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#
# Copyright (c) 2012 Red Hat.
# Copyright (c) 2008 Aconex. All Rights Reserved.
#
# 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.
#
use strict;
use warnings;
use PCP::PMDA;
use vars qw( $pmda );
my $kvm_path = '/sys/kernel/debug/kvm';
sub kvm_fetch_callback
{
my ($cluster, $item, $inst) = @_;
my $metric_name = pmda_pmid_name($cluster, $item);
my ($path, $value, $fh);
# $pmda->log("kvm_fetch_callback $metric_name $cluster:$item ($inst)\n");
if ($inst != PM_IN_NULL) { return (PM_ERR_INST, 0); }
if (!defined($metric_name)) { return (PM_ERR_PMID, 0); }
$path = $metric_name;
$path =~ s/^kvm\./$kvm_path\//;
open($fh, $path) || return (PM_ERR_APPVERSION, 0);
$value = <$fh>;
close $fh;
if (!defined($value)) { return (PM_ERR_APPVERSION, 0); }
return ($value, 1);
}
$pmda = PCP::PMDA->new('kvm', 95);
$pmda->connect_pmcd;
# May need to be root to read the directory $kvm_path (/sys/kernel/debug/kvm)
# and so
# (a) do not use $pmda->set_user('pcp') below, and
# (b) need forced_restart=true in the Install script so pmcd is restarted
# and we're running as root at this point (SIGHUP pmcd once it has
# changed to user "pcp" is not going to work for PMDA installation)
#
my $pmid = 0;
opendir(DIR, $kvm_path) || $pmda->err("pmdakvm failed to open $kvm_path: $!");
my @metrics = grep {
unless (/^\./) {
$pmda->add_metric(pmda_pmid(0,$pmid++), PM_TYPE_U64, PM_INDOM_NULL,
PM_SEM_COUNTER, pmda_units(0,0,1,0,0,PM_COUNT_ONE),
"kvm.$_", '', '');
# $pmda->log("pmdakvm added metric kvm.$_\n");
}
} readdir(DIR);
closedir DIR;
$pmda->set_fetch_callback(\&kvm_fetch_callback);
# Careful with permissions - may need to be root to read /sys/kernel/debug/kvm
# see note above.
#$pmda->set_user('pcp') if -r $kvm_path;
$pmda->run;
=pod
=head1 NAME
pmdakvm - Linux virtualisation performance metrics domain agent (PMDA)
=head1 DESCRIPTION
B<pmdakvm> is a Performance Metrics Domain Agent (PMDA) which exports
metric values from the Linux KVM virtualisation subsystem.
Unlike many PMDAs it dynamically enumerates its metric hierarchy,
based entirely on the contents of /sys/kernel/debug/kvm.
=head1 INSTALLATION
If you want access to the names and values for the kvm performance
metrics, do the following as root:
# cd $PCP_PMDAS_DIR/kvm
# ./Install
If you want to undo the installation, do the following as root:
# cd $PCP_PMDAS_DIR/kvm
# ./Remove
B<pmdakvm> is launched by pmcd(1) and should never be executed
directly. The Install and Remove scripts notify pmcd(1) when
the agent is installed or removed.
=head1 FILES
=over
=item $PCP_PMDAS_DIR/kvm/Install
installation script for the B<pmdakvm> agent
=item $PCP_PMDAS_DIR/kvm/Remove
undo installation script for the B<pmdakvm> agent
=item $PCP_LOG_DIR/pmcd/kvm.log
default log file for error messages from B<pmdakvm>
=back
=head1 SEE ALSO
pmcd(1) and kvm(1).
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