simple python script to check cpu utilization of lxc containers and print percentage

lxc_cpu_top.py

#!/usr/bin/python

# See https://gist.github.com/wryfi/3902757

# Crude CPU usage thing for container(s).

import multiprocessing, os, re, sys, time
import getopt

cgroup_dir = '/sys/fs/cgroup/lxc/'

# some sort of regexp to match container names you want to report on.
node_rgx = u'[a-z0-9]{3,}'

def main(interval, show_all = False):
    cpus = multiprocessing.cpu_count()
    startval = get_values()
    time.sleep(interval)
    endval = get_values()
    for key, value in startval.iteritems():
        if key in endval:
            delta = int(endval[key]) - int(startval[key])
        dpns = float(delta / interval)
        dps = dpns / 1000000000
        percent = dps / cpus
        if show_all == False and percent <= 0.1 : # ignore < 0.1%
            continue
        print key + ':' + '{percent:.2%}'.format(percent=percent)


def get_values():
    values = {}

    # read the 'parent' cgroup for total figures.
    if os.path.exists('%s/cpuacct.usage' % cgroup_dir):
        with open('%s/cpuacct.usage' % cgroup_dir, 'rb') as tobj:
            values['total'] = tobj.read()
    else:
        print "cpuacct.usage doesn't exist for cgroup_dir (%s) - invalid cgroup config?" % cgroup_dir
        sys.exit(1)

    # no go through each cgroup(note: node_rgx) , and find usage from it
    for fd in os.listdir(cgroup_dir):
        if os.path.isdir('%s/%s' % (cgroup_dir, fd)) and re.match(node_rgx, fd):
            acctf = '%s/%s/cpuacct.usage' % (cgroup_dir, fd) 
            if os.path.isfile(acctf):
                with open(acctf, 'rb') as accto:
                    values[fd] = accto.read()
    return values


def usage() :
    print "Usage: -i <interval> -a (show all, regardless of usage) or -h (show help). "

if __name__ == "__main__":

    interval = 1
    show_all = False
    try :
        opts, args = getopt.getopt(sys.argv[1:], 'hai:', ['help', 'all', 'interval='])
    except getopt.GetoptError as err:
        print str(err);
        usage()
        sys.exit(1)
    for o, a in opts:
        if o in ( '-i', '--interval') :
            interval = int(a)
        elif o in ( '-a', '--all' ):
            show_all = True
        elif o in ( '-h', '--help' ):
            usage()
            sys.exit(0)
        else:
            assert False, "Invalid option."

    main(interval, show_all)

Changes: added some getopt fun (-a for all instances otherwise we omit those which have less than 0.1% of cpu time, and -i to change the interval we record over.)