en/appendix/preseed.xml

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Be carefull with the format of this file as it is parsed to generate
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In that file all text between <informalexample> tags that have the
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<appendix id="appendix-preseed">
<title>Automating the installation using preseeding</title>

<para>

This appendix explains the intricacies of preseeding answers to questions in
&d-i; to automate your installation.

</para><para>

The configuration fragments used in this appendix are also available as an
example preseed file from &urlset-example-preseed;.

</para>

 <sect1 id="preseed-intro">
 <title>Introduction</title>
<para>

Preseeding provides a way to set answers to questions asked during the
installation process, without having to manually enter the answers while
the installation is running. This makes it possible to fully automate most
types of installation and even offers some features not available during
normal installations.

</para>

  <sect2 id="preseed-methods">
  <title>Preseeding methods</title>
<para>

There are three methods that can be used for preseeding:
<firstterm>initrd</firstterm>, <firstterm>file</firstterm> and
<firstterm>network</firstterm>. Initrd preseeding will work with any
installation method and supports preseeding of more things, but it requires
the most preparation. File and network preseeding each can be used with
different installation methods. With file and network preseeding the first
few installer questions cannot be preseeded because the preseed configuration
file is only loaded after they have been asked.

</para><para>

The following table shows which preseeding methods can be used with which
installation methods.

<informaltable>
<tgroup cols="4">
<thead>
<row>
  <entry>Installation method</entry><entry>initrd</entry>
  <entry>file</entry><entry>network</entry>
</row>
</thead>

<tbody>
<row>
  <entry>CD/DVD</entry>
  <entry>yes</entry>
  <entry>yes</entry>
  <entry>no</entry>
</row><row>
  <entry>netboot</entry>
  <entry>yes</entry>
  <entry>no</entry>
  <entry>yes</entry>
</row><row>
  <entry>hd-media <phrase condition="bootable-usb">(including usb-stick)</phrase></entry>
  <entry>yes</entry>
  <entry>yes</entry>
  <entry>no</entry>
</row><row condition="supports-floppy-boot">
  <entry>floppy based (cd-drivers)</entry>
  <entry>yes</entry>
  <entry>yes</entry>
  <entry>no</entry>
</row><row condition="supports-floppy-boot">
  <entry>floppy based (net-drivers)</entry>
  <entry>yes</entry>
  <entry>no</entry>
  <entry>yes</entry>
</row><row arch="s390">
  <entry>generic/tape</entry>
  <entry>yes</entry>
  <entry>no</entry>
  <entry>yes</entry>
</row>
</tbody>

</tgroup></informaltable>

</para><para>

An important difference between the preseeding methods is the point at which
the preseed configuration file is loaded and processed. For initrd preseeding
this is right at the start of the installation, before the first question is
even asked. For file preseeding this is after the CD or CD image has been
loaded. For network preseeding it is only after the network has been
configured.

</para><para>

In practical terms this means for file and network preseeding that the
questions about language, country and keyboard selection will already have
been asked. For network preseeding add to that any questions related to
network configuration. Some other questions that are only displayed
at medium or low priority (like the first hardware detection run) will
also already have been processed.

</para><para>

Obviously, any questions that have been processed before the
preseeding configuration file is loaded cannot be preseeded.
<xref linkend="preseed-bootparms"/> offers a way to avoid these
questions being asked.

</para>
  </sect2>

  <sect2 id="preseed-limitations">
  <title>Limitations</title>
<para>

Although most questions used by &d-i; can be preseeded using this method,
there are some notable exceptions. You must (re)partition an entire disk
or use available free space on a disk; it is not possible to use existing
partitions. You currently cannot use preseeding to set up RAID and LVM.

</para>
  </sect2>

<!-- Joeyh feels this is too technical, so leave it out for now
  <sect2 id="preseed-debconf">
  <title>Debconf basics</title>
<para>

Preseeding makes use of the <classname>debconf</classname> framework. This
framework is the preferred mechanism used in Debian to interact with the user
when configuring packages and also forms the heart of &d-i;.
In the <classname>debconf</classname> framework questions or dialogs are
based on <firstterm>templates</firstterm>. There are different types of
templates for different types of questions. The actual questions are
<quote>generated</quote> from templates at runtime;  multiple questions can
use the same template.

