Ceph 自动reweight脚本

Ceph的数据分布是由CRUSH Map解决定的，而CRUSH算法是伪HASH的，所以在一定时间内，数据会存在倾斜，这就需要我们用脚本来进行定期的reweight:

#author jesse.js.lyu@gmail.com

#reweight for ceph osds

import hashlib

import commands

import threading

import sys

from time import ctime,sleep

import urllib2

import json

def doReweight(osdMaxUtilId, osdTargetReweight):

print 'ceph osd reweight ' + str(osdMaxUtilId) + ' ' + str(osdTargetReweight)

(status,output) = commands.getstatusoutput('ceph osd reweight '+ str(osdMaxUtilId) +' ' + str(osdTargetReweight))

print status,output

def canOSDReweight():

#

canDoReweight = False

pgStateIsOk = False

osdUtilDiffEnough = False

#determine pg status

(status,output) = commands.getstatusoutput('ceph -s --format=json-pretty')

pgMapJson = json.loads(output)

#print pgMapJson['pgmap']['pgs_by_state']

numPGS = pgMapJson['pgmap']['num_pgs']

for pgState in pgMapJson['pgmap']['pgs_by_state']:

if pgState['state_name'] == 'active+clean' and pgState['count'] == numPGS:

pgStateIsOk = True

if pgStateIsOk == False:

print "pg is reweighting or can't do reweight right now...."

exit

#determine OSD util diff

(status,output) = commands.getstatusoutput('ceph osd df --format=json-pretty')

#print status,output

osdMaxUtil=0

osdMaxUtilId=-1

osdMaxReweight=1

osdMinUtil=100

osdMinUtilId=-1

osdReweightStep=0.01

if status == 0:

osdDictJson = json.loads(output)

for node in osdDictJson['nodes']:

if node['utilization'] > osdMaxUtil:

osdMaxUtilId = node['id']

osdMaxUtil = node['utilization']

osdMaxReweight = node['reweight']

if node['utilization'] < osdMinUtil:

osdMinUtilId = node['id']

osdMinUtil = node['utilization']

osdTargetReweight = osdMaxReweight - osdReweightStep

osdUtilDiff = (osdMaxUtil - osdMinUtil)/osdMinUtil*100

if osdUtilDiff > 10:

osdUtilDiffEnough = True

print "Max and Min OSD's utilization diff is " + str(osdUtilDiff)

else:

print "Max and Min OSD's utilization diff is " + str(osdUtilDiff) + ",less then 10%, give up..."

exit

if pgStateIsOk == True and osdUtilDiffEnough == True and osdTargetReweight > 0:

print "================ doing reweight ==============="

print osdMaxUtilId,osdMaxUtil,osdMaxReweight

print osdMinUtilId,osdMinUtil

doReweight(osdMaxUtilId, osdTargetReweight)

def invokeOSDReweight():

while True:

sleep(30)

canOSDReweight()

if __name__ == '__main__':

invokeOSDReweight()