Archiso

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Revision as of 00:16, 1 December 2014 by Ajbibb (talk | contribs) (build.sh requires the loop kernel module to be loaded, added this to the wiki)
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zh-CN:Archiso

Archiso is a small set of bash scripts capable of building fully functional Arch Linux based live CD and USB images. It is the tool used to generate the official CD/USB images, however it is a very generic tool and it could potentially be used to generate anything from rescue systems, install disks, to special interest live CD/DVD/USB systems, and who knows what else. Simply put, if it involves Arch on a shiny coaster, it can do it. The heart and soul of Archiso is mkarchiso. All of its options are documented in its usage output, so its direct usage won't be covered here. Instead, this wiki article will act as a guide for rolling your own live media in no time!

Setup

Note: It is recommended to act as root in all the following steps. If not, it is very likely to have problems with false permissions later.

Before we begin, we need to install archiso from the official repositories. Alternatively, archiso-gitAUR can be found in the AUR.

Create a directory to work within, this is where all the modifications to the live image will take place: ~/archlive should do fine.

$ mkdir ~/archlive

The archiso scripts that were installed to the host system earlier now need to be copied over into the newly created directory you will be working within.

Archiso comes with two "profiles": releng and baseline.

If you wish to create a fully customised live version of Arch Linux, pre-installed with all your favourite programs and configurations, use releng.

If you just want to create the most basic live medium, with no pre-installed packages and a minimalistic configuration, use baseline.

So, depending on your needs, execute the following, replacing 'PROFILE' with either releng or baseline.

# cp -r /usr/share/archiso/configs/PROFILE/ ~/archlive

The build scripts require that the loop kernel module be loaded. From the command line:

# modprobe loop

If you are using the releng profile to make a fully customised image, then you can proceed onto #Configure our live medium.

If you are using the baseline profile to create a bare image, then you won't be needing to do any customisations and can proceed onto #Build the ISO.

Configure our live medium

This section details configuring the image you will be creating, allowing you to define the packages and configurations you want your live image to contain.

Change into the directory we created earlier (~/archlive/releng/ if you have been following this guide), you will see a number of files and directories; we are only concerned with a few of these, mainly: packages.* - this is where you list, line by line, the packages you want to have installed, and the airootfs directory - this directory acts as an overlay and it is where you make all the customisations.

Generally, every administrative task that you would normally do after a fresh install except for package installation can be scripted into ~/archlive/releng/airootfs/root/customize-airootfs.sh. It has to be written from the perspective of the new environment, so / in the script means the root of the live-iso which is created.

Installing packages

You will want to create a list of packages you want installed on your live CD system. A file full of package names, one-per-line, is the format for this. This is great for special interest live CDs, just specify packages you want in packages.both and bake the image. The packages.i686 and packages.x86_64 files allow you to install software on just 32bit or 64bit, respectively.

I recommend installing "rsync" if you wish to install the system later on with no internet connection or skipping downloading it all over again. (#Installation)

Custom local repository

Merge-arrows-2.pngThis article or section is a candidate for merging with Pacman tips#Custom local repository.Merge-arrows-2.png

Notes: Move the general information (e.g. repo tree) into the main article. (Discuss in Talk:Archiso#)

You can also create a custom local repository for the purpose of preparing custom packages or packages from AUR/ABS. When doing so with packages for both architectures, you should follow a certain directory order to not run into problems.

For instance:

  • ~/customrepo
    • ~/customrepo/x86_64
      • ~/customrepo/x86_64/foo-x86_64.pkg.tar.xz
      • ~/customrepo/x86_64/customrepo.db.tar.gz
      • ~/customrepo/x86_64/customrepo.db (symlink created by repo-add)
    • ~/customrepo/i686
      • ~/customrepo/i686/foo-i686.pkg.tar.xz
      • ~/customrepo/i686/customrepo.db.tar.gz
      • ~/customrepo/i686/customrepo.db (symlink created by repo-add)

You can then add your repository by putting the following into ~/archlive/releng/pacman.conf, above the other repository entries (for top priority):

# custom repository
[customrepo]
SigLevel = Optional TrustAll
Server = file:///home/user/customrepo/$arch

So, the build scripts just look for the appropriate packages.

