mypapers/debconf-install/debconf-install.html

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  11     <h1>Automated installations in Skolelinux
  12       <br>using debian-installer and base-config</h1>
  13
  14     <p>Skolelinux is a Debian-based Linux distribution with simple
  15       installation and preconfigured services targeted for schools.
  16       The presentation will present how the standard debian
  17       installation system is customised for this purpose.</p>
  18
  19     <div class="presenter">Petter Reinholdtsen
  20       <br>pere@hungry.com
  21       <br>Debconf3, 2003-07-20</div>
  22
  23     <h2>Skolelinux</h2>
  24     <ul>
  25       <li>Based on Debian/Woody (to get security updates)
  26       <li>Simple installation
  27
  28       <li>Translated to several local languages
  29       <li>Includes all the software needed in primary schools
  30
  31       <li>Preconfigured services (syslog, dns, ntp, dhcp, ssh, ldap,
  32           nfs, smb, smtp, imap, ipp, http, web-proxy, ltsp and more)
  33
  34       <li>No license administration
  35       <li>Admin friendly
  36       <li>Scalable
  37     </ul>
  38
  39     <h2>The Skolelinux architecture</h2>
  40
  41     <p><img src="http://developer.skolelinux.no/arkitektur/network-arch_en.jpg">
  42
  43     <h2>The skolelinux install</h2>
  44     <ul>
  45       <li>Simple (two questions and the root password)
  46       <li>Automatic
  47       <li>Using debian-installer (d-i) and base-config (b-c)
  48       <li>Complete (everything work out of the box)
  49       <li>Very little skolelinux-specific code (two udebs and three
  50         config packages).
  51       <li>Rewriting the config of other packages to get the services
  52         preconfigured out of the box (against policy?)
  53
  54     </ul>
  55
  56     <h2>The two stages of the Debian installation</h2>
  57     <h3>First stage (debian-installer)</h3>
  58     <ul>
  59       <li>Booting from cd/floppy/net/whatever
  60       <li>Installing base system
  61       <li>Making HD bootable
  62     </ul>
  63     <h3>Second stage stage (base-config)</h3>
  64     <ul>
  65       <li>Booting from HD
  66       <li>Installing and configuring the non-base system
  67     </ul>
  68
  69     <h2>The first stage (debian-installer)</h2>
  70     <ul>
  71       <li>Modular
  72       <li>Extendible
  73       <li>Using debconf to ask questions
  74       <li>Can be mostly automatic
  75       <li>Very Flexible
  76     </ul>
  77
  78     <h2>debian-installer structure</h2>
  79     <ul>
  80       <li>Selector for installer modules (udebs)
  81       <li>Select language and region
  82       <li>Autodetect hardware
  83       <li>Locate APT source (CD, Net or floppy)
  84       <li>Load the rest of the installer modules
  85       <li>Partition hard-drive
  86       <li>Make filesystems or swap
  87       <li>Mount filesystems
  88       <li>Install base system
  89       <li>Install kernel
  90       <li>Install boot loader
  91       <li>Reboot
  92     </ul>
  93
  94     <h2>debian-installer hooks</h2>
  95     <ul>
  96       <li>Include or exclude d-i modules
  97       <li>Running script at install system boot time
  98       <li>Include or excluding packages going into the HD
  99       <li>Running scripts before reboot from HD
 100       <li>Partitioning
 101     </ul>
 102
 103     <h2>The second stage (base-config)</h2>
 104     <ul>
 105       <li>Executed from init on first boot
 106       <li>Modular (reading /usr/lib/base-config)
 107       <li>Able to adjust the order of the scripts on the fly using
 108         return codes.
 109       <li>Partly using debconf for configuration decisions.
