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# Copyright (C) 2011 Canonical Ltd.
# Copyright (C) 2013 Hewlett-Packard Development Company, L.P.
#
# Author: Scott Moser <scott.moser@canonical.com>
# Author: Juerg Haefliger <juerg.haefliger@hp.com>
#
# This file is part of cloud-init. See LICENSE file for license information.
"""Growpart: Grow partitions"""
import base64
import copy
import json
import logging
import os
import os.path
import re
import stat
from abc import ABC, abstractmethod
from contextlib import suppress
from pathlib import Path
from textwrap import dedent
from typing import Optional, Tuple
from cloudinit import subp, temp_utils, util
from cloudinit.cloud import Cloud
from cloudinit.config import Config
from cloudinit.config.schema import MetaSchema, get_meta_doc
from cloudinit.distros import ALL_DISTROS, Distro
from cloudinit.settings import PER_ALWAYS
MODULE_DESCRIPTION = """\
Growpart resizes partitions to fill the available disk space.
This is useful for cloud instances with a larger amount of disk space available
than the pristine image uses, as it allows the instance to automatically make
use of the extra space. Note that this only works if the partition to be
resized is the last one on a disk with classic partitioning scheme (MBR, BSD,
GPT). LVM, Btrfs and ZFS have no such restrictions.
The devices on which to run growpart are specified as a list under the
``devices`` key.
There is some functionality overlap between this module and the ``growroot``
functionality of ``cloud-initramfs-tools``. However, there are some situations
where one tool is able to function and the other is not. The default
configuration for both should work for most cloud instances. To explicitly
prevent ``cloud-initramfs-tools`` from running ``growroot``, the file
``/etc/growroot-disabled`` can be created. By default, both ``growroot`` and
``cc_growpart`` will check for the existence of this file and will not run if
it is present. However, this file can be ignored for ``cc_growpart`` by setting
``ignore_growroot_disabled`` to ``true``. For more information on
``cloud-initramfs-tools`` see: https://launchpad.net/cloud-initramfs-tools
On FreeBSD, there is also the ``growfs`` service, which has a lot of overlap
with ``cc_growpart`` and ``cc_resizefs``, but only works on the root partition.
In that configuration, we use it, otherwise, we fall back to ``gpart``.
Note however, that ``growfs`` may insert a swap partition, if none is present,
unless instructed not to via ``growfs_swap_size=0`` in either ``kenv(1)``, or
``rc.conf(5)``.
Growpart is enabled by default on the root partition. The default config for
growpart is::
growpart:
mode: auto
devices: ["/"]
ignore_growroot_disabled: false
"""
frequency = PER_ALWAYS
meta: MetaSchema = {
"id": "cc_growpart",
"name": "Growpart",
"title": "Grow partitions",
"description": MODULE_DESCRIPTION,
"distros": [ALL_DISTROS],
"frequency": frequency,
"examples": [
dedent(
"""\
growpart:
mode: auto
devices: ["/"]
ignore_growroot_disabled: false
"""
),
dedent(
"""\
growpart:
mode: growpart
devices:
- "/"
- "/dev/vdb1"
ignore_growroot_disabled: true
"""
),
],
"activate_by_schema_keys": [],
}
__doc__ = get_meta_doc(meta)
DEFAULT_CONFIG = {
"mode": "auto",
"devices": ["/"],
"ignore_growroot_disabled": False,
}
KEYDATA_PATH = Path("/cc_growpart_keydata")
class RESIZE:
SKIPPED = "SKIPPED"
CHANGED = "CHANGED"
NOCHANGE = "NOCHANGE"
FAILED = "FAILED"
LOG = logging.getLogger(__name__)
def resizer_factory(mode: str, distro: Distro, devices: list):
resize_class = None
if mode == "auto":
for _name, resizer in RESIZERS:
cur = resizer(distro)
if cur.available(devices=devices):
resize_class = cur
break
if not resize_class:
raise ValueError("No resizers available")
else:
mmap = {}
for k, v in RESIZERS:
mmap[k] = v
if mode not in mmap:
raise TypeError("unknown resize mode %s" % mode)
mclass = mmap[mode](distro)
if mclass.available(devices=devices):
resize_class = mclass
if not resize_class:
raise ValueError("mode %s not available" % mode)
return resize_class
class ResizeFailedException(Exception):
pass
class Resizer(ABC):
def __init__(self, distro: Distro):
self._distro = distro
@abstractmethod
def available(self, devices: list) -> bool:
...
