nova/nova/virt/disk/api.py

584 lines
19 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.
#
# Copyright 2011, Piston Cloud Computing, 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.
"""
Utility methods to resize, repartition, and modify disk images.
Includes injection of SSH PGP keys into authorized_keys file.
"""
import os
import random
import tempfile
if os.name != 'nt':
import crypt
from oslo.config import cfg
from nova import exception
from nova.openstack.common import jsonutils
from nova.openstack.common import log as logging
from nova.openstack.common import processutils
from nova import paths
from nova import utils
from nova.virt.disk.mount import api as mount
from nova.virt.disk.vfs import api as vfs
from nova.virt import images
LOG = logging.getLogger(__name__)
disk_opts = [
cfg.StrOpt('injected_network_template',
default=paths.basedir_def('nova/virt/interfaces.template'),
help='Template file for injected network'),
# NOTE(yamahata): ListOpt won't work because the command may include a
# comma. For example:
#
# mkfs.ext3 -O dir_index,extent -E stride=8,stripe-width=16
# --label %(fs_label)s %(target)s
#
# list arguments are comma separated and there is no way to
# escape such commas.
#
cfg.MultiStrOpt('virt_mkfs',
default=[
'default=mkfs.ext3 -L %(fs_label)s -F %(target)s',
'linux=mkfs.ext3 -L %(fs_label)s -F %(target)s',
'windows=mkfs.ntfs'
' --force --fast --label %(fs_label)s %(target)s',
# NOTE(yamahata): vfat case
#'windows=mkfs.vfat -n %(fs_label)s %(target)s',
],
help='mkfs commands for ephemeral device. '
'The format is <os_type>=<mkfs command>'),
]
CONF = cfg.CONF
CONF.register_opts(disk_opts)
_MKFS_COMMAND = {}
_DEFAULT_MKFS_COMMAND = None
for s in CONF.virt_mkfs:
# NOTE(yamahata): mkfs command may includes '=' for its options.
# So item.partition('=') doesn't work here
os_type, mkfs_command = s.split('=', 1)
if os_type:
_MKFS_COMMAND[os_type] = mkfs_command
if os_type == 'default':
_DEFAULT_MKFS_COMMAND = mkfs_command
def mkfs(os_type, fs_label, target):
mkfs_command = (_MKFS_COMMAND.get(os_type, _DEFAULT_MKFS_COMMAND) or
'') % {'fs_label': fs_label, 'target': target}
if mkfs_command:
utils.execute(*mkfs_command.split(), run_as_root=True)
def resize2fs(image, check_exit_code=False, run_as_root=False):
utils.execute('e2fsck', '-fp', image,
check_exit_code=check_exit_code,
run_as_root=run_as_root)
utils.execute('resize2fs', image,
check_exit_code=check_exit_code,
run_as_root=run_as_root)
def get_disk_size(path):
"""Get the (virtual) size of a disk image
:param path: Path to the disk image
:returns: Size (in bytes) of the given disk image as it would be seen
by a virtual machine.
"""
return images.qemu_img_info(path).virtual_size
def extend(image, size):
"""Increase image to size."""
virt_size = get_disk_size(image)
if virt_size >= size:
return
utils.execute('qemu-img', 'resize', image, size)
# NOTE(vish): attempts to resize filesystem
resize2fs(image)
def can_resize_fs(image, size, use_cow=False):
"""Check whether we can resize contained file system."""
LOG.debug(_('Checking if we can resize image %(image)s. '
'size=%(size)s, CoW=%(use_cow)s'),
{'image': image, 'size': size, 'use_cow': use_cow})
# Check that we're increasing the size
virt_size = get_disk_size(image)
if virt_size >= size:
LOG.debug(_('Cannot resize filesystem %s to a smaller size.'),
image)
return False
# Check the image is unpartitioned
if use_cow:
try:
fs = vfs.VFS.instance_for_image(image, 'qcow2', None)
fs.setup()
fs.teardown()
except exception.NovaException as e:
LOG.debug(_('Unable to mount image %(image)s with '
'error %(error)s. Cannot resize.'),
{'image': image,
'error': e})
return False
else:
# For raw, we can directly inspect the file system
try:
utils.execute('e2label', image)
except processutils.ProcessExecutionError as e:
LOG.debug(_('Unable to determine label for image %(image)s with '
'error %(errror)s. Cannot resize.'),
{'image': image,
'error': e})
return False
return True
class _DiskImage(object):
"""Provide operations on a disk image file."""
