cinder/cinder/volume/drivers/lvm.py

633 lines
26 KiB
Python

# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright 2010 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
# All Rights Reserved.
#
# 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.
"""
Driver for Linux servers running LVM.
"""
import math
import os
import re
from cinder import exception
from cinder import flags
from cinder.image import image_utils
from cinder.openstack.common import cfg
from cinder.openstack.common import log as logging
from cinder import utils
from cinder.volume import driver
from cinder.volume import iscsi
LOG = logging.getLogger(__name__)
volume_opts = [
cfg.StrOpt('volume_group',
default='cinder-volumes',
help='Name for the VG that will contain exported volumes'),
cfg.StrOpt('volume_clear',
default='zero',
help='Method used to wipe old volumes (valid options are: '
'none, zero, shred)'),
cfg.IntOpt('volume_clear_size',
default=0,
help='Size in MiB to wipe at start of old volumes. 0 => all'),
cfg.StrOpt('pool_size',
default=None,
help='Size of thin provisioning pool '
'(None uses entire cinder VG)'),
cfg.IntOpt('lvm_mirrors',
default=0,
help='If set, create lvms with multiple mirrors. Note that '
'this requires lvm_mirrors + 2 pvs with available space'),
]
FLAGS = flags.FLAGS
FLAGS.register_opts(volume_opts)
class LVMVolumeDriver(driver.VolumeDriver):
"""Executes commands relating to Volumes."""
def __init__(self, *args, **kwargs):
super(LVMVolumeDriver, self).__init__(*args, **kwargs)
self.configuration.append_config_values(volume_opts)
def check_for_setup_error(self):
"""Returns an error if prerequisites aren't met"""
out, err = self._execute('vgs', '--noheadings', '-o', 'name',
run_as_root=True)
volume_groups = out.split()
if self.configuration.volume_group not in volume_groups:
exception_message = (_("volume group %s doesn't exist")
% self.configuration.volume_group)
raise exception.VolumeBackendAPIException(data=exception_message)
def _create_volume(self, volume_name, sizestr):
cmd = ['lvcreate', '-L', sizestr, '-n', volume_name,
self.configuration.volume_group]
if self.configuration.lvm_mirrors:
cmd += ['-m', self.configuration.lvm_mirrors, '--nosync']
terras = int(sizestr[:-1]) / 1024.0
if terras >= 1.5:
rsize = int(2 ** math.ceil(math.log(terras) / math.log(2)))
# NOTE(vish): Next power of two for region size. See:
# http://red.ht/U2BPOD
cmd += ['-R', str(rsize)]
self._try_execute(*cmd, run_as_root=True)
def _copy_volume(self, srcstr, deststr, size_in_g, clearing=False):
# Use O_DIRECT to avoid thrashing the system buffer cache
extra_flags = ['iflag=direct', 'oflag=direct']
# Check whether O_DIRECT is supported
try:
self._execute('dd', 'count=0', 'if=%s' % srcstr, 'of=%s' % deststr,
*extra_flags, run_as_root=True)
except exception.ProcessExecutionError:
extra_flags = []
# If the volume is being unprovisioned then
# request the data is persisted before returning,
# so that it's not discarded from the cache.
if clearing and not extra_flags:
extra_flags.append('conv=fdatasync')
# Perform the copy
self._execute('dd', 'if=%s' % srcstr, 'of=%s' % deststr,
'count=%d' % (size_in_g * 1024), 'bs=1M',
*extra_flags, run_as_root=True)
def _volume_not_present(self, volume_name):
path_name = '%s/%s' % (self.configuration.volume_group, volume_name)
try:
self._try_execute('lvdisplay', path_name, run_as_root=True)
except Exception as e:
# If the volume isn't present
return True
return False
def _delete_volume(self, volume, size_in_g):
"""Deletes a logical volume."""
