cinder/cinder/volume/drivers/rbd.py

303 lines
12 KiB
Python

# Copyright 2012 OpenStack LLC
#
# 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.
"""
RADOS Block Device Driver
"""
import json
import os
import tempfile
import urllib
from oslo.config import cfg
from cinder import exception
from cinder.image import image_utils
from cinder.openstack.common import log as logging
from cinder import utils
from cinder.volume import driver
LOG = logging.getLogger(__name__)
rbd_opts = [
cfg.StrOpt('rbd_pool',
default='rbd',
help='the RADOS pool in which rbd volumes are stored'),
cfg.StrOpt('rbd_user',
default=None,
help='the RADOS client name for accessing rbd volumes'),
cfg.StrOpt('rbd_secret_uuid',
default=None,
help='the libvirt uuid of the secret for the rbd_user'
'volumes'),
cfg.StrOpt('volume_tmp_dir',
default=None,
help='where to store temporary image files if the volume '
'driver does not write them directly to the volume'), ]
VERSION = '1.0'
class RBDDriver(driver.VolumeDriver):
"""Implements RADOS block device (RBD) volume commands"""
def __init__(self, *args, **kwargs):
super(RBDDriver, self).__init__(*args, **kwargs)
self.configuration.append_config_values(rbd_opts)
self._stats = dict(
volume_backend_name='RBD',
vendor_name='Open Source',
driver_version=VERSION,
storage_protocol='ceph',
total_capacity_gb='unknown',
free_capacity_gb='unknown',
reserved_percentage=0)
def check_for_setup_error(self):
"""Returns an error if prerequisites aren't met"""
(stdout, stderr) = self._execute('rados', 'lspools')
pools = stdout.split("\n")
if self.configuration.rbd_pool not in pools:
exception_message = (_("rbd has no pool %s") %
self.configuration.rbd_pool)
raise exception.VolumeBackendAPIException(data=exception_message)
def _update_volume_stats(self):
stats = dict(
total_capacity_gb='unknown',
free_capacity_gb='unknown')
try:
stdout, _err = self._execute('rados', 'df', '--format', 'json')
new_stats = json.loads(stdout)
total = int(new_stats['total_space']) / 1024 ** 2
free = int(new_stats['total_avail']) / 1024 ** 2
stats['total_capacity_gb'] = total
stats['free_capacity_gb'] = free
except exception.ProcessExecutionError:
# just log and return unknown capacities
LOG.exception(_('error refreshing volume stats'))
self._stats.update(stats)
def get_volume_stats(self, refresh=False):
"""Return the current state of the volume service. If 'refresh' is
True, run the update first."""
if refresh:
self._update_volume_stats()
return self._stats
def _supports_layering(self):
stdout, _ = self._execute('rbd', '--help')
return 'clone' in stdout
def create_cloned_volume(self, volume, src_vref):
raise NotImplementedError()
def create_volume(self, volume):
"""Creates a logical volume."""
if int(volume['size']) == 0:
size = 100
else:
size = int(volume['size']) * 1024
args = ['rbd', 'create',
'--pool', self.configuration.rbd_pool,
'--size', size,
volume['name']]
if self._supports_layering():
args += ['--new-format']
self._try_execute(*args)
def _clone(self, volume, src_pool, src_image, src_snap):
self._try_execute('rbd', 'clone',
'--pool', src_pool,
'--image', src_image,
'--snap', src_snap,
'--dest-pool', self.configuration.rbd_pool,
'--dest', volume['name'])
def _resize(self, volume):
size = int(volume['size']) * 1024
self._try_execute('rbd', 'resize',
'--pool', self.configuration.rbd_pool,
'--image', volume['name'],
'--size', size)
def create_volume_from_snapshot(self, volume, snapshot):
"""Creates a volume from a snapshot."""
self._clone(volume, self.configuration.rbd_pool,
snapshot['volume_name'], snapshot['name'])
if int(volume['size']):
self._resize(volume)
def delete_volume(self, volume):
"""Deletes a logical volume."""
