B.4. Contents of the preconfiguration file (for bookworm)

The configuration fragments used in this appendix are also available as an example preconfiguration file from https://www.debian.org/releases/bookworm/example-preseed.txt.

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.

Details on how the different Debian Installer components actually work can be found in Section 6.3, “Using Individual Components”.

B.4.1. Localization

During a normal install the questions about localization are asked first, so these values can only be preseeded via the initrd or kernel boot parameter methods. Auto mode (Section B.2.3, “Auto mode”) includes the setting of auto-install/enable=true (normally via the auto preseed alias). This delays the asking of the localisation questions, so that they can be preseeded by any method.

The locale can be used to specify both language and country and can be any combination of a language supported by debian-installer and a recognized country. If the combination does not form a valid locale, the installer will automatically select a locale that is valid for the selected language. To specify the locale as a boot parameter, use locale=en_US.

Although this method is very easy to use, it does not allow preseeding of all possible combinations of language, country and locale[19]. So alternatively the values can be preseeded individually. Language and country can also be specified as boot parameters.

# Preseeding only locale sets language, country and locale.
d-i debian-installer/locale string en_US

# The values can also be preseeded individually for greater flexibility.
#d-i debian-installer/language string en
#d-i debian-installer/country string NL
#d-i debian-installer/locale string en_GB.UTF-8
# Optionally specify additional locales to be generated.
#d-i localechooser/supported-locales multiselect en_US.UTF-8, nl_NL.UTF-8

Keyboard configuration consists of selecting a keymap and (for non-latin keymaps) a toggle key to switch between the non-latin keymap and the US keymap. Only basic keymap variants are available during installation. Advanced variants are available only in the installed system, through dpkg-reconfigure keyboard-configuration.

# Keyboard selection.
d-i keyboard-configuration/xkb-keymap select us
# d-i keyboard-configuration/toggle select No toggling

To skip keyboard configuration, preseed keymap with skip-config. This will result in the kernel keymap remaining active.

B.4.2. Network configuration

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

If you need to pick a particular interface when netbooting before loading a preconfiguration file from the network, use a boot parameter such as interface=eth1.

Although preseeding the network configuration is normally not possible when using network preseeding (using preseed/url), you can use the following hack to work around that, for example if you'd like to set a static address for the network interface. The hack is to force the network configuration to run again after the preconfiguration file has been loaded by creating a preseed/run script containing the following commands:

kill-all-dhcp; netcfg

The following debconf variables are relevant for network configuration.

# Disable network configuration entirely. This is useful for cdrom
# installations on non-networked devices where the network questions,
# warning and long timeouts are a nuisance.
#d-i netcfg/enable boolean false

# 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

# To pick a particular interface instead:
#d-i netcfg/choose_interface select eth1

# To set a different link detection timeout (default is 3 seconds).
# Values are interpreted as seconds.
#d-i netcfg/link_wait_timeout string 10

# 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
#d-i netcfg/dhcpv6_timeout string 60

# Automatic network configuration is the default.
# If you prefer to configure the network manually, uncomment this line and
# the static network configuration below.
#d-i netcfg/disable_autoconfig boolean true

# If you want the preconfiguration file to work on systems both with and
# without a dhcp server, uncomment these lines and the static network
# configuration below.
#d-i netcfg/dhcp_failed note
#d-i netcfg/dhcp_options select Configure network manually

# Static network configuration.
# IPv4 example
#d-i netcfg/get_ipaddress string
#d-i netcfg/get_netmask string
#d-i netcfg/get_gateway string
#d-i netcfg/get_nameservers string
#d-i netcfg/confirm_static boolean true
# IPv6 example
#d-i netcfg/get_ipaddress string fc00::2
#d-i netcfg/get_netmask string ffff:ffff:ffff:ffff::
#d-i netcfg/get_gateway string fc00::1
#d-i netcfg/get_nameservers string fc00::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

# If you want to force a hostname, regardless of what either the DHCP
# server returns or what the reverse DNS entry for the IP is, uncomment
# and adjust the following line.
#d-i netcfg/hostname string somehost

# 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

# If you want to completely disable firmware lookup (i.e. not use firmware
# files or packages that might be available on installation images):
#d-i hw-detect/firmware-lookup string never

# If non-free firmware is needed for the network or other hardware, you can
# configure the installer to always try to load it, without prompting. Or
# change to false to disable asking.
#d-i hw-detect/load_firmware boolean true

Please note that netcfg will automatically determine the netmask if netcfg/get_netmask is not preseeded. In this case, the variable has to be marked as seen for automatic installations. Similarly, netcfg will choose an appropriate address if netcfg/get_gateway is not set. As a special case, you can set netcfg/get_gateway to none to specify that no gateway should be used.