tmp_prefix = 'openstack-disk-mount-tmp'
def __init__(self, image, partition=None, use_cow=False, mount_dir=None):
# These passed to each mounter
self.image = image
self.partition = partition
self.mount_dir = mount_dir
self.use_cow = use_cow
# Internal
self._mkdir = False
self._mounter = None
self._errors = []
if mount_dir:
device = self._device_for_path(mount_dir)
if device:
self._reset(device)
@staticmethod
def _device_for_path(path):
device = None
path = os.path.realpath(path)
with open("/proc/mounts", 'r') as ifp:
for line in ifp:
fields = line.split()
if fields[1] == path:
device = fields[0]
break
return device
def _reset(self, device):
"""Reset internal state for a previously mounted directory."""
self._mounter = mount.Mount.instance_for_device(self.image,
self.mount_dir,
self.partition,
device)
mount_name = os.path.basename(self.mount_dir or '')
self._mkdir = mount_name.startswith(self.tmp_prefix)
@property
def errors(self):
"""Return the collated errors from all operations."""
return '\n--\n'.join([''] + self._errors)
def mount(self):
"""Mount a disk image, using the object attributes.
The first supported means provided by the mount classes is used.
True, or False is returned and the 'errors' attribute
contains any diagnostics.
"""
if self._mounter:
raise exception.NovaException(_('image already mounted'))
if not self.mount_dir:
self.mount_dir = tempfile.mkdtemp(prefix=self.tmp_prefix)
self._mkdir = True
imgfmt = "raw"
if self.use_cow:
imgfmt = "qcow2"
mounter = mount.Mount.instance_for_format(self.image,
self.mount_dir,
self.partition,
imgfmt)
if mounter.do_mount():
self._mounter = mounter
else:
LOG.debug(mounter.error)
self._errors.append(mounter.error)
return bool(self._mounter)
def umount(self):
"""Umount a mount point from the filesystem."""
if self._mounter:
self._mounter.do_umount()
self._mounter = None
def teardown(self):
"""Remove a disk image from the file system."""
try:
if self._mounter:
self._mounter.do_teardown()
self._mounter = None
finally:
if self._mkdir:
os.rmdir(self.mount_dir)
# Public module functions
def inject_data(image, key=None, net=None, metadata=None, admin_password=None,
files=None, partition=None, use_cow=False, mandatory=()):
"""Inject the specified items into a disk image.
If an item name is not specified in the MANDATORY iterable, then a warning
is logged on failure to inject that item, rather than raising an exception.
it will mount the image as a fully partitioned disk and attempt to inject
into the specified partition number.
If PARTITION is not specified the image is mounted as a single partition.
Returns True if all requested operations completed without issue.
Raises an exception if a mandatory item can't be injected.
"""
LOG.debug(_("Inject data image=%(image)s key=%(key)s net=%(net)s "
"metadata=%(metadata)s admin_password=<SANITIZED> "
"files=%(files)s partition=%(partition)s use_cow=%(use_cow)s"),
{'image': image, 'key': key, 'net': net, 'metadata': metadata,
'files': files, 'partition': partition, 'use_cow': use_cow})
fmt = "raw"
if use_cow:
fmt = "qcow2"
try:
fs = vfs.VFS.instance_for_image(image, fmt, partition)
fs.setup()
except Exception as e:
# If a mandatory item is passed to this function,
# then reraise the exception to indicate the error.
for inject in mandatory:
inject_val = locals()[inject]
if inject_val:
raise
LOG.warn(_('Ignoring error injecting data into image '
'(%(e)s)'), {'e': e})
return False
try:
return inject_data_into_fs(fs, key, net, metadata,
admin_password, files, mandatory)
finally:
fs.teardown()
def setup_container(image, container_dir, use_cow=False):
"""Setup the LXC container.
It will mount the loopback image to the container directory in order
to create the root filesystem for the container.
