openstack-helm-infra/ceph-mon/templates/bin/utils/_checkPGs.py.tpl
Al Lau d6cfd78c4d A script to check the failure domains of OSDs in PGs
The checkPGs script is implemented to check the Object Storage
Daemons (OSDs) in Placement Groups (PGs) of ceph pools to make
sure OSDs were not allocated from the same failure domain.  This
script is intended to run from any one of the ceph-mon pods.

Invoke the checkPGs script with --help to get the details on how
to run it.

A Kubernetes cron job is created to schedule the execution of
this script at a regular interval.  The execution frequency is
defined in the ceph-mon/values.yaml file.

Change-Id: I5d46bc824e88545cde1cc448ae714d7d3c243817
2018-09-06 06:06:28 -07:00

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#!/usr/bin/python2
import subprocess
import json
import sys
from argparse import *
class cephCRUSH():
"""
Currently, this script is coded to work with the ceph clusters that have
these type-ids -- osd, host, rack, root. To add other type_ids to the
CRUSH map, this script needs enhancements to include the new type_ids.
type_id name
------- ----
0 osd
1 host
2 chassis
3 rack
4 row
5 pdu
6 pod
7 room
8 datacenter
9 region
10 root
Ceph organizes the CRUSH map in hierarchical topology. At the top, it is
the root. The next levels are racks, hosts, and OSDs, respectively. The
OSDs are at the leaf level. This script looks at OSDs in each placement
group of a ceph pool. For each OSD, starting from the OSD leaf level, this
script traverses up to the root. Along the way, the host and rack are
recorded and then verified to make sure the paths to the root are in
separate failure domains. This script reports the offending PGs to stdout.
"""
"""
This list stores the ceph crush hierarchy retrieved from the
ceph osd crush tree -f json-pretty
"""
crushHierarchy = []
"""
Failure Domains - currently our crush map uses these type IDs - osd,
host, rack, root
If we need to add chassis type (or other types) later on, add the
type to the if statement in the crushFD construction section.
crushFD[0] = {'id': -2, 'name': 'host1', 'type': 'host'}
crushFD[23] = {'id': -5, 'name': 'host2', 'type': 'host'}
crushFD[68] = {'id': -7, 'name': 'host3', 'type': 'host'}
rack_FD[-2] = {'id': -9, 'name': 'rack1', 'type': 'rack' }
rack_FD[-15] = {'id': -17, 'name': 'rack2', 'type': 'rack' }
root_FD[-17] = {'id': -1, 'name': 'default', 'type': 'root' }}
root_FD[-9] = {'id': -1, 'name': 'default', 'type': 'root' }}
"""
crushFD = {}
def __init__(self, poolName):
if 'all' in poolName or 'All' in poolName:
try:
poolLs = 'ceph osd pool ls -f json-pretty'
poolstr = subprocess.check_output(poolLs, shell=True)
self.listPoolName = json.loads(poolstr)
except subprocess.CalledProcessError as e:
print('{}'.format(e))
"""Unable to get all pools - cannot proceed"""
sys.exit(2)
else:
self.listPoolName = poolName
try:
"""Retrieve the crush hierarchies"""
crushTree = "ceph osd crush tree -f json-pretty | grep -v '^\[\]'"
chstr = subprocess.check_output(crushTree, shell=True)
self.crushHierarchy = json.loads(chstr)
except subprocess.CalledProcessError as e:
print('{}'.format(e))
"""Unable to get crush hierarchy - cannot proceed"""
sys.exit(2)
"""
Number of racks configured in the ceph cluster. The racks that are
present in the crush hierarchy may not be used. The un-used rack
would not show up in the crushFD.
"""
self.count_racks = 0
"""depth level - 3 is OSD, 2 is host, 1 is rack, 0 is root"""
self.osd_depth = 0
"""Construct the Failure Domains - OSD -> Host -> Rack -> Root"""
for chitem in self.crushHierarchy:
if chitem['type'] == 'host' or \
chitem['type'] == 'rack' or \
chitem['type'] == 'root':
for child in chitem['children']:
self.crushFD[child] = {'id': chitem['id'], 'name': chitem['name'], 'type': chitem['type']}
if chitem['type'] == 'rack' and len(chitem['children']) > 0:
self.count_racks += 1
elif chitem['type'] == 'osd':
if self.osd_depth == 0:
self.osd_depth = chitem['depth']
"""[ { 'pg-name' : [osd.1, osd.2, osd.3] } ... ]"""
self.poolPGs = []
"""Replica of the pool. Initialize to 0."""
self.poolSize = 0
def getPoolSize(self, poolName):
"""
size (number of replica) is an attribute of a pool
{ "pool": "rbd", "pool_id": 1, "size": 3 }
"""
pSize = {}
"""Get the size attribute of the poolName"""
try:
