cfg.StrOpt('nfs_shares_config',

default='/etc/cinder/nfs_shares',

help='File with the list of available NFS shares'),

cfg.BoolOpt('nfs_sparsed_volumes',

default=True,

help=('Create volumes as sparsed files which take no space.'

'If set to False volume is created as regular file.'

'In such case volume creation takes a lot of time.')),

# TODO(tbarron): remove nfs_used_ratio in the Mitaka release.

cfg.FloatOpt('nfs_used_ratio',

default=NFS_USED_RATIO_DEFAULT,

help=('Percent of ACTUAL usage of the underlying volume '

'before no new volumes can be allocated to the volume '

'destination. Note that this option is deprecated '

'in favor of "reserved_percentage" and will be removed '

'in the Mitaka release.')),

# TODO(tbarron): remove nfs_oversub_ratio in the Mitaka release.

cfg.FloatOpt('nfs_oversub_ratio',

default=NFS_OVERSUB_RATIO_DEFAULT,

help=('This will compare the allocated to available space on '

'the volume destination. If the ratio exceeds this '

'number, the destination will no longer be valid. '

'Note that this option is deprecated in favor of '

'"max_oversubscription_ratio" and will be removed '

'in the Mitaka release.')),

cfg.StrOpt('nfs_mount_point_base',

default='$state_path/mnt',

help=('Base dir containing mount points for NFS shares.')),

cfg.StrOpt('nfs_mount_options',

help=('Mount options passed to the NFS client. See section '

'of the NFS man page for details.')),

cfg.IntOpt('nfs_mount_attempts',

default=3,

help=('The number of attempts to mount NFS shares before '

'raising an error. At least one attempt will be '

'made to mount an NFS share, regardless of the '

'value specified.')),

"""NFS based cinder driver.

Creates file on NFS share for using it as block device on hypervisor.

"""

driver_volume_type = 'nfs'

driver_prefix = 'nfs'

volume_backend_name = 'Generic_NFS'

VERSION = VERSION

def __init__(self, execute=putils.execute, *args, **kwargs):

self._remotefsclient = None

super(NfsDriver, self).__init__(*args, **kwargs)

self.configuration.append_config_values(nfs_opts)

root_helper = utils.get_root_helper()

# base bound to instance is used in RemoteFsConnector.

self.base = getattr(self.configuration,

'nfs_mount_point_base',

CONF.nfs_mount_point_base)

self.base = os.path.realpath(self.base)

opts = getattr(self.configuration,

'nfs_mount_options',

CONF.nfs_mount_options)

nas_mount_options = getattr(self.configuration,

'nas_mount_options',

None)

if nas_mount_options is not None:

LOG.debug('overriding nfs_mount_options with nas_mount_options')

opts = nas_mount_options

self._remotefsclient = remotefs_brick.RemoteFsClient(

'nfs', root_helper, execute=execute,

nfs_mount_point_base=self.base,

nfs_mount_options=opts)

self._sparse_copy_volume_data = True

self.reserved_percentage = self._get_reserved_percentage()

self.over_subscription_ratio = self._get_over_subscription_ratio()

def do_setup(self, context):

"""Any initialization the volume driver does while starting."""

super(NfsDriver, self).do_setup(context)

config = self.configuration.nfs_shares_config

if not config:

msg = (_("There's no NFS config file configured (%s)") %

'nfs_shares_config')

LOG.warning(msg)

raise exception.NfsException(msg)

if not os.path.exists(config):

msg = (_("NFS config file at %(config)s doesn't exist") %

{'config': config})

LOG.warning(msg)

raise exception.NfsException(msg)

self.shares = {} # address : options

# Check if mount.nfs is installed on this system; note that we

# need to be root, to also find mount.nfs on distributions, where

# it is not located in an unprivileged users PATH (e.g. /sbin).

package = 'mount.nfs'

try:

self._execute(package, check_exit_code=False,

run_as_root=True)

except OSError as exc:

if exc.errno == errno.ENOENT:

msg = _('%s is not installed') % package

raise exception.NfsException(msg)

else:

raise

# Now that all configuration data has been loaded (shares),

# we can "set" our final NAS file security options.

self.set_nas_security_options(self._is_voldb_empty_at_startup)

def _ensure_share_mounted(self, nfs_share):

mnt_flags = []

if self.shares.get(nfs_share) is not None:

mnt_flags = self.shares[nfs_share].split()

num_attempts = max(1, self.configuration.nfs_mount_attempts)

for attempt in range(num_attempts):

try:

self._remotefsclient.mount(nfs_share, mnt_flags)

return

except Exception as e:

if attempt == (num_attempts - 1):