@abstractmethod
def resize(self, diskdev, partnum, partdev):
...
class ResizeGrowPart(Resizer):
def available(self, devices: list):
try:
out = subp.subp(
["growpart", "--help"], update_env={"LANG": "C"}
).stdout
if re.search(r"--update\s+", out):
return True
except subp.ProcessExecutionError:
pass
return False
def resize(self, diskdev, partnum, partdev):
before = get_size(partdev)
# growpart uses tmp dir to store intermediate states
# and may conflict with systemd-tmpfiles-clean
tmp_dir = self._distro.get_tmp_exec_path()
with temp_utils.tempdir(dir=tmp_dir, needs_exe=True) as tmpd:
growpart_tmp = os.path.join(tmpd, "growpart")
my_env = {"LANG": "C", "TMPDIR": growpart_tmp}
if not os.path.exists(growpart_tmp):
os.mkdir(growpart_tmp, 0o700)
try:
subp.subp(
["growpart", "--dry-run", diskdev, partnum],
update_env=my_env,
)
except subp.ProcessExecutionError as e:
if e.exit_code != 1:
util.logexc(
LOG,
"Failed growpart --dry-run for (%s, %s)",
diskdev,
partnum,
)
raise ResizeFailedException(e) from e
return (before, before)
try:
subp.subp(["growpart", diskdev, partnum], update_env=my_env)
except subp.ProcessExecutionError as e:
util.logexc(LOG, "Failed: growpart %s %s", diskdev, partnum)
raise ResizeFailedException(e) from e
return (before, get_size(partdev))
class ResizeGrowFS(Resizer):
"""
Use FreeBSD ``growfs`` service to grow root partition to fill available
space, optionally adding a swap partition at the end.
Note that the service file warns us that it uses ``awk(1)``, and as
such requires ``/usr`` to be present. However, cloud-init is installed
into ``/usr/local``, so we should be fine.
We invoke the ``growfs`` with ``service growfs onestart``, so it
doesn't need to be enabled in ``rc.conf``.
"""
def available(self, devices: list):
"""growfs only works on the root partition"""
return os.path.isfile("/etc/rc.d/growfs") and devices == ["/"]
def resize(self, diskdev, partnum, partdev):
before = get_size(partdev)
try:
self._distro.manage_service(action="onestart", service="growfs")
except subp.ProcessExecutionError as e:
util.logexc(LOG, "Failed: service growfs onestart")
raise ResizeFailedException(e) from e
return (before, get_size(partdev))
class ResizeGpart(Resizer):
def available(self, devices: list):
try:
err = subp.subp(
["gpart", "help"], update_env={"LANG": "C"}, rcs=[0, 1]
).stderr
if re.search(r"gpart recover ", err):
return True
except subp.ProcessExecutionError:
pass
return False
def resize(self, diskdev, partnum, partdev):
"""
GPT disks store metadata at the beginning (primary) and at the
end (secondary) of the disk. When launching an image with a
larger disk compared to the original image, the secondary copy
is lost. Thus, the metadata will be marked CORRUPT, and need to
be recovered.
