[grml-autoconfig.git] / doc / grml-autoconfig.1.txt

grml-autoconfig(1)
==================

Name
----
grml-autoconfig - main bootup process of a grml system

Synopsis
--------
None - it is a framework. See grml-autoconfig(8) for information regarding
the interface script.

Introduction
------------

By using the config framework, it is possible to customize Grml's startup in a
multitude of ways. It allows to:

- execute one or more scripts on startup
- install Debian packages from deb files on startup
- unpack configuration on startup

The combination of Debs, Configuration and Scripts is called DCS in Grml. DCS
can be read from the Live Image itself, from an arbitrary file system on the
local system which is marked with the volume label GRMLCFG, or from the file
system pointed to by the myconfig boot parameter.

The DCS handling is controlled by a number of boot parameters.

The scripts save-config and restore-config can be used to create and handle
files called 'grml configuration archive', abbreviated GCA. save-config stores
the running configuration inside a GCA; restore-config is a script to restore a
configuration from a GCA.

[TIP]
A GCA is a plain bzip2 compressed tar archive. All the files are generated
starting from the root-directory '/' so it is easy to handle. You can generate
configuration archives manually as well. save-config is just a frontend which
should make it easier to use.

The grml-autoconfig code has been re-worked in August 2009. This document
handles both the behavior of Grml releases up to 2009.05  (see
<<up-to-200905,section 'Behavior up to grml 2009.05'>>) and the current behavior
(see <<current-versions,section 'Behavior in current Grml versions'>>). Great
care has been taken to provide maximum backwards compatibility during the
rewrite.

[IMPORTANT]
Starting with grml release 2009.05 its possible to use root persistency on grml.
This means you can store your settings and reuse them on reboot, without having
to deal with this config framework. Visit
link:http://wiki.grml.org/doku.php?id=persistency for further information.

[[up-to-200905]]
Behavior up to grml 2009.05
---------------------------

This section applies to all Grml versions older than and including release 2009.05.

Autoconfiguration
~~~~~~~~~~~~~~~~~

By default the booting process tries to mount a device labeled 'GRMLCFG'. This
provides the possibility to restore a configuration (named config.tbz) and
execute a script (named grml.sh) without the need to specify any bootparams. If
you want to disable this feature please take a look at the 'noautoconfig'
bootparam.

Boot parameters
~~~~~~~~~~~~~~~

As you probably know you can adjust boot parameters on the bootprompt.  You want
to set some boot parameters permanently? That's possible via adding a directory
named 'bootparams' to the Grml-ISO which has to be located at the root-directory
/bootparams/ (note: the directory is known as /live/image/bootparams/ on a
_running_ grml system then). Place a textfile inside the directory containing
the boot parameters which should be appended to default ones (this corresponds
to booting without any special parameters). If you want to be able to boot from
your Grml-CD you have to create a multisession CD. See the <<X7,usage
scenarios>> for more details how to use it or consider booting from a USB device
(checkout grml2usb).

The following boot parameters are supported. Use them at the (isolinux)
bootprompt as documented here.

myconfig::

   This parameter is for restoring configuration using the file config.tbz
    on the specified device. Usage examples:

  myconfig=/dev/sda1                        => use file config.tbz from usb-device
  myconfig=/dev/fd0                         => use file config.tbz from floppy-disk
  myconfig=/dev/sda1 file=config_foobar.tbz => use file config_foobar.tbz from usb-device

home::

    This parameter is for setting a specific partition as home directory.
    Usage examples:

  home=/dev/sda3    =>  use /dev/sda3 as the homepartition
  home=scan         =>  scan through the available partitions and search
                        for file grml.img

partconf::

    This parameter mounts the specified device in read-only mode and tries to
    copy all files specified in /etc/grml/partconf to the Grml system. This
    provides the possibility to use the configuration of a harddisk
    installation. For example using the network configuration (which is
    specified in /etc/network) is possible using this boot parameter. Usage
    example:

  partconf=/dev/sda2 => try to mount /dev/sda2 and copy files specified
                        in /etc/grml/partconf to the booted Grml system

netconfig::

    Use this parameter to restore configuration using wget to download a
    configuration file from specified destination. Usage example:

  netconfig=server.tld/path/to/config.tbz  =>   restore configuration using wget to download file config.tbz

extract::

    Extract specific directories from configuration archive. Notice: This
    bootparam is useful only with bootparams which are able to extract
    configuration archives.

  extract=/home/grml         => extract only /home/grml from archive
  extract=/etc               => extract only /etc from archive
  extract=/home/grml/config  => extract only $HOME/config from archive

scripts::

