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
  62     def process_args(self, args):
  63         if not self.settings['image']:
  64             raise cliapp.AppException('You must give image filename.')
  65         if not self.settings['size']:
  66             raise cliapp.AppException('You must give image size.')
  67
  68         self.remove_dirs = []
  69         self.mount_points = []
  70
  71         try:
  72             self.create_empty_image()
  73             self.partition_image()
  74             self.install_mbr()
  75             rootdev = self.setup_kpartx()
  76             self.mkfs(rootdev)
  77             rootdir = self.mount(rootdev)
  78             self.debootstrap(rootdir)
  79             self.set_hostname(rootdir)
  80             self.create_fstab(rootdir)
  81             self.set_root_password(rootdir)
  82             self.remove_udev_persistent_rules(rootdir)
  83             self.setup_networking(rootdir)
  84             self.install_extlinux(rootdev, rootdir)
  85             self.customize(rootdir)
  86         except BaseException, e:
  87             self.message('EEEK! Something bad happened...')
  88             self.cleanup()
  89             raise
  90         else:
  91             self.cleanup()
  92
  93     def message(self, msg):
  94         if self.settings['verbose']:
  95             print msg
  96
  97     def runcmd(self, argv, stdin='', ignore_fail=False, **kwargs):
  98         logging.debug('runcmd: %s %s' % (argv, kwargs))
  99         p = subprocess.Popen(argv, stdin=subprocess.PIPE,
 100                              stdout=subprocess.PIPE, stderr=subprocess.PIPE,
 101                              **kwargs)
 102         out, err = p.communicate(stdin)
 103         if p.returncode != 0:
 104             msg = 'command failed: %s\n%s\n%s' % (argv, out, err)
 105             logging.error(msg)
 106             if not ignore_fail:
 107                 raise cliapp.AppException(msg)
 108         return out
 109
 110     def mkdtemp(self):
 111         dirname = tempfile.mkdtemp()
 112         self.remove_dirs.append(dirname)
 113         logging.debug('mkdir %s' % dirname)
 114         return dirname
 115
 116     def mount(self, device):
 117         self.message('Mounting %s' % device)
 118         mount_point = self.mkdtemp()
 119         self.runcmd(['mount', device, mount_point])
 120         self.mount_points.append(mount_point)
 121         logging.debug('mounted %s on %s' % (device, mount_point))
 122         return mount_point
 123
 124     def create_empty_image(self):
 125         self.message('Creating disk image')
 126         self.runcmd(['qemu-img', 'create', '-f', 'raw',
 127                      self.settings['image'],
 128                      str(self.settings['size'])])
 129
 130     def partition_image(self):
 131         self.message('Creating partitions')
 132         self.runcmd(['parted', '-s', self.settings['image'],
 133                      'mklabel', 'msdos'])
 134         self.runcmd(['parted', '-s', self.settings['image'],
 135                      'mkpart', 'primary', '0%', '100%'])
 136         self.runcmd(['parted', '-s', self.settings['image'],
 137                      'set', '1', 'boot', 'on'])
 138
 139     def install_mbr(self):
 140         self.message('Installing MBR')
 141         self.runcmd(['install-mbr', self.settings['image']])
 142
 143     def setup_kpartx(self):
 144         out = self.runcmd(['kpartx', '-av', self.settings['image']])
 145         devices = [line.split()[2]
 146                    for line in out.splitlines()
 147                    if line.startswith('add map ')]
 148         if len(devices) != 1:
 149             raise cliapp.AppException('Surprising number of partitions')
 150         return '/dev/mapper/%s' % devices[0]
 151
 152     def mkfs(self, device):
 153         self.message('Creating filesystem')
 154         self.runcmd(['mkfs', '-t', 'ext2', device])
 155
 156     def debootstrap(self, rootdir):
 157         self.message('Debootstrapping')
 158
 159         if self.settings['arch'] == 'i386':
 160             kernel_arch = 'i686'
 161         else:
 162             kernel_arch = self.settings['arch']
 163         kernel_image = 'linux-image-2.6-%s' % kernel_arch
 164
 165         include = [kernel_image] + self.settings['package']
 166
 167         self.runcmd(['debootstrap',
 168                      '--arch=%s' % self.settings['arch'],
 169                      '--include=%s' % ','.join(include),
 170                      self.settings['distribution'],
 171                      rootdir,
 172                      self.settings['mirror']])
 173
 174     def set_hostname(self, rootdir):
 175         hostname = self.settings['hostname']
 176         with open(os.path.join(rootdir, 'etc', 'hostname'), 'w') as f:
 177             f.write('%s\n' % hostname)
 178
 179         etc_hosts = os.path.join(rootdir, 'etc', 'hosts')
 180         with open(etc_hosts, 'r') as f:
 181             data = f.read()
 182         with open(etc_hosts, 'w') as f:
 183             for line in data.splitlines():
 184                 if line.startswith('127.0.0.1'):
 185                     line += ' %s' % hostname
 186                 f.write('%s\n' % line)
 187
 188     def create_fstab(self, rootdir):
 189         fstab = os.path.join(rootdir, 'etc', 'fstab')
 190         with open(fstab, 'w') as f:
 191             f.write('proc /proc proc defaults 0 0\n')
 192             f.write('/dev/sda1 / ext4 errors=remount-ro 0 1\n')
 193
 194     def set_root_password(self, rootdir):
 195         if self.settings['root-password']:
 196             self.message('Setting root password')
 197             encrypted = crypt.crypt(self.settings['root-password'], '..')