# zero out old volumes to prevent data leaking between users
# TODO(ja): reclaiming space should be done lazy and low priority
dev_path = self.local_path(volume)
if os.path.exists(dev_path):
self.clear_volume(volume)
self._try_execute('lvremove', '-f', "%s/%s" %
(self.configuration.volume_group,
self._escape_snapshot(volume['name'])),
run_as_root=True)
def _sizestr(self, size_in_g):
if int(size_in_g) == 0:
return '100M'
return '%sG' % size_in_g
# Linux LVM reserves name that starts with snapshot, so that
# such volume name can't be created. Mangle it.
def _escape_snapshot(self, snapshot_name):
if not snapshot_name.startswith('snapshot'):
return snapshot_name
return '_' + snapshot_name
def create_volume(self, volume):
"""Creates a logical volume. Can optionally return a Dictionary of
changes to the volume object to be persisted."""
self._create_volume(volume['name'], self._sizestr(volume['size']))
def create_volume_from_snapshot(self, volume, snapshot):
"""Creates a volume from a snapshot."""
self._create_volume(volume['name'], self._sizestr(volume['size']))
self._copy_volume(self.local_path(snapshot), self.local_path(volume),
snapshot['volume_size'])
def delete_volume(self, volume):
"""Deletes a logical volume."""
if self._volume_not_present(volume['name']):
# If the volume isn't present, then don't attempt to delete
return True
# TODO(yamahata): lvm can't delete origin volume only without
# deleting derived snapshots. Can we do something fancy?
out, err = self._execute('lvdisplay', '--noheading',
'-C', '-o', 'Attr',
'%s/%s' % (self.configuration.volume_group,
volume['name']),
run_as_root=True)
# fake_execute returns None resulting unit test error
if out:
out = out.strip()
if (out[0] == 'o') or (out[0] == 'O'):
raise exception.VolumeIsBusy(volume_name=volume['name'])
self._delete_volume(volume, volume['size'])
def clear_volume(self, volume):
"""unprovision old volumes to prevent data leaking between users."""
vol_path = self.local_path(volume)
size_in_g = volume.get('size')
size_in_m = self.configuration.volume_clear_size
if not size_in_g:
return
if self.configuration.volume_clear == 'none':
return
LOG.info(_("Performing secure delete on volume: %s") % volume['id'])
if self.configuration.volume_clear == 'zero':
if size_in_m == 0:
return self._copy_volume('/dev/zero', vol_path, size_in_g,
clearing=True)
else:
clear_cmd = ['shred', '-n0', '-z', '-s%dMiB' % size_in_m]
elif self.configuration.volume_clear == 'shred':
clear_cmd = ['shred', '-n3']
if size_in_m:
clear_cmd.append('-s%dMiB' % size_in_m)
else:
LOG.error(_("Error unrecognized volume_clear option: %s"),
self.configuration.volume_clear)
return
clear_cmd.append(vol_path)
self._execute(*clear_cmd, run_as_root=True)
def create_snapshot(self, snapshot):
"""Creates a snapshot."""
orig_lv_name = "%s/%s" % (self.configuration.volume_group,
snapshot['volume_name'])
self._try_execute('lvcreate', '-L',
self._sizestr(snapshot['volume_size']),
'--name', self._escape_snapshot(snapshot['name']),
'--snapshot', orig_lv_name, run_as_root=True)
def delete_snapshot(self, snapshot):
"""Deletes a snapshot."""
if self._volume_not_present(self._escape_snapshot(snapshot['name'])):
# If the snapshot isn't present, then don't attempt to delete
return True
# TODO(yamahata): zeroing out the whole snapshot triggers COW.
# it's quite slow.
self._delete_volume(snapshot, snapshot['volume_size'])
def local_path(self, volume):
# NOTE(vish): stops deprecation warning
escaped_group = self.configuration.volume_group.replace('-', '--')
escaped_name = self._escape_snapshot(volume['name']).replace('-', '--')
return "/dev/mapper/%s-%s" % (escaped_group, escaped_name)
def copy_image_to_volume(self, context, volume, image_service, image_id):
"""Fetch the image from image_service and write it to the volume."""
image_utils.fetch_to_raw(context,
image_service,
image_id,
self.local_path(volume))
def copy_volume_to_image(self, context, volume, image_service, image_meta):
"""Copy the volume to the specified image."""
image_utils.upload_volume(context,
image_service,
image_meta,
self.local_path(volume))
def create_cloned_volume(self, volume, src_vref):
"""Creates a clone of the specified volume."""
