## page was renamed from DebianInstallerPreseed #language en ~-[[DebianWiki/EditorGuide#translation|Translation(s)]]: English - [[fr/DebianInstaller/Preseed|Français]]-~ ---- {{{#!wiki debian https://www.debian.org/releases/stable/amd64/apb.en.html - Debian GNU/Linux installation guide - Appendix B. Automating the installation using preseeding }}} . <> = Preseeding d-i = 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. Most of the questions asked by DebianInstaller can be preseeded by setting the answers in the [[debconf]] database. The Installation Guide includes an extensive appendix dedicated to preseeding ([[https://www.debian.org/releases/stable/amd64/apb.en.html|stable:amd64]], [[https://www.debian.org/releases/testing/amd64/apb.en.html|testing:amd64]] ). For concrete preseed files look below. Feel free to add any information that is not covered in the manual to the notes below. = Preseed syntax = [[https://www.debian.org/releases/stable/example-preseed.txt|Here is an example]] of a Debian preseed file. The [[https://www.debian.org/releases/stable/amd64/apbs03.en.html|installation guide]] provides additional details about the syntax and meaning of each field. '''⚠ A preseed file is not a shell script,''' despite the syntax looking similar (comments with #, continued lines with backslash). It may not contain {{{ if }}} tests, variables, etc. = Preseeding methods = As mentioned in the [[https://www.debian.org/releases/stable/i386/apb.en.html|official installation guide]], there are several ways to feed the preseed file to the installer. As of Debian 10 preseed file can be loaded using these ''URL'' schemes: '''file floppy http https tftp''' ''file URL scheme'' requires a full path inside the installer initrd. The second partition of the installer USB disk which is mounted at '''/media''' in the installer initrd usually has a little space where you can put a preseed file. == Adding the preseed file to the installer's initrd.gz == Installation can be fully automated by adding a preseed file to the installer ISO's initrd.gz. This method is described in detail in [[DebianInstaller/Preseed/EditIso|this wiki article]]. The downside of this method is that new installer has to be generated whenever a preseed file is modified. == Autoloading the preseeding file from a webserver via DHCP == If you have control over the DHCP server on your network, this method allows fully automated installations; as demonstrated and documented at [[https://hands.com/d-i/|"Hands-off" Debian Installation]]. == Loading the preseeding file from a webserver == Most install methods you can interrupt early on and add a URL to a preseed file, for an almost fully automated installations. Here exemplified with the graphical installer: * When the graphical ''installer boot menu'' appears, select the "Help" entry * You get a generic help screen, which has a boot: prompt at the bottom. * Type "auto url=http://webserver/path/preseed.cfg" there, replacing the URL with the address to your preseed configuration file The "auto" command launches the installation in the automated mode, where the configuration of hostname, locale and keymap are postponed so that they can be answered from the preseed file loaded from the network. You could use "install url=..." but you'd have to answer these questions manually, regardless of what you have in the preseed config. If a server path isn't specified the path 'd-i//preseed.cfg' will be tried, for example `d-i/stretch/preseed.cfg`. Note that network configuration options (`netcfg/*`) cannot be applied via a network-loaded preseed.cfg file, as the network must be configured before the preseed file can be fetched. If network configuration options must be declared, needed options have be passed as kernel options (eg `netcfg/choose_interface=eth0`). Note that if the preseed config is loaded over https the install environment may not recognise the certificates presented by the webserver. You can add the option "debian-installer/allow_unauthenticated_ssl=true" to bypass certificate checks. = Default preseed files = When creating a preseed file, you should start from a known good, default preseed file: * [[https://www.debian.org/releases/stable/example-preseed.txt|Preseed file example]] for [[DebianStable|Debian Stable]] If you use a preseed file for an older, newer or otherwise different OS, you will most likely be prompted for answers at some point, even if you thought you automated everything. = Obtaining the answers given during an interactive installer run = The DebianInstaller logs the answers given during an interactive installation which can then be used to preseed a noninteractive installation. Those logs can be accessed by giving the --installer option to debconf-get-selections. More information can be found in [[https://d-i.debian.org/doc/installation-guide/en.amd64/apbs03.html|chapter B.3 of the installation guide]]. = Custom preseed files = Some packages use [[debconf]] questions/dialogs or default values to create configuration at installation time. You