vmdebootstrap

   1 #!/usr/bin/python
   2 # Copyright 2011  Lars Wirzenius
   3 #
   4 # This program is free software: you can redistribute it and/or modify
   5 # it under the terms of the GNU General Public License as published by
   6 # the Free Software Foundation, either version 3 of the License, or
   7 # (at your option) any later version.
   8 #
   9 # This program is distributed in the hope that it will be useful,
  10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 # GNU General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU General Public License
  15 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 import cliapp
  18 import crypt
  19 import logging
  20 import os
  21 import re
  22 import shutil
  23 import subprocess
  24 import tempfile
  25
  26
  27 class VmDebootstrap(cliapp.Application):
  28
  29     def add_settings(self):
  30         default_arch = 'amd64'
  31
  32         self.settings.boolean(['verbose'], 'report what is going on')
  33         self.settings.string(['image'], 'put created disk image in FILE',
  34                              metavar='FILE')
  35         self.settings.bytesize(['size'],
  36                                'create a disk image of size SIZE (%default)',
  37                                metavar='SIZE',
  38                                default='1G')
  39         self.settings.string(['mirror'],
  40                              'use MIRROR as package source (%default)',
  41                              metavar='URL',
  42                              default='http://cdn.debian.net/debian/')
  43         self.settings.string(['arch'], 'architecture to use (%default)',
  44                              metavar='ARCH',
  45                              default=default_arch)
  46         self.settings.string(['distribution'],
  47                              'release to use (%default)',
  48                              metavar='NAME',
  49                              default='stable')
  50         self.settings.string_list(['package'], 'install PACKAGE onto system')
  51         self.settings.boolean(['enable-dhcp'], 'enable DHCP on eth0')
  52         self.settings.string(['root-password'], 'set root password',
  53                              metavar='PASSWORD')
  54         self.settings.string(['customize'],
  55                              'run SCRIPT after setting up system',
  56                              metavar='SCRIPT')
  57         self.settings.string(['hostname'],
  58                              'set name to HOSTNAME (%default)',
  59                              metavar='HOSTNAME',
  60                              default='debian')
  61         self.settings.string_list(['user'],
  62                                   'create USER with PASSWORD',
  63                                   metavar='USER/PASSWORD')
  64
  65     def process_args(self, args):
  66         if not self.settings['image']:
  67             raise cliapp.AppException('You must give image filename.')
  68         if not self.settings['size']:
  69             raise cliapp.AppException('You must give image size.')
  70
  71         self.remove_dirs = []
  72         self.mount_points = []
  73
  74         try:
  75             self.create_empty_image()
  76             self.partition_image()
  77             self.install_mbr()
  78             rootdev = self.setup_kpartx()
  79             self.mkfs(rootdev)
  80             rootdir = self.mount(rootdev)
  81             self.debootstrap(rootdir)
  82             self.set_hostname(rootdir)
  83             self.create_fstab(rootdir)
  84             self.set_root_password(rootdir)
  85             self.create_users(rootdir)
  86             self.remove_udev_persistent_rules(rootdir)
  87             self.setup_networking(rootdir)
  88             self.install_extlinux(rootdev, rootdir)
  89             self.customize(rootdir)
  90         except BaseException, e:
  91             self.message('EEEK! Something bad happened...')
