2af89cfea0
When hosts apply config `CONF.force_config_drive=True`, the existing VMs shouldn't be enforced to must have config drive device. For they may have been cloud-inited via metadata service, and may not need and have any config drive device ever. In contrast, the newly being-built ones should. Instance attr `launched_at` serves as an apparent flag to distinguish the two kinds of VMs. When hard reboots happend, existing VMs skip config drive enforcement, and therefore avoid hitting 'No such file or directory (config drive device)' error. Change-Id: I0558ece92f8657c2f6294e07965c619eb7c8dfcf Closes-Bug: #1827492
183 lines
6.3 KiB
Python
183 lines
6.3 KiB
Python
# Copyright 2012 Michael Still and Canonical 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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"""Config Drive v2 helper."""
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import os
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import shutil
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from oslo_concurrency import processutils
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from oslo_utils import fileutils
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from oslo_utils import units
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import six
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import nova.conf
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from nova import exception
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from nova.objects import fields
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import nova.privsep.fs
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from nova import utils
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from nova import version
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CONF = nova.conf.CONF
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# Config drives are 64mb, if we can't size to the exact size of the data
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CONFIGDRIVESIZE_BYTES = 64 * units.Mi
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class ConfigDriveBuilder(object):
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"""Build config drives, optionally as a context manager."""
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def __init__(self, instance_md=None):
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self.imagefile = None
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self.mdfiles = []
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if instance_md is not None:
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self.add_instance_metadata(instance_md)
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def __enter__(self):
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return self
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def __exit__(self, exctype, excval, exctb):
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if exctype is not None:
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# NOTE(mikal): this means we're being cleaned up because an
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# exception was thrown. All bets are off now, and we should not
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# swallow the exception
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return False
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self.cleanup()
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def _add_file(self, basedir, path, data):
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filepath = os.path.join(basedir, path)
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dirname = os.path.dirname(filepath)
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fileutils.ensure_tree(dirname)
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with open(filepath, 'wb') as f:
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# the given data can be either text or bytes. we can only write
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# bytes into files.
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if isinstance(data, six.text_type):
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data = data.encode('utf-8')
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f.write(data)
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def add_instance_metadata(self, instance_md):
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for (path, data) in instance_md.metadata_for_config_drive():
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self.mdfiles.append((path, data))
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def _write_md_files(self, basedir):
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for data in self.mdfiles:
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self._add_file(basedir, data[0], data[1])
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def _make_iso9660(self, path, tmpdir):
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publisher = "%(product)s %(version)s" % {
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'product': version.product_string(),
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'version': version.version_string_with_package()
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}
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processutils.execute(CONF.mkisofs_cmd,
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'-o', path,
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'-ldots',
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'-allow-lowercase',
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'-allow-multidot',
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'-l',
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'-publisher',
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publisher,
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'-quiet',
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'-J',
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'-r',
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'-V', 'config-2',
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tmpdir,
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attempts=1,
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run_as_root=False)
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def _make_vfat(self, path, tmpdir):
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# NOTE(mikal): This is a little horrible, but I couldn't find an
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# equivalent to genisoimage for vfat filesystems.
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with open(path, 'wb') as f:
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f.truncate(CONFIGDRIVESIZE_BYTES)
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nova.privsep.fs.unprivileged_mkfs('vfat', path, label='config-2')
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with utils.tempdir() as mountdir:
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mounted = False
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try:
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_, err = nova.privsep.fs.mount(
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None, path, mountdir,
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['-o', 'loop,uid=%d,gid=%d' % (os.getuid(), os.getgid())])
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if err:
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raise exception.ConfigDriveMountFailed(operation='mount',
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error=err)
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mounted = True
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# NOTE(mikal): I can't just use shutils.copytree here,
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# because the destination directory already
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# exists. This is annoying.
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for ent in os.listdir(tmpdir):
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shutil.copytree(os.path.join(tmpdir, ent),
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os.path.join(mountdir, ent))
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finally:
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if mounted:
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nova.privsep.fs.umount(mountdir)
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def make_drive(self, path):
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"""Make the config drive.
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:param path: the path to place the config drive image at
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:raises ProcessExecuteError if a helper process has failed.
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"""
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with utils.tempdir() as tmpdir:
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self._write_md_files(tmpdir)
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if CONF.config_drive_format == 'iso9660':
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self._make_iso9660(path, tmpdir)
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elif CONF.config_drive_format == 'vfat':
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self._make_vfat(path, tmpdir)
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else:
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raise exception.ConfigDriveUnknownFormat(
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format=CONF.config_drive_format)
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def cleanup(self):
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if self.imagefile:
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fileutils.delete_if_exists(self.imagefile)
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def __repr__(self):
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return "<ConfigDriveBuilder: " + str(self.mdfiles) + ">"
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def required_by(instance):
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image_prop = instance.image_meta.properties.get(
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"img_config_drive",
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fields.ConfigDrivePolicy.OPTIONAL)
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# NOTE(pandatt): Option CONF.force_config_drive only applies to newly
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# being-built VMs. And already launched VMs shouldn't be forced a config
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# drive, because they may have been cloud-inited via metadata service, and
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# do not need and have any config drive device. The `launched_at` property
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# is an apparent flag to tell VMs being built from launched ones.
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return (instance.config_drive or
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(CONF.force_config_drive and not instance.launched_at) or
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image_prop == fields.ConfigDrivePolicy.MANDATORY
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)
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def update_instance(instance):
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"""Update the instance config_drive setting if necessary
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The image or configuration file settings may override the default instance
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setting. In this case the instance needs to mirror the actual
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virtual machine configuration.
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"""
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if not instance.config_drive and required_by(instance):
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instance.config_drive = True
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