 110     </ul>
 111
 112     <h2>base-config structure</h2>
 113     <ul>
 114       <li>Generate locale if needed
 115       <li>Start terminal emulator (for non-ascii installs) if needed
 116       <li>Load variables based from first stage (/root/dbootstrap_settings)
 117       <li>Turn off screen saver
 118       <li>Show intro screen
 119       <li>Set up console keyboard
 120       <li>Set up time zone
 121       <li>Configure /etc/passwd, root password and local user
 122       <li>Enable ppp?
 123       <li>Configure APT sources
 124       <li>Select packages to install
 125       <li>Fetch packages
 126       <li>Configure exim
 127       <li>Disable ppp?
 128       <li>Show "successful install" screen
 129       <li>Rewrite /etc/inittab to not start base-config on next boot
 130     </ul>
 131
 132     <h2>base-config hooks</h2>
 133       <ul>
 134         <li>add scripts to /usr/lib/base-config/
 135         <li>update debconf database
 136       </ul>
 137     </ul>
 138
 139     <h2>Skolelinux specific code</h2>
 140     <h3>First stage</h3>
 141     <ul>
 142        <li>Ask about profile with automatic partitioning
 143        <li>Reorder d-i module order using dependencies and menu-item value
 144        <li>Install extra packages into the HD
 145        <li>Pass info to second stage
 146     </ul>
 147     <h3>Second stage</h3>
 148     <ul>
 149        <li>Preload debconf answers based on profile question
 150        <li>Automatically install packages
 151        <li>Rewrite/replace config files
 152        <li>Restart servers (except kdm)
 153        <li>Check installation
 154        <li>Restart kdm
 155     </ul>
 156
 157     <h2>Some solved problems</h2>
 158     <ul>
 159
 160       <li>Preloading debconf answers need a dummy question template
 161
 162       <li>Packages with insufficient install configuration support
 163         get their config files rewritten using cfengine.
 164
 165       <li>Selecting packages to install using meta-packages.
 166
 167       <li>
 168
 169     </ul>
 170
 171     <h2>Conclusion</h2>
 172
 173     <ul>
 174       <li>The current debian-installer is extendible and can do
 175         automated installation, with the hooks needed by Skolelinux.
 176
 177       <li>The current base-config is is flexible enough for
 178         Skolelinux, but could use more hooks to reduce the amount of
 179         Skolelinux specific code.
 180     </ul>
 181
 182     <h2>References</h2>
 183
 184     <ul>
 185
 186       <li><a href="http://www.skolelinux.no/">Skolelinux web site</a>
 187       <li><a href="http://developer.skolelinux.no/">Skolelinux
 188           developers web site</a>
 189       <li><a href="http://developer.skolelinux.no/arkitektur/arkitektur.html.en">The Skolelinux architeture description</a>
 190       <li><a href="http://people.debian.org/~pere/debian-installer/">Debian
 191           installer web page</a>
 192     </ul>
 193
 194     <h2>Thank you very much</h2>
 195
 196     <h3>Questions?</h3>
 197
 198     <p>This presentation is available from
 199     <tt>http://www.hungry.com/~pere/mypapers/debconf-install/debconf-install.html</tt>
 200
 201 <!--
 202
 203  Random notes for the introduction to debconf.
 204
 205   My name is Petter Reinholdtsen.  I am president of the norwegian
 206   unix user group and the system architect for skolelinux.  I am also
 207   the head of the group of local organisers of debcamp and debconf.
 208   If you have any problems unsolvable for the help desk, please
 209   contact me or Andreas and we will find a solution.
 210
 211   NUUG and Skolelinux are very pleased to assist in making this
 212   conference happening, and we appreciate the progress done during
 213   debcamp.
 214
 215   Some practical details:
 216
 217    - ask at the
 218    - remember to hand in food cupons
 219
 220   For the norwegian audience: NUUG prize will be handed out this fall.
 221   We need nominations
 222
 223   For the rest of you: Keep up the good work, and good luck with the
 224   conference.
 225
 226
 227 d-i meeting:
 228  - kernel module split (netcard, scsi)
 229  - discover2
 230  -
 231
 232 -->
 233
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