If this is not the case you will be running into error messages similar to this:

error: failed to prepare transaction (package architecture is not valid)
:: package foo-i686 does not have a valid architecture

Avoid installation of packages belonging to base group

By, default /usr/bin/mkarchiso, a script which is used by ~/archlive/releng/build.sh, calls one of the arch-install-scripts named pacstrap without the -i flag, which causes Pacman to not wait for user input during the installation process.

When blacklisting base group packages by adding them to the IgnorePkg line in ~/archlive/releng/pacman.conf, Pacman asks if they still should be installed, which means they will when user input is bypassed. To get rid of these packages there are several options:

  • Dirty: Add the -i flag to each line calling pacstrap in /usr/bin/mkarchiso.
  • Clean: Create a copy of /usr/bin/mkarchiso in which you add the flag and adapt ~/archlive/releng/build.sh so that it calls the modified version of the mkarchiso script.
  • Advanced: Create a function for ~/archlive/releng/build.sh which explicitly removes the packages after the base installation. This would leave you the comfort of not having to type enter so much during the installation process.

Adding a user

User management can be handled the same way as during the normal installation process, except you put your commands scripted into ~/archlive/releng/airootfs/root/customize_airootfs.sh. For further information have a look at User management.

Adding files to image

Note: You must be root to do this, do not change the ownership of any of the files you copy over, everything within the airootfs directory must be root owned. Proper ownerships will be sorted out shortly.

The airootfs directory acts as an overlay, think of it as root directory '/' on your current system, so any files you place within this directory will be copied over on boot-up.

So if you have a set of iptables scripts on your current system you want to be used on you live image, copy them over as such:

# cp -r /etc/iptables ~/archlive/releng/airootfs/etc

Placing files in the users home directory is a little different. Do not place them within airootfs/home, but instead create a skel directory within airootfs/ and place them there. We will then add the relevant commands to the customize_root_image.sh which we are going to use to copy them over on boot and sort out the permissions.

First, create the skel directory; making sure you are within ~/archlive/releng/airootfs/etc directory (if this is where you are working from):

# cd ~/archlive/releng/airootfs/etc && mkdir skel

Now copy the 'home' files to the skel directory, again doing everything as root! e.g for .bashrc.

# cp ~/.bashrc ~/archlive/releng/airootfs/etc/skel/

When ~/archlive/releng/airootfs/root/customize-airootfs.sh is executed and a new user is created, the files from the skel directory will automatically be copied over to the new home folder, permissions set right.

Boot Loader

The default file should work fine, so you should not need to touch it.

Due to the modular nature of isolinux, you are able to use lots of addons since all *.c32 files are copied and available to you. Take a look at the official syslinux site and the archiso git repo. Using said addons, it is possible to make visually attractive and complex menus. See here.

Login manager

Starting X at boot is done by enabling your login manager's systemd service. If you know which .service file needs a softlink: Great. If not, you can easily find out in case you're using the same program on the system you build your iso on. Just use

# systemctl disable nameofyourloginmanager

to temporarily turn it off. Next type the same command again and replace "disable" with "enable" to activate it again. Systemctl prints information about softlink it creates. Now change to ~/archiso/releng/airootfs/etc/systemd/system and create the same softlink there.

An example (make sure you're either in ~/archiso/releng/airootfs/etc/systemd/system or add it to the command):

# ln -s /usr/lib/systemd/system/lxdm.service display-manager.service

This will enable LXDM at system start on your live system.

Changing Automatic Login

The configuration for getty's automatic login is located under airootfs/etc/systemd/system/getty@tty1.service.d/autologin.conf.

You can modify this file to change the auto login user:

[Service]
ExecStart=
ExecStart=-/sbin/agetty --autologin isouser --noclear %I 38400 linux

Or remove it altogether to disable auto login.

Build the ISO

Now you are ready to turn your files into the .iso which you can then burn to CD or USB: Inside the directory you are working with, either ~/archlive/releng, or ~/archlive/baseline, execute:

# ./build.sh -v

The script will now download and install the packages you specified to work/*/airootfs, create the kernel and init images, apply your customizations and finally build the iso into out/.

Note: If you want to use a window manager in the Live CD then you must add the necessary and correct video drivers, or the WM may freeze on loading.

Rebuild the ISO

If you want to rebuild your iso again after a few modifications, you have to remove lock files in the work directory:

# rm -v work/build.make_*

Using the ISO

CD

Just burn the iso to a cd. You can follow CD Burning as you wish.