B.4.3. Network console

# Use the following settings if you wish to make use of the network-console
# component for remote installation over SSH. This only makes sense if you
# intend to perform the remainder of the installation manually.
#d-i anna/choose_modules string network-console
#d-i network-console/authorized_keys_url string
#d-i network-console/password password r00tme
#d-i network-console/password-again password r00tme

More information related to network-console can be found in Section 6.3.10, “Installation over network-console”.

B.4.4. Mirror settings

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

The parameter mirror/suite determines the suite for the installed system.

The parameter mirror/udeb/suite 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. Normally the installer will automatically use the correct value and there should be no need to set this.

# Mirror protocol:
# If you select ftp, the mirror/country string does not need to be set.
# Default value for the mirror protocol: http.
#d-i mirror/protocol string ftp
d-i mirror/country string manual
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

B.4.5. Account setup

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 crypt(3) hashes.

[Warning] Warning

Be aware that preseeding passwords is not completely secure as everyone with access to the preconfiguration file will have the knowledge of these passwords. Storing hashed passwords is considered secure unless a weak hashing algorithm like DES or MD5 is used which allow for bruteforce attacks. Recommended password hashing algorithms are SHA-256 and SHA512.

# Skip creation of a root account (normal user account will be able to
# use sudo).
#d-i passwd/root-login boolean false
# Alternatively, to skip creation of a normal user account.
#d-i passwd/make-user boolean false

# Root password, either in clear text
#d-i passwd/root-password password r00tme
#d-i passwd/root-password-again password r00tme
# or encrypted using a crypt(3)  hash.
#d-i passwd/root-password-crypted password [crypt(3) hash]

# To 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 a crypt(3) hash.
#d-i passwd/user-password-crypted password [crypt(3) hash]
# Create the first user with the specified UID instead of the default.
#d-i passwd/user-uid string 1010

# The user account will be added to some standard initial groups. To
# override that, use this.
#d-i passwd/user-default-groups string audio cdrom video

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

The following command (available from the whois package) can be used to generate a SHA-512 based crypt(3) hash for a password:

mkpasswd -m sha-512

B.4.6. Clock and time zone setup

# 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

# Controls whether to use NTP to set the clock during the install
d-i clock-setup/ntp boolean true
# NTP server to use. The default is almost always fine here.
#d-i clock-setup/ntp-server string ntp.example.com

B.4.7. Partitioning

Using preseeding to partition the harddisk is limited to what is supported by partman-auto. You can choose to partition either 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 preconfiguration file.

Preseeding of advanced partition setups using RAID, LVM and encryption is supported, but not with the full flexibility possible when partitioning during a non-preseeded install.

The examples below only provide basic information on the use of recipes. For detailed information see the files partman-auto-recipe.txt and partman-auto-raid-recipe.txt included in the debian-installer package. Both files are also available from the debian-installer source repository. Note that the supported functionality may change between releases.

[Warning] Warning

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.

B.4.7.1. Partitioning example

# If the system has free space you can choose to only partition that space.
# This is only honoured if partman-auto/method (below) is not set.
#d-i partman-auto/init_automatically_partition select biggest_free

# Alternatively, you may specify a disk to partition. If the system has only
# one disk the installer will default to using that, but otherwise the device
# name must be given in traditional, non-devfs format (so e.g. /dev/sda
# and not e.g. /dev/discs/disc0/disc).
# For example, to use the first SCSI/SATA hard disk:
#d-i partman-auto/disk string /dev/sda
# In addition, you'll need to specify the method to use.
# The presently available methods are:
# - regular: use the usual partition types for your architecture
# - lvm:     use LVM to partition the disk
# - crypto:  use LVM within an encrypted partition
d-i partman-auto/method string lvm

# You can define the amount of space that will be used for the LVM volume
# group. It can either be a size with its unit (eg. 20 GB), a percentage of
# free space or the 'max' keyword.
d-i partman-auto-lvm/guided_size string max

# If one of the disks that are going to be automatically partitioned
# contains an old LVM configuration, the user will normally receive a
# warning. This can be preseeded away...
d-i partman-lvm/device_remove_lvm boolean true
# The same applies to pre-existing software RAID array:
d-i partman-md/device_remove_md boolean true
# And the same goes for the confirmation to write the lvm partitions.
d-i partman-lvm/confirm boolean true
d-i partman-lvm/confirm_nooverwrite boolean true

# You can choose one of the three predefined partitioning recipes:
# - atomic: all files in one partition
# - home:   separate /home partition
# - multi:  separate /home, /var, and /tmp partitions
d-i partman-auto/choose_recipe select atomic

# Or provide a recipe of your own...
# 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 into the preconfiguration 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{ }                \
#              .