LOG.error(_LE('Mount failure for %(share)s after '

'%(count)d attempts.'), {

'share': nfs_share,

'count': num_attempts})

raise exception.NfsException(six.text_type(e))

LOG.debug('Mount attempt %(attempt)d failed: %(exc)s.\n'

'Retrying mount ...',

{'attempt': attempt, 'exc': e})

time.sleep(1)

def _find_share(self, volume_size_in_gib):

"""Choose NFS share among available ones for given volume size.

For instances with more than one share that meets the criteria, the

share with the least "allocated" space will be selected.

:param volume_size_in_gib: int size in GB

"""

if not self._mounted_shares:

raise exception.NfsNoSharesMounted()

target_share = None

target_share_reserved = 0

for nfs_share in self._mounted_shares:

total_size, total_available, total_allocated = (

self._get_capacity_info(nfs_share))

share_info = {'total_size': total_size,

'total_available': total_available,

'total_allocated': total_allocated,

}

if not self._is_share_eligible(nfs_share, volume_size_in_gib,

share_info):

continue

if target_share is not None:

if target_share_reserved > total_allocated:

target_share = nfs_share

target_share_reserved = total_allocated

else:

target_share = nfs_share

target_share_reserved = total_allocated

if target_share is None:

raise exception.NfsNoSuitableShareFound(

volume_size=volume_size_in_gib)

LOG.debug('Selected %s as target NFS share.', target_share)

return target_share

def _is_share_eligible(self, nfs_share, volume_size_in_gib,

share_info=None):

"""Verifies NFS share is eligible to host volume with given size.

First validation step: ratio of actual space (used_space / total_space)

is less than 'nfs_used_ratio'. Second validation step: apparent space

allocated (differs from actual space used when using sparse files)

and compares the apparent available

space (total_available * nfs_oversub_ratio) to ensure enough space is

available for the new volume.

:param nfs_share: NFS share

:param volume_size_in_gib: int size in GB

"""

# Because the generic NFS driver aggregates over all shares

# when reporting capacity and usage stats to the scheduler,

# we still have to perform some scheduler-like capacity

# checks here, and these have to take into account

# configuration for reserved space and oversubscription.

# It would be better to do all this in the scheduler, but

# this requires either pool support for the generic NFS

# driver or limiting each NFS backend driver to a single share.

# 'nfs_used_ratio' is deprecated, so derive used_ratio from

# reserved_percentage.

if share_info is None:

total_size, total_available, total_allocated = (

self._get_capacity_info(nfs_share))

share_info = {'total_size': total_size,

'total_available': total_available,

'total_allocated': total_allocated,

}

used_percentage = 100 - self.reserved_percentage

used_ratio = used_percentage / 100.0

oversub_ratio = self.over_subscription_ratio

requested_volume_size = volume_size_in_gib * units.Gi

apparent_size = max(0, share_info['total_size'] * oversub_ratio)

apparent_available = max(0, apparent_size -

share_info['total_allocated'])

actual_used_ratio = ((share_info['total_size'] -

share_info['total_available']) /

float(share_info['total_size']))

if actual_used_ratio > used_ratio:

# NOTE(morganfainberg): We check the used_ratio first since

# with oversubscription it is possible to not have the actual

# available space but be within our oversubscription limit

# therefore allowing this share to still be selected as a valid

# target.

LOG.debug('%s is above nfs_used_ratio', nfs_share)

return False

if apparent_available <= requested_volume_size:

LOG.debug('%s is above nfs_oversub_ratio', nfs_share)

return False

if share_info['total_allocated'] / share_info['total_size'] >= (

oversub_ratio):

LOG.debug('%s reserved space is above nfs_oversub_ratio',

nfs_share)

return False

return True

def _get_mount_point_for_share(self, nfs_share):

"""Needed by parent class."""

return self._remotefsclient.get_mount_point(nfs_share)

def _get_capacity_info(self, nfs_share):

"""Calculate available space on the NFS share.