"""
try:
subp.subp(["gpart", "recover", diskdev])
except subp.ProcessExecutionError as e:
if e.exit_code != 0:
util.logexc(LOG, "Failed: gpart recover %s", diskdev)
raise ResizeFailedException(e) from e
before = get_size(partdev)
try:
subp.subp(["gpart", "resize", "-i", partnum, diskdev])
except subp.ProcessExecutionError as e:
util.logexc(LOG, "Failed: gpart resize -i %s %s", partnum, diskdev)
raise ResizeFailedException(e) from e
return (before, get_size(partdev))
def get_size(filename) -> Optional[int]:
fd = None
try:
fd = os.open(filename, os.O_RDONLY)
return os.lseek(fd, 0, os.SEEK_END)
except FileNotFoundError:
return None
finally:
if fd:
os.close(fd)
def device_part_info(devpath):
# convert an entry in /dev/ to parent disk and partition number
# input of /dev/vdb or /dev/disk/by-label/foo
# rpath is hopefully a real-ish path in /dev (vda, sdb..)
rpath = os.path.realpath(devpath)
bname = os.path.basename(rpath)
syspath = "/sys/class/block/%s" % bname
if util.is_BSD():
# FreeBSD doesn't know of sysfs so just get everything we need from
# the device, like /dev/vtbd0p2.
fpart = "/dev/" + util.find_freebsd_part(devpath)
# Handle both GPT partitions and MBR slices with partitions
m = re.search(
r"^(?P<dev>/dev/.+)[sp](?P<part_slice>\d+[a-z]*)$", fpart
)
if m:
return m["dev"], m["part_slice"]
if not os.path.exists(syspath):
raise ValueError("%s had no syspath (%s)" % (devpath, syspath))
ptpath = os.path.join(syspath, "partition")
if not os.path.exists(ptpath):
raise TypeError("%s not a partition" % devpath)
ptnum = util.load_text_file(ptpath).rstrip()
# for a partition, real syspath is something like:
# /sys/devices/pci0000:00/0000:00:04.0/virtio1/block/vda/vda1
rsyspath = os.path.realpath(syspath)
disksyspath = os.path.dirname(rsyspath)
diskmajmin = util.load_text_file(os.path.join(disksyspath, "dev")).rstrip()
diskdevpath = os.path.realpath("/dev/block/%s" % diskmajmin)
# diskdevpath has something like 253:0
# and udev has put links in /dev/block/253:0 to the device name in /dev/
return (diskdevpath, ptnum)
def devent2dev(devent):
if devent.startswith("/dev/"):
return devent
else:
result = util.get_mount_info(devent)
if not result:
raise ValueError("Could not determine device of '%s' % dev_ent")
dev = result[0]
container = util.is_container()
# Ensure the path is a block device.
if dev == "/dev/root" and not container:
dev = util.rootdev_from_cmdline(util.get_cmdline())
if dev is None:
if os.path.exists(dev):
# if /dev/root exists, but we failed to convert
# that to a "real" /dev/ path device, then return it.
return dev
raise ValueError("Unable to find device '/dev/root'")
return dev
def get_mapped_device(blockdev, distro_name):
"""Returns underlying block device for a mapped device.
If it is mapped, blockdev will usually take the form of
/dev/mapper/some_name
If blockdev is a symlink pointing to a /dev/dm-* device, return
the device pointed to. Otherwise, return None.
"""
realpath = os.path.realpath(blockdev)
if distro_name == "alpine":
if blockdev.startswith("/dev/mapper"):
# For Alpine systems a /dev/mapper/ entry is *not* a
# symlink to the related /dev/dm-X block device,
# rather it is a block device itself.
# Get the major/minor of the /dev/mapper block device
major = os.major(os.stat(blockdev).st_rdev)
minor = os.minor(os.stat(blockdev).st_rdev)
# Find the /dev/dm-X device with the same major/minor
with os.scandir("/dev/") as it:
for deventry in it:
if deventry.name.startswith("dm-"):
res = os.lstat(deventry.path)
if stat.S_ISBLK(res.st_mode):
if (
os.major(os.stat(deventry.path).st_rdev)
== major
and os.minor(os.stat(deventry.path).st_rdev)
== minor
):
realpath = os.path.realpath(deventry.path)
break
if realpath.startswith("/dev/dm-"):
LOG.debug("%s is a mapped device pointing to %s", blockdev, realpath)
return realpath
return None
def is_encrypted(blockdev, partition) -> bool:
"""
Check if a device is an encrypted device. blockdev should have
a /dev/dm-* path whereas partition is something like /dev/sda1.
