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 logging
  19 import os
  20 import re
  21 import shutil
  22 import subprocess
  23 import tempfile
  24
  25
  26 class VmDebootstrap(cliapp.Application):
  27
  28     def add_settings(self):
  29         default_arch = 'amd64'
  30
  31         self.settings.add_boolean_setting(['verbose'],
  32                                           'report what is going on')
  33         self.settings.add_string_setting(['image'],
  34                                          'put created disk image in FILE',
  35                                          metavar='FILE')
  36         self.settings.add_bytesize_setting(['size'],
  37                                            'create a disk image of size SIZE '
  38                                             '(%default)',
  39                                            metavar='SIZE',
  40                                            default='1G')
  41         self.settings.add_string_setting(['mirror'],
  42                                          'use MIRROR as package source '
  43                                             '(%default)',
  44                                          metavar='URL',
  45                                      default='http://cdn.debian.net/debian/')
  46         self.settings.add_string_setting(['arch'],
  47                                          'architecture to use '
  48                                             '(%default)',
  49                                          metavar='ARCH',
  50                                          default=default_arch)
  51         self.settings.add_string_setting(['distribution'],
  52                                          'release to use (%default)',
  53                                          metavar='NAME',
  54                                          default='stable')
  55         self.settings.add_string_list_setting(['package'],
  56                                               'install PACKAGE onto system')
  57         self.settings.add_boolean_setting(['enable-dhcp'],
  58                                           'enable DHCP on eth0')
  59
  60     def process_args(self, args):
  61         if not self.settings['image']:
  62             raise cliapp.AppException('You must give image filename.')
  63         if not self.settings['size']:
  64             raise cliapp.AppException('You must give image size.')
  65
  66         self.remove_dirs = []
  67         self.mount_points = []
  68
  69         try:
  70             self.create_empty_image()
  71             self.partition_image()
  72             self.install_mbr()
  73             rootdev = self.setup_kpartx()
  74             self.mkfs(rootdev)
  75             rootdir = self.mount(rootdev)
  76             self.debootstrap(rootdir)
  77             self.set_root_password(rootdir)
  78             self.remove_udev_persistent_rules(rootdir)
  79             self.setup_networking(rootdir)
  80             self.install_extlinux(rootdev, rootdir)
  81         except:
  82             self.cleanup()
  83             raise
  84         else:
  85             self.cleanup()
  86
  87     def message(self, msg):
  88         if self.settings['verbose']:
  89             print msg
  90
  91     def runcmd(self, argv, stdin='', ignore_fail=False, **kwargs):
  92         logging.debug('runcmd: %s %s' % (argv, kwargs))
  93         p = subprocess.Popen(argv, stdin=subprocess.PIPE,
  94                              stdout=subprocess.PIPE, stderr=subprocess.PIPE,
  95                              **kwargs)
  96         out, err = p.communicate(stdin)
  97         if p.returncode != 0:
  98             msg = 'command failed: %s\n%s\n%s' % (argv, out, err)
  99             logging.error(msg)
 100             if not ignore_fail:
 101                 raise cliapp.AppException(msg)
 102         return out
 103
 104     def mkdtemp(self):
 105         dirname = tempfile.mkdtemp()
 106         self.remove_dirs.append(dirname)
 107         logging.debug('mkdir %s' % dirname)
 108         return dirname
 109
 110     def mount(self, device):
 111         self.message('Mounting %s' % device)
 112         mount_point = self.mkdtemp()
 113         self.runcmd(['mount', device, mount_point])
 114         self.mount_points.append(mount_point)
 115         logging.debug('mounted %s on %s' % (device, mount_point))
 116         return mount_point
 117
 118     def create_empty_image(self):
 119         self.message('Creating disk image')
 120         self.runcmd(['qemu-img', 'create', '-f', 'raw',
 121                      self.settings['image'],
 122                      str(self.settings['size'])])
 123
 124     def partition_image(self):
 125         self.message('Creating partitions')
 126         self.runcmd(['parted', '-s', self.settings['image'],