"""
img = _DiskImage(image=image, use_cow=use_cow, mount_dir=container_dir)
if not img.mount():
LOG.error(_("Failed to mount container filesystem '%(image)s' "
"on '%(target)s': %(errors)s"),
{"image": img, "target": container_dir,
"errors": img.errors})
raise exception.NovaException(img.errors)
def teardown_container(container_dir):
"""Teardown the container rootfs mounting once it is spawned.
It will umount the container that is mounted,
and delete any linked devices.
"""
try:
img = _DiskImage(image=None, mount_dir=container_dir)
img.teardown()
except Exception as exn:
LOG.exception(_('Failed to teardown ntainer filesystem: %s'), exn)
def clean_lxc_namespace(container_dir):
"""Clean up the container namespace rootfs mounting one spawned.
It will umount the mounted names that is mounted
but leave the linked deivces alone.
"""
try:
img = _DiskImage(image=None, mount_dir=container_dir)
img.umount()
except Exception as exn:
LOG.exception(_('Failed to umount container filesystem: %s'), exn)
def inject_data_into_fs(fs, key, net, metadata, admin_password, files,
mandatory=()):
"""Injects data into a filesystem already mounted by the caller.
Virt connections can call this directly if they mount their fs
in a different way to inject_data.
If an item name is not specified in the MANDATORY iterable, then a warning
is logged on failure to inject that item, rather than raising an exception.
Returns True if all requested operations completed without issue.
Raises an exception if a mandatory item can't be injected.
"""
status = True
for inject in ('key', 'net', 'metadata', 'admin_password', 'files'):
inject_val = locals()[inject]
inject_func = globals()['_inject_%s_into_fs' % inject]
if inject_val:
try:
inject_func(inject_val, fs)
except Exception as e:
if inject in mandatory:
raise
LOG.warn(_('Ignoring error injecting %(inject)s into image '
'(%(e)s)'), {'e': e, 'inject': inject})
status = False
return status
def _inject_files_into_fs(files, fs):
for (path, contents) in files:
_inject_file_into_fs(fs, path, contents)
def _inject_file_into_fs(fs, path, contents, append=False):
LOG.debug(_("Inject file fs=%(fs)s path=%(path)s append=%(append)s"),
{'fs': fs, 'path': path, 'append': append})
if append:
fs.append_file(path, contents)
else:
fs.replace_file(path, contents)
def _inject_metadata_into_fs(metadata, fs):
LOG.debug(_("Inject metadata fs=%(fs)s metadata=%(metadata)s"),
{'fs': fs, 'metadata': metadata})
metadata = dict([(m['key'], m['value']) for m in metadata])
_inject_file_into_fs(fs, 'meta.js', jsonutils.dumps(metadata))
def _setup_selinux_for_keys(fs, sshdir):
"""Get selinux guests to ensure correct context on injected keys."""
if not fs.has_file(os.path.join("etc", "selinux")):
return
rclocal = os.path.join('etc', 'rc.local')
rc_d = os.path.join('etc', 'rc.d')
if not fs.has_file(rclocal) and fs.has_file(rc_d):
rclocal = os.path.join(rc_d, 'rc.local')
# Note some systems end rc.local with "exit 0"
# and so to append there you'd need something like:
# utils.execute('sed', '-i', '${/^exit 0$/d}' rclocal, run_as_root=True)
restorecon = [
'\n',
'# Added by Nova to ensure injected ssh keys have the right context\n',
'restorecon -RF %s 2>/dev/null || :\n' % sshdir,
]
if not fs.has_file(rclocal):
restorecon.insert(0, '#!/bin/sh')
_inject_file_into_fs(fs, rclocal, ''.join(restorecon), append=True)
fs.set_permissions(rclocal, 0o700)
def _inject_key_into_fs(key, fs):
"""Add the given public ssh key to root's authorized_keys.
key is an ssh key string.
fs is the path to the base of the filesystem into which to inject the key.