# The full recipe format is documented in the file partman-auto-recipe.txt
# included in the 'debian-installer' package or available from D-I source
# repository. This also documents how to specify settings such as file
# system labels, volume group names and which physical devices to include
# in a volume group.

## Partitioning for EFI
# If your system needs an EFI partition you could add something like
# this to the recipe above, as the first element in the recipe:
#               538 538 1075 free                              \
#                      $iflabel{ gpt }                         \
#                      $reusemethod{ }                         \
#                      method{ efi }                           \
#                      format{ }                               \
#               .                                              \
# The fragment above is for the amd64 architecture; the details may be
# different on other architectures. The 'partman-auto' package in the
# D-I source repository may have an example you can follow.

# This makes partman automatically partition without confirmation, provided
# that you told it what to do using one of the methods above.
d-i partman-partitioning/confirm_write_new_label boolean true
d-i partman/choose_partition select finish
d-i partman/confirm boolean true
d-i partman/confirm_nooverwrite boolean true

# Force UEFI booting ('BIOS compatibility' will be lost). Default: false.
#d-i partman-efi/non_efi_system boolean true
# Ensure the partition table is GPT - this is required for EFI
#d-i partman-partitioning/choose_label select gpt
#d-i partman-partitioning/default_label string gpt

# When disk encryption is enabled, skip wiping the partitions beforehand.
#d-i partman-auto-crypto/erase_disks boolean false

B.4.7.2. Partitioning using RAID

You can also use preseeding to set up partitions on software RAID arrays. Supported are RAID levels 0, 1, 5, 6 and 10, creating degraded arrays and specifying spare devices.

[Warning] Warning

This type of automated partitioning is easy to get wrong. It is also functionality that receives relatively little testing from the developers of debian-installer. The responsibility to get the various recipes right (so they make sense and don't conflict) lies with the user. Check /var/log/syslog if you run into problems.

# The method should be set to "raid".
#d-i partman-auto/method string raid
# Specify the disks to be partitioned. They will all get the same layout,
# so this will only work if the disks are the same size.
#d-i partman-auto/disk string /dev/sda /dev/sdb

# Next you need to specify the physical partitions that will be used. 
#d-i partman-auto/expert_recipe string \
#      multiraid ::                                         \
#              1000 5000 4000 raid                          \
#                      $primary{ } method{ raid }           \
#              .                                            \
#              64 512 300% raid                             \
#                      method{ raid }                       \
#              .                                            \
#              500 10000 1000000000 raid                    \
#                      method{ raid }                       \
#              .

# Last you need to specify how the previously defined partitions will be
# used in the RAID setup. Remember to use the correct partition numbers
# for logical partitions. RAID levels 0, 1, 5, 6 and 10 are supported;
# devices are separated using "#".
# Parameters are:
# <raidtype> <devcount> <sparecount> <fstype> <mountpoint> \
#          <devices> <sparedevices>

#d-i partman-auto-raid/recipe string \
#    1 2 0 ext3 /                    \
#          /dev/sda1#/dev/sdb1       \
#    .                               \
#    1 2 0 swap -                    \
#          /dev/sda5#/dev/sdb5       \
#    .                               \
#    0 2 0 ext3 /home                \
#          /dev/sda6#/dev/sdb6       \
#    .

# For additional information see the file partman-auto-raid-recipe.txt
# included in the 'debian-installer' package or available from D-I source
# repository.

# This makes partman automatically partition without confirmation.
d-i partman-md/confirm boolean true
d-i partman-partitioning/confirm_write_new_label boolean true
d-i partman/choose_partition select finish
d-i partman/confirm boolean true
d-i partman/confirm_nooverwrite boolean true

B.4.7.3. Controlling how partitions are mounted

Normally, filesystems are mounted using a universally unique identifier (UUID) as a key; this allows them to be mounted properly even if their device name changes. UUIDs are long and difficult to read, so, if you prefer, the installer can mount filesystems based on the traditional device names, or based on a label you assign. If you ask the installer to mount by label, any filesystems without a label will be mounted using a UUID instead.

Devices with stable names, such as LVM logical volumes, will continue to use their traditional names rather than UUIDs.

[Warning] Warning

Traditional device names may change based on the order in which the kernel discovers devices at boot, which may cause the wrong filesystem to be mounted. Similarly, labels are likely to clash if you plug in a new disk or a USB drive, and if that happens your system's behaviour when started will be random.

# The default is to mount by UUID, but you can also choose "traditional" to
# use traditional device names, or "label" to try filesystem labels before
# falling back to UUIDs.
#d-i partman/mount_style select uuid

B.4.8. Base system installation

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.