"""
if not subp.which("cryptsetup"):
LOG.debug("cryptsetup not found. Assuming no encrypted partitions")
return False
try:
subp.subp(["cryptsetup", "status", blockdev])
except subp.ProcessExecutionError as e:
if e.exit_code == 4:
LOG.debug("Determined that %s is not encrypted", blockdev)
else:
LOG.warning(
"Received unexpected exit code %s from "
"cryptsetup status. Assuming no encrypted partitions.",
e.exit_code,
)
return False
with suppress(subp.ProcessExecutionError):
subp.subp(["cryptsetup", "isLuks", partition])
LOG.debug("Determined that %s is encrypted", blockdev)
return True
return False
def get_underlying_partition(blockdev):
command = ["dmsetup", "deps", "--options=devname", blockdev]
dep: str = subp.subp(command)[0] # pyright: ignore
# Returned result should look something like:
# 1 dependencies : (vdb1)
if not dep.startswith("1 depend"):
raise RuntimeError(
f"Expecting '1 dependencies' from 'dmsetup'. Received: {dep}"
)
try:
return f'/dev/{dep.split(": (")[1].split(")")[0]}'
except IndexError as e:
raise RuntimeError(
f"Ran `{command}`, but received unexpected stdout: `{dep}`"
) from e
def resize_encrypted(blockdev, partition) -> Tuple[str, str]:
"""Use 'cryptsetup resize' to resize LUKS volume.
The loaded keyfile is json formatted with 'key' and 'slot' keys.
key is base64 encoded. Example:
{"key":"XFmCwX2FHIQp0LBWaLEMiHIyfxt1SGm16VvUAVledlY=","slot":5}
"""
if not KEYDATA_PATH.exists():
return (RESIZE.SKIPPED, "No encryption keyfile found")
try:
with KEYDATA_PATH.open() as f:
keydata = json.load(f)
key = keydata["key"]
decoded_key = base64.b64decode(key)
slot = keydata["slot"]
except Exception as e:
raise RuntimeError(
"Could not load encryption key. This is expected if "
"the volume has been previously resized."
) from e
try:
subp.subp(
["cryptsetup", "--key-file", "-", "resize", blockdev],
data=decoded_key,
)
finally:
try:
subp.subp(
[
"cryptsetup",
"luksKillSlot",
"--batch-mode",
partition,
str(slot),
]
)
except subp.ProcessExecutionError as e:
LOG.warning(
"Failed to kill luks slot after resizing encrypted volume: %s",
e,
)
try:
KEYDATA_PATH.unlink()
except Exception:
util.logexc(
LOG, "Failed to remove keyfile after resizing encrypted volume"
)
return (
RESIZE.CHANGED,
f"Successfully resized encrypted volume '{blockdev}'",
)
def resize_devices(resizer, devices, distro_name):
# returns a tuple of tuples containing (entry-in-devices, action, message)
devices = copy.copy(devices)
info = []
while devices:
devent = devices.pop(0)
try:
blockdev = devent2dev(devent)
except ValueError as e:
info.append(
(
devent,
RESIZE.SKIPPED,
"unable to convert to device: %s" % e,
)
)
continue
try:
statret = os.stat(blockdev)
except OSError as e:
info.append(
(
devent,
RESIZE.SKIPPED,
"stat of '%s' failed: %s" % (blockdev, e),
)
)
continue
if not stat.S_ISBLK(statret.st_mode) and not stat.S_ISCHR(
statret.st_mode
):
info.append(
(
devent,
RESIZE.SKIPPED,
"device '%s' not a block device" % blockdev,
)
)
continue
underlying_blockdev = get_mapped_device(blockdev, distro_name)
if underlying_blockdev:
try:
# We need to resize the underlying partition first
partition = get_underlying_partition(blockdev)
if is_encrypted(underlying_blockdev, partition):