LOG.info(_('Creating clone of volume: %s') % src_vref['id'])
volume_name = FLAGS.volume_name_template % src_vref['id']
temp_id = 'tmp-snap-%s' % src_vref['id']
temp_snapshot = {'volume_name': volume_name,
'size': src_vref['size'],
'volume_size': src_vref['size'],
'name': 'clone-snap-%s' % src_vref['id'],
'id': temp_id}
self.create_snapshot(temp_snapshot)
self._create_volume(volume['name'], self._sizestr(volume['size']))
try:
self._copy_volume(self.local_path(temp_snapshot),
self.local_path(volume),
src_vref['size'])
finally:
self.delete_snapshot(temp_snapshot)
def clone_image(self, volume, image_location):
return False
class LVMISCSIDriver(LVMVolumeDriver, driver.ISCSIDriver):
"""Executes commands relating to ISCSI volumes.
We make use of model provider properties as follows:
``provider_location``
if present, contains the iSCSI target information in the same
format as an ietadm discovery
i.e. '<ip>:<port>,<portal> <target IQN>'
``provider_auth``
if present, contains a space-separated triple:
'<auth method> <auth username> <auth password>'.
`CHAP` is the only auth_method in use at the moment.
"""
def __init__(self, *args, **kwargs):
self.tgtadm = iscsi.get_target_admin()
super(LVMISCSIDriver, self).__init__(*args, **kwargs)
def set_execute(self, execute):
super(LVMISCSIDriver, self).set_execute(execute)
self.tgtadm.set_execute(execute)
def ensure_export(self, context, volume):
"""Synchronously recreates an export for a logical volume."""
# NOTE(jdg): tgtadm doesn't use the iscsi_targets table
# TODO(jdg): In the future move all of the dependent stuff into the
# cooresponding target admin class
if isinstance(self.tgtadm, iscsi.LioAdm):
try:
volume_info = self.db.volume_get(context, volume['id'])
(auth_method,
auth_user,
auth_pass) = volume_info['provider_auth'].split(' ', 3)
chap_auth = self._iscsi_authentication(auth_method,
auth_user,
auth_pass)
except exception.NotFound:
LOG.debug("volume_info:", volume_info)
LOG.info(_("Skipping ensure_export. No iscsi_target "
"provision for volume: %s"), volume['id'])
return
iscsi_name = "%s%s" % (FLAGS.iscsi_target_prefix, volume['name'])
volume_path = "/dev/%s/%s" % (FLAGS.volume_group, volume['name'])
iscsi_target = 1
self.tgtadm.create_iscsi_target(iscsi_name, iscsi_target,
0, volume_path, chap_auth,
check_exit_code=False)
return
if not isinstance(self.tgtadm, iscsi.TgtAdm):
try:
iscsi_target = self.db.volume_get_iscsi_target_num(
context,
volume['id'])
except exception.NotFound:
LOG.info(_("Skipping ensure_export. No iscsi_target "
"provisioned for volume: %s"), volume['id'])
return
else:
iscsi_target = 1 # dummy value when using TgtAdm
chap_auth = None
# Check for https://bugs.launchpad.net/cinder/+bug/1065702
old_name = None
volume_name = volume['name']
if (volume['provider_location'] is not None and
volume['name'] not in volume['provider_location']):
msg = _('Detected inconsistency in provider_location id')
LOG.debug(msg)
old_name = self._fix_id_migration(context, volume)
if 'in-use' in volume['status']:
volume_name = old_name
old_name = None
iscsi_name = "%s%s" % (self.configuration.iscsi_target_prefix,
volume_name)
volume_path = "/dev/%s/%s" % (self.configuration.volume_group,
volume_name)
# NOTE(jdg): For TgtAdm case iscsi_name is the ONLY param we need
# should clean this all up at some point in the future
self.tgtadm.create_iscsi_target(iscsi_name, iscsi_target,
0, volume_path, chap_auth,
check_exit_code=False,
old_name=old_name)
def _fix_id_migration(self, context, volume):
"""Fix provider_location and dev files to address bug 1065702.
For volumes that the provider_location has NOT been updated
and are not currently in-use we'll create a new iscsi target
and remove the persist file.
If the volume is in-use, we'll just stick with the old name
and when detach is called we'll feed back into ensure_export
again if necessary and fix things up then.