</para><para>

The following types of templates are relevant for preseeding.

</para>

<itemizedlist>
<listitem><para>
  string: allows the user to type any value
</para></listitem>
<listitem><para>
  password: similar to string but the value typed is not displayed
</para></listitem>
<listitem><para>
  boolean: for yes/no or true/false type of questions
</para></listitem>
<listitem><para>
  select: allows the user to select one option from a list
</para></listitem>
<listitem><para>
  multiselect: allows the user to select zero, one or more options from a list
</para></listitem>
<listitem><para>
  note: used to display a message
</para></listitem>
</itemizedlist>

<para>

In &d-i; templates are stored in a readable file
<filename>/var/cache/debconf/templates.dat</filename>. This file contains all fixed
text and all translations. It can also contain a default value for the
template. The fixed text can include variables that will be replaced at
runtime.

</para><para>

Another readable file <filename>/var/cache/debconf/questions.dat</filename>
is used to store the values for variables and the answers given to questions.
A question always refers to the template used to ask it. For obvious
security reasons the values for templates of type <quote>password</quote>
are stored in a separate, non-readable file in the same directory.

</para>
  </sect2>
-->

  <sect2 id="preseed-hooks">
  <title>Running custom commands during the installation</title>
<para>

A very powerful and flexible option offered by the preseeding tools is the
ability to run commands or scripts at certain points in the installation.
See <xref linkend="preseed-shell"/> for details.

</para>

<itemizedlist>
<listitem><para>
  <userinput>preseed/early_command</userinput>: is run as soon as the the
  preseeding configuration file has been loaded
</para></listitem>
<listitem><para>
  <userinput>preseed/late_command</userinput>: is run just before the reboot
  at the end of the install, but before the <filename>/target</filename>
  filesystem has been unmounted
</para></listitem>
</itemizedlist>

  </sect2>

  <sect2 id="preseed-seenflag">
  <title>Using preseeding to change default values</title>
<para>

It is possible to use preseeding to change the default answer for a
question, but still have the question asked. To do this the
<firstterm>seen</firstterm> flag must be reset to <quote>false</quote> after
setting the value for a template.

</para>

<informalexample><screen>
d-i foo/bar string value
d-i foo/bar seen false
</screen></informalexample>

  </sect2>
 </sect1>

 <sect1 id="preseed-using">
 <title>Using preseeding</title>
<para>

Of course you will first need to create a preseed file and place it in the
location from where you want to use it. Creating the preseed file is covered
later in this appendix. Putting it in the correct location is fairly
straightforward for network preseeding or if you want to read the file off
a floppy or usb-stick. If you want to include the file on a CD or DVD, you
will have to remaster the ISO image. How to get the preseed file included
in the initrd is outside the scope of this document; please consult the
developers documentation for &d-i;.

</para><para>

An example preseed file that you can use as basis for your preseed file is
available from &urlset-example-preseed;. This file is based on the
configuration fragments included in this appendix.

</para>

  <sect2 id="preseed-loading">
  <title>Loading the preseed file</title>
<para>

If you are using initrd preseeding, you only have to make sure a file named
<filename>preseed.cfg</filename> is included in the root directory of the
initrd. The installer will automatically check if this file is present and
load it.

</para><para>

For the other preseeding methods you need to tell the installer what file to
use when you boot it. This is done by passing the kernel a boot parameter,
either manually at boot time or by editing the bootloader configuration file
(e.g. <filename>syslinux.cfg</filename>) and adding the parameter to the end
of the append line(s) for the kernel.

</para><para>

If you do specify the preseed file in the bootloader configuration, you might
change the configuration so you don't need to hit enter to boot the installer.
For syslinux this means setting the timeout to 1 in
<filename>syslinux.cfg</filename>.

</para><para>

To make sure the installer gets the right preseed file, you can optionally
specify a checksum for the file. Currently this needs to be a md5sum, and if
specified it must match the preseed file or the installer will refuse to use it.

