Munin contributed plugins

#!/usr/bin/python

# -*- coding: utf-8 -*-

# vim: set fileencoding=utf-8

#

# Munin plugin to show io by vm

#

# Copyright Maxence Dunnewind, Rodolphe Quiédeville

#

# License : GPLv3

#

# parsed environment variables:

# vmsuffix: part of vm name to be removed

#

#%# capabilities=autoconf

#%# family=contrib

import re, os, 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 KVM

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.draw LINE1" % vm

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

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

        print "%s_write.type COUNTER" % vm

        print "%s_write.min 0" % vm        

        print "%s_write.draw LINE1" % 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)

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

def fetch(vms):

    ''' Fetch values for a list of pids

    @param dictionnary {kvm_pid: cleaned vm name}

    '''

    res = {}

    for pid in vms:

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

        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            

        f.close()

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 dictionnary 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"^.*-name\x00([a-zA-Z0-9.-]*)\x00\-.*$",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 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"

        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()))