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.add_boolean_setting(['verbose'],
  33                                           'report what is going on')
  34         self.settings.add_string_setting(['image'],
  35                                          'put created disk image in FILE',
  36                                          metavar='FILE')
  37         self.settings.add_bytesize_setting(['size'],
  38                                            'create a disk image of size SIZE '
  39                                             '(%default)',
  40                                            metavar='SIZE',
  41                                            default='1G')
  42         self.settings.add_string_setting(['mirror'],
  43                                          'use MIRROR as package source '
  44                                             '(%default)',
  45                                          metavar='URL',
  46                                      default='http://cdn.debian.net/debian/')
  47         self.settings.add_string_setting(['arch'],
  48                                          'architecture to use '
  49                                             '(%default)',
  50                                          metavar='ARCH',
  51                                          default=default_arch)
  52         self.settings.add_string_setting(['distribution'],
  53                                          'release to use (%default)',
  54                                          metavar='NAME',
  55                                          default='stable')
  56         self.settings.add_string_list_setting(['package'],
  57                                               'install PACKAGE onto system')
  58         self.settings.add_boolean_setting(['enable-dhcp'],
  59                                           'enable DHCP on eth0')
  60         self.settings.add_string_setting(['root-password'],
  61                                          'set root password',
  62                                          metavar='PASSWORD')
  63         self.settings.add_string_setting(['customize'],
  64                                          'run SCRIPT after setting up system',
  65                                          metavar='SCRIPT')
  66         self.settings.add_string_setting(['hostname'],
  67                                          'set name to HOSTNAME (%default)',
  68                                          metavar='HOSTNAME',
  69                                          default='debian')
  70
  71     def process_args(self, args):
  72         if not self.settings['image']:
  73             raise cliapp.AppException('You must give image filename.')
  74         if not self.settings['size']:
  75             raise cliapp.AppException('You must give image size.')
  76
  77         self.remove_dirs = []
  78         self.mount_points = []
  79
  80         try:
  81             self.create_empty_image()
  82             self.partition_image()
  83             self.install_mbr()
  84             rootdev = self.setup_kpartx()
  85             self.mkfs(rootdev)
  86             rootdir = self.mount(rootdev)
  87             self.debootstrap(rootdir)
  88             self.set_hostname(rootdir)
  89             self.set_root_password(rootdir)
  90             self.remove_udev_persistent_rules(rootdir)
  91             self.setup_networking(rootdir)
  92             self.install_extlinux(rootdev, rootdir)
  93             self.customize(rootdir)
  94         except:
  95             self.cleanup()
  96             raise
  97         else:
  98             self.cleanup()
  99
 100     def message(self, msg):
 101         if self.settings['verbose']:
 102             print msg
 103
 104     def runcmd(self, argv, stdin='', ignore_fail=False, **kwargs):
 105         logging.debug('runcmd: %s %s' % (argv, kwargs))
 106         p = subprocess.Popen(argv, stdin=subprocess.PIPE,
 107                              stdout=subprocess.PIPE, stderr=subprocess.PIPE,
 108                              **kwargs)
 109         out, err = p.communicate(stdin)
 110         if p.returncode != 0:
 111             msg = 'command failed: %s\n%s\n%s' % (argv, out, err)
 112             logging.error(msg)
 113             if not ignore_fail:
 114                 raise cliapp.AppException(msg)
 115         return out
 116
 117     def mkdtemp(self):
 118         dirname = tempfile.mkdtemp()
 119         self.remove_dirs.append(dirname)
 120         logging.debug('mkdir %s' % dirname)
 121         return dirname
 122
 123     def mount(self, device):
 124         self.message('Mounting %s' % device)
 125         mount_point = self.mkdtemp()
 126         self.runcmd(['mount', device, mount_point])
 127         self.mount_points.append(mount_point)
 128         logging.debug('mounted %s on %s' % (device, mount_point))
 129         return mount_point
 130
 131     def create_empty_image(self):
 132         self.message('Creating disk image')
 133         self.runcmd(['qemu-img', 'create', '-f', 'raw',
 134                      self.settings['image'],
 135                      str(self.settings['size'])])
 136
 137     def partition_image(self):
 138         self.message('Creating partitions')
 139         self.runcmd(['parted', '-s', self.settings['image'],
 140                      'mklabel', 'msdos'])
 141         self.runcmd(['parted', '-s', self.settings['image'],
 142                      'mkpart', 'primary', '0%', '100%'])
 143         self.runcmd(['parted', '-s', self.settings['image'],
 144                      'set', '1', 'boot', 'on'])
 145
 146     def install_mbr(self):
 147         self.message('Installing MBR')
 148         self.runcmd(['install-mbr', self.settings['image']])
 149
 150     def setup_kpartx(self):
 151         out = self.runcmd(['kpartx', '-av', self.settings['image']])
 152         devices = [line.split()[2]
 153                    for line in out.splitlines()
 154                    if line.startswith('add map ')]
 155         if len(devices) != 1:
 156             raise cliapp.AppException('Surprising number of partitions')
 157         return '/dev/mapper/%s' % devices[0]
 158
 159     def mkfs(self, device):
 160         self.message('Creating filesystem')
 161         self.runcmd(['mkfs', '-t', 'ext2', device])
 162
 163     def debootstrap(self, rootdir):
 164         self.message('Debootstrapping')
 165
 166         if self.settings['arch'] == 'i386':
 167             kernel_arch = 'i686'
 168         else:
 169             kernel_arch = self.settings['arch']
 170         kernel_image = 'linux-image-2.6-%s' % kernel_arch
 171
 172         include = [kernel_image] + self.settings['package']
 173
 174         self.runcmd(['debootstrap',
 175                      '--arch=%s' % self.settings['arch'],
 176                      '--include=%s' % ','.join(include),
 177                      self.settings['distribution'],
 178                      rootdir,
 179                      self.settings['mirror']])
 180
 181     def set_hostname(self, rootdir):
 182         hostname = self.settings['hostname']
 183         f = open(os.path.join(rootdir, 'etc', 'hostname'), 'w')
 184         f.write(hostname)
 185         f.close()
 186
 187     def set_root_password(self, rootdir):
 188         if self.settings['root-password']:
 189             self.message('Setting root password')
 190             encrypted = crypt.crypt(self.settings['root-password'], '..')