</para>

<informalexample><screen>
Boot parameters to specify:
- if you're netbooting:
  preseed/url=http://host/path/to/preseed.cfg
  preseed/url/checksum=5da499872becccfeda2c4872f9171c3d

- if you're booting a remastered CD:
  preseed/file=/cdrom/preseed.cfg
  preseed/file/checksum=5da499872becccfeda2c4872f9171c3d

- if you're installing from USB media (put the preseed file in the
  toplevel directory of the USB stick):
  preseed/file=/hd-media/preseed.cfg
  preseed/file/checksum=5da499872becccfeda2c4872f9171c3d
</screen></informalexample>

<para>

While you're at it, you may want to add a boot parameter
<userinput>debconf/priority=critical</userinput>. This will avoid most
questions even if the preseeding below misses some.

</para>
  </sect2>

  <sect2 id="preseed-bootparms">
  <title>Using boot parameters to supplement preseeding</title>
<para>

Some parts of the installation process cannot be automated using some forms
of preseeding because the questions are asked before the preseed file is
loaded. For example, if the preseed file is downloaded over the network,
the network setup must be done first. One reason to use initrd preseeding
is that it allows preseeding of even these early steps of the installation
process.

</para><para>

If a preseed file cannot be used to preseed some steps, the install can
still be fully automated, since you can pass preseed values to the kernel
on the command line. Just pass <userinput>path/to/var=value</userinput>
for any of the preseed variables listed in the examples.

</para>
<note><para>

The 2.4 kernel accepts a maximum of 8 command line options and
8 environment options (including any options added by default for the
installer). If these numbers are exceeded, 2.4 kernels will drop any
excess options and 2.6 kernels will panic. For kernel 2.6.9 and later,
you can use 32 command line options and 32 environment options.

</para></note>
<para>

For most installations some of the default options in your bootloader
configuration file, like 'vga=normal', may be safely removed which may
allow you to add more options for preseeding.

</para>
<note><para>

It may not always be possible to specify values with spaces for boot
parameters, even if you delimit them with quotes.

</para></note>
  </sect2>
 </sect1>

 <sect1 condition="FIXME" id="preseed-creating">
 <title>Creating a preseed file</title>
<para>

The preconfiguration file is in the format used by the
<command>debconf-set-selections</command> command.

</para>

<itemizedlist>
<listitem><para>
  File format
</para></listitem>
<listitem><para>
  Only single space allowed between template type and value
</para></listitem>
<listitem><para>
  Relation with /var/lib/(c)debconf/templates
</para></listitem>
<listitem><para>
  Types of templates and how to provide values for them
</para></listitem>
<listitem><para>
  Most values need to be in English or codes
</para></listitem>
<listitem><para>
  Using a manual installation as base
</para></listitem>
<listitem><para>
  Finding other possible values
</para></listitem>
</itemizedlist>

<para>

To check if the format of your preseed file is valid before performing an
install, you can use the command <command>debconf-set-selections -c
<replaceable>preseed.cfg</replaceable></command>.

</para>
 </sect1>

 <sect1 id="preseed-contents">
 <title>Contents of the preseed file</title>
<para>

The configuration fragments used in this appendix are also available as an
example preseed file from &urlset-example-preseed;.

</para><para>

Note that this example is based on an installation for the Intel x86
architecture. If you are installing a different architecture, some of the
examples (like keyboard selection and bootloader installation) may not be
relevant and will need to be replaced by debconf settings appropriate for your
architecture.

</para>
 
  <sect2 id="preseed-l10n">
  <title>Localization</title>
<para>

Setting localization values will only work if you are using initrd preseeding.
With all other methods the preseed file will only be loaded after these
questions have been asked.

</para><para>

The locale can be used to specify both language and country.
To specify the locale as a boot parameter, use
<userinput>debian-installer/locale=<replaceable>en_US</replaceable></userinput>.

<informalexample role="example"><screen>
# Locale sets language and country.
d-i debian-installer/locale string en_US
</screen></informalexample>

</para><para>

Keyboard configuration consists of selecting a keyboard architecture and a
keymap. In most cases the correct keyboard architecture is selected by
default, so there's normally no need to preseed it. The keymap must
be valid for the selected  keyboard architecture.