stdout, _ = self._execute('rbd', 'snap', 'ls',
'--pool', self.configuration.rbd_pool,
volume['name'])
if stdout.count('\n') > 1:
raise exception.VolumeIsBusy(volume_name=volume['name'])
self._try_execute('rbd', 'rm',
'--pool', self.configuration.rbd_pool,
volume['name'])
def create_snapshot(self, snapshot):
"""Creates an rbd snapshot"""
self._try_execute('rbd', 'snap', 'create',
'--pool', self.configuration.rbd_pool,
'--snap', snapshot['name'],
snapshot['volume_name'])
if self._supports_layering():
self._try_execute('rbd', 'snap', 'protect',
'--pool', self.configuration.rbd_pool,
'--snap', snapshot['name'],
snapshot['volume_name'])
def delete_snapshot(self, snapshot):
"""Deletes an rbd snapshot"""
if self._supports_layering():
try:
self._try_execute('rbd', 'snap', 'unprotect',
'--pool', self.configuration.rbd_pool,
'--snap', snapshot['name'],
snapshot['volume_name'])
except exception.ProcessExecutionError:
raise exception.SnapshotIsBusy(snapshot_name=snapshot['name'])
self._try_execute('rbd', 'snap', 'rm',
'--pool', self.configuration.rbd_pool,
'--snap', snapshot['name'],
snapshot['volume_name'])
def local_path(self, volume):
"""Returns the path of the rbd volume."""
# This is the same as the remote path
# since qemu accesses it directly.
return "rbd:%s/%s" % (self.configuration.rbd_pool, volume['name'])
def ensure_export(self, context, volume):
"""Synchronously recreates an export for a logical volume."""
pass
def create_export(self, context, volume):
"""Exports the volume"""
pass
def remove_export(self, context, volume):
"""Removes an export for a logical volume"""
pass
def initialize_connection(self, volume, connector):
return {
'driver_volume_type': 'rbd',
'data': {
'name': '%s/%s' % (self.configuration.rbd_pool,
volume['name']),
'auth_enabled': (self.configuration.rbd_secret_uuid
is not None),
'auth_username': self.configuration.rbd_user,
'secret_type': 'ceph',
'secret_uuid': self.configuration.rbd_secret_uuid, }
}
def terminate_connection(self, volume, connector, **kwargs):
pass
def _parse_location(self, location):
prefix = 'rbd://'
if not location.startswith(prefix):
reason = _('Not stored in rbd')
raise exception.ImageUnacceptable(image_id=location, reason=reason)
pieces = map(urllib.unquote, location[len(prefix):].split('/'))
if any(map(lambda p: p == '', pieces)):
reason = _('Blank components')
raise exception.ImageUnacceptable(image_id=location, reason=reason)
if len(pieces) != 4:
reason = _('Not an rbd snapshot')
raise exception.ImageUnacceptable(image_id=location, reason=reason)
return pieces
def _get_fsid(self):
stdout, _ = self._execute('ceph', 'fsid')
return stdout.rstrip('\n')
def _is_cloneable(self, image_location):
try:
fsid, pool, image, snapshot = self._parse_location(image_location)
except exception.ImageUnacceptable:
return False
if self._get_fsid() != fsid:
reason = _('%s is in a different ceph cluster') % image_location
LOG.debug(reason)
return False
# check that we can read the image
try:
self._execute('rbd', 'info',
'--pool', pool,
'--image', image,
'--snap', snapshot)
except exception.ProcessExecutionError:
LOG.debug(_('Unable to read image %s') % image_location)
return False
return True
def clone_image(self, volume, image_location):
if image_location is None or not self._is_cloneable(image_location):
return False
_, pool, image, snapshot = self._parse_location(image_location)
self._clone(volume, pool, image, snapshot)
self._resize(volume)
return True
def _ensure_tmp_exists(self):
tmp_dir = self.configuration.volume_tmp_dir
if tmp_dir and not os.path.exists(tmp_dir):
os.makedirs(tmp_dir)
def copy_image_to_volume(self, context, volume, image_service, image_id):
# TODO(jdurgin): replace with librbd
# this is a temporary hack, since rewriting this driver
# to use librbd would take too long
self._ensure_tmp_exists()
tmp_dir = self.configuration.volume_tmp_dir
with tempfile.NamedTemporaryFile(dir=tmp_dir) as tmp:
image_utils.fetch_to_raw(context, image_service, image_id,
tmp.name)
# import creates the image, so we must remove it first
self._try_execute('rbd', 'rm',
'--pool', self.configuration.rbd_pool,
volume['name'])
args = ['rbd', 'import',
'--pool', self.configuration.rbd_pool,
tmp.name, volume['name']]
if self._supports_layering():
args += ['--new-format']
self._try_execute(*args)
self._resize(volume)
def copy_volume_to_image(self, context, volume, image_service, image_meta):
self._ensure_tmp_exists()
tmp_dir = self.configuration.volume_tmp_dir or '/tmp'
tmp_file = os.path.join(tmp_dir,
volume['name'] + '-' + image_meta['id'])
with utils.remove_path_on_error(tmp_file):
self._try_execute('rbd', 'export',
'--pool', self.configuration.rbd_pool,
volume['name'], tmp_file)
image_utils.upload_volume(context, image_service,
image_meta, tmp_file)
os.unlink(tmp_file)