set-guest-hypervisor-fact

#!/usr/bin/perl
# set-guest-hypervisor-fact v0.1
#
# (c)2018 Marcel Klapwijk
# Please leave suggestions and bug reports at:
#  - https://gist.github.com/mdklapwijk/
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty
# of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# you should have received a copy of the GNU General Public License
# along with this program (or with Nagios);  if not, write to the
# Free Software Foundation, Inc., 59 Temple Place - Suite 330,
# Boston, MA 02111-1307, USA
#
# Purpose:
#  Create a custom puppet fact with details of the hypervisor on
#  kvm guest systems running gemu-ga. This fact can then be used
#  by the puppet agent on the guest system to set sysLocation for
#  snmpd to match the host node in a multi datacenter cluster.
#
#
# Installation:
#  Place an executable copy of this file in /usr/local/bin on every
#  kvm hypervisor in your cluster (e.g. Proxmox).
#
#  To make sure the fact on the guest gets updated after a guest
#  migration to another node in the cluster, place the following line
#  in a cron like /etc/cron.d/set-guest-hypervisor-fact:
#   -  */5 * * * *  root  /usr/local/bin/set-guest-hypervisor-fact
#
#  Make sure the puppet installation on the guest system has the
#  path for custom facts created/available:
#   -  /etc/puppetlabs/facter/facts.d
#
#
#  Usage:
#  If all elements installed and configured correctly (script, cron,
#  qemu-ga, puppet agent) the facter command should give something
#  like the following:
#    root@kvm-guest-01:~/# facter hypervisor
#    {
#      fqdn => "hypervisor-node-01.int.domain.com",
#      hostname => "hypervisor-node-01"
#    }
#
#
# Note:
#  NO WARRANTY and NO ERROR_HANDLING, so use at you own risk!
#
#
# Version history:
#  - 0.1) Initial version.

use strict;
use warnings;
use Net::Domain qw(hostname hostfqdn hostdomain domainname);
use MIME::Base64;
use IPC::Open2;
use JSON;

my($file)='/etc/puppetlabs/facter/facts.d/hypervisor.json';
my(%values);
my($json)=JSON->new;

$values{'hypervisor'}{'hostname'}=hostname();
$values{'hypervisor'}{'fqdn'}=hostfqdn();

my($base64)=encode_base64($json->canonical->pretty->encode(\%values),'');

foreach my $qga (glob('/var/run/qemu-server/*.qga'))
{
  my($handle);
  my($pid)=open2(*RH, *WH, 'socat -T1 '.$qga.' STDIO');
  print WH '{"execute":"guest-file-open", "arguments":{"path":"'.$file.'","mode":"w+"}}';
  while(<RH>)
  {
    #print("$_");
    if(/{"return": (\d+)}/)
    {
      $handle=$1;
    }
    if($handle)
    {
      print WH '{"execute":"guest-file-write", "arguments":{"handle":'.$handle.',"buf-b64":"'.$base64.'"}}';
      print WH '{"execute":"guest-file-close", "arguments":{"handle":'.$handle.'}}';
      undef($handle);
    }
  }
  close(WH);
  close(RH);
  waitpid($pid,0);
}
exit();

New qemu-guest-agents does not seem to handle multiline base64 correctly anymore...