"""
LOG.debug(_("Inject key fs=%(fs)s key=%(key)s"), {'fs': fs, 'key': key})
sshdir = os.path.join('root', '.ssh')
fs.make_path(sshdir)
fs.set_ownership(sshdir, "root", "root")
fs.set_permissions(sshdir, 0o700)
keyfile = os.path.join(sshdir, 'authorized_keys')
key_data = ''.join([
'\n',
'# The following ssh key was injected by Nova',
'\n',
key.strip(),
'\n',
])
_inject_file_into_fs(fs, keyfile, key_data, append=True)
fs.set_permissions(keyfile, 0o600)
_setup_selinux_for_keys(fs, sshdir)
def _inject_net_into_fs(net, fs):
"""Inject /etc/network/interfaces into the filesystem rooted at fs.
net is the contents of /etc/network/interfaces.
"""
LOG.debug(_("Inject key fs=%(fs)s net=%(net)s"), {'fs': fs, 'net': net})
netdir = os.path.join('etc', 'network')
fs.make_path(netdir)
fs.set_ownership(netdir, "root", "root")
fs.set_permissions(netdir, 0o744)
netfile = os.path.join('etc', 'network', 'interfaces')
_inject_file_into_fs(fs, netfile, net)
def _inject_admin_password_into_fs(admin_passwd, fs):
"""Set the root password to admin_passwd
admin_password is a root password
fs is the path to the base of the filesystem into which to inject
the key.
This method modifies the instance filesystem directly,
and does not require a guest agent running in the instance.
"""
# The approach used here is to copy the password and shadow
# files from the instance filesystem to local files, make any
# necessary changes, and then copy them back.
LOG.debug(_("Inject admin password fs=%(fs)s "
"admin_passwd=<SANITIZED>"), {'fs': fs})
admin_user = 'root'
fd, tmp_passwd = tempfile.mkstemp()
os.close(fd)
fd, tmp_shadow = tempfile.mkstemp()
os.close(fd)
passwd_path = os.path.join('etc', 'passwd')
shadow_path = os.path.join('etc', 'shadow')
passwd_data = fs.read_file(passwd_path)
shadow_data = fs.read_file(shadow_path)
new_shadow_data = _set_passwd(admin_user, admin_passwd,
passwd_data, shadow_data)
fs.replace_file(shadow_path, new_shadow_data)
def _generate_salt():
salt_set = ('abcdefghijklmnopqrstuvwxyz'
'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
'0123456789./')
salt = 16 * ' '
return ''.join([random.choice(salt_set) for c in salt])
def _set_passwd(username, admin_passwd, passwd_data, shadow_data):
"""set the password for username to admin_passwd
The passwd_file is not modified. The shadow_file is updated.
if the username is not found in both files, an exception is raised.
:param username: the username
:param encrypted_passwd: the encrypted password
:param passwd_file: path to the passwd file
:param shadow_file: path to the shadow password file
:returns: nothing
:raises: exception.NovaException(), IOError()
"""
if os.name == 'nt':
raise exception.NovaException(_('Not implemented on Windows'))
# encryption algo - id pairs for crypt()
algos = {'SHA-512': '$6$', 'SHA-256': '$5$', 'MD5': '$1$', 'DES': ''}
salt = _generate_salt()
# crypt() depends on the underlying libc, and may not support all
# forms of hash. We try md5 first. If we get only 13 characters back,
# then the underlying crypt() didn't understand the '$n$salt' magic,
# so we fall back to DES.
# md5 is the default because it's widely supported. Although the
# local crypt() might support stronger SHA, the target instance
# might not.
encrypted_passwd = crypt.crypt(admin_passwd, algos['MD5'] + salt)
if len(encrypted_passwd) == 13:
encrypted_passwd = crypt.crypt(admin_passwd, algos['DES'] + salt)
p_file = passwd_data.split("\n")
s_file = shadow_data.split("\n")
# username MUST exist in passwd file or it's an error
found = False
for entry in p_file:
split_entry = entry.split(':')
if split_entry[0] == username:
found = True
break
if not found:
msg = _('User %(username)s not found in password file.')
raise exception.NovaException(msg % username)
# update password in the shadow file.It's an error if the
# the user doesn't exist.
new_shadow = list()
found = False
for entry in s_file:
split_entry = entry.split(':')
if split_entry[0] == username:
split_entry[1] = encrypted_passwd
found = True
new_entry = ':'.join(split_entry)
new_shadow.append(new_entry)
if not found:
msg = _('User %(username)s not found in shadow file.')
raise exception.NovaException(msg % username)
return "\n".join(new_shadow)