  92             self.cleanup()
  93             raise
  94         else:
  95             self.cleanup()
  96
  97     def message(self, msg):
  98         if self.settings['verbose']:
  99             print msg
 100
 101     def runcmd(self, argv, stdin='', ignore_fail=False, **kwargs):
 102         logging.debug('runcmd: %s %s' % (argv, kwargs))
 103         p = subprocess.Popen(argv, stdin=subprocess.PIPE,
 104                              stdout=subprocess.PIPE, stderr=subprocess.PIPE,
 105                              **kwargs)
 106         out, err = p.communicate(stdin)
 107         if p.returncode != 0:
 108             msg = 'command failed: %s\n%s\n%s' % (argv, out, err)
 109             logging.error(msg)
 110             if not ignore_fail:
 111                 raise cliapp.AppException(msg)
 112         return out
 113
 114     def mkdtemp(self):
 115         dirname = tempfile.mkdtemp()
 116         self.remove_dirs.append(dirname)
 117         logging.debug('mkdir %s' % dirname)
 118         return dirname
 119
 120     def mount(self, device):
 121         self.message('Mounting %s' % device)
 122         mount_point = self.mkdtemp()
 123         self.runcmd(['mount', device, mount_point])
 124         self.mount_points.append(mount_point)
 125         logging.debug('mounted %s on %s' % (device, mount_point))
 126         return mount_point
 127
 128     def create_empty_image(self):
 129         self.message('Creating disk image')
 130         self.runcmd(['qemu-img', 'create', '-f', 'raw',
 131                      self.settings['image'],
 132                      str(self.settings['size'])])
 133
 134     def partition_image(self):
 135         self.message('Creating partitions')
 136         self.runcmd(['parted', '-s', self.settings['image'],
 137                      'mklabel', 'msdos'])
 138         self.runcmd(['parted', '-s', self.settings['image'],
 139                      'mkpart', 'primary', '0%', '100%'])
 140         self.runcmd(['parted', '-s', self.settings['image'],
 141                      'set', '1', 'boot', 'on'])
 142
 143     def install_mbr(self):
 144         self.message('Installing MBR')
 145         self.runcmd(['install-mbr', self.settings['image']])
 146
 147     def setup_kpartx(self):
 148         out = self.runcmd(['kpartx', '-av', self.settings['image']])
 149         devices = [line.split()[2]
 150                    for line in out.splitlines()
 151                    if line.startswith('add map ')]
 152         if len(devices) != 1:
 153             raise cliapp.AppException('Surprising number of partitions')
 154         return '/dev/mapper/%s' % devices[0]
 155
 156     def mkfs(self, device):
 157         self.message('Creating filesystem')
 158         self.runcmd(['mkfs', '-t', 'ext2', device])
 159
 160     def debootstrap(self, rootdir):
 161         self.message('Debootstrapping')
 162
 163         if self.settings['arch'] == 'i386':
 164             kernel_arch = '686'
 165         else:
 166             kernel_arch = self.settings['arch']
 167         kernel_image = 'linux-image-2.6-%s' % kernel_arch
 168
 169         include = [kernel_image] + self.settings['package']
 170
 171         self.runcmd(['debootstrap',
 172                      '--arch=%s' % self.settings['arch'],
 173                      '--include=%s' % ','.join(include),
 174                      self.settings['distribution'],
 175                      rootdir,
 176                      self.settings['mirror']])
 177
 178     def set_hostname(self, rootdir):
 179         hostname = self.settings['hostname']
 180         with open(os.path.join(rootdir, 'etc', 'hostname'), 'w') as f:
 181             f.write('%s\n' % hostname)
 182
 183         etc_hosts = os.path.join(rootdir, 'etc', 'hosts')
 184         with open(etc_hosts, 'r') as f:
 185             data = f.read()
 186         with open(etc_hosts, 'w') as f:
 187             for line in data.splitlines():
 188                 if line.startswith('127.0.0.1'):
 189                     line += ' %s' % hostname
 190                 f.write('%s\n' % line)
 191
 192     def create_fstab(self, rootdir):
 193         fstab = os.path.join(rootdir, 'etc', 'fstab')
 194         with open(fstab, 'w') as f:
 195             f.write('proc /proc proc defaults 0 0\n')
 196             f.write('/dev/sda1 / ext4 errors=remount-ro 0 1\n')
 197
 198     def set_root_password(self, rootdir):
 199         if self.settings['root-password']:
 200             self.message('Setting root password')
 201             self.set_password(rootdir, 'root', self.settings['root-password'])
 202         else:
 203             self.message('Locking root password')
 204             self.runcmd(['chroot', rootdir, 'passwd', '-l', 'root'])
 205
 206     def create_users(self, rootdir):
 207         def create_user(user):
 208             self.runcmd(['chroot', rootdir, 'adduser', '--gecos', user,
 209                          '--disabled-password', user])
 210
 211         for userpass in self.settings['user']:
 212             if '/' in userpass:
 213                 user, password = userpass.split('/', 1)
 214                 create_user(user)
 215                 self.set_password(rootdir, user, password)
 216             else:
 217                 create_user(userpass)
 218
 219     def set_password(self, rootdir, user, password):
 220         encrypted = crypt.crypt(password, '..')