 191             self.runcmd(['chroot', rootdir, 'usermod', '-p', encrypted,
 192                          'root'])
 193         else:
 194             self.message('Locking root password')
 195             self.runcmd(['chroot', rootdir, 'passwd', '-l', 'root'])
 196
 197     def remove_udev_persistent_rules(self, rootdir):
 198         self.message('Removing udev persistent cd and net rules')
 199         for x in ['70-persistent-cd.rules', '70-persistent-net.rules']:
 200             pathname = os.path.join(rootdir, 'etc', 'udev', 'rules.d', x)
 201             if os.path.exists(pathname):
 202                 logging.debug('rm %s' % pathname)
 203                 os.remove(pathname)
 204             else:
 205                 logging.debug('not removing non-existent %s' % pathname)
 206
 207     def setup_networking(self, rootdir):
 208         self.message('Setting up networking')
 209
 210         f = open(os.path.join(rootdir, 'etc', 'network', 'interfaces'), 'w')
 211         f.write('auto lo\n')
 212         f.write('iface lo inet loopback\n')
 213
 214         if self.settings['enable-dhcp']:
 215             f.write('\n')
 216             f.write('allow-hotplug eth0\n')
 217             f.write('iface eth0 inet dhcp\n')
 218
 219         f.close()
 220
 221     def install_extlinux(self, rootdev, rootdir):
 222         self.message('Installing extlinux')
 223
 224         def find(pattern):
 225             dirname = os.path.join(rootdir, 'boot')
 226             basenames = os.listdir(dirname)
 227             logging.debug('find: %s' % basenames)
 228             for basename in basenames:
 229                 if re.search(pattern, basename):
 230                     return os.path.join('boot', basename)
 231             raise cliapp.AppException('Cannot find match: %s' % pattern)
 232
 233         kernel_image = find('vmlinuz-.*')
 234         initrd_image = find('initrd.img-.*')
 235
 236         out = self.runcmd(['blkid', '-c', '/dev/null', '-o', 'value',
 237                            '-s', 'UUID', rootdev])
 238         uuid = out.splitlines()[0].strip()
 239
 240         conf = os.path.join(rootdir, 'extlinux.conf')
 241         logging.debug('configure extlinux %s' % conf)
 242         f = open(conf, 'w')
 243         f.write('''
 244 default linux
 245 timeout 1
 246
 247 label linux
 248 kernel %(kernel)s
 249 append initrd=%(initrd)s root=UUID=%(uuid)s ro quiet
 250 ''' % {
 251     'kernel': kernel_image,
 252     'initrd': initrd_image,
 253     'uuid': uuid,
 254 })
 255         f.close()
 256
 257         self.runcmd(['extlinux', '--install', rootdir])
 258         self.runcmd(['sync'])
 259         import time; time.sleep(2)
 260
 261     def cleanup(self):
 262         # Clean up after any errors.
 263
 264         self.message('Cleaning up')
 265
 266         for mount_point in self.mount_points:
 267             self.runcmd(['umount', mount_point], ignore_fail=True)
 268
 269         self.runcmd(['kpartx', '-d', self.settings['image']], ignore_fail=True)
 270
 271         for dirname in self.remove_dirs:
 272             shutil.rmtree(dirname)
 273
 274     def customize(self, rootdir):
 275         script = self.settings['customize']
 276         if script:
 277             self.message('Running customize script %s' % script)
 278             self.runcmd([script, rootdir])
 279
 280
 281 if __name__ == '__main__':
 282     VmDebootstrap().run()
 283