# Configure APT to not install recommended packages by default. Use of this
# option can result in an incomplete system and should only be used by very
# experienced users.
#d-i base-installer/install-recommends boolean false

# The kernel image (meta) package to be installed; "none" can be used if no
# kernel is to be installed.
#d-i base-installer/kernel/image string linux-image-686

B.4.9. Apt setup

Setup of the /etc/apt/sources.list and basic configuration options is fully automated based on your installation method and answers to earlier questions. You can optionally add other (local) repositories.

# Choose, if you want to scan additional installation media
# (default: false).
d-i apt-setup/cdrom/set-first boolean false
# You can choose to install non-free firmware.
#d-i apt-setup/non-free-firmware boolean true
# 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
# Uncomment the following line, if you don't want to have the sources.list
# entry for a DVD/BD installation image active in the installed system
# (entries for netinst or CD images will be disabled anyway, regardless of
# this setting).
#d-i apt-setup/disable-cdrom-entries boolean true
# Uncomment this if you don't want to use a network mirror.
#d-i apt-setup/use_mirror boolean false
# Select which update services to use; define the mirrors to be used.
# Values shown below are the normal defaults.
#d-i apt-setup/services-select multiselect security, updates
#d-i apt-setup/security_host string security.debian.org

# Additional repositories, local[0-9] available
#d-i apt-setup/local0/repository string \
#       http://local.server/debian stable main
#d-i apt-setup/local0/comment string local server
# Enable deb-src lines
#d-i apt-setup/local0/source boolean true
# URL to the public key of the local repository; you must provide a key or
# apt will complain about the unauthenticated repository and so the
# sources.list line will be left commented out.
#d-i apt-setup/local0/key string http://local.server/key
# or one can provide it in-line by base64 encoding the contents of the
# key file (with `base64 -w0`) and specifying it thus:
#d-i apt-setup/local0/key string base64://LS0tLS1CRUdJTiBQR1AgUFVCTElDIEtFWSBCTE9DSy0tLS0tCi4uLgo=
# The content of the key file is checked to see if it appears to be ASCII-armoured.
# If so it will be saved with an ".asc" extension, otherwise it gets a '.gpg' extension.
# "keybox database" format is currently not supported. (see generators/60local in apt-setup's source)

# By default the installer requires that repositories be authenticated
# using a known gpg key. This setting can be used to disable that
# authentication. Warning: Insecure, not recommended.
#d-i debian-installer/allow_unauthenticated boolean true

# Uncomment this to add multiarch configuration for i386
#d-i apt-setup/multiarch string i386

B.4.10. Package selection

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

  • standard (standard tools)

  • desktop (graphical desktop)

  • gnome-desktop (Gnome desktop)

  • xfce-desktop (XFCE desktop)

  • kde-desktop (KDE Plasma desktop)

  • cinnamon-desktop (Cinnamon desktop)

  • mate-desktop (MATE desktop)

  • lxde-desktop (LXDE desktop)

  • web-server (web server)

  • ssh-server (SSH server)

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 standard task.

Or if you don't want the tasksel dialog to be shown at all, preseed pkgsel/run_tasksel (no packages are installed via tasksel in that case).

If you want to install some individual packages in addition to packages installed by tasks, you can use the parameter pkgsel/include. The value of this parameter can be a list of packages separated by either commas or spaces, which allows it to be used easily on the kernel command line as well.

#tasksel tasksel/first multiselect standard, web-server, kde-desktop

# Or choose to not get the tasksel dialog displayed at all (and don't install
# any packages):
#d-i pkgsel/run_tasksel boolean false

# Individual additional packages to install
#d-i pkgsel/include string openssh-server build-essential
# Whether to upgrade packages after debootstrap.
# Allowed values: none, safe-upgrade, full-upgrade
#d-i pkgsel/upgrade select none

# You can choose, if your system will 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 should be included on the first CD/DVD.
#popularity-contest popularity-contest/participate boolean false

B.4.11. Finishing up the installation

# During installations from serial console, the regular virtual consoles
# (VT1-VT6) are normally disabled in /etc/inittab. Uncomment the next
# line to prevent this.
#d-i finish-install/keep-consoles boolean true

# Avoid that last message about the install being complete.
d-i finish-install/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

# This is how to make the installer shutdown when finished, but not
# reboot into the installed system.
#d-i debian-installer/exit/halt boolean true
# This will power off the machine instead of just halting it.
#d-i debian-installer/exit/poweroff boolean true

B.4.12. Preseeding other packages

# 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

[19] Preseeding locale to en_NL would for example result in en_US.UTF-8 as default locale for the installed system. If e.g. en_GB.UTF-8 is preferred instead, the values will need to be preseeded individually.