 221         self.runcmd(['chroot', rootdir, 'usermod', '-p', encrypted, user])
 222
 223     def remove_udev_persistent_rules(self, rootdir):
 224         self.message('Removing udev persistent cd and net rules')
 225         for x in ['70-persistent-cd.rules', '70-persistent-net.rules']:
 226             pathname = os.path.join(rootdir, 'etc', 'udev', 'rules.d', x)
 227             if os.path.exists(pathname):
 228                 logging.debug('rm %s' % pathname)
 229                 os.remove(pathname)
 230             else:
 231                 logging.debug('not removing non-existent %s' % pathname)
 232
 233     def setup_networking(self, rootdir):
 234         self.message('Setting up networking')
 235
 236         f = open(os.path.join(rootdir, 'etc', 'network', 'interfaces'), 'w')
 237         f.write('auto lo\n')
 238         f.write('iface lo inet loopback\n')
 239
 240         if self.settings['enable-dhcp']:
 241             f.write('\n')
 242             f.write('allow-hotplug eth0\n')
 243             f.write('iface eth0 inet dhcp\n')
 244
 245         f.close()
 246
 247     def install_extlinux(self, rootdev, rootdir):
 248         self.message('Installing extlinux')
 249
 250         def find(pattern):
 251             dirname = os.path.join(rootdir, 'boot')
 252             basenames = os.listdir(dirname)
 253             logging.debug('find: %s' % basenames)
 254             for basename in basenames:
 255                 if re.search(pattern, basename):
 256                     return os.path.join('boot', basename)
 257             raise cliapp.AppException('Cannot find match: %s' % pattern)
 258
 259         kernel_image = find('vmlinuz-.*')
 260         initrd_image = find('initrd.img-.*')
 261
 262         out = self.runcmd(['blkid', '-c', '/dev/null', '-o', 'value',
 263                            '-s', 'UUID', rootdev])
 264         uuid = out.splitlines()[0].strip()
 265
 266         conf = os.path.join(rootdir, 'extlinux.conf')
 267         logging.debug('configure extlinux %s' % conf)
 268         f = open(conf, 'w')
 269         f.write('''
 270 default linux
 271 timeout 1
 272
 273 label linux
 274 kernel %(kernel)s
 275 append initrd=%(initrd)s root=UUID=%(uuid)s ro quiet
 276 ''' % {
 277     'kernel': kernel_image,
 278     'initrd': initrd_image,
 279     'uuid': uuid,
 280 })
 281         f.close()
 282
 283         self.runcmd(['extlinux', '--install', rootdir])
 284         self.runcmd(['sync'])
 285         import time; time.sleep(2)
 286
 287     def cleanup(self):
 288         # Clean up after any errors.
 289
 290         self.message('Cleaning up')
 291
 292         for mount_point in self.mount_points:
 293             self.runcmd(['umount', mount_point], ignore_fail=True)
 294
 295         self.runcmd(['kpartx', '-d', self.settings['image']], ignore_fail=True)
 296
 297         for dirname in self.remove_dirs:
 298             shutil.rmtree(dirname)
 299
 300     def customize(self, rootdir):
 301         script = self.settings['customize']
 302         if script:
 303             self.message('Running customize script %s' % script)
 304             self.runcmd([script, rootdir])
 305
 306
 307 if __name__ == '__main__':
 308     VmDebootstrap().run()
 309