268 lines
11 KiB
Python
268 lines
11 KiB
Python
# Copyright (c) 2012 NetApp, Inc.
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import errno
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import os
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from oslo.config import cfg
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from cinder.brick.remotefs import remotefs as remotefs_brick
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from cinder import exception
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from cinder.i18n import _
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from cinder.image import image_utils
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from cinder.openstack.common import log as logging
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from cinder.openstack.common import processutils as putils
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from cinder.openstack.common import units
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from cinder import utils
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from cinder.volume.drivers import remotefs
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VERSION = '1.1.0'
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LOG = logging.getLogger(__name__)
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volume_opts = [
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cfg.StrOpt('nfs_shares_config',
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default='/etc/cinder/nfs_shares',
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help='File with the list of available nfs shares'),
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cfg.BoolOpt('nfs_sparsed_volumes',
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default=True,
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help=('Create volumes as sparsed files which take no space.'
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'If set to False volume is created as regular file.'
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'In such case volume creation takes a lot of time.')),
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cfg.FloatOpt('nfs_used_ratio',
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default=0.95,
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help=('Percent of ACTUAL usage of the underlying volume '
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'before no new volumes can be allocated to the volume '
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'destination.')),
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cfg.FloatOpt('nfs_oversub_ratio',
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default=1.0,
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help=('This will compare the allocated to available space on '
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'the volume destination. If the ratio exceeds this '
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'number, the destination will no longer be valid.')),
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cfg.StrOpt('nfs_mount_point_base',
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default='$state_path/mnt',
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help=('Base dir containing mount points for nfs shares.')),
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cfg.StrOpt('nfs_mount_options',
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default=None,
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help=('Mount options passed to the nfs client. See section '
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'of the nfs man page for details.')),
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]
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CONF = cfg.CONF
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CONF.register_opts(volume_opts)
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class NfsDriver(remotefs.RemoteFSDriver):
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"""NFS based cinder driver. Creates file on NFS share for using it
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as block device on hypervisor.
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"""
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driver_volume_type = 'nfs'
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driver_prefix = 'nfs'
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volume_backend_name = 'Generic_NFS'
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VERSION = VERSION
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def __init__(self, execute=putils.execute, *args, **kwargs):
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self._remotefsclient = None
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super(NfsDriver, self).__init__(*args, **kwargs)
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self.configuration.append_config_values(volume_opts)
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root_helper = utils.get_root_helper()
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# base bound to instance is used in RemoteFsConnector.
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self.base = getattr(self.configuration,
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'nfs_mount_point_base',
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CONF.nfs_mount_point_base)
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opts = getattr(self.configuration,
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'nfs_mount_options',
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CONF.nfs_mount_options)
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self._remotefsclient = remotefs_brick.RemoteFsClient(
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'nfs', root_helper, execute=execute,
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nfs_mount_point_base=self.base,
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nfs_mount_options=opts)
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def set_execute(self, execute):
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super(NfsDriver, self).set_execute(execute)
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if self._remotefsclient:
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self._remotefsclient.set_execute(execute)
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def do_setup(self, context):
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"""Any initialization the volume driver does while starting."""
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super(NfsDriver, self).do_setup(context)
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config = self.configuration.nfs_shares_config
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if not config:
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msg = (_("There's no NFS config file configured (%s)") %
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'nfs_shares_config')
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LOG.warn(msg)
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raise exception.NfsException(msg)
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if not os.path.exists(config):
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msg = (_("NFS config file at %(config)s doesn't exist") %
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{'config': config})
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LOG.warn(msg)
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raise exception.NfsException(msg)
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if not self.configuration.nfs_oversub_ratio > 0:
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msg = _("NFS config 'nfs_oversub_ratio' invalid. Must be > 0: "
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"%s") % self.configuration.nfs_oversub_ratio
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LOG.error(msg)
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raise exception.NfsException(msg)
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if ((not self.configuration.nfs_used_ratio > 0) and
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(self.configuration.nfs_used_ratio <= 1)):
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msg = _("NFS config 'nfs_used_ratio' invalid. Must be > 0 "
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"and <= 1.0: %s") % self.configuration.nfs_used_ratio
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LOG.error(msg)
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raise exception.NfsException(msg)
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self.shares = {} # address : options
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# Check if mount.nfs is installed
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try:
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self._execute('mount.nfs', check_exit_code=False, run_as_root=True)
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except OSError as exc:
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if exc.errno == errno.ENOENT:
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raise exception.NfsException('mount.nfs is not installed')
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else:
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raise exc
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def _ensure_share_mounted(self, nfs_share):
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mnt_flags = []
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if self.shares.get(nfs_share) is not None:
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mnt_flags = self.shares[nfs_share].split()
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self._remotefsclient.mount(nfs_share, mnt_flags)
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def _find_share(self, volume_size_in_gib):
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"""Choose NFS share among available ones for given volume size.