 127                      'mklabel', 'msdos'])
 128         self.runcmd(['parted', '-s', self.settings['image'],
 129                      'mkpart', 'primary', '0%', '100%'])
 130         self.runcmd(['parted', '-s', self.settings['image'],
 131                      'set', '1', 'boot', 'on'])
 132
 133     def install_mbr(self):
 134         self.message('Installing MBR')
 135         self.runcmd(['install-mbr', self.settings['image']])
 136
 137     def setup_kpartx(self):
 138         out = self.runcmd(['kpartx', '-av', self.settings['image']])
 139         devices = [line.split()[2]
 140                    for line in out.splitlines()
 141                    if line.startswith('add map ')]
 142         if len(devices) != 1:
 143             raise cliapp.AppException('Surprising number of partitions')
 144         return '/dev/mapper/%s' % devices[0]
 145
 146     def mkfs(self, device):
 147         self.message('Creating filesystem')
 148         self.runcmd(['mkfs', '-t', 'ext2', device])
 149
 150     def debootstrap(self, rootdir):
 151         self.message('Debootstrapping')
 152
 153         if self.settings['arch'] == 'i386':
 154             kernel_arch = 'i686'
 155         else:
 156             kernel_arch = self.settings['arch']
 157         kernel_image = 'linux-image-2.6-%s' % kernel_arch
 158
 159         include = [kernel_image] + self.settings['package']
 160
 161         self.runcmd(['debootstrap',
 162                      '--arch=%s' % self.settings['arch'],
 163                      '--include=%s' % ','.join(include),
 164                      self.settings['distribution'],
 165                      rootdir,
 166                      self.settings['mirror']])
 167
 168     def set_root_password(self, rootdir):
 169         self.message('Removing root password')
 170         self.runcmd(['chroot', rootdir, 'passwd', '-d', 'root'])
 171
 172     def remove_udev_persistent_rules(self, rootdir):
 173         self.message('Removing udev persistent cd and net rules')
 174         for x in ['70-persistent-cd.rules', '70-persistent-net.rules']:
 175             pathname = os.path.join(rootdir, 'etc', 'udev', 'rules.d', x)
 176             if os.path.exists(pathname):
 177                 logging.debug('rm %s' % pathname)
 178                 os.remove(pathname)
 179             else:
 180                 logging.debug('not removing non-existent %s' % pathname)
 181
 182     def setup_networking(self, rootdir):
 183         self.message('Setting up networking')
 184
 185         f = open(os.path.join(rootdir, 'etc', 'network', 'interfaces'), 'w')
 186         f.write('auto lo\n')
 187         f.write('iface lo inet loopback\n')
 188
 189         if self.settings['enable-dhcp']:
 190             f.write('\n')
 191             f.write('allow-hotplug eth0\n')
 192             f.write('iface eth0 inet dhcp\n')
 193
 194         f.close()
 195
 196     def install_extlinux(self, rootdev, rootdir):
 197         self.message('Installing extlinux')
 198
 199         def find(pattern):
 200             dirname = os.path.join(rootdir, 'boot')
 201             basenames = os.listdir(dirname)
 202             logging.debug('find: %s' % basenames)
 203             for basename in basenames:
 204                 if re.search(pattern, basename):
 205                     return os.path.join('boot', basename)
 206             raise cliapp.AppException('Cannot find match: %s' % pattern)
 207
 208         kernel_image = find('vmlinuz-.*')
 209         initrd_image = find('initrd.img-.*')
 210
 211         out = self.runcmd(['blkid', '-c', '/dev/null', '-o', 'value',
 212                            '-s', 'UUID', rootdev])
 213         uuid = out.splitlines()[0].strip()
 214
 215         conf = os.path.join(rootdir, 'extlinux.conf')
 216         logging.debug('configure extlinux %s' % conf)
 217         f = open(conf, 'w')
 218         f.write('''
 219 default linux
 220 timeout 1
 221
 222 label linux
 223 kernel %(kernel)s
 224 append initrd=%(initrd)s root=UUID=%(uuid)s ro quiet
 225 ''' % {
 226     'kernel': kernel_image,
 227     'initrd': initrd_image,
 228     'uuid': uuid,
 229 })
 230         f.close()
 231
 232         self.runcmd(['extlinux', '--install', rootdir])
 233         self.runcmd(['sync'])
 234         import time; time.sleep(2)
 235
 236     def cleanup(self):
 237         # Clean up after any errors.
 238
 239         self.message('Cleaning up')
 240
 241         for mount_point in self.mount_points:
 242             self.runcmd(['umount', mount_point], ignore_fail=True)
 243
 244         self.runcmd(['kpartx', '-d', self.settings['image']], ignore_fail=True)
 245
 246         for dirname in self.remove_dirs:
 247             shutil.rmtree(dirname)
 248
 249
 250 if __name__ == '__main__':
 251     VmDebootstrap().run()
 252