# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import logging
import os
from oslo_concurrency import processutils
from oslo_config import cfg
from oslo_utils import imageutils
from oslo_utils import units
import tenacity
from ironic_lib.common.i18n import _
from ironic_lib import utils
opts = [
cfg.IntOpt('image_convert_memory_limit',
default=2048,
help='Memory limit for "qemu-img convert" in MiB. Implemented '
'via the address space resource limit.'),
cfg.IntOpt('image_convert_attempts',
default=3,
help='Number of attempts to convert an image.'),
]
LOG = logging.getLogger(__name__)
CONF = cfg.CONF
CONF.register_opts(opts, group='disk_utils')
# Limit the memory address space to 1 GiB when running qemu-img
QEMU_IMG_LIMITS = None
def _qemu_img_limits():
global QEMU_IMG_LIMITS
if QEMU_IMG_LIMITS is None:
QEMU_IMG_LIMITS = processutils.ProcessLimits(
address_space=CONF.disk_utils.image_convert_memory_limit
* units.Mi)
return QEMU_IMG_LIMITS
def _retry_on_res_temp_unavailable(exc):
if (isinstance(exc, processutils.ProcessExecutionError)
and ('Resource temporarily unavailable' in exc.stderr
or 'Cannot allocate memory' in exc.stderr)):
return True
return False
[docs]
def image_info(path):
"""Return an object containing the parsed output from qemu-img info."""
if not os.path.exists(path):
raise FileNotFoundError(_("File %s does not exist") % path)
out, err = utils.execute('env', 'LC_ALL=C', 'LANG=C',
'qemu-img', 'info', path,
'--output=json',
prlimit=_qemu_img_limits())
return imageutils.QemuImgInfo(out, format='json')
[docs]
@tenacity.retry(
retry=tenacity.retry_if_exception(_retry_on_res_temp_unavailable),
stop=tenacity.stop_after_attempt(CONF.disk_utils.image_convert_attempts),
reraise=True)
def convert_image(source, dest, out_format, run_as_root=False, cache=None,
out_of_order=False, sparse_size=None):
"""Convert image to other format."""
cmd = ['qemu-img', 'convert', '-O', out_format]
if cache is not None:
cmd += ['-t', cache]
if sparse_size is not None:
cmd += ['-S', sparse_size]
if out_of_order:
cmd.append('-W')
cmd += [source, dest]
# NOTE(TheJulia): Statically set the MALLOC_ARENA_MAX to prevent leaking
# and the creation of new malloc arenas which will consume the system
# memory. If limited to 1, qemu-img consumes ~250 MB of RAM, but when
# another thread tries to access a locked section of memory in use with
# another thread, then by default a new malloc arena is created,
# which essentially balloons the memory requirement of the machine.
# Default for qemu-img is 8 * nCPU * ~250MB (based on defaults +
# thread/code/process/library overhead. In other words, 64 GB. Limiting
# this to 3 keeps the memory utilization in happy cases below the overall
# threshold which is in place in case a malicious image is attempted to
# be passed through qemu-img.
env_vars = {'MALLOC_ARENA_MAX': '3'}
try:
utils.execute(*cmd, run_as_root=run_as_root,
prlimit=_qemu_img_limits(),
use_standard_locale=True,
env_variables=env_vars)
except processutils.ProcessExecutionError as e:
if ('Resource temporarily unavailable' in e.stderr
or 'Cannot allocate memory' in e.stderr):
LOG.debug('Failed to convert image, retrying. Error: %s', e)
# Sync disk caches before the next attempt
utils.execute('sync')
raise
[docs]
def list_opts():
"""Entry point for oslo-config-generator."""
return [('disk_utils', opts)]