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For instances with more than one share that meets the criteria, the
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share with the least "allocated" space will be selected.
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:param volume_size_in_gib: int size in GB
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"""
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if not self._mounted_shares:
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raise exception.NfsNoSharesMounted()
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target_share = None
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target_share_reserved = 0
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for nfs_share in self._mounted_shares:
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if not self._is_share_eligible(nfs_share, volume_size_in_gib):
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continue
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total_size, total_available, total_allocated = \
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self._get_capacity_info(nfs_share)
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if target_share is not None:
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if target_share_reserved > total_allocated:
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target_share = nfs_share
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target_share_reserved = total_allocated
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else:
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target_share = nfs_share
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target_share_reserved = total_allocated
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if target_share is None:
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raise exception.NfsNoSuitableShareFound(
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volume_size=volume_size_in_gib)
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LOG.debug('Selected %s as target nfs share.', target_share)
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return target_share
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def _is_share_eligible(self, nfs_share, volume_size_in_gib):
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"""Verifies NFS share is eligible to host volume with given size.
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First validation step: ratio of actual space (used_space / total_space)
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is less than 'nfs_used_ratio'. Second validation step: apparent space
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allocated (differs from actual space used when using sparse files)
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and compares the apparent available
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space (total_available * nfs_oversub_ratio) to ensure enough space is
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available for the new volume.
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:param nfs_share: nfs share
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:param volume_size_in_gib: int size in GB
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"""
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used_ratio = self.configuration.nfs_used_ratio
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oversub_ratio = self.configuration.nfs_oversub_ratio
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requested_volume_size = volume_size_in_gib * units.Gi
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total_size, total_available, total_allocated = \
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self._get_capacity_info(nfs_share)
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apparent_size = max(0, total_size * oversub_ratio)
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apparent_available = max(0, apparent_size - total_allocated)
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used = (total_size - total_available) / total_size
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if used > used_ratio:
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# NOTE(morganfainberg): We check the used_ratio first since
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# with oversubscription it is possible to not have the actual
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# available space but be within our oversubscription limit
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# therefore allowing this share to still be selected as a valid
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# target.
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LOG.debug('%s is above nfs_used_ratio', nfs_share)
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return False
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if apparent_available <= requested_volume_size:
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LOG.debug('%s is above nfs_oversub_ratio', nfs_share)
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return False
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if total_allocated / total_size >= oversub_ratio:
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LOG.debug('%s reserved space is above nfs_oversub_ratio',
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nfs_share)
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return False
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return True
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def _get_mount_point_for_share(self, nfs_share):
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"""Needed by parent class."""
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return self._remotefsclient.get_mount_point(nfs_share)
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def _get_capacity_info(self, nfs_share):
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"""Calculate available space on the NFS share.
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:param nfs_share: example 172.18.194.100:/var/nfs
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"""
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mount_point = self._get_mount_point_for_share(nfs_share)
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df, _ = self._execute('stat', '-f', '-c', '%S %b %a', mount_point,
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run_as_root=True)
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block_size, blocks_total, blocks_avail = map(float, df.split())
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total_available = block_size * blocks_avail
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total_size = block_size * blocks_total
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du, _ = self._execute('du', '-sb', '--apparent-size', '--exclude',
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'*snapshot*', mount_point, run_as_root=True)
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total_allocated = float(du.split()[0])
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return total_size, total_available, total_allocated
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def _get_mount_point_base(self):
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return self.base
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def extend_volume(self, volume, new_size):
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"""Extend an existing volume to the new size."""
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LOG.info(_('Extending volume %s.'), volume['id'])
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extend_by = int(new_size) - volume['size']
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if not self._is_share_eligible(volume['provider_location'],
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extend_by):
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raise exception.ExtendVolumeError(reason='Insufficient space to'
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' extend volume %s to %sG'
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% (volume['id'], new_size))
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path = self.local_path(volume)
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LOG.info(_('Resizing file to %sG...'), new_size)
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image_utils.resize_image(path, new_size)
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if not self._is_file_size_equal(path, new_size):
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raise exception.ExtendVolumeError(
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reason='Resizing image file failed.')
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def _is_file_size_equal(self, path, size):
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"""Checks if file size at path is equal to size."""
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data = image_utils.qemu_img_info(path)
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virt_size = data.virtual_size / units.Gi
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return virt_size == size
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