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.set_root_password(rootdir)
  81             self.remove_udev_persistent_rules(rootdir)
  82             self.setup_networking(rootdir)
  83             self.install_extlinux(rootdev, rootdir)
  84             self.customize(rootdir)
  85         except BaseException, e:
  86             self.message('EEEK! Something bad happened...')
  87             self.cleanup()
  88             raise
  89         else:
  90             self.cleanup()
  91
  92     def message(self, msg):
  93         if self.settings['verbose']:
  94             print msg
  95
  96     def runcmd(self, argv, stdin='', ignore_fail=False, **kwargs):
  97         logging.debug('runcmd: %s %s' % (argv, kwargs))
  98         p = subprocess.Popen(argv, stdin=subprocess.PIPE,
  99                              stdout=subprocess.PIPE, stderr=subprocess.PIPE,
 100                              **kwargs)
 101         out, err = p.communicate(stdin)
 102         if p.returncode != 0:
 103             msg = 'command failed: %s\n%s\n%s' % (argv, out, err)
 104             logging.error(msg)
 105             if not ignore_fail:
 106                 raise cliapp.AppException(msg)
 107         return out
 108
 109     def mkdtemp(self):
 110         dirname = tempfile.mkdtemp()
 111         self.remove_dirs.append(dirname)
 112         logging.debug('mkdir %s' % dirname)
 113         return dirname
 114
 115     def mount(self, device):
 116         self.message('Mounting %s' % device)
 117         mount_point = self.mkdtemp()
 118         self.runcmd(['mount', device, mount_point])
 119         self.mount_points.append(mount_point)
 120         logging.debug('mounted %s on %s' % (device, mount_point))
 121         return mount_point
 122
 123     def create_empty_image(self):
 124         self.message('Creating disk image')
 125         self.runcmd(['qemu-img', 'create', '-f', 'raw',
 126                      self.settings['image'],
 127                      str(self.settings['size'])])
 128
 129     def partition_image(self):
 130         self.message('Creating partitions')
 131         self.runcmd(['parted', '-s', self.settings['image'],
 132                      'mklabel', 'msdos'])
 133         self.runcmd(['parted', '-s', self.settings['image'],
 134                      'mkpart', 'primary', '0%', '100%'])
 135         self.runcmd(['parted', '-s', self.settings['image'],
 136                      'set', '1', 'boot', 'on'])
 137
 138     def install_mbr(self):
 139         self.message('Installing MBR')
 140         self.runcmd(['install-mbr', self.settings['image']])
 141
 142     def setup_kpartx(self):
 143         out = self.runcmd(['kpartx', '-av', self.settings['image']])
 144         devices = [line.split()[2]
 145                    for line in out.splitlines()
 146                    if line.startswith('add map ')]
 147         if len(devices) != 1:
 148             raise cliapp.AppException('Surprising number of partitions')
 149         return '/dev/mapper/%s' % devices[0]
 150
 151     def mkfs(self, device):
 152         self.message('Creating filesystem')
 153         self.runcmd(['mkfs', '-t', 'ext2', device])
 154
 155     def debootstrap(self, rootdir):
 156         self.message('Debootstrapping')
 157
 158         if self.settings['arch'] == 'i386':
 159             kernel_arch = 'i686'
 160         else:
 161             kernel_arch = self.settings['arch']
 162         kernel_image = 'linux-image-2.6-%s' % kernel_arch
 163
 164         include = [kernel_image] + self.settings['package']
 165
 166         self.runcmd(['debootstrap',
 167                      '--arch=%s' % self.settings['arch'],
 168                      '--include=%s' % ','.join(include),
 169                      self.settings['distribution'],
 170                      rootdir,
 171                      self.settings['mirror']])
 172
 173     def set_hostname(self, rootdir):
 174         hostname = self.settings['hostname']
 175         with open(os.path.join(rootdir, 'etc', 'hostname'), 'w') as f:
 176             f.write('%s\n' % hostname)
 177
 178         etc_hosts = os.path.join(rootdir, 'etc', 'hosts')
 179         with open(etc_hosts, 'r') as f:
 180             data = f.read()
 181         with open(etc_hosts, 'w') as f:
 182             for line in data.splitlines():
 183                 if line.startswith('127.0.0.1'):
 184                     line += ' %s' % hostname
 185                 f.write('%s\n' % line)
 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