    This parameter executes a script located in the root-directory /scripts/ on
    the Grml media/ISO (note: the directory is known as /live/image/scripts/ on
    a _running_ Grml system then). Usage examples:

  scripts               =>   run script [/live/image]/scripts/grml.sh
  scripts=foobar.sh     =>   run script foobar.sh in [/live/image]/scripts/

config::

    This parameter restores a configuration using root-directory /config/ on the
    Grml media/ISO (note: the directory is known as /live/image/config on a
    _running_ Grml system then). Usage examples:

  config                    =>   restore configuration using file config.tbz from directory [/live/image]/config/
  config=config_foobar.tbz  =>   restore configuration using file config_foobar.tbz from directory [/live/image]/config/

debs::

    This parameter allows automatic installation of deb packages while booting.
    The debian packages have to be located in the root-directory /debs/ on the
    Grml media/ISO (note: the directory is known as /live/image/debs/ on a
    _running_ Grml system then). Usage examples:

  debs              =>   install all debian packages (suffix .deb) from directory [/live/image]/debs/
  debs=01           =>   install all debian packages (suffix .deb) starting with 01 in the filename from directory [/live/image]/debs/


noautoconfig::

    Deactivate automounting. By default the command 'mount' tries to mount a
    device with label 'GRMLCFG'. If you specify the noautoconfig bootparam the
    automounting will be deactivated.

  noautoconfig            => disables auto mounting of label 'GRMLCFG'

[[current-versions]]
Behavior in current Grml versions
---------------------------------

This section applies to all Grml versions newer than release 2009.05.

The central concept of grml-autoconfig is the DCS directory which holds debs,
configuration and scripts which are used during system startup.

Determination of DCS directory
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The DCS directory defaults to the root directory of the GRML live image. If a
file system labeled GRMLCFG is found, the DCS directory is the root directory of
that file system. Alternatively, the myconfig boot parameter can be used to
directly specify a device which is then taken as DCS directory
(myconfig=/dev/sda1, for example).

Without any additional boot parameters, the GCA at DCSDIR/config.tbz is
automatically unpacked and DCSDIR/scrips/grml.sh is automaitcally executed on
system startup. The 'noautoconfig' boot parameter disables this automatic
behavior.

