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jimjcollinsjimjcollins
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Added support for storing and displaying device names using the persistent (across reboots) and user friendly device mapper alias names
1 parent 6008baa commit acb4108

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Lines changed: 124 additions & 7 deletions

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‎diskstat/python_modules/diskstat.py‎

Lines changed: 124 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -40,6 +40,8 @@
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import subprocess
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import traceback
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import logging
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import os
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import stat
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descriptors = []
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@@ -61,8 +63,100 @@
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PARTITIONS_FILE = '/proc/partitions'
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DISKSTATS_FILE = '/proc/diskstats'
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DMDIR = '/dev/mapper'
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device_mapper = ''
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PARTITIONS = []
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dmnames = []
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dm2pair = {}
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pair2dm = {}
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devnames = []
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dev2pair = {}
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pair2dev = {}
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def build_dmblock_major_minor_tables():
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"""Returns
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1) a table of filenames that are all device mapper block special files
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2) a dict mapping each device mapper name to (major,minor)
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3) a dict mapping each (major,minor) pair to a table of devce mapper names"""
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names = []
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name2pair = {}
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pair2name = {}
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mapper_entries = []
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mapper_entries = os.listdir(DMDIR)
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for n in mapper_entries:
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s = os.lstat(DMDIR + '/' + n)
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if stat.S_ISBLK(s[stat.ST_MODE]):
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names.append(n)
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maj = str(os.major(s.st_rdev))
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min = str(os.minor(s.st_rdev))
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name2pair[n] = (maj, min)
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pair2name[(maj, min)] = n
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logging.debug('grabbed dmsetup device info')
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logging.debug('dmsetup devices: ' + str(name2pair))
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return (names, name2pair, pair2name)
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def build_block_major_minor_tables():
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"""Returns
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1) a table of filenames that are all block special files
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2) a dict mapping each dev name to (major,minor)
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3) a dict mapping each (major,minor) pair to a table of dev names"""
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dnames = []
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d2p = {}
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p2d = {}
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# Get values from diskstats file
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p = subprocess.Popen("awk '{print $1,$2, $3}' " + DISKSTATS_FILE, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
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out, err = p.communicate()
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logging.debug('grabbed diskstat device info')
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logging.debug('diskstat devices: ' + str(out))
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for n in out.split('\n'):
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if n:
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[maj, min, name] = n.split()
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dnames.append(name)
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d2p[name] = (maj, min)
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p2d[(maj, min)] = name
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return (dnames, d2p, p2d)
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def get_devname(dev):
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"""Returns
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device mapper name converted to dev name"""
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(maj,min) = dm2pair[dev]
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name = pair2dev[(maj,min)]
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return name
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def list_dmnames():
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"""Returns
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string of device names associated with device mapper names"""
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global dmnames
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global dm2pair
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global pair2dm
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global devnames
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global dev2pair
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global pair2dev
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devlist = ''
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dmnames, dm2pair, pair2dm = build_dmblock_major_minor_tables()
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logging.debug('dmnames: ' + str(dmnames))
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devnames, dev2pair, pair2dev = build_block_major_minor_tables()
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logging.debug('devnames: ' + str(dmnames))
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for d in dmnames:
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devlist = devlist + ' ' + str(d)
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logging.debug('devlist: ' + str(devlist))
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return devlist
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67161
def get_partitions():
68162
logging.debug('getting partitions')
@@ -161,13 +255,22 @@ def update_stats():
161255
if not dev in last_val:
162256
last_val[dev] = {}
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# Convert from dmname to devname for use by awk
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if device_mapper == 'true':
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olddev = dev
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dev = get_devname(dev)
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# Get values from diskstats file
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p = subprocess.Popen("awk -v dev=" + dev + " '$3 == dev' " + DISKSTATS_FILE, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
166265
out, err = p.communicate()
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168267
vals = out.split()
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logging.debug(' vals: ' + str(vals))
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270+
# Reset back to orignal dev name
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if device_mapper == 'true':
272+
dev = olddev
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171274
get_diff(dev, 'reads', int(vals[3]))
172275
get_diff(dev, 'writes', int(vals[7]))
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@@ -267,10 +370,18 @@ def get_stat(name):
267370
return 0
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269372
def metric_init(params):
270-
global descriptors
271-
global MIN_DISK_SIZE, DEVICES
272-
273-
DEVICES = params.get('devices')
373+
global descriptors, device_mapper
374+
global MIN_DISK_SIZE, DEVICES, IGNORE_DEV
375+
376+
# Use params.get here to assure function via gmond
377+
if params.get('device-mapper') == 'true':
378+
devices = list_dmnames()
379+
DEVICES = devices
380+
IGNORE_DEV = 'loop|drbd'
381+
device_mapper = 'true'
382+
logging.debug('dm block devices: ' + str(devices))
383+
else:
384+
DEVICES = params.get('devices')
274385

275386
logging.debug('init: ' + str(params))
276387

@@ -371,13 +482,19 @@ def metric_cleanup():
371482
parser.add_option('-b', '--gmetric-bin', dest='gmetric_bin', default='/usr/bin/gmetric', help='path to gmetric binary')
372483
parser.add_option('-c', '--gmond-conf', dest='gmond_conf', default='/etc/ganglia/gmond.conf', help='path to gmond.conf')
373484
parser.add_option('-g', '--gmetric', dest='gmetric', action='store_true', default=False, help='submit via gmetric')
485+
parser.add_option('-m', '--device-mapper', dest='device_mapper', action='store_true', default=False, help='utilize all device mapper devices if set')
374486
parser.add_option('-q', '--quiet', dest='quiet', action='store_true', default=False)
375487

376488
(options, args) = parser.parse_args()
377489

378-
metric_init({
379-
'devices': options.devices,
380-
})
490+
if options.device_mapper:
491+
metric_init({
492+
'device-mapper': 'true',
493+
})
494+
else:
495+
metric_init({
496+
'devices': options.devices,
497+
})
381498

382499
while True:
383500
for d in descriptors:

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