:param nfs_share: example 172.18.194.100:/var/nfs

"""

run_as_root = self._execute_as_root

mount_point = self._get_mount_point_for_share(nfs_share)

df, _ = self._execute('stat', '-f', '-c', '%S %b %a', mount_point,

run_as_root=run_as_root)

block_size, blocks_total, blocks_avail = map(float, df.split())

total_available = block_size * blocks_avail

total_size = block_size * blocks_total

du, _ = self._execute('du', '-sb', '--apparent-size', '--exclude',

'*snapshot*', mount_point,

run_as_root=run_as_root)

total_allocated = float(du.split()[0])

return total_size, total_available, total_allocated

def _get_mount_point_base(self):

return self.base

def extend_volume(self, volume, new_size):

"""Extend an existing volume to the new size."""

LOG.info(_LI('Extending volume %s.'), volume['id'])

extend_by = int(new_size) - volume['size']

if not self._is_share_eligible(volume['provider_location'],

extend_by):

raise exception.ExtendVolumeError(reason='Insufficient space to'

' extend volume %s to %sG'

% (volume['id'], new_size))

path = self.local_path(volume)

LOG.info(_LI('Resizing file to %sG...'), new_size)

image_utils.resize_image(path, new_size,

run_as_root=self._execute_as_root)

if not self._is_file_size_equal(path, new_size):

raise exception.ExtendVolumeError(

reason='Resizing image file failed.')

def _is_file_size_equal(self, path, size):

"""Checks if file size at path is equal to size."""

data = image_utils.qemu_img_info(path,

run_as_root=self._execute_as_root)

virt_size = data.virtual_size / units.Gi

return virt_size == size

def set_nas_security_options(self, is_new_cinder_install):

"""Determine the setting to use for Secure NAS options.

Value of each NAS Security option is checked and updated. If the

option is currently 'auto', then it is set to either true or false

based upon if this is a new Cinder installation. The RemoteFS variable

'_execute_as_root' will be updated for this driver.

:param is_new_cinder_install: bool indication of new Cinder install

"""

doc_html = "http://docs.openstack.org/admin-guide-cloud" \

"/blockstorage_nfs_backend.html"

self._ensure_shares_mounted()

if not self._mounted_shares:

raise exception.NfsNoSharesMounted()

nfs_mount = self._get_mount_point_for_share(self._mounted_shares[0])

self.configuration.nas_secure_file_permissions = \

self._determine_nas_security_option_setting(

self.configuration.nas_secure_file_permissions,

nfs_mount, is_new_cinder_install)

LOG.debug('NAS variable secure_file_permissions setting is: %s',

self.configuration.nas_secure_file_permissions)

if self.configuration.nas_secure_file_permissions == 'false':

LOG.warning(_LW("The NAS file permissions mode will be 666 "

"(allowing other/world read & write access). "

"This is considered an insecure NAS environment. "

"Please see %s for information on a secure "

"NFS configuration."),

doc_html)

self.configuration.nas_secure_file_operations = \

self._determine_nas_security_option_setting(

self.configuration.nas_secure_file_operations,

nfs_mount, is_new_cinder_install)

# If secure NAS, update the '_execute_as_root' flag to not

# run as the root user; run as process' user ID.

if self.configuration.nas_secure_file_operations == 'true':

self._execute_as_root = False

LOG.debug('NAS variable secure_file_operations setting is: %s',

self.configuration.nas_secure_file_operations)

if self.configuration.nas_secure_file_operations == 'false':

LOG.warning(_LW("The NAS file operations will be run as "

"root: allowing root level access at the storage "

"backend. This is considered an insecure NAS "

"environment. Please see %s "

"for information on a secure NAS configuration."),

doc_html)

def update_migrated_volume(self, ctxt, volume, new_volume,

original_volume_status):

"""Return the keys and values updated from NFS for migrated volume.

