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