Spotter-VM/vm/sbin/extend-disk

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#!/usr/bin/python3
# -*- coding: utf-8 -*-
import os
import subprocess
message_printed = False
def print_message():
# Print user-friendly message
global message_printed
if not message_printed:
print()
print('Bylo detekováno zvětšení virtuálního disku.')
print('Systém nyní upraví nastavení diskových oddílů.')
print()
message_printed = True
def get_sizes():
# Returns device sizes in MB
sizes = {}
lsblk = subprocess.run(['/bin/lsblk', '-bnro', 'PATH,SIZE'], capture_output=True, check=True).stdout.decode()
for line in lsblk.splitlines():
line = line.split()
sizes[line[0]] = int(line[1])//1024**2
return sizes
# Determine partition and disk paths
with open('/etc/crypttab') as f:
crypttab = dict(line.split()[:2] for line in f.read().splitlines())
partition = subprocess.run(['/sbin/findfs', crypttab['system']], capture_output=True, check=True).stdout.decode().strip()
disk = partition.rstrip('0123456789')
# Resize physical partition when there is more than 10M unallocated
sizes = get_sizes()
free_space = sizes[disk] - sum([size for part,size in sizes.items() if part.startswith(disk) and part[len(disk):].isdigit()])
if free_space > 10:
print_message()
try:
# Force busybox fdisk as util-linux fdisk breaks the subsequent partx command by notifying kernel too hard
input = 'd\n2\nn\np\n2\n\n\nt\n2\n8e\nw'.encode()
subprocess.run(['/bin/busybox', 'fdisk', disk], input=input, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL, check=True)
except subprocess.CalledProcessError as e:
# Returns code 1 because of the nofication failure, but the resize is successful anyway
if e.returncode != 1:
raise
# Re-read partition (partx is from util-linux, issues BLKPG_RESIZE_PARTITION ioctl to update the kernel partition table)
subprocess.run(['/usr/sbin/partx', '-u', partition], stdout=subprocess.DEVNULL, check=True)
sizes = get_sizes()
# Resize dmcrypt when there is more than 10M of free space (16M is consumed by dmcrypt)
free_space = sizes[partition] - sizes['/dev/mapper/system'] - 16
if free_space > 10:
print_message()
# Create locking dir for cryptsetup to suppress warning
try:
os.mkdir('/run/cryptsetup', 0o700)
except FileExistsError:
pass
# Ask for password 3 times, then fail
fails = 0
while True:
try:
subprocess.run(['/sbin/cryptsetup', 'resize', 'system'], check=True)
break
except (subprocess.CalledProcessError, KeyboardInterrupt):
fails += 1
if fails == 3:
raise
sizes = get_sizes()
# Resize LVM PV when there is more than 10M of free space
free_space = sizes['/dev/mapper/system'] - sum(size for part,size in sizes.items() if part.startswith('/dev/mapper/vg0'))
if free_space > 10:
print_message()
subprocess.run(['/sbin/pvresize', '/dev/mapper/system'], stdout=subprocess.DEVNULL, check=True)
# Create swap if it doesn't exist yet and there's at least 4 GB of free space
if '/dev/mapper/vg0-swap' not in sizes and free_space > 4*1024:
subprocess.run(['/sbin/lvcreate', '-L', '4G', 'vg0', '-n', 'swap'], stdout=subprocess.DEVNULL, check=True)
subprocess.run(['/sbin/mkswap', '/dev/mapper/vg0-swap'], stdout=subprocess.DEVNULL, check=True)
subprocess.run(['/sbin/swapon', '/dev/mapper/vg0-swap'], stdout=subprocess.DEVNULL, check=True)
sizes = get_sizes()
free_space = sizes['/dev/mapper/system'] - sum(size for part,size in sizes.items() if part.startswith('/dev/mapper/vg0'))
# Resize LVM LV when there is more than 10M of free space
if free_space > 10:
subprocess.run(['/sbin/lvextend', '-l', '+100%FREE', '/dev/mapper/vg0-root'], stdout=subprocess.DEVNULL, check=True)
subprocess.run(['/usr/sbin/resize2fs', '/dev/mapper/vg0-root'], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL, check=True)