Boot Parameters
~~~~~~~~~~~~~~~

The following boot parameters are supported. Use them at the (isolinux)
bootprompt as documented here.

myconfig::

   This parameter directly sets DCSDIR to the root directory of the specified
   device. Usage examples:

  myconfig=/dev/sda1                        => read DCS from usb-device
  myconfig=/dev/fd0                         => read DCS from floppy-disk

home::

    This parameter is for setting a specific partition as home directory.  Usage
    examples:

  home=/dev/sda3    =>  use /dev/sda3 as the homepartition
  home=scan         =>  scan through the available partitions and search
                        for file grml.img

partconf::

    This parameter mounts the specified device in read-only mode and tries to
    copy all files specified in /etc/grml/partconf to the Grml system. This
    provides the possibility to use the configuration of a harddisk
    installation. For example using the network configuration (which is
    specified in /etc/network) is possible using this boot parameter. Usage
    example:

  partconf=/dev/sda2 => try to mount /dev/sda2 and copy files specified
                        in /etc/grml/partconf to the booted Grml system

netconfig::

    Use this parameter to restore configuration using wget to download a GCA
    from the specified destination. You can also add variables to change the
    file name depending on the host configuration. Predefined and useful
    variables are $ARCH, $HOSTNAME and $KERNEL. Usage example:

  netconfig=server.tld/path/to/config.tbz  =>   restore configuration using wget to download file config.tbz
  netconfig=server.tld/config-$ARCH.tbz    =>   download config for specified architecture

netscript::
    Use this parameter to download and run a script from specified destination:
    You can also add variables to change the file name depending on the host
    configuration. Predefined and useful variables are $ARCH, $HOSTNAME and
    $KERNEL. Usage example:

  netcript=server.tld/path/to/script       =>   download and run script/executable from server
  netscript=server.tld/script-$HOSTNAME    =>   download and run script/executable for specific host

extract::

    Extract specific directories from the GCA which needs to be specified by
    other means.

  extract=/home/grml         => extract only /home/grml from archive
  extract=/etc               => extract only /etc from archive
  extract=/home/grml/config  => extract only $HOME/config from archive

scripts::

    This parameter executes scripts. If an optional path is given, it is
    relative to DCSDIR. If it points to a directory, all scripts inside this
    directory are executed. If the path points to a file, this single file is
    executed. If no path is given, it defaults to scripts/grml.sh. Usage
    examples:

  scripts               =>   run script DCSDIR/scripts/grml.sh
  scripts=foobar.sh     =>   run script foobar.sh in DCSDIR
  scripts=foobar        =>   run all scripts inside DCSDIR/foobar directory

config::

    This parameter restores a configuration using a GCA. If an optional path is
    given, it is relative to DCSDIR. If no path is given, it defaults to
    DCSDIR/config.tbz. Usage examples:

  config                    =>   restore configuration using file DCSDIR/config.tbz
  config=config_foobar.tbz  =>   restore configuration using file DCSDIR/config_foobar.tbz

debs::

    This parameter allows automatic installation of deb packages while booting.
    The path is relative to DCSDIR, not optional and is a shell wildcard. All
    Files matching the wildcard are installed in a single dpkg --install call.
    For backwards compatibility, if no slash is contained in the path, it is
    taken relative to DCSDIR/debs.

    Usage examples:

  debs=*.deb        =>   install all debian packages (suffix .deb) from directory DCSDIR/debs/
  debs=foo/01*.deb  =>   install all debian packages (suffix .deb) starting with 01 in the filename from directory DCSDIR/foo


noautoconfig::

    Deactivate automounting. By default the scripts try to mount a device with
    label 'GRMLCFG'. If you specify the noautoconfig bootparam this automounting
    will be deactivated.

  noautoconfig            => disables auto mounting of label 'GRMLCFG'


Permanently adjust boot parameters
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

As you probably know you can adjust boot parameters on the bootprompt.  You want
to set some boot parameters permanently? That's possible via adding a directory
named 'bootparams' to the Grml ISO which has to be located at the root-directory
/bootparams/ (note: the directory is known as /live/image/bootparams/ on a
_running_ Grml system then). Place a textfile inside the directory containing
the boot parameters which should be appended to default ones (this corresponds
to booting without any special parameters).

  mkdir bootparams
  echo lang=de > bootparams/my_bootparams

Then burn a multisession CD where directory bootparams is located in the root
directory of the CD.

[NOTE]
Not all boot parameters can be used via /bootparams/. This is a limitation of
the way the kernel and userspace retrieve boot parameters. Boot parameter
regarding the kernel definitely do *NOT* work. Boot parameter related to
grml-autoconfig (the main part of the boot process in Grml running in userspace,
being all the stuff after startup of udev) are expected to work. Boot parameter
related to initrd/initramfs (the part between 'Searching for GRML file' and
startup of udev) are *NOT* covered by /bootparams/ as well yet.

TIP: the application k3b (not available on the live-CD but available through the
Debian repositories) provides an easy to use interface for doing the
multisession task.

[[X7]]
Usage scenarios
---------------

Personal configuration files
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

You are a fan of the editor vim? Great. You probably have your own ~/.vimrc and
want to use it on the Grml system. You also don't like the default zsh
configuration and want to use your own ~/.zshrc?  How to procede? Copy your
.vimrc and .zshrc to $HOME of user 'grml'.  Place additional files in
$HOME/config. Now create a configuration for your files running:

  save-config -home -configdir

Now you should have a file named config.tbz containing your configuration files.
You can copy the archive to a webserver and restore it via downloading during
reboot using the following commandline on bootprompt:

  grml netconfig=server.tld/path/to/config.tbz

You don't have network access but own a floppy drive? Copy the file to a floppy
disk and boot with:

  grml myconfig=/dev/fd0

Floppy is to small or to slow? Ok, let's use a usb device:

  grml myconfig=/dev/sda1

Network configuration
~~~~~~~~~~~~~~~~~~~~~

You need a specific network setup and want to use your own
/etc/network/interfaces by default? Generate the configuration archive running
the following command as user root:

  save-config -etc

Now you should have a file named config.tbz containing your configuration files.
If you want to use it with a floppy disk copy the file to a floppy and boot via
using the following command on bootprompt:

  grml myconfig=/dev/fd0

Floppy is to small or to slow? Ok, let's use a usb device:

  grml myconfig=/dev/sda1

You do have an existing harddisk installation and want to use its configuration?
Let's say the debian system is located in /dev/sda2. You want to use the
directory /etc/network. This directory is activated by default in
/etc/grml/partconf so we don't have to do any further work.  We just need to
activate it via using the following commandline on bootprompt:

  grml partconf=/dev/sda2

Automatic installation of debian packages
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

You have a specified debian package named 'foobar.deb' and want to use it with
(therefore: install it on) Grml by default? Notice: this feature is useful
especially for grml-small (a ~100 MB ISO). If you want to use it with the large
version of Grml you might have to overburn the ISO.