Details at: https://bugs.launchpad.net/cinder/+bug/1065702
"""
model_update = {}
pattern = re.compile(r":|\s")
fields = pattern.split(volume['provider_location'])
old_name = fields[3]
volume['provider_location'] = \
volume['provider_location'].replace(old_name, volume['name'])
model_update['provider_location'] = volume['provider_location']
self.db.volume_update(context, volume['id'], model_update)
start = os.getcwd()
os.chdir('/dev/%s' % self.configuration.volume_group)
try:
(out, err) = self._execute('readlink', old_name)
except exception.ProcessExecutionError:
link_path = '/dev/%s/%s' % (self.configuration.volume_group,
old_name)
LOG.debug(_('Symbolic link %s not found') % link_path)
os.chdir(start)
return
rel_path = out.rstrip()
self._execute('ln',
'-s',
rel_path, volume['name'],
run_as_root=True)
os.chdir(start)
return old_name
def _ensure_iscsi_targets(self, context, host):
"""Ensure that target ids have been created in datastore."""
# NOTE(jdg): tgtadm doesn't use the iscsi_targets table
# TODO(jdg): In the future move all of the dependent stuff into the
# cooresponding target admin class
if not isinstance(self.tgtadm, iscsi.TgtAdm):
host_iscsi_targets = self.db.iscsi_target_count_by_host(context,
host)
if host_iscsi_targets >= self.configuration.iscsi_num_targets:
return
# NOTE(vish): Target ids start at 1, not 0.
target_end = self.configuration.iscsi_num_targets + 1
for target_num in xrange(1, target_end):
target = {'host': host, 'target_num': target_num}
self.db.iscsi_target_create_safe(context, target)
def create_export(self, context, volume):
"""Creates an export for a logical volume."""
iscsi_name = "%s%s" % (self.configuration.iscsi_target_prefix,
volume['name'])
volume_path = "/dev/%s/%s" % (self.configuration.volume_group,
volume['name'])
model_update = {}
# TODO(jdg): In the future move all of the dependent stuff into the
# cooresponding target admin class
if not isinstance(self.tgtadm, iscsi.TgtAdm):
lun = 0
self._ensure_iscsi_targets(context, volume['host'])
iscsi_target = self.db.volume_allocate_iscsi_target(context,
volume['id'],
volume['host'])
else:
lun = 1 # For tgtadm the controller is lun 0, dev starts at lun 1
iscsi_target = 0 # NOTE(jdg): Not used by tgtadm
# Use the same method to generate the username and the password.
chap_username = utils.generate_username()
chap_password = utils.generate_password()
chap_auth = self._iscsi_authentication('IncomingUser', chap_username,
chap_password)
# NOTE(jdg): For TgtAdm case iscsi_name is the ONLY param we need
# should clean this all up at some point in the future
tid = self.tgtadm.create_iscsi_target(iscsi_name,
iscsi_target,
0,
volume_path,
chap_auth)
model_update['provider_location'] = self._iscsi_location(
self.configuration.iscsi_ip_address, tid, iscsi_name, lun)
model_update['provider_auth'] = self._iscsi_authentication(
'CHAP', chap_username, chap_password)
return model_update
def remove_export(self, context, volume):
"""Removes an export for a logical volume."""
# NOTE(jdg): tgtadm doesn't use the iscsi_targets table
# TODO(jdg): In the future move all of the dependent stuff into the
# cooresponding target admin class
if isinstance(self.tgtadm, iscsi.LioAdm):
try:
iscsi_target = self.db.volume_get_iscsi_target_num(
context,
volume['id'])
except exception.NotFound:
LOG.info(_("Skipping remove_export. No iscsi_target "
"provisioned for volume: %s"), volume['id'])
return
self.tgtadm.remove_iscsi_target(iscsi_target, 0, volume['id'])
return
elif not isinstance(self.tgtadm, iscsi.TgtAdm):
try:
iscsi_target = self.db.volume_get_iscsi_target_num(
context,
volume['id'])
except exception.NotFound:
LOG.info(_("Skipping remove_export. No iscsi_target "
"provisioned for volume: %s"), volume['id'])
return
else:
iscsi_target = 0
try:
# NOTE: provider_location may be unset if the volume hasn't
# been exported
location = volume['provider_location'].split(' ')
iqn = location[1]
# ietadm show will exit with an error
# this export has already been removed
self.tgtadm.show_target(iscsi_target, iqn=iqn)
except Exception as e:
LOG.info(_("Skipping remove_export. No iscsi_target "
"is presently exported for volume: %s"), volume['id'])
return
self.tgtadm.remove_iscsi_target(iscsi_target, 0, volume['id'])
def get_volume_stats(self, refresh=False):
"""Get volume status.
