ceph/tasks/mds_full.py
John Spray 997c0c3d62 tasks/cephfs: remove config from Filesystem cons
This was only used in get_first_mon, which doesn't actually
need the parameter itself.  Makes it easier to casually
use Filesystem from any place with a ctx to hand.

Signed-off-by: John Spray <john.spray@redhat.com>
2015-01-09 10:09:53 +00:00

364 lines
14 KiB
Python

"""
Exercise the MDS and Client behaviour when the cluster fills up.
"""
import contextlib
import json
import logging
import os
from textwrap import dedent
import time
from teuthology.orchestra.run import CommandFailedError
from tasks.cephfs.filesystem import Filesystem
from tasks.cephfs.cephfs_test_case import CephFSTestCase, run_tests
log = logging.getLogger(__name__)
class TestClusterFull(CephFSTestCase):
# Persist-between-tests constants
pool_capacity = None
def setUp(self):
super(TestClusterFull, self).setUp()
if self.pool_capacity is None:
# This is a hack to overcome weird fluctuations in the reported
# `max_avail` attribute of pools that sometimes occurs in between
# tests (reason as yet unclear, but this dodges the issue)
TestClusterFull.pool_capacity = self.fs.get_pool_df(self._data_pool_name())['max_avail']
def test_barrier(self):
"""
That when an OSD epoch barrier is set on an MDS, subsequently
issued capabilities cause clients to update their OSD map to that
epoch.
"""
# Check the initial barrier epoch on the MDS: this should be
# set to the latest map at MDS startup
initial_osd_epoch = json.loads(
self.fs.mon_manager.raw_cluster_cmd("osd", "dump", "--format=json").strip()
)['epoch']
self.assertGreaterEqual(self.fs.mds_asok(["status"])['osdmap_epoch_barrier'], initial_osd_epoch)
# Sync up clients with initial MDS OSD map barrier
self.mount_a.open_no_data("foo")
self.mount_b.open_no_data("bar")
# Grab mount_a's initial OSD epoch: later we will check that
# it hasn't advanced beyond this point.
mount_a_initial_epoch = self.mount_a.get_osd_epoch()[0]
# Freshly mounted at start of test, should be up to date with OSD map
self.assertGreaterEqual(mount_a_initial_epoch, initial_osd_epoch)
self.assertGreaterEqual(self.mount_b.get_osd_epoch()[0], initial_osd_epoch)
# Set and unset a flag to cause OSD epoch to increment
self.fs.mon_manager.raw_cluster_cmd("osd", "set", "pause")
self.fs.mon_manager.raw_cluster_cmd("osd", "unset", "pause")
out = self.fs.mon_manager.raw_cluster_cmd("osd", "dump", "--format=json").strip()
new_epoch = json.loads(out)['epoch']
self.assertNotEqual(initial_osd_epoch, new_epoch)
# Do a metadata operation on client A, witness that it ends up with
# the old OSD map from startup time (nothing has prompted it
# to update its map)
self.mount_a.open_no_data("alpha")
# Sleep long enough that if the OSD map was propagating it would
# have done so (this is arbitrary because we are 'waiting' for something
# to *not* happen).
time.sleep(30)
mount_a_epoch, mount_a_barrier = self.mount_a.get_osd_epoch()
self.assertEqual(mount_a_epoch, mount_a_initial_epoch)
# Set a barrier on the MDS
self.fs.mds_asok(["osdmap", "barrier", new_epoch.__str__()])
# Do an operation on client B, witness that it ends up with
# the latest OSD map from the barrier
self.mount_b.run_shell(["touch", "bravo"])
self.mount_b.open_no_data("bravo")
# Some time passes here because the metadata part of the operation
# completes immediately, while the resulting OSD map update happens
# asynchronously (it's an Objecter::_maybe_request_map) as a result
# of seeing the new epoch barrier.
self.wait_until_equal(
lambda: self.mount_b.get_osd_epoch(),
(new_epoch, new_epoch),
30,
lambda x: x[0] > new_epoch or x[1] > new_epoch)
# ...and none of this should have affected the oblivious mount a,
# because it wasn't doing any data or metadata IO
mount_a_epoch, mount_a_barrier = self.mount_a.get_osd_epoch()
self.assertEqual(mount_a_epoch, mount_a_initial_epoch)
def _data_pool_name(self):
data_pool_names = self.fs.get_data_pool_names()
if len(data_pool_names) > 1:
raise RuntimeError("This test can't handle multiple data pools")
else:
return data_pool_names[0]
def _test_full(self, easy_case):
"""
- That a client trying to write data to a file is prevented
from doing so with an -EFULL result
- That they are also prevented from creating new files by the MDS.
