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
  58     def process_args(self, args):
  59         if not self.settings['image']:
  60             raise cliapp.AppException('You must give image filename.')
  61         if not self.settings['size']:
  62             raise cliapp.AppException('You must give image size.')
  63
  64         self.remove_dirs = []
  65         self.mount_points = []
  66
  67         try:
  68             self.create_empty_image()
  69             self.partition_image()
  70             self.install_mbr()
  71             rootdev = self.setup_kpartx()
  72             self.mkfs(rootdev)
  73             rootdir = self.mount(rootdev)
  74             self.debootstrap(rootdir)
  75             self.set_root_password(rootdir)
  76             self.remove_udev_persistent_rules(rootdir)
  77             self.install_extlinux(rootdev, rootdir)
  78         except:
  79             self.cleanup()
  80             raise
  81         else:
  82             self.cleanup()
  83
  84     def message(self, msg):
  85         if self.settings['verbose']:
  86             print msg
  87
  88     def runcmd(self, argv, stdin='', ignore_fail=False, **kwargs):
  89         logging.debug('runcmd: %s %s' % (argv, kwargs))
  90         p = subprocess.Popen(argv, stdin=subprocess.PIPE,
  91                              stdout=subprocess.PIPE, stderr=subprocess.PIPE,
  92                              **kwargs)
  93         out, err = p.communicate(stdin)
  94         if p.returncode != 0:
  95             msg = 'command failed: %s\n%s\n%s' % (argv, out, err)
  96             logging.error(msg)
  97             if not ignore_fail:
  98                 raise cliapp.AppException(msg)
  99         return out
 100
 101     def mkdtemp(self):
 102         dirname = tempfile.mkdtemp()
 103         self.remove_dirs.append(dirname)
 104         logging.debug('mkdir %s' % dirname)
 105         return dirname
 106
 107     def mount(self, device):
 108         self.message('Mounting %s' % device)
 109         mount_point = self.mkdtemp()
 110         self.runcmd(['mount', device, mount_point])
 111         self.mount_points.append(mount_point)
 112         logging.debug('mounted %s on %s' % (device, mount_point))
 113         return mount_point
 114
 115     def create_empty_image(self):
 116         self.message('Creating disk image')
 117         self.runcmd(['qemu-img', 'create', '-f', 'raw',
 118                      self.settings['image'],
 119                      str(self.settings['size'])])
 120
 121     def partition_image(self):
 122         self.message('Creating partitions')
 123         self.runcmd(['parted', '-s', self.settings['image'],
 124                      'mklabel', 'msdos'])
 125         self.runcmd(['parted', '-s', self.settings['image'],
 126                      'mkpart', 'primary', '0%', '100%'])
 127         self.runcmd(['parted', '-s', self.settings['image'],
 128                      'set', '1', 'boot', 'on'])
 129
 130     def install_mbr(self):
 131         self.message('Installing MBR')
 132         self.runcmd(['install-mbr', self.settings['image']])
 133
 134     def setup_kpartx(self):
 135         out = self.runcmd(['kpartx', '-av', self.settings['image']])
 136         devices = [line.split()[2]
 137                    for line in out.splitlines()
 138                    if line.startswith('add map ')]
 139         if len(devices) != 1:
 140             raise cliapp.AppException('Surprising number of partitions')
 141         return '/dev/mapper/%s' % devices[0]
 142
 143     def mkfs(self, device):
 144         self.message('Creating filesystem')
 145         self.runcmd(['mkfs', '-t', 'ext2', device])
 146
 147     def debootstrap(self, rootdir):
 148         self.message('Debootstrapping')
 149
 150         if self.settings['arch'] == 'i386':
 151             kernel_arch = 'i686'
 152         else:
 153             kernel_arch = self.settings['arch']
 154         kernel_image = 'linux-image-2.6-%s' % kernel_arch
 155
 156         include = [kernel_image] + self.settings['package']
 157
 158         self.runcmd(['debootstrap',
 159                      '--arch=%s' % self.settings['arch'],
 160                      '--include=%s' % ','.join(include),
 161                      self.settings['distribution'],
 162                      rootdir,
 163                      self.settings['mirror']])
 164
 165     def set_root_password(self, rootdir):
 166         self.message('Removing root password')
 167         self.runcmd(['chroot', rootdir, 'passwd', '-d', 'root'])
 168
 169     def remove_udev_persistent_rules(self, rootdir):
 170         self.message('Removing udev persistent cd and net rules')
 171         for x in ['70-persistent-cd.rules', '70-persistent-net.rules']:
 172             pathname = os.path.join(rootdir, 'etc', 'udev', 'rules.d', x)
 173             if os.path.exists(pathname):
 174                 logging.debug('rm %s' % pathname)
 175                 os.remove(pathname)
 176             else:
 177                 logging.debug('not removing non-existent %s' % pathname)
 178
 179     def install_extlinux(self, rootdev, rootdir):
 180         self.message('Installing extlinux')
 181
 182         def find(pattern):
 183             dirname = os.path.join(rootdir, 'boot')
 184             basenames = os.listdir(dirname)
 185             logging.debug('find: %s' % basenames)
 186             for basename in basenames:
 187                 if re.search(pattern, basename):
 188                     return os.path.join('boot', basename)
 189             raise cliapp.AppException('Cannot find match: %s' % pattern)
 190
 191         kernel_image = find('vmlinuz-.*')
 192         initrd_image = find('initrd.img-.*')
 193
 194         out = self.runcmd(['blkid', '-c', '/dev/null', '-o', 'value',
 195                            '-s', 'UUID', rootdev])
 196         uuid = out.splitlines()[0].strip()
 197
 198         conf = os.path.join(rootdir, 'extlinux.conf')
 199         logging.debug('configure extlinux %s' % conf)
 200         f = open(conf, 'w')
 201         f.write('''
 202 default linux
 203 timeout 1
 204
 205 label linux
 206 kernel %(kernel)s
 207 append initrd=%(initrd)s root=UUID=%(uuid)s ro quiet
 208 ''' % {
 209     'kernel': kernel_image,
 210     'initrd': initrd_image,
 211     'uuid': uuid,
 212 })
 213         f.close()
 214
 215         self.runcmd(['extlinux', '--install', rootdir])
 216         self.runcmd(['sync'])
 217         import time; time.sleep(2)
 218
 219     def cleanup(self):
 220         # Clean up after any errors.
 221
 222         self.message('Cleaning up')
 223
 224         for mount_point in self.mount_points:
 225             self.runcmd(['umount', mount_point], ignore_fail=True)
 226
 227         self.runcmd(['kpartx', '-d', self.settings['image']], ignore_fail=True)
 228
 229         for dirname in self.remove_dirs:
 230             shutil.rmtree(dirname)
 231
 232
 233 if __name__ == '__main__':
 234     VmDebootstrap().run()
 235