poolGet = 'ceph osd pool get ' + poolName + ' size -f json-pretty'
szstr = subprocess.check_output(poolGet, shell=True)
pSize = json.loads(szstr)
self.poolSize = pSize['size']
except subprocess.CalledProcessError as e:
print('{}'.format(e))
self.poolSize = 0
"""Continue on"""
return
def checkPGs(self, poolName):
if not len(self.poolPGs) > 0:
return
print('Checking PGs in pool {} ...'.format(poolName)),
badPGs = False
for pg in self.poolPGs:
osdUp = pg['up']
"""
Construct the OSD path from the leaf to the root. If the
replica is set to 3 and there are 3 racks. Each OSD has its
own rack (failure domain). If more than one OSD has the
same rack, this is a violation. If the number of rack is
one, then we need to make sure the hosts for the three OSDs
are different.
"""
check_FD = {}
checkFailed = False
for osd in osdUp:
traverseID = osd
"""Start the level with 1 to include the OSD leaf"""
traverseLevel = 1
while (self.crushFD[traverseID]['type'] != 'root'):
crushType = self.crushFD[traverseID]['type']
crushName = self.crushFD[traverseID]['name']
if crushType in check_FD:
check_FD[crushType].append(crushName)
else:
check_FD[crushType] = [crushName]
"""traverse up (to the root) one level"""
traverseID = self.crushFD[traverseID]['id']
traverseLevel += 1
assert (traverseLevel == self.osd_depth), "OSD depth mismatch"
"""
check_FD should have
{
'host': ['host1', 'host2', 'host3', 'host4'],
'rack': ['rack1', 'rack2', 'rack3']
}
Not checking for the 'root' as there is only one root.
"""
for ktype in check_FD:
kvalue = check_FD[ktype]
if ktype == 'host':
"""
At the host level, every OSD should come from different
host. It is a violation if duplicate hosts are found.
"""
if len(kvalue) != len(set(kvalue)):
if not badPGs:
print('Failed')
badPGs = True
print('OSDs {} in PG {} failed check in host {}'.format(pg['up'], pg['pgid'], kvalue))
elif ktype == 'rack':
if len(kvalue) == len(set(kvalue)):
continue
else:
"""
There are duplicate racks. This could be due to
situation like pool's size is 3 and there are only
two racks (or one rack). OSDs should come from
different hosts as verified in the 'host' section.
"""
if self.count_racks == len(set(kvalue)):
continue
elif self.count_racks > len(set(kvalue)):
"""Not all the racks were used to allocate OSDs"""
if not badPGs:
print('Failed')
badPGs = True
print('OSDs {} in PG {} failed check in rack {}'.format(pg['up'], pg['pgid'], kvalue))
check_FD.clear()
if not badPGs:
print('Passed')
return
def checkPoolPGs(self):
for pool in self.listPoolName:
self.getPoolSize(pool)
if self.poolSize == 1:
"""No need to check pool with the size set to 1 copy"""
print('Checking PGs in pool {} ... {}'.format(pool, 'Skipped'))
continue
elif self.poolSize == 0:
print('Pool {} was not found.'.format(pool))
continue
assert (self.poolSize > 1), "Pool size was incorrectly set"
try:
"""Get the list of PGs in the pool"""
lsByPool = 'ceph pg ls-by-pool ' + pool + ' -f json-pretty'
pgstr = subprocess.check_output(lsByPool, shell=True)
self.poolPGs = json.loads(pgstr)
"""Check that OSDs in the PG are in separate failure domains"""
self.checkPGs(pool)
except subprocess.CalledProcessError as e:
print('{}'.format(e))
"""Continue to the next pool (if any)"""
return
def Main():
parser = ArgumentParser(description='''
Cross-check the OSDs assigned to the Placement Groups (PGs) of a ceph pool
with the CRUSH topology. The cross-check compares the OSDs in a PG and
verifies the OSDs reside in separate failure domains. PGs with OSDs in
the same failure domain are flagged as violation. The offending PGs are
printed to stdout.
This CLI is executed on-demand on a ceph-mon pod. To invoke the CLI, you
can specify one pool or list of pools to check. The special pool name
All (or all) checks all the pools in the ceph cluster.
''',
formatter_class=RawTextHelpFormatter)
parser.add_argument('PoolName', type=str, nargs='+',
help='List of pools (or All) to validate the PGs and OSDs mapping')
args = parser.parse_args()
if ('all' in args.PoolName or
'All' in args.PoolName) and len(args.PoolName) > 1:
print('You only need to give one pool with special pool All')
sys.exit(1)
"""
Retrieve the crush hierarchies and store it. Cross-check the OSDs
in each PG searching for failure domain violation.
"""
ccm = cephCRUSH(args.PoolName)
ccm.checkPoolPGs()
if __name__ == '__main__':
Main()