Shulou(Shulou.com)06/02 Report--

The data distribution of Ceph is determined by CRUSH Map, while the CRUSH algorithm is pseudo-HASH, so the data will be skewed within a certain period of time, which requires us to use scripts to reweight periodically:

# 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 ()

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