<informalexample role="example"><screen>
# Keyboard selection.
#d-i console-tools/archs select at
d-i console-keymaps-at/keymap select us
# Example for a different keyboard architecture
#d-i console-keymaps-usb/keymap select mac-usb-us
</screen></informalexample>

</para><para>

To skip keyboard configuration preseed
<classname>console-tools/archs</classname> with
<userinput>skip-config</userinput>.
This will result in the kernel keymap remaining active.

</para>

<note><para>

The changes in the input layer for 2.6 kernels have made the keyboard
architecture virtually obsolete. For 2.6 kernels normally a <quote>PC</quote>
(<userinput>at</userinput>) keymap should be selected.

</para></note>
  </sect2>

  <sect2 id="preseed-network">
  <title>Network configuration</title>
<para>

Of course, preseeding the network configuration won't work if you're
loading your preseed file from the network. But it's great when you're
booting from CD or USB stick. If you are loading preseed files from
the network, you can pass network config parameters in using kernel
boot parameters.

</para>

<informalexample role="example"><screen>
# netcfg will choose an interface that has link if possible. This makes it
# skip displaying a list if there is more than one interface.
d-i netcfg/choose_interface select auto

# If you have a slow dhcp server and the installer times out waiting for
# it, this might be useful.
#d-i netcfg/dhcp_timeout string 60

# If you prefer to configure the network manually, here's how:
#d-i netcfg/disable_dhcp boolean true
#d-i netcfg/get_nameservers string 192.168.1.1
#d-i netcfg/get_ipaddress string 192.168.1.42
#d-i netcfg/get_netmask string 255.255.255.0
#d-i netcfg/get_gateway string 192.168.1.1
#d-i netcfg/confirm_static boolean true

# Any hostname and domain names assigned from dhcp take precedence over
# values set here. However, setting the values still prevents the questions
# from being shown, even if values come from dhcp.
d-i netcfg/get_hostname string unassigned-hostname
d-i netcfg/get_domain string unassigned-domain

# Disable that annoying WEP key dialog.
d-i netcfg/wireless_wep string
# The wacky dhcp hostname that some ISPs use as a password of sorts.
#d-i netcfg/dhcp_hostname string radish
</screen></informalexample>

  </sect2>

  <sect2 id="preseed-mirror">
  <title>Mirror settings</title>
<para>

Depending on the installation method you use, a mirror may be used both to
download additional components of the installer, the base system and to
set up the <filename>/etc/apt/sources.list</filename> for the installed
system.

</para><para>

The parameter <classname>mirror/suite</classname> determines the suite for
the installed system.

</para><para>

The parameter <classname>mirror/udeb/suite</classname> determines the suite
for additional components for the installer. It is only useful to set this
if components are actually downloaded over the network and should match the
suite that was used to build the initrd for the installation method used for
the installation.
By default the value for <classname>mirror/udeb/suite</classname> is the same
as <classname>mirror/suite</classname>.

</para>

<informalexample role="example"><screen>
d-i mirror/country string enter information manually
d-i mirror/http/hostname string http.us.debian.org
d-i mirror/http/directory string /debian
d-i mirror/http/proxy string

# Suite to install.
#d-i mirror/suite string testing
# Suite to use for loading installer components (optional).
#d-i mirror/udeb/suite string testing
</screen></informalexample>

  </sect2>

  <sect2 id="preseed-partman">
  <title>Partitioning</title>
<para>

Using preseeding to partition the harddisk is very much limited to what is
supported by <classname>partman-auto</classname>. You can choose to either
partition existing free space on a disk or a whole disk. The layout of the
disk can be determined by using a predefined recipe, a custom recipe from
a recipe file or a recipe included in the preseed file. It is currently not
possible to partition multiple disks using preseeding nor to set up RAID or
LVM.

</para>

<warning><para>

The identification of disks is dependent on the order in which their drivers
are loaded. If there are multiple disks in the system, make very sure the
correct one will be selected before using preseeding.