Let's assume you have burned the Grml iso to a CD-RW using a commandline like:

  cdrecord dev=/dev/hdc -v -multi -tao grml_0.5.iso

Now create a directory named debs and place foobar.deb in it:

  mkdir debs/ && cp foobar.deb debs/

Notice: This directory will be located in /live/image after burning the second
session.

Now create the second session containing this directory:

  mkisofs -M grml_0.5.iso -C `cdrecord -msinfo dev=/dev/hdc` -R -o 2nd_session.iso debs

Finally append the second session to the cd using:

  cdrecord dev=/dev/hdc -v -multi -tao 2nd_session.iso

TIP: the application k3b (not available on the live CD but available through the
Debian repositories) provides an easy to use interface for doing the
multisession task.

Now boot from your new personalized Grml CD using the debs parameter:

  grml debs

Run your own commands on startup
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

You know that booting with 'grml service=foobar' executes /etc/init.d/foobar
when booting Grml. But you want to setup a more complex network configuration,
adjust some other stuff and so on on your own? Just write a script named grml.sh
which does the job and use own of the mentioned bootparams. Let's say you have
placed grml.sh on your usb device (usb stick) then use the following commandline
on bootprompt:

  grml myconfig=/dev/sda1

Or even better: create a floppy disk with label GRMLCFG running:

  fdformat /dev/fd0   # format the floppy disk if not done already
  mkfs.ext2 -L GRMLCFG /dev/fd0   # now create ext2 filesystem with label GRMLCFG on it:

TIP: several filesystems provide the possibility to provide a label.  For
example FAT provides this through: 'mkfs.vfat -n GRMLCFG /dev/sda1' (attention:
this will destroy data on /dev/sda1 of course!). Take a look at the
documentation/manpage of the filesystem you want to use.

Now place your configuration archive (see save-config and the other usage
scenarios) and the script grml.sh on the floppy disk. Now you can boot your
system without specifying any bootparameters on bootprompt because devices
labeled with GRMLCFG are mounted readonly and used by default. If you did not
label your device you can use the device anyway using 'grml myconfig=/dev/ice'
on the bootprompt.

Debug remote systems
~~~~~~~~~~~~~~~~~~~~

You are responsible for a customer's system in her data center. The system has
failed and you need to debug from remote, and the remote hands available in the
data center do not have enough knowledge to get Grml booted and configure the
network without external help?

If the hard disk of the system is still available, you hopefully have saved a
configuration file with IP address, netmask and default gateway somewhere on
that hard disk. Grml can use the information found on a partition. Take a look
at the 'partconf' boot parameter.  Usage example: 'grml partconf=/dev/sda2'
copies files defined in /etc/grml/partconf from /dev/sda2 to the Grml system. As
/etc/network is predefined in /etc/grml/partconf the configuration from
/dev/sda2 will be taken.

Or you use a standard Grml medium and have grml read IP address, netmask and
default gateway from another medium like a floppy or an USB stick. Take a look
at the script saveconfig and the boot parameter myconfig.

Or you put a grml.iso file on your hard disk (maybe in /boot/grml) or on an USB
stick, use grub to boot from there and place debs, configuration scripts or Grml
configuraton archives alongside the .iso.

Use persistent home directory
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

You want to use a persistent home directory which includes all the files located
in $HOME. Use the script mkpersistenthome to create such a persistent home
directory. You have the options to either use a specific partition as your home
directory or add a loopback file named grml.img on the specified partition (the
default).

TIP: /dev/external in the partition selection of mkpersistenthome is an usb
device without partitions. /dev/external1 corresponds to the first partition on
an usb device (usually an usb stick).

After running the script mkpersistenthome you can use the boot parameter home to
activate the home directory. If you are using the option with the loopback file
(grml.img) you can boot via:

  grml home=scan

which will scan through the partitions and if a file grml.img is found it will
be mounted as your $HOME-directory. If you want to use a partition as your home
directory specify the device as an option. If you want to use /dev/sda2 as your
$HOME boot via:

  grml home=/dev/sda2

Notice: the files located in /etc/skel will be copied to the partition (but will
not overwrite any files).

Bugs
----
If you find a bug please report it. See link:http://grml.org/bugs/ for details
about how to report bugs.

See also
--------
grml-autoconfig(8), mkpersistenthome(1), restore-config(1), save-config(1)

Author
------
(c) 2005++, Michael Prokop <mika@grml.org>