can preseed answers for any debconf item in the following way: * Install the [[DebianPkg:debconf-utils]] package * Get current debconf settings for DebianInstaller: {{{debconf-get-selections --installer}}} * Get current debconf settings for installed packages: {{{debconf-get-selections}}} Copy any relevant values from the output of these commands, and add it to your custom {{{preseed.cfg}}} file. Do not work off a {{{debconf-get-selections}}} ({{{--installer}}}) generated {{{preseed.cfg}}} but get the values from it and modify the example preseed file with them. You can check that the preseed file syntax is valid with {{{debconf-set-selections -c preseed.cfg}}}. = Exhaustive preseed files = SteveMcIntyre [[https://preseed.debian.net/debian-preseed/|provides]] preseed files that contain the full list of available preseed options, extracted from the templates in all packages in the Debian archive. = Preseeding and the installer's debconf templates = As part of its construction the DebianInstaller uses [[https://d-i.debian.org/doc/internals/ch03.html|udeb]] files. These files are similar to normal .debs and have a control section which may contain a file called ''templates'' which, amongst other things, contains questions which can be asked during the installation. The answers to these questions can, in many cases, be preseeded. Not all udebs have a templates file. If you have a ''.udeb'' its templates file can be extracted using apt-extracttemplates, which is in the apt-utils package. The command {{{ apt-extracttemplates -t $PWD file.udeb }}} produces two files in the same directory as file.udeb. With ''ls -l'' you should see something like {{{ file.config.S7Fsld file.template.4tyDFV }}} The terminating string is a random one and the second file is the one of interest. This contains the information necessary to preseed answers to questions asked by the installer. == Processing templates files == Let's assume you have all the available udeb files for your chosen suite (stable, testing or unstable) and are in the directory containing them. The templates files from them will be extracted by {{{ #!/bin/bash UDEBS=*.udeb mkdir $PWD/templates for i in $UDEBS do apt-extracttemplates -t $PWD $i rm *.config* 2>/dev/null done }}} This is a script to obtain all English language information from a selection of templates and put it in a single file after changing to the templates directory: {{{ #!/bin/bash FILES=*.template* for f in $FILES do # Have titled sections for data from each template file. TITLE=$(echo $f |cut -d"." -f1) echo -e "\n\n\n********** $TITLE **********" >> preseed.all # Extract data from templates and do a bit of tidying up. sed '/^Indices-.*\.UTF/d' $f \ | sed '/^Choices-.*\.UTF-8/d' \ | awk '/^Template:/,/-.*\.UTF-8:/' \ | awk '!/-.*\.UTF-8:/' \ | sed '/^Template:/{x;p;x;}' \ >> preseed.all done }}} Most of the non-question data can be eliminated with {{{ #!/bin/bash FILES=*.template* for f in $FILES do # Have titled sections for data from each template file. TITLE=$(echo $f |cut -d"." -f1) echo -e "\n\n\n********** $TITLE **********" >> preseed.all # Extract data from templates and remove text, error, title # and note data types. sed '/^Indices-.*\.UTF-8/d' $f \ | sed '/^Choices-.*\.UTF-8/d' \ | awk '/^Template:/,/-.*\.UTF-8:/' \ | awk '!/-.*\.UTF-8:/' \ | sed '/^Template:/{x;p;x;}' \ | sed ':a $!N;s/\nType: text/ Type: text/;ta P;D' \ | sed '/Type: text/,/^$/d' \ | sed ':a $!N;s/\nType: error/ Type: error/;ta P;D' \ | sed '/Type: error/,/^$/d' \ | sed ':a $!N;s/\nType: title/ Type: title/;ta P;D' \ | sed '/Type: title/,/^$/d' \ | sed ':a $!N;s/\nType: note/ Type: note/;ta P;D' \ | sed '/Type: note/,/^$/d' \ >> preseed.all done }}} == Obtaining udeb files from a Debian archive == For a small handful of files it is probably convenient to download them from Debian website's [[https://www.debian.org/distrib/packages|Packages page]] (View package lists). However, it is worthwhile considering using ''apt-get'' and an archive in /etc/apt/sources.list. A suitable entry is: {{{ deb https://deb.debian.org/debian stable main/debian-installer }}} Then {{{ apt-get update apt-get install }}} With the previous entry as the only one in sources.list a list of available udebs can be written to a file using {{{ apt-cache dumpavail | grep ^Package: | cut -d" " -f2 > udebpkgs }}} and the contents of udebpkgs downloaded with {{{ for pkg in $(cat udebpkgs) ; do apt-get download $pkg ; done }}}Post-processing with apt-extracttemplates and a script is undertaken as described in [[DebianInstaller/Preseed#Processing templates files|a previous section]]. == Obtaining udeb files from a Debian ISO == Without root privileges extraction of all the udebs used in an ISO can do done with {{{ bsdtar -C -xf --strip-components 4 --exclude '*.deb' /pool/main }}} Post-processing with apt-extracttemplates and a script is carried out [[DebianInstaller/Preseed#Processing templates files|as described earlier]]. == Obtaining deb files from a Debian ISO == Without root privileges extraction of all the debs used in an ISO can do done with {{{ bsdtar -C -xf --strip-components 4 --exclude '*.udeb' /pool/main }}} Change to and run the next script to extract the templates from the debs: {{{ #!