Munin contributed plugins

#!/usr/bin/env python3

"""

=encoding utf8

=head1 NAME

kvm_cpu - show CPU usage of VM

=head1 CONFIGURATION

Parsed environment variables:

 vmsuffix: part of VM name to be removed

=head1 LICENSE

GPLv3

SPDX-License-Identifier: GPL-3.0-only

=head1 AUTHORS

Maxence Dunnewind

Rodolphe Quiédeville

=head1 MAGIC MARKERS

 #%# capabilities=autoconf

 #%# family=contrib

=cut

"""

import os

import re

import sys

from subprocess import Popen, PIPE

def config(vm_names):

    ''' Print the plugin's config

    @param vm_names : a list of "cleaned" vms' name

    '''

    percent = 100 * len(

        list(

            filter(

                lambda x: x[0:3] == 'cpu' and x[3] != ' ', open('/proc/stat', 'r').readlines())))

    base_config = """graph_title KVM Virtual Machine CPU usage

graph_vlabel %%

graph_category virtualization

graph_scale no

graph_period second

graph_info This graph shows the current CPU used by virtual machines

graph_args --base 1000 -r --lower-limit 0 --upper-limit %d""" % percent

    print(base_config)

    for vm in vm_names:

        print("%s_cpu.label %s" % (vm, vm))

        print("%s_cpu.min 0" % vm)

        print("%s_cpu.type DERIVE" % vm)

        print("%s_cpu.draw AREASTACK" % vm)

        print("%s_cpu.info percent of cpu time used by virtual machine" % vm)

def clean_vm_name(vm_name):

    ''' Replace all special chars

    @param vm_name : a vm's name

    @return cleaned vm's name

    '''

    # suffix part defined in conf

    suffix = os.getenv('vmsuffix')

    if suffix:

        vm_name = re.sub(suffix, '', vm_name)

    # proxmox uses kvm with -name parameter

    parts = vm_name.split('\x00')

    if parts[0].endswith('kvm'):

        try:

            return parts[parts.index('-name') + 1]

        except ValueError:

            pass

    return re.sub(r"[^a-zA-Z0-9_]", "_", vm_name)

def detect_kvm():

    ''' Check if kvm is installed '''

    kvm = Popen("which kvm", shell=True, stdout=PIPE)

    kvm.communicate()

    return not bool(kvm.returncode)

def find_vm_names(pids):

    '''Find and clean vm names from pids

    @return a dictionary of {pids : cleaned vm name}

    '''

    result = {}

    for pid in pids:

        cmdline = open("/proc/%s/cmdline" % pid, "r")

        result[pid] = clean_vm_name(

            re.sub(r"^.*guest=([a-zA-Z0-9.-_-]*).*$", r"\1", cmdline.readline()))

    return result

def list_pids():

    ''' Find the pid of kvm processes

    @return a list of pids from running kvm

    '''

    pid = Popen("pidof qemu-kvm qemu-system-x86_64 kvm", shell=True, stdout=PIPE)

    return pid.communicate()[0].decode().split()

def fetch(vms):

    ''' Fetch values for a list of pids

    @param dictionary {kvm_pid: cleaned vm name}

    '''

    for pid, name in vms.items():

        user, system = open("/proc/%s/stat" % pid, 'r').readline().split(' ')[13:15]

        print('%s_cpu.value %d' % (name, int(user) + int(system)))

if __name__ == "__main__":

    if len(sys.argv) > 1:

        if sys.argv[1] in ['autoconf', 'detect']:

            if detect_kvm():

                print("yes")

            else:

                print("no")

        elif sys.argv[1] == "config":

            config(find_vm_names(list_pids()).values())

        else:

            fetch(find_vm_names(list_pids()))

    else:

        fetch(find_vm_names(list_pids()))