- That they may delete another file to get the system healthy again
:param easy_case: if true, delete a successfully written file to
free up space. else, delete the file that experienced
the failed write.
"""
osd_mon_report_interval_max = int(self.fs.get_config("osd_mon_report_interval_max", service_type='osd'))
mon_osd_full_ratio = float(self.fs.get_config("mon_osd_full_ratio"))
pool_capacity = self.pool_capacity
fill_mb = int(1.05 * mon_osd_full_ratio * (pool_capacity / (1024.0 * 1024.0))) + 2
log.info("Writing {0}MB should fill this cluster".format(fill_mb))
# Fill up the cluster. This dd may or may not fail, as it depends on
# how soon the cluster recognises its own fullness
self.mount_a.write_n_mb("large_file_a", fill_mb / 2)
try:
self.mount_a.write_n_mb("large_file_b", fill_mb / 2)
except CommandFailedError:
log.info("Writing file B failed (full status happened already)")
assert self.fs.is_full()
else:
log.info("Writing file B succeeded (full status will happen soon)")
self.wait_until_true(lambda: self.fs.is_full(),
timeout=osd_mon_report_interval_max * 5)
# Attempting to write more data should give me ENOSPC
with self.assertRaises(CommandFailedError) as ar:
self.mount_a.write_n_mb("large_file_b", 50, seek=fill_mb / 2)
self.assertEqual(ar.exception.exitstatus, 1) # dd returns 1 on "No space"
# Wait for the MDS to see the latest OSD map so that it will reliably
# be applying the policy of rejecting non-deletion metadata operations
# while in the full state.
osd_epoch = json.loads(self.fs.mon_manager.raw_cluster_cmd("osd", "dump", "--format=json-pretty"))['epoch']
self.wait_until_true(
lambda: self.fs.mds_asok(['status'])['osdmap_epoch'] >= osd_epoch,
timeout=10)
with self.assertRaises(CommandFailedError):
self.mount_a.write_n_mb("small_file_1", 0)
# Clear out some space
if easy_case:
self.mount_a.run_shell(['rm', '-f', 'large_file_a'])
self.mount_a.run_shell(['rm', '-f', 'large_file_b'])
else:
# In the hard case it is the file that filled the system.
# Before the new #7317 (ENOSPC, epoch barrier) changes, this
# would fail because the last objects written would be
# stuck in the client cache as objecter operations.
self.mount_a.run_shell(['rm', '-f', 'large_file_b'])
self.mount_a.run_shell(['rm', '-f', 'large_file_a'])
# Here we are waiting for two things to happen:
# * The MDS to purge the stray folder and execute object deletions
# * The OSDs to inform the mon that they are no longer full
self.wait_until_true(lambda: not self.fs.is_full(),
timeout=osd_mon_report_interval_max * 5)
# Wait for the MDS to see the latest OSD map so that it will reliably
# be applying the free space policy
osd_epoch = json.loads(self.fs.mon_manager.raw_cluster_cmd("osd", "dump", "--format=json-pretty"))['epoch']
self.wait_until_true(
lambda: self.fs.mds_asok(['status'])['osdmap_epoch'] >= osd_epoch,
timeout=10)
# Now I should be able to write again
self.mount_a.write_n_mb("large_file", 50, seek=0)
# Ensure that the MDS keeps its OSD epoch barrier across a restart
def test_full_different_file(self):
self._test_full(True)
def test_full_same_file(self):
self._test_full(False)
def _remote_write_test(self, template):
"""
Run some remote python in a way that's useful for
testing free space behaviour (see test_* methods using this)
"""
file_path = os.path.join(self.mount_a.mountpoint, "full_test_file")
# Enough to trip the full flag
osd_mon_report_interval_max = int(self.fs.get_config("osd_mon_report_interval_max", service_type='osd'))
mon_osd_full_ratio = float(self.fs.get_config("mon_osd_full_ratio"))
pool_capacity = self.pool_capacity
# Sufficient data to cause RADOS cluster to go 'full'
fill_mb = int(1.05 * mon_osd_full_ratio * (pool_capacity / (1024.0 * 1024.0)))
log.info("pool capacity {0}, {1}MB should be enough to fill it".format(pool_capacity, fill_mb))
# Long enough for RADOS cluster to notice it is full and set flag on mons
full_wait = osd_mon_report_interval_max * 1.5
# Configs for this test should bring this setting down in order to
# run reasonably quickly
if osd_mon_report_interval_max > 10:
log.warn("This test may run rather slowly unless you decrease"
"osd_mon_report_interval_max (5 is a good setting)!")