/bin/bash DEBS=*.deb mkdir $PWD/templates for i in $DEBS do apt-extracttemplates -t $PWD $i rm *.config* 2>/dev/null done }}} Then process them [[DebianInstaller/Preseed#Processing templates files|with a script]]. The popularity-contest and tasksel templates are likely to find a use in preseeding choices used during the installation. For the eventual rebooted system and new installation the console-setup, exim4-config and keyboard-configuration templates could form part of the preseeding strategy. = All templates from all .deb files = Packages with a dependency on debconf would be expected to have a templates file. After removing the pipe symbol and duplicate entries {{{ DEBS=$(apt-cache rdepends debconf | tr -d'| ' | uniq | grep -v ReverseDepends) }}} will hold a list of such debs and {{{ apt-get download $DEBS }}} will put them on your machine [[DebianInstaller/Preseed#Processing templates files|to be processed]]. The rebooted system could have some non-installer packages already downloaded and configured with a late_command. = Examples = Post here any links you have to example preseed files. Note that using any of these files directly is not wise, as a malicious person could probably come up with values for a preseed file that makes d-i misbehave. Also, the files are downloaded over http, so are vulnerable to man-in-the-middle spoof attacks. The best way to use any preseed file is to copy it to your own local web server or media, and look it over before using it. * Christian Perrier's page documenting [[https://web.archive.org/web/20101031133327/https://people.debian.org/~bubulle/d-i/vmware-fai.html|automated d-i installs in vmware, using netboot]]. * Holger Levsen's d-i examples [[http://layer-acht.org/d-i/|showing]] a way to preserve partitions and ssh-host-keys: * Enrico Zinis [[https://www.enricozini.org/blog/2008/tips/d-i-conditional-partitioning/|conditional partitioning hints]] * Using network-console and preseeding is described on two pages, DebianInstaller/NetworkConsole and [[DebianInstaller/Remote]] * Phil Hands' [[https://hands.com/d-i/|d-i setup]], that allows minimal (i.e. no exim) installs, works from CD, PXE & USB (read the HOWTO's), and allows custom configs to be specified at the boot: prompt * DebianInstaller/AsSshClient for using d-i as a ssh terminal * Christian Perrier documented a D-I demo setup in DebianInstaller/BabelBox * Debian Administration has an article on [[https://web.archive.org/web/20150914170955/https://www.debian-administration.org/article/394/Automating_new_Debian_installations_with_preseeding|using preseeding]] * Filip Van Raemdonck documented [[DebianInstaller/Preseed/EditIso|modifying an iso to include the preseed file]] * [[https://lackof.org/taggart/hacking/d-i_preseed/|Matt Taggart's notes and configuration]], including using serial console and postfix. * Step by Step guide on how to integrate non-free firmware and preseed.cfg while [[https://wiki.n0r1sk.com/index.php/Debian_Remaster_Netinstaller_-_Integrate_Firmware_bnx2x_and_Preseed|remastering a netinstaller image]] * In debian-boot Charles Plessey [[https://lists.debian.org/debian-boot/2016/09/msg00075.html|posted]] about a [[https://people.debian.org/~plessy/debconfTemplateToHTML.hs|script]] he is using to collate debconf templates in a [[https://people.debian.org/~plessy/DebianInstallerDebconfTemplates.html|single HTML page]]. * ShowMeBox has [[https://alioth-archive.debian.org/git/showme/|scripts]] to repackage a netinst image embedding a preseeding file. * [[https://www.linuxjournal.com/content/preseeding-full-disk-encryption|LinuxJournal's preseed guide]] to automate Full Disk Encryption using [[LVM#Encrypted_LVM|Encrypted LVM]] = Notes = * Be aware there is only one space in preseed files between subkey and value on "{{{owner key/subkey value}}}" lines. * Do not reboot in the {{{base-config/late_command}}} command, the installation process will start again at the start of the 2nd stage. * Preseeding has changed significantly in etch, preseed files for sarge will need to be updated or re-done. The largest change is the removal of base-config, which means that {{{base-config/late_command}}} and {{{base-config/early_command}}} are no longer available. * To install additional packages in etch, you can use {{{preseed preseed/early_command}}} to run "apt-install package". * Look in debconf-devel(7) in the debconf-doc package for more docs about d-i and debian-installer preseed questions. * If your preseed value is being ignored and whilst using DEBCONF_DEBUG=5 to watch the debconf output you see "FSET blah false" it just means that a piece of code really wants that question to be seen, and such questions are not normally preseedable - the only way to avoid them is to avoid the situation that gives rise to that question being asked. CategoryPackageManagement CategoryDebianInstaller