Munin contributed plugins

#!/usr/bin/env python3

"""

=encoding utf8

=head1 NAME

kvm_io - show IO 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 re

import os

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

    '''

    base_config = """graph_title KVM Virtual Machine IO usage

graph_vlabel Bytes read(-)/written(+) per second

graph_category virtualization

graph_info This graph shows the block device I/O used of virtual machines

graph_args --base 1024"""

    print(base_config)

    for vm in vm_names:

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

        print("%s_read.type COUNTER" % vm)

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

        print("%s_read.info I/O used by virtual machine %s" % (vm, vm))

        print("%s_read.graph no" % vm)

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

        print("%s_write.type COUNTER" % vm)

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

        print("%s_write.negative %s_read" % (vm, vm))

        print("%s_write.info I/O used by virtual machine %s" % (vm, 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 fetch(vms):

    ''' Fetch values for a list of pids

    @param dictionary {kvm_pid: cleaned vm name}

    '''

    for pid in vms:

        with open("/proc/%s/io" % pid.decode(), "r") as f:

            for line in f.readlines():

                if "read_bytes" in line:

                    read = line.split()[1]

                    print("%s_read.value %s" % (vms[pid], read))

                if "write_bytes" in line:

                    write = line.split()[1]

                    print("%s_write.value %s" % (vms[pid], write))

                    break

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:

        with open("/proc/%s/cmdline" % pid.decode(), "r") as cmdline:

            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].split()

if __name__ == "__main__":

    if len(sys.argv) > 1:

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

            if detect_kvm():

                print("yes")

            else:

                print("no (detect_kvm failed - is kvm installed?)")

        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()))