nova/nova/virt/configdrive.py

188 lines
6.4 KiB
Python

# Copyright 2012 Michael Still and Canonical Inc
# 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.
"""Config Drive v2 helper."""
import os
import shutil
from oslo.config import cfg
from oslo.utils import strutils
from oslo.utils import units
from nova import exception
from nova.i18n import _LW
from nova.openstack.common import fileutils
from nova.openstack.common import log as logging
from nova import utils
from nova import version
LOG = logging.getLogger(__name__)
configdrive_opts = [
cfg.StrOpt('config_drive_format',
default='iso9660',
help='Config drive format. One of iso9660 (default) or vfat'),
# force_config_drive is a string option, to allow for future behaviors
# (e.g. use config_drive based on image properties)
cfg.StrOpt('force_config_drive',
help='Set to force injection to take place on a config drive '
'(if set, valid options are: always)'),
cfg.StrOpt('mkisofs_cmd',
default='genisoimage',
help='Name and optionally path of the tool used for '
'ISO image creation')
]
CONF = cfg.CONF
CONF.register_opts(configdrive_opts)
# Config drives are 64mb, if we can't size to the exact size of the data
CONFIGDRIVESIZE_BYTES = 64 * units.Mi
class ConfigDriveBuilder(object):
"""Build config drives, optionally as a context manager."""
def __init__(self, instance_md=None):
self.imagefile = None
self.mdfiles = []
if instance_md is not None:
self.add_instance_metadata(instance_md)
def __enter__(self):
return self
def __exit__(self, exctype, excval, exctb):
if exctype is not None:
# NOTE(mikal): this means we're being cleaned up because an
# exception was thrown. All bets are off now, and we should not
# swallow the exception
return False
self.cleanup()
def _add_file(self, basedir, path, data):
filepath = os.path.join(basedir, path)
dirname = os.path.dirname(filepath)
fileutils.ensure_tree(dirname)
with open(filepath, 'wb') as f:
f.write(data)
def add_instance_metadata(self, instance_md):
for (path, data) in instance_md.metadata_for_config_drive():
self.mdfiles.append((path, data))
def _write_md_files(self, basedir):
for data in self.mdfiles:
self._add_file(basedir, data[0], data[1])
def _make_iso9660(self, path, tmpdir):
publisher = "%(product)s %(version)s" % {
'product': version.product_string(),
'version': version.version_string_with_package()
}
utils.execute(CONF.mkisofs_cmd,
'-o', path,
'-ldots',
'-allow-lowercase',
'-allow-multidot',
'-l',
'-publisher',
publisher,
'-quiet',
'-J',
'-r',
'-V', 'config-2',
tmpdir,
attempts=1,
run_as_root=False)
def _make_vfat(self, path, tmpdir):
# NOTE(mikal): This is a little horrible, but I couldn't find an
# equivalent to genisoimage for vfat filesystems.
with open(path, 'wb') as f:
f.truncate(CONFIGDRIVESIZE_BYTES)
utils.mkfs('vfat', path, label='config-2')
with utils.tempdir() as mountdir:
mounted = False
try:
_, err = utils.trycmd(
'mount', '-o', 'loop,uid=%d,gid=%d' % (os.getuid(),
os.getgid()),
path,
mountdir,
run_as_root=True)
if err:
raise exception.ConfigDriveMountFailed(operation='mount',
error=err)
mounted = True
# NOTE(mikal): I can't just use shutils.copytree here,
# because the destination directory already
# exists. This is annoying.
for ent in os.listdir(tmpdir):
shutil.copytree(os.path.join(tmpdir, ent),
os.path.join(mountdir, ent))
finally:
if mounted:
utils.execute('umount', mountdir, run_as_root=True)
def make_drive(self, path):
"""Make the config drive.
:param path: the path to place the config drive image at
:raises ProcessExecuteError if a helper process has failed.
"""
with utils.tempdir() as tmpdir:
self._write_md_files(tmpdir)
if CONF.config_drive_format == 'iso9660':
self._make_iso9660(path, tmpdir)
elif CONF.config_drive_format == 'vfat':
self._make_vfat(path, tmpdir)
else:
raise exception.ConfigDriveUnknownFormat(
format=CONF.config_drive_format)
def cleanup(self):
if self.imagefile:
fileutils.delete_if_exists(self.imagefile)
def __repr__(self):
return "<ConfigDriveBuilder: " + str(self.mdfiles) + ">"
def required_by(instance):
image_prop = utils.instance_sys_meta(instance).get(
utils.SM_IMAGE_PROP_PREFIX + 'img_config_drive', 'optional')
if image_prop not in ['optional', 'mandatory']:
LOG.warning(_LW('Image config drive option %(image_prop)s is invalid '
'and will be ignored'),
{'image_prop': image_prop},
instance=instance)
return (instance.get('config_drive') or
'always' == CONF.force_config_drive or
strutils.bool_from_string(CONF.force_config_drive) or
image_prop == 'mandatory'
)