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         self.settings.string_list(['user'],
  62                                   'create USER with PASSWORD',
  63                                   metavar='USER/PASSWORD')
  64         self.settings.boolean(['serial-console'],
  65                               'configure image to use a serial console')
  66
  67     def process_args(self, args):
  68         if not self.settings['image']:
  69             raise cliapp.AppException('You must give image filename.')
  70         if not self.settings['size']:
  71             raise cliapp.AppException('You must give image size.')
  72
  73         self.remove_dirs = []
  74         self.mount_points = []
  75
  76         try:
  77             self.create_empty_image()
  78             self.partition_image()
  79             self.install_mbr()
  80             rootdev = self.setup_kpartx()
  81             self.mkfs(rootdev)
  82             rootdir = self.mount(rootdev)
  83             self.debootstrap(rootdir)
  84             self.set_hostname(rootdir)
  85             self.create_fstab(rootdir)
  86             self.set_root_password(rootdir)
  87             self.create_users(rootdir)
  88             self.remove_udev_persistent_rules(rootdir)
  89             self.setup_networking(rootdir)
  90             self.install_extlinux(rootdev, rootdir)
  91             self.customize(rootdir)
  92         except BaseException, e:
  93             self.message('EEEK! Something bad happened...')
  94             self.cleanup()
  95             raise
  96         else:
  97             self.cleanup()
  98
  99     def message(self, msg):
 100         if self.settings['verbose']:
 101             print msg
 102
 103     def runcmd(self, argv, stdin='', ignore_fail=False, **kwargs):
 104         logging.debug('runcmd: %s %s' % (argv, kwargs))
 105         p = subprocess.Popen(argv, stdin=subprocess.PIPE,
 106                              stdout=subprocess.PIPE, stderr=subprocess.PIPE,
 107                              **kwargs)
 108         out, err = p.communicate(stdin)
 109         if p.returncode != 0:
 110             msg = 'command failed: %s\n%s\n%s' % (argv, out, err)
 111             logging.error(msg)
 112             if not ignore_fail:
 113                 raise cliapp.AppException(msg)
 114         return out
 115
 116     def mkdtemp(self):
 117         dirname = tempfile.mkdtemp()
 118         self.remove_dirs.append(dirname)
 119         logging.debug('mkdir %s' % dirname)
 120         return dirname
 121
 122     def mount(self, device):
 123         self.message('Mounting %s' % device)
 124         mount_point = self.mkdtemp()
 125         self.runcmd(['mount', device, mount_point])
 126         self.mount_points.append(mount_point)
 127         logging.debug('mounted %s on %s' % (device, mount_point))
 128         return mount_point
 129
 130     def create_empty_image(self):
 131         self.message('Creating disk image')
 132         self.runcmd(['qemu-img', 'create', '-f', 'raw',
 133                      self.settings['image'],
 134                      str(self.settings['size'])])
 135
 136     def partition_image(self):
 137         self.message('Creating partitions')
 138         self.runcmd(['parted', '-s', self.settings['image'],
 139                      'mklabel', 'msdos'])
 140         self.runcmd(['parted', '-s', self.settings['image'],
 141                      'mkpart', 'primary', '0%', '100%'])
 142         self.runcmd(['parted', '-s', self.settings['image'],
 143                      'set', '1', 'boot', 'on'])
 144
 145     def install_mbr(self):
 146         self.message('Installing MBR')
 147         self.runcmd(['install-mbr', self.settings['image']])
 148
 149     def setup_kpartx(self):
 150         out = self.runcmd(['kpartx', '-av', self.settings['image']])
 151         devices = [line.split()[2]
 152                    for line in out.splitlines()
 153                    if line.startswith('add map ')]
 154         if len(devices) != 1:
 155             raise cliapp.AppException('Surprising number of partitions')
 156         return '/dev/mapper/%s' % devices[0]
 157
 158     def mkfs(self, device):
 159         self.message('Creating filesystem')
 160         self.runcmd(['mkfs', '-t', 'ext2', device])
 161
 162     def debootstrap(self, rootdir):
 163         self.message('Debootstrapping')
 164
 165         if self.settings['arch'] == 'i386':
 166             kernel_arch = '686'
 167         else:
 168             kernel_arch = self.settings['arch']
 169         kernel_image = 'linux-image-2.6-%s' % kernel_arch
 170
 171         include = [kernel_image] + self.settings['package']
 172
 173         self.runcmd(['debootstrap',
 174                      '--arch=%s' % self.settings['arch'],
 175                      '--include=%s' % ','.join(include),
 176                      self.settings['distribution'],
 177                      rootdir,
 178                      self.settings['mirror']])
 179
 180     def set_hostname(self, rootdir):
 181         hostname = self.settings['hostname']
 182         with open(os.path.join(rootdir, 'etc', 'hostname'), 'w') as f:
 183             f.write('%s\n' % hostname)
 184
 185         etc_hosts = os.path.join(rootdir, 'etc', 'hosts')
 186         with open(etc_hosts, 'r') as f:
 187             data = f.read()
 188         with open(etc_hosts, 'w') as f:
 189             for line in data.splitlines():
 190                 if line.startswith('127.0.0.1'):
 191                     line += ' %s' % hostname
 192                 f.write('%s\n' % line)
 193
 194     def create_fstab(self, rootdir):
 195         fstab = os.path.join(rootdir, 'etc', 'fstab')
 196         with open(fstab, 'w') as f:
 197             f.write('proc /proc proc defaults 0 0\n')
 198             f.write('/dev/sda1 / ext4 errors=remount-ro 0 1\n')
 199
 200     def set_root_password(self, rootdir):
 201         if self.settings['root-password']:
 202             self.message('Setting root password')
 203             self.set_password(rootdir, 'root', self.settings['root-password'])
 204         else:
 205             self.message('Locking root password')
 206             self.runcmd(['chroot', rootdir, 'passwd', '-l', 'root'])
 207
 208     def create_users(self, rootdir):
 209         def create_user(user):
 210             self.runcmd(['chroot', rootdir, 'adduser', '--gecos', user,
 211                          '--disabled-password', user])
 212
 213         for userpass in self.settings['user']:
 214             if '/' in userpass:
 215                 user, password = userpass.split('/', 1)
 216                 create_user(user)
 217                 self.set_password(rootdir, user, password)
 218             else:
 219                 create_user(userpass)
 220
 221     def set_password(self, rootdir, user, password):
 222         encrypted = crypt.crypt(password, '..')