</para></warning>

<informalexample role="example"><screen>
# If the system has free space you can choose to only partition that space.
#d-i partman-auto/init_automatically_partition \
#      select Use the largest continuous free space

# Alternatively, you can specify a disk to partition. The device name can
# be given in either devfs or traditional non-devfs format.
# For example, to use the first disk devfs knows of:
d-i partman-auto/disk string /dev/discs/disc0/disc

# You can choose from any of the predefined partitioning recipes:
d-i partman-auto/choose_recipe \
       select All files in one partition (recommended for new users)
#d-i partman-auto/choose_recipe \
#       select Separate /home partition
#d-i partman-auto/choose_recipe \
#       select Separate /home, /usr, /var, and /tmp partitions

# Or provide a recipe of your own...
# The recipe format is documented in the file devel/partman-auto-recipe.txt.
# If you have a way to get a recipe file into the d-i environment, you can
# just point at it.
#d-i partman-auto/expert_recipe_file string /hd-media/recipe

# If not, you can put an entire recipe the preseed file in one (logical)
# line. This example creates a small /boot partition, suitable swap, and
# uses the rest of the space for the root partition:
#d-i partman-auto/expert_recipe string                         \
#      boot-root ::                                            \
#              40 50 100 ext3                                  \
#                      $primary{ } $bootable{ }                \
#                      method{ format } format{ }              \
#                      use_filesystem{ } filesystem{ ext3 }    \
#                      mountpoint{ /boot }                     \
#              .                                               \
#              500 10000 1000000000 ext3                       \
#                      method{ format } format{ }              \
#                      use_filesystem{ } filesystem{ ext3 }    \
#                      mountpoint{ / }                         \
#              .                                               \
#              64 512 300% linux-swap                          \
#                      method{ swap } format{ }                \
#              .

# This makes partman automatically partition without confirmation.
d-i partman/confirm_write_new_label boolean true
d-i partman/choose_partition \
       select Finish partitioning and write changes to disk
d-i partman/confirm boolean true
</screen></informalexample>

  </sect2>

  <sect2 id="preseed-time">
  <title>Clock and time zone setup</title>

<informalexample role="example"><screen>
# Controls whether or not the hardware clock is set to UTC.
d-i clock-setup/utc boolean true

# You may set this to any valid setting for $TZ; see the contents of
# /usr/share/zoneinfo/ for valid values.
d-i time/zone string US/Eastern
</screen></informalexample>

  </sect2>

  <sect2 id="preseed-apt">
  <title>Apt setup</title>
<para>

Setup of the <filename>/etc/apt/sources.list</filename> and basic configuration
options is fully automated based on your installation method and answers to
earlier questions. Only the three variables below are relevant for preseeding.

</para>

<informalexample role="example"><screen>
# You can choose to install non-free and contrib software.
#d-i apt-setup/non-free boolean true
#d-i apt-setup/contrib boolean true
# To avoid adding security sources, or to use a different server
# than security.debian.org.
#d-i apt-setup/security_host string 
</screen></informalexample>

  </sect2>

  <sect2 id="preseed-account">
  <title>Account setup</title>
<para>

The password for the root account and name and password for a first regular
user's account can be preseeded. For the passwords you can use either clear
text values or MD5 <emphasis>hashes</emphasis>.

</para>
<warning><para>

Be aware that preseeding passwords is not completely secure as everyone
with access to the preseed file will have the knowledge of these passwords.
Using MD5 hashes is considered slightly better in terms of security but it
might also give a false sense of security as access to a MD5 hash allows
for brute force attacks.

</para></warning>

<informalexample role="example"><screen>
# Root password, either in clear text
#d-i passwd/root-password password r00tme
#d-i passwd/root-password-again password r00tme
# or encrypted using an MD5 hash.
#d-i passwd/root-password-crypted password [MD5 hash]

# Skip creation of a normal user account.
#d-i passwd/make-user boolean false

# Alternatively, create a normal user account.
#d-i passwd/user-fullname string Debian User
#d-i passwd/username string debian
# Normal user's password, either in clear text
#d-i passwd/user-password password insecure
#d-i passwd/user-password-again password insecure
# or encrypted using an MD5 hash.
#d-i passwd/user-password-crypted password [MD5 hash]
</screen></informalexample>

<para>

The <classname>passwd/root-password-crypted</classname> and
<classname>passwd/user-password-crypted</classname> variables can also be
preseeded with <quote>!</quote> as their value. In that case, the corresponding
account is disabled. This may be convenient for the root account, provided
of course that an alternate method is setup to allow administrative
activities or root login (for instance by using SSH key authentication or
sudo).