USB

See USB flash installation media.

GRUB

See Multiboot_USB_drive#Arch_Linux.

grub4dos

Grub4dos is a utility that can be used to create multiboot usbs, able to boot multiple linux distros from the same usb stick.

To boot the generated system on a usb with grub4dos already installed, loop mount the ISO and copy the entire /arch directory to the root of the usb. Then edit the menu.lst file from the grub4dos (it must be on the usb root) and add these lines:

title Archlinux x86_64
kernel /arch/boot/x86_64/vmlinuz archisolabel=<your usb label>
initrd /arch/boot/x86_64/archiso.img

Change the x86_64 part as necessary and put your real usb label there.

Installation without Internet access

If you wish to install the archiso(e.g. the offical monthly release) as it is without an Internet connection, or, if you don't want to download the packages you want again:

First, please follow the beginners' guide and skip some parts(like #Establish_an_internet_connection) until the #Install_the_base_system step.

Install the archiso to the new root

Instead of installing the packages with pacstrap(as it downloads every packages from remote repository and we have no Internet access now), please copy everything in the Live environment to the new root:

# time (cp -ax /{usr,bin,lib,lib64,sbin,etc,home,opt,root,srv,var} /mnt)
Note: This command excludes some special directories, as they should not be copied to the new root.

Then, create some directories and copy the kernel image to the new root, in order to keep the integrity of the new system:

# mkdir -vm755 /mnt/{boot,dev,run,mnt}
# cp -vaT /run/archiso/bootmnt/arch/boot/$(uname -m)/vmlinuz /mnt/boot/vmlinuz-linux
# mkdir -vm1777 /mnt/tmp
# mkdir -vm555 /mnt/{sys,proc}

After that, please generate a fstab as described in Beginners' guide#Generate_an_fstab.

Chroot and configure the base system

Next, chroot into your newly installed system:

# arch-chroot /mnt /bin/bash

Please note that before you configure the locale,keymap,etc,... there are something necessary to do, in order to get rid of the trace of a Live environment(in other words, the customization of archiso which does not fit a non-Live environment).

Restore the configuration of journald

This customization of archiso will lead to storing the system journal in RAM, it means that the journal will not available after reboot:

# sed -i 's/Storage=volatile/#Storage=auto/' /etc/systemd/journald.conf

Reset the pam's configuration

This configuration of pam perhaps break the security of your new system, it's recommend to use the default configuration:

# nano /etc/pam.d/su
#%PAM-1.0
auth            sufficient      pam_rootok.so
# Uncomment the following line to implicitly trust users in the "wheel" group.
#auth           sufficient      pam_wheel.so trust use_uid
# Uncomment the following line to require a user to be in the "wheel" group.
#auth           required        pam_wheel.so use_uid
auth            required        pam_unix.so
account         required        pam_unix.so
session         required        pam_unix.so

Remove special udev rule

This rule of udev starts the dhcpcd automatically if there are any wired network interfaces.

# rm /etc/udev/rules.d/81-dhcpcd.rules

Disable and remove the services created by archiso

Some service files are created for the Live environment, please disable the services and remove the file as they are unnecessary for the new system:

# systemctl disable pacman-init.service choose-mirror.service
# rm -r /etc/systemd/system/{choose-mirror.service,pacman-init.service,etc-pacman.d-gnupg.mount,getty@tty1.service.d}
# rm /etc/systemd/scripts/choose-mirror

Remove special scripts of the Live environment

There are some scripts installed in the live system by archiso scripts, which are unnecessary for the new system:

# rm /etc/systemd/system/getty@tty1.service.d/autologin.conf
# rm /root/{.automated_script.sh,.zlogin}
# rm /etc/sudoers.d/g_wheel
# rm /etc/mkinitcpio-archiso.conf
# rm -r /etc/initcpio

Set the password of arch

The customization script created a normal user called arch for the Live environment. You can set a passwd for user arch in order to login with this username(there is no passwd for arch by default):

# passwd arch

Or, if you don't want to use this username, please remove this user:

# userdel -r arch

Create an initial ramdisk environment

Please create an initial ramdisk as described in Beginners'_guide#Create_an_initial_ramdisk_environment.

Normal configuration

After all of these, now you can follow the beginners' guide and finish the installation.

See also

Documentation and tutorials

Example customization template