 198             self.runcmd(['chroot', rootdir, 'usermod', '-p', encrypted,
 199                          'root'])
 200         else:
 201             self.message('Locking root password')
 202             self.runcmd(['chroot', rootdir, 'passwd', '-l', 'root'])
 203
 204     def remove_udev_persistent_rules(self, rootdir):
 205         self.message('Removing udev persistent cd and net rules')
 206         for x in ['70-persistent-cd.rules', '70-persistent-net.rules']:
 207             pathname = os.path.join(rootdir, 'etc', 'udev', 'rules.d', x)
 208             if os.path.exists(pathname):
 209                 logging.debug('rm %s' % pathname)
 210                 os.remove(pathname)
 211             else:
 212                 logging.debug('not removing non-existent %s' % pathname)
 213
 214     def setup_networking(self, rootdir):
 215         self.message('Setting up networking')
 216
 217         f = open(os.path.join(rootdir, 'etc', 'network', 'interfaces'), 'w')
 218         f.write('auto lo\n')
 219         f.write('iface lo inet loopback\n')
 220
 221         if self.settings['enable-dhcp']:
 222             f.write('\n')
 223             f.write('allow-hotplug eth0\n')
 224             f.write('iface eth0 inet dhcp\n')
 225
 226         f.close()
 227
 228     def install_extlinux(self, rootdev, rootdir):
 229         self.message('Installing extlinux')
 230
 231         def find(pattern):
 232             dirname = os.path.join(rootdir, 'boot')
 233             basenames = os.listdir(dirname)
 234             logging.debug('find: %s' % basenames)
 235             for basename in basenames:
 236                 if re.search(pattern, basename):
 237                     return os.path.join('boot', basename)
 238             raise cliapp.AppException('Cannot find match: %s' % pattern)
 239
 240         kernel_image = find('vmlinuz-.*')
 241         initrd_image = find('initrd.img-.*')
 242
 243         out = self.runcmd(['blkid', '-c', '/dev/null', '-o', 'value',
 244                            '-s', 'UUID', rootdev])
 245         uuid = out.splitlines()[0].strip()
 246
 247         conf = os.path.join(rootdir, 'extlinux.conf')
 248         logging.debug('configure extlinux %s' % conf)
 249         f = open(conf, 'w')
 250         f.write('''
 251 default linux
 252 timeout 1
 253
 254 label linux
 255 kernel %(kernel)s
 256 append initrd=%(initrd)s root=UUID=%(uuid)s ro quiet
 257 ''' % {
 258     'kernel': kernel_image,
 259     'initrd': initrd_image,
 260     'uuid': uuid,
 261 })
 262         f.close()
 263
 264         self.runcmd(['extlinux', '--install', rootdir])
 265         self.runcmd(['sync'])
 266         import time; time.sleep(2)
 267
 268     def cleanup(self):
 269         # Clean up after any errors.
 270
 271         self.message('Cleaning up')
 272
 273         for mount_point in self.mount_points:
 274             self.runcmd(['umount', mount_point], ignore_fail=True)
 275
 276         self.runcmd(['kpartx', '-d', self.settings['image']], ignore_fail=True)
 277
 278         for dirname in self.remove_dirs:
 279             shutil.rmtree(dirname)
 280
 281     def customize(self, rootdir):
 282         script = self.settings['customize']
 283         if script:
 284             self.message('Running customize script %s' % script)
 285             self.runcmd([script, rootdir])
 286
 287
 288 if __name__ == '__main__':
 289     VmDebootstrap().run()
 290