</para><para>

An MD5 hash for a password can be generated using the following command.

<informalexample><screen>
$ echo "r00tme" | mkpasswd -s -H MD5
</screen></informalexample>

</para>
  </sect2>

  <sect2 id="preseed-base-installer">
  <title>Base system installation</title>
<para>

There is actually not very much that can be preseeded for this stage of the
installation. The only questions asked concern the installation of the kernel.

</para>

<informalexample role="example"><screen>
# Select the initramfs generator used to generate the initrd for 2.6 kernels.
#d-i base-installer/kernel/linux/initramfs-generators string yaird
</screen></informalexample>

  </sect2>

  <sect2 id="preseed-bootloader">
  <title>Boot loader installation</title>

<informalexample role="example"><screen>
# Grub is the default boot loader (for x86). If you want lilo installed
# instead, uncomment this:
#d-i grub-installer/skip boolean true

# This is fairly safe to set, it makes grub install automatically to the MBR
# if no other operating system is detected on the machine.
d-i grub-installer/only_debian boolean true

# This one makes grub-installer install to the MBR if if finds some other OS
# too, which is less safe as it might not be able to boot that other OS.
d-i grub-installer/with_other_os boolean true

# Alternatively, if you want to install to a location other than the mbr,
# uncomment and edit these lines:
#d-i grub-installer/bootdev  string (hd0,0)
#d-i grub-installer/only_debian boolean false
#d-i grub-installer/with_other_os boolean false
</screen></informalexample>

  </sect2>

  <sect2 id="preseed-pkgsel">
  <title>Package selection</title>
<para>

You can choose to install any combination of tasks that are available.
Available tasks as of this writing include:

</para>

<itemizedlist>
<listitem><para>
  <userinput>Standard system</userinput>
</para></listitem>
<listitem><para>
  <userinput>Desktop environment</userinput>
</para></listitem>
<listitem><para>
  <userinput>Web server</userinput>
</para></listitem>
<listitem><para>
  <userinput>Print server</userinput>
</para></listitem>
<listitem><para>
  <userinput>DNS server</userinput>
</para></listitem>
<listitem><para>
  <userinput>File server</userinput>
</para></listitem>
<listitem><para>
  <userinput>Mail server</userinput>
</para></listitem>
<listitem><para>
  <userinput>SQL database</userinput>
</para></listitem>
<listitem><para>
  <userinput>Laptop</userinput>
</para></listitem>
</itemizedlist>

<para>

You can also choose to install no tasks, and force the installation of a
set of packages in some other way. We recommend always including the
<userinput>Standard system</userinput> task.

</para>

<informalexample role="example"><screen>
tasksel tasksel/first multiselect Standard system, Desktop environment
#tasksel tasksel/first multiselect Standard system, Web server

# Some versions of the installer can report back on what software you have
# installed, and what software you use. The default is not to report back,
# but sending reports helps the project determine what software is most
# popular and include it on CDs.
#popularity-contest popularity-contest/participate boolean false
</screen></informalexample>

  </sect2>

  <sect2 id="preseed-finish">
  <title>Finishing up the first stage install</title>

<informalexample role="example"><screen>
# Avoid that last message about the install being complete.
d-i prebaseconfig/reboot_in_progress note

# This will prevent the installer from ejecting the CD during the reboot,
# which is useful in some situations.
#d-i cdrom-detect/eject boolean false
</screen></informalexample>

  </sect2>

  <sect2 id="preseed-mailer">
  <title>Mailer configuration</title>
<para>

During a normal install, exim asks only a few questions. Here's how to
avoid even those. More complicated preseeding is possible.