if partition not in [x[0] for x in info]:
# We shouldn't attempt to resize this mapped partition
# until the underlying partition is resized, so re-add
# our device to the beginning of the list we're
# iterating over, then add our underlying partition
# so it can get processed first
devices.insert(0, devent)
devices.insert(0, partition)
continue
status, message = resize_encrypted(blockdev, partition)
info.append(
(
devent,
status,
message,
)
)
else:
info.append(
(
devent,
RESIZE.SKIPPED,
f"Resizing mapped device ({blockdev}) skipped "
"as it is not encrypted.",
)
)
except Exception as e:
info.append(
(
devent,
RESIZE.FAILED,
f"Resizing encrypted device ({blockdev}) failed: {e}",
)
)
# At this point, we WON'T resize a non-encrypted mapped device
# though we should probably grow the ability to
continue
try:
(disk, ptnum) = device_part_info(blockdev)
except (TypeError, ValueError) as e:
info.append(
(
devent,
RESIZE.SKIPPED,
"device_part_info(%s) failed: %s" % (blockdev, e),
)
)
continue
try:
old, new = resizer.resize(disk, ptnum, blockdev)
if old == new:
info.append(
(
devent,
RESIZE.NOCHANGE,
"no change necessary (%s, %s)" % (disk, ptnum),
)
)
elif new is None or old is None:
info.append(
(
devent,
RESIZE.CHANGED,
"changed (%s, %s) size, new size is unknown"
% (disk, ptnum),
)
)
else:
info.append(
(
devent,
RESIZE.CHANGED,
"changed (%s, %s) from %s to %s"
% (disk, ptnum, old, new),
)
)
except ResizeFailedException as e:
info.append(
(
devent,
RESIZE.FAILED,
"failed to resize: disk=%s, ptnum=%s: %s"
% (disk, ptnum, e),
)
)
return info
def handle(name: str, cfg: Config, cloud: Cloud, args: list) -> None:
if "growpart" not in cfg:
LOG.debug(
"No 'growpart' entry in cfg. Using default: %s", DEFAULT_CONFIG
)
cfg["growpart"] = DEFAULT_CONFIG
mycfg = cfg.get("growpart")
if not isinstance(mycfg, dict):
LOG.warning("'growpart' in config was not a dict")
return
mode = mycfg.get("mode", "auto")
if util.is_false(mode):
if mode != "off":
util.deprecate(
deprecated="Growpart's 'mode' key with value '{mode}'",
deprecated_version="22.2",
extra_message="Use 'off' instead.",
)
LOG.debug("growpart disabled: mode=%s", mode)
return
if util.is_false(mycfg.get("ignore_growroot_disabled", False)):
if os.path.isfile("/etc/growroot-disabled"):
LOG.debug("growpart disabled: /etc/growroot-disabled exists")
LOG.debug("use ignore_growroot_disabled to ignore")
return
devices = util.get_cfg_option_list(mycfg, "devices", ["/"])
if not len(devices):
LOG.debug("growpart: empty device list")
return
try:
resizer = resizer_factory(mode, distro=cloud.distro, devices=devices)
except (ValueError, TypeError) as e:
LOG.debug("growpart unable to find resizer for '%s': %s", mode, e)
if mode != "auto":
raise e
return
resized = util.log_time(
logfunc=LOG.debug,
msg="resize_devices",
func=resize_devices,
args=(resizer, devices, cloud.distro.name),
)
for entry, action, msg in resized:
if action == RESIZE.CHANGED:
LOG.info("'%s' resized: %s", entry, msg)
else:
LOG.debug("'%s' %s: %s", entry, action, msg)
RESIZERS = (
("growpart", ResizeGrowPart),
("growfs", ResizeGrowFS),
("gpart", ResizeGpart),
)
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