 223         self.runcmd(['chroot', rootdir, 'usermod', '-p', encrypted, user])
 224
 225     def remove_udev_persistent_rules(self, rootdir):
 226         self.message('Removing udev persistent cd and net rules')
 227         for x in ['70-persistent-cd.rules', '70-persistent-net.rules']:
 228             pathname = os.path.join(rootdir, 'etc', 'udev', 'rules.d', x)
 229             if os.path.exists(pathname):
 230                 logging.debug('rm %s' % pathname)
 231                 os.remove(pathname)
 232             else:
 233                 logging.debug('not removing non-existent %s' % pathname)
 234
 235     def setup_networking(self, rootdir):
 236         self.message('Setting up networking')
 237
 238         f = open(os.path.join(rootdir, 'etc', 'network', 'interfaces'), 'w')
 239         f.write('auto lo\n')
 240         f.write('iface lo inet loopback\n')
 241
 242         if self.settings['enable-dhcp']:
 243             f.write('\n')
 244             f.write('allow-hotplug eth0\n')
 245             f.write('iface eth0 inet dhcp\n')
 246
 247         f.close()
 248
 249     def install_extlinux(self, rootdev, rootdir):
 250         self.message('Installing extlinux')
 251
 252         def find(pattern):
 253             dirname = os.path.join(rootdir, 'boot')
 254             basenames = os.listdir(dirname)
 255             logging.debug('find: %s' % basenames)
 256             for basename in basenames:
 257                 if re.search(pattern, basename):
 258                     return os.path.join('boot', basename)
 259             raise cliapp.AppException('Cannot find match: %s' % pattern)
 260
 261         kernel_image = find('vmlinuz-.*')
 262         initrd_image = find('initrd.img-.*')
 263
 264         out = self.runcmd(['blkid', '-c', '/dev/null', '-o', 'value',
 265                            '-s', 'UUID', rootdev])
 266         uuid = out.splitlines()[0].strip()
 267
 268         conf = os.path.join(rootdir, 'extlinux.conf')
 269         logging.debug('configure extlinux %s' % conf)
 270         f = open(conf, 'w')
 271         f.write('''
 272 default linux
 273 timeout 1
 274
 275 label linux
 276 kernel %(kernel)s
 277 append initrd=%(initrd)s root=UUID=%(uuid)s ro quiet %(kserial)s
 278 %(extserial)s
 279 ''' % {
 280     'kernel': kernel_image,
 281     'initrd': initrd_image,
 282     'uuid': uuid,
 283     'kserial':
 284         'console=ttyS0,115200' if self.settings['serial-console'] else '',
 285     'extserial': 'serial 0 115200' if self.settings['serial-console'] else '',
 286 })
 287         f.close()
 288
 289         if self.settings['serial-console']:
 290             logging.debug('adding getty to serial console')
 291             inittab = os.path.join(rootdir, 'etc/inittab')
 292             with open(inittab, 'a') as f:
 293                 f.write('\nS0:23:respawn:/sbin/getty -L ttyS0 115200 vt100\n')
 294
 295         self.runcmd(['extlinux', '--install', rootdir])
 296         self.runcmd(['sync'])
 297         import time; time.sleep(2)
 298
 299     def cleanup(self):
 300         # Clean up after any errors.
 301
 302         self.message('Cleaning up')
 303
 304         for mount_point in self.mount_points:
 305             self.runcmd(['umount', mount_point], ignore_fail=True)
 306
 307         self.runcmd(['kpartx', '-d', self.settings['image']], ignore_fail=True)
 308
 309         for dirname in self.remove_dirs:
 310             shutil.rmtree(dirname)
 311
 312     def customize(self, rootdir):
 313         script = self.settings['customize']
 314         if script:
 315             self.message('Running customize script %s' % script)
 316             self.runcmd([script, rootdir])
 317
 318
 319 if __name__ == '__main__':
 320     VmDebootstrap().run()
 321