</para>

<informalexample role="example"><screen>
exim4-config exim4/dc_eximconfig_configtype \
       select no configuration at this time
exim4-config exim4/no_config boolean true
exim4-config exim4/no_config boolean true
exim4-config exim4/dc_postmaster string
</screen></informalexample>

  </sect2>

  <sect2 id="preseed-X">
  <title>X configuration</title>
<para>

Preseeding Debian's X config is possible, but you probably need to know
some details about the video hardware of the machine, since Debian's X
configurator does not do fully automatic configuration of everything.

</para>

<informalexample role="example"><screen>
# X can detect the right driver for some cards, but if you're preseeding,
# you override whatever it chooses. Still, vesa will work most places.
#xserver-xorg xserver-xorg/config/device/driver select vesa

# A caveat with mouse autodetection is that if it fails, X will retry it
# over and over. So if it's preseeded to be done, there is a possibility of
# an infinite loop if the mouse is not autodetected.
#xserver-xorg xserver-xorg/autodetect_mouse boolean true

# Monitor autodetection is recommended.
xserver-xorg xserver-xorg/autodetect_monitor boolean true
# Uncomment if you have an LCD display.
#xserver-xorg xserver-xorg/config/monitor/lcd boolean true
# X has three configuration paths for the monitor. Here's how to preseed
# the "medium" path, which is always available. The "simple" path may not
# be available, and the "advanced" path asks too many questions.
xserver-xorg xserver-xorg/config/monitor/selection-method \
       select medium
xserver-xorg xserver-xorg/config/monitor/mode-list \
       select 1024x768 @ 60 Hz
</screen></informalexample>

  </sect2>

  <sect2 id="preseed-other">
  <title>Preseeding other packages</title>

<informalexample role="example"><screen>
# Depending on what software you choose to install, or if things go wrong
# during the installation process, it's possible that other questions may
# be asked. You can preseed those too, of course. To get a list of every
# possible question that could be asked during an install, do an
# installation, and then run these commands:
#   debconf-get-selections --installer > file
#   debconf-get-selections >> file
</screen></informalexample>

  </sect2>
 </sect1>

 <sect1 id="preseed-advanced">
 <title>Advanced options</title>

  <sect2 id="preseed-shell">
  <title>Shell commands</title>

<informalexample role="example"><screen>
# d-i preseeding is inherently not secure. Nothing in the installer checks
# for attempts at buffer overflows or other exploits of the values of a
# preseed file like this one. Only use preseed files from trusted
# locations! To drive that home, and because it's generally useful, here's
# a way to run any shell command you'd like inside the installer,
# automatically.

# This first command is run as early as possible, just after
# preseeding is read.
#d-i preseed/early_command string anna-install some-udeb

# This command is run just before the install finishes, but when there is
# still a usable /target directory. You can chroot to /target and use it
# directly, or use the apt-install and in-target commands to easily install
# packages and run commands in the target system.
#d-i preseed/late_command string apt-install zsh; in-target chsh -s /bin/zsh
</screen></informalexample>

  </sect2>

  <sect2 id="preseed-chainload">
  <title>Chainloading preseed files</title>
<para>

It is possible to include other preseed files from a preseed file. Any
settings in those files will override pre-existing settings from files
loaded earlier. This makes it possible to put, for example, general
networking settings for your location in one file and more specific
settings for certain configurations in other files.

</para>

<informalexample><screen>
# More that one file can be listed, separated by spaces; all will be
# loaded. The included files can have preseed/include directives of their
# own as well. Note that if the filenames are relative, they are taken from
# the same directory as the preseed file that includes them.
#d-i preseed/include string x.cfg

# The installer can optionally verify checksums of preseed files before
# using them. Currently only md5sums are supported, list the md5sums
# in the same order as the list of files to include.
#d-i preseed/include/checksum string 5da499872becccfeda2c4872f9171c3d

# More flexibly, this runs a shell command and if it outputs the names of
# preseed files, includes those files. 
#d-i preseed/include_command \
#      string echo if [ "`hostname`" = bob ]; then echo bob.cfg; fi
</screen></informalexample>

  </sect2>
 </sect1>
</appendix>