This method should rename the back-end volume name(id) on the

destination host back to its original name(id) on the source host.

:param ctxt: The context used to run the method update_migrated_volume

:param volume: The original volume that was migrated to this backend

:param new_volume: The migration volume object that was created on

this backend as part of the migration process

:param original_volume_status: The status of the original volume

:returns: model_update to update DB with any needed changes

"""

# TODO(vhou) This method may need to be updated after

# NFS snapshots are introduced.

name_id = None

if original_volume_status == 'available':

current_name = CONF.volume_name_template % new_volume['id']

original_volume_name = CONF.volume_name_template % volume['id']

current_path = self.local_path(new_volume)

# Replace the volume name with the original volume name

original_path = current_path.replace(current_name,

original_volume_name)

try:

os.rename(current_path, original_path)

except OSError:

LOG.error(_LE('Unable to rename the logical volume '

'for volume: %s'), volume['id'])

# If the rename fails, _name_id should be set to the new

# volume id and provider_location should be set to the

# one from the new volume as well.

name_id = new_volume['_name_id'] or new_volume['id']

else:

# The back-end will not be renamed.

name_id = new_volume['_name_id'] or new_volume['id']

return {'_name_id': name_id,

'provider_location': new_volume['provider_location']}

def _update_volume_stats(self):

"""Retrieve stats info from volume group."""

super(NfsDriver, self)._update_volume_stats()

self._stats['sparse_copy_volume'] = True

data = self._stats

global_capacity = data['total_capacity_gb']

global_free = data['free_capacity_gb']

thin_enabled = self.configuration.nfs_sparsed_volumes

if thin_enabled:

provisioned_capacity = self._get_provisioned_capacity()

else:

provisioned_capacity = round(global_capacity - global_free, 2)

data['provisioned_capacity_gb'] = provisioned_capacity

data['max_over_subscription_ratio'] = self.over_subscription_ratio

data['reserved_percentage'] = self.reserved_percentage

data['thin_provisioning_support'] = thin_enabled

data['thick_provisioning_support'] = not thin_enabled

self._stats = data

def _get_over_subscription_ratio(self):

legacy_oversub_ratio = self.configuration.nfs_oversub_ratio

if legacy_oversub_ratio == NFS_OVERSUB_RATIO_DEFAULT:

return self.configuration.max_over_subscription_ratio

# Honor legacy option if its value is not the default.

msg = _LW("The option 'nfs_oversub_ratio' is deprecated and will "

"be removed in the Mitaka release. Please set "

"'max_over_subscription_ratio = %s' instead.") % (

self.configuration.nfs_oversub_ratio)

versionutils.report_deprecated_feature(LOG, msg)

if not self.configuration.nfs_oversub_ratio > 0:

msg = _("NFS config 'nfs_oversub_ratio' invalid. Must be > 0: "

"%s.") % self.configuration.nfs_oversub_ratio

LOG.error(msg)

raise exception.InvalidConfigurationValue(msg)

return legacy_oversub_ratio

def _get_reserved_percentage(self):

legacy_used_ratio = self.configuration.nfs_used_ratio

legacy_reserved_ratio = 1 - legacy_used_ratio

legacy_percentage = legacy_reserved_ratio * 100

if legacy_used_ratio == NFS_USED_RATIO_DEFAULT:

return self.configuration.reserved_percentage

# Honor legacy option if its value is not the default.

msg = _LW("The option 'nfs_used_ratio' is deprecated and will "

"be removed in the Mitaka release. Please set "

"'reserved_percentage = %d' instead.") % (

legacy_percentage)

versionutils.report_deprecated_feature(LOG, msg)

if not ((self.configuration.nfs_used_ratio > 0) and

(self.configuration.nfs_used_ratio <= 1)):

msg = _("NFS config 'nfs_used_ratio' invalid. Must be > 0 "

"and <= 1.0: %s.") % self.configuration.nfs_used_ratio

LOG.error(msg)

raise exception.InvalidConfigurationValue(msg)