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# Copyright (C) 2011 Canonical Ltd.
# Copyright (C) 2013 Hewlett-Packard Development Company, L.P.
# Author: Scott Moser <>
# Author: Juerg Haefliger <>
# This file is part of cloud-init. See LICENSE file for license information.
**Summary:** grow partitions
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.
The devices run growpart on are specified as a list under the ``devices`` key.
Each entry in the devices list can be either the path to the device's
mountpoint in the filesystem or a path to the block device in ``/dev``.
The utility to use for resizing can be selected using the ``mode`` config key.
If ``mode`` key is set to ``auto``, then any available utility (either
``growpart`` or BSD ``gpart``) will be used. If neither utility is available,
no error will be raised. If ``mode`` is set to ``growpart``, then the
``growpart`` utility will be used. If this utility is not available on the
system, this will result in an error. If ``mode`` is set to ``off`` or
``false``, then ``cc_growpart`` will take no action.
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 existance 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:
Growpart is enabled by default on the root partition. The default config for
growpart is::
mode: auto
devices: ["/"]
ignore_growroot_disabled: false
**Internal name:** ``cc_growpart``
**Module frequency:** per always
**Supported distros:** all
**Config keys**::
mode: <auto/growpart/off/false>
- "/"
- "/dev/vdb1"
ignore_growroot_disabled: <true/false>
import os
import os.path
import re
import stat
from cloudinit import log as logging
from cloudinit.settings import PER_ALWAYS
from cloudinit import subp
from cloudinit import util
frequency = PER_ALWAYS
'mode': 'auto',
'devices': ['/'],
'ignore_growroot_disabled': False,
class RESIZE(object):
LOG = logging.getLogger(__name__)
def resizer_factory(mode):
resize_class = None
if mode == "auto":
for (_name, resizer) in RESIZERS:
cur = resizer()
if cur.available():
resize_class = cur
if not resize_class:
raise ValueError("No resizers available")
mmap = {}
for (k, v) in RESIZERS:
mmap[k] = v
if mode not in mmap:
raise TypeError("unknown resize mode %s" % mode)
mclass = mmap[mode]()
if mclass.available():
resize_class = mclass
if not resize_class:
raise ValueError("mode %s not available" % mode)
return resize_class
class ResizeFailedException(Exception):
class ResizeGrowPart(object):
def available(self):
myenv = os.environ.copy()
myenv['LANG'] = 'C'
(out, _err) = subp.subp(["growpart", "--help"], env=myenv)
if"--update\s+", out):
return True
except subp.ProcessExecutionError:
return False
def resize(self, diskdev, partnum, partdev):
before = get_size(partdev)
subp.subp(["growpart", '--dry-run', diskdev, partnum])
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)
return (before, before)
subp.subp(["growpart", diskdev, partnum])
except subp.ProcessExecutionError as e:
util.logexc(LOG, "Failed: growpart %s %s", diskdev, partnum)
raise ResizeFailedException(e)
return (before, get_size(partdev))
class ResizeGpart(object):
def available(self):
myenv = os.environ.copy()
myenv['LANG'] = 'C'
(_out, err) = subp.subp(["gpart", "help"], env=myenv, rcs=[0, 1])
if"gpart recover ", err):
return True
except subp.ProcessExecutionError:
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.
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)
before = get_size(partdev)
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)
# Since growing the FS requires a reboot, make sure we reboot
# first when this module has finished.
open('/var/run/reboot-required', 'a').close()
return (before, get_size(partdev))
def get_size(filename):
fd =, os.O_RDONLY)
return os.lseek(fd, 0, os.SEEK_END)
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
# FreeBSD doesn't know of sysfs so just get everything we need from
# the device, like /dev/vtbd0p2.
if util.is_FreeBSD():
freebsd_part = "/dev/" + util.find_freebsd_part(devpath)
m ='^(/dev/.+)p([0-9])$', freebsd_part)
return (,
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_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_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
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 resize_devices(resizer, devices):
# returns a tuple of tuples containing (entry-in-devices, action, message)
info = []
for devent in devices:
blockdev = devent2dev(devent)
except ValueError as e:
info.append((devent, RESIZE.SKIPPED,
"unable to convert to device: %s" % e,))
statret = os.stat(blockdev)
except OSError as e:
info.append((devent, RESIZE.SKIPPED,
"stat of '%s' failed: %s" % (blockdev, e),))
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,))
(disk, ptnum) = device_part_info(blockdev)
except (TypeError, ValueError) as e:
info.append((devent, RESIZE.SKIPPED,
"device_part_info(%s) failed: %s" % (blockdev, e),))
(old, new) = resizer.resize(disk, ptnum, blockdev)
if old == new:
info.append((devent, RESIZE.NOCHANGE,
"no change necessary (%s, %s)" % (disk, ptnum),))
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, cfg, _cloud, log, _args):
if 'growpart' not in cfg:
log.debug("No 'growpart' entry in cfg. Using default: %s" %
cfg['growpart'] = DEFAULT_CONFIG
mycfg = cfg.get('growpart')
if not isinstance(mycfg, dict):
log.warning("'growpart' in config was not a dict")
mode = mycfg.get('mode', "auto")
if util.is_false(mode):
log.debug("growpart disabled: mode=%s" % mode)
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")
devices = util.get_cfg_option_list(mycfg, "devices", ["/"])
if not len(devices):
log.debug("growpart: empty device list")
resizer = resizer_factory(mode)
except (ValueError, TypeError) as e:
log.debug("growpart unable to find resizer for '%s': %s" % (mode, e))
if mode != "auto":
raise e
resized = util.log_time(logfunc=log.debug, msg="resize_devices",
func=resize_devices, args=(resizer, devices))
for (entry, action, msg) in resized:
if action == RESIZE.CHANGED:"'%s' resized: %s" % (entry, msg))
log.debug("'%s' %s: %s" % (entry, action, msg))
RESIZERS = (('growpart', ResizeGrowPart), ('gpart', ResizeGpart))
# vi: ts=4 expandtab