $graphlimit\n";

   print "graph_vlabel %\n";

   print "graph_scale no\n";

   print "graph_period second\n";

   print "graph_category virtualization\n";

   print "graph_info This graph shows docker container CPU usage.\n";

   foreach(@result)

   {

      print "$$_{'name'}.label $$_{'label'}\n";

      print "$$_{'name'}.draw LINE2\n";

      print "$$_{'name'}.min 0\n";

      print "$$_{'name'}.type DERIVE\n";

      print "$$_{'name'}.cdef $$_{'name'},$nanoSecondsInSecond,/\n";

   }

   exit 0;

}

# Note: Counters/derive need to report integer values.

foreach(@result)

{

   $tcpu = ($$_{'total_cpu_ns'}*100); #to percentage

   print "$$_{'name'}.value $tcpu\n";

}

# vim:syntax=perl