If 'refresh' is True, run update the stats first."""
if refresh:
self._update_volume_status()
return self._stats
def _update_volume_status(self):
"""Retrieve status info from volume group."""
LOG.debug(_("Updating volume status"))
data = {}
# Note(zhiteng): These information are driver/backend specific,
# each driver may define these values in its own config options
# or fetch from driver specific configuration file.
backend_name = self.configuration.safe_get('volume_backend_name')
data["volume_backend_name"] = backend_name or 'LVM_iSCSI'
data["vendor_name"] = 'Open Source'
data["driver_version"] = '1.0'
data["storage_protocol"] = 'iSCSI'
data['total_capacity_gb'] = 0
data['free_capacity_gb'] = 0
data['reserved_percentage'] = self.configuration.reserved_percentage
data['QoS_support'] = False
try:
out, err = self._execute('vgs', '--noheadings', '--nosuffix',
'--unit=G', '-o', 'name,size,free',
self.configuration.volume_group,
run_as_root=True)
except exception.ProcessExecutionError as exc:
LOG.error(_("Error retrieving volume status: "), exc.stderr)
out = False
if out:
volume = out.split()
data['total_capacity_gb'] = float(volume[1])
data['free_capacity_gb'] = float(volume[2])
self._stats = data
def _iscsi_location(self, ip, target, iqn, lun=None):
return "%s:%s,%s %s %s" % (ip, self.configuration.iscsi_port,
target, iqn, lun)
def _iscsi_authentication(self, chap, name, password):
return "%s %s %s" % (chap, name, password)
class ThinLVMVolumeDriver(LVMISCSIDriver):
"""Subclass for thin provisioned LVM's."""
def __init__(self, *args, **kwargs):
super(ThinLVMVolumeDriver, self).__init__(*args, **kwargs)
def check_for_setup_error(self):
"""Returns an error if prerequisites aren't met"""
out, err = self._execute('lvs', '--option',
'name', '--noheadings',
run_as_root=True)
pool_name = "%s-pool" % FLAGS.volume_group
if pool_name not in out:
if not FLAGS.pool_size:
out, err = self._execute('vgs', FLAGS.volume_group,
'--noheadings', '--options',
'name,size', run_as_root=True)
size = re.sub(r'[\.][\d][\d]', '', out.split()[1])
else:
size = "%s" % FLAGS.pool_size
pool_path = '%s/%s' % (FLAGS.volume_group, pool_name)
out, err = self._execute('lvcreate', '-T', '-L', size,
pool_path, run_as_root=True)
def _do_lvm_snapshot(self, src_lvm_name, dest_vref, is_cinder_snap=True):
if is_cinder_snap:
new_name = self._escape_snapshot(dest_vref['name'])
else:
new_name = dest_vref['name']
self._try_execute('lvcreate', '-s', '-n', new_name,
src_lvm_name, run_as_root=True)
def create_volume(self, volume):
"""Creates a logical volume. Can optionally return a Dictionary of
changes to the volume object to be persisted."""
sizestr = self._sizestr(volume['size'])
vg_name = ("%s/%s-pool" % (FLAGS.volume_group, FLAGS.volume_group))
self._try_execute('lvcreate', '-T', '-V', sizestr, '-n',
volume['name'], vg_name, run_as_root=True)
def delete_volume(self, volume):
"""Deletes a logical volume."""
if self._volume_not_present(volume['name']):
return True
self._try_execute('lvremove', '-f', "%s/%s" %
(FLAGS.volume_group,
self._escape_snapshot(volume['name'])),
run_as_root=True)
def create_cloned_volume(self, volume, src_vref):
"""Creates a clone of the specified volume."""
LOG.info(_('Creating clone of volume: %s') % src_vref['id'])
orig_lv_name = "%s/%s" % (FLAGS.volume_group, src_vref['name'])
self._do_lvm_snapshot(orig_lv_name, volume, False)
def create_snapshot(self, snapshot):
"""Creates a snapshot of a volume."""
orig_lv_name = "%s/%s" % (FLAGS.volume_group, snapshot['volume_name'])
self._do_lvm_snapshot(orig_lv_name, snapshot)