self.mount_a.run_python(template.format(
fill_mb=fill_mb,
file_path=file_path,
full_wait=full_wait
))
def test_full_fclose(self):
# A remote script which opens a file handle, fills up the filesystem, and then
# checks that ENOSPC errors on buffered writes appear correctly as errors in fsync
remote_script = dedent("""
import time
import datetime
import subprocess
import os
# Write some buffered data through before going full, all should be well
bytes = 0
f = os.open("{file_path}", os.O_WRONLY | os.O_CREAT)
bytes += os.write(f, 'a' * 4096)
os.fsync(f)
# Okay, now we're going to fill up the filesystem, and then keep
# writing until we see an error from fsync. As long as we're doing
# buffered IO, the error should always only appear from fsync and not
# from write
full = False
for n in range(0, {fill_mb}):
bytes += os.write(f, 'x' * 1024 * 1024)
# OK, now we should sneak in under the full condition
# due to the time it takes the OSDs to report to the
# mons, and get a successful fsync on our full-making data
os.fsync(f)
# Now wait for the full flag to get set so that our
# next flush IO will fail
time.sleep(30)
# A buffered IO, should succeed
os.write(f, 'x' * 4096)
# Wait long enough for a background flush that should fail
time.sleep(30)
# ...and check that the failed background flush is reflected in fclose
try:
os.close(f)
except OSError:
print "close() returned an error as expected"
else:
raise RuntimeError("close() failed to raise error")
os.unlink("{file_path}")
""")
self._remote_write_test(remote_script)
def test_full_fsync(self):
"""
That when the full flag is encountered during asynchronous
flushes, such that an fwrite() succeeds but an fsync/fclose()
should return the ENOSPC error.
"""
# A remote script which opens a file handle, fills up the filesystem, and then
# checks that ENOSPC errors on buffered writes appear correctly as errors in fsync
remote_script = dedent("""
import time
import datetime
import subprocess
import os
# Write some buffered data through before going full, all should be well
bytes = 0
f = os.open("{file_path}", os.O_WRONLY | os.O_CREAT)
bytes += os.write(f, 'a' * 4096)
os.fsync(f)
# Okay, now we're going to fill up the filesystem, and then keep
# writing until we see an error from fsync. As long as we're doing
# buffered IO, the error should always only appear from fsync and not
# from write
full = False
for n in range(0, {fill_mb} + 1):
bytes += os.write(f, 'x' * 1024 * 1024)
try:
os.fsync(f)
except OSError as e:
print "Reached fullness after %.2f MB" % (bytes / (1024.0 * 1024.0))
full = True
break
else:
print "Not full yet after %.2f MB" % (bytes / (1024.0 * 1024.0))
if n > {fill_mb} * 0.8:
# Be cautious in the last region where we expect to hit
# the full condition, so that we don't overshoot too dramatically
time.sleep({full_wait})
if not full:
raise RuntimeError("Failed to reach fullness after writing %d bytes" % bytes)
# The error sticks to the inode until we dispose of it
try:
os.close(f)
except OSError:
print "Saw error from close() as expected"
else:
raise RuntimeError("Did not see expected error from close()")
os.unlink("{file_path}")
""")
self._remote_write_test(remote_script)
@contextlib.contextmanager
def task(ctx, config):
fs = Filesystem(ctx)
# Pick out the clients we will use from the configuration
# =======================================================
if len(ctx.mounts) < 2:
raise RuntimeError("Need at least two clients")
mount_a = ctx.mounts.values()[0]
mount_b = ctx.mounts.values()[1]
# Stash references on ctx so that we can easily debug in interactive mode
# =======================================================================
ctx.filesystem = fs
ctx.mount_a = mount_a
ctx.mount_b = mount_b
run_tests(ctx, config, TestClusterFull, {
'fs': fs,
'mount_a': mount_a,
'mount_b': mount_b
})
# Continue to any downstream tasks
# ================================
yield