Difference between revisions of "Install from existing Linux"

From ArchWiki
Jump to: navigation, search
m (Script)
(remove beginners' guide link, see Talk:Installation guide#The Great Merge)
 
(235 intermediate revisions by 77 users not shown)
Line 1: Line 1:
 
[[Category:Getting and installing Arch]]
 
[[Category:Getting and installing Arch]]
[[es:Install from Existing Linux]]
+
[[es:Install from existing Linux]]
 
[[fr:Install chroot]]
 
[[fr:Install chroot]]
[[it:Install from Existing Linux]]
+
[[it:Install from existing Linux]]
[[ru:Install from Existing Linux]]
+
[[ja:既存の Linux からインストール]]
[[uk:Install from Existing Linux]]
+
[[pt:Install from existing Linux]]
[[zh-CN:Install from Existing Linux]]
+
[[ru:Install from existing Linux]]
[[zh-TW:Install from Existing Linux]]
+
[[uk:Install from existing Linux]]
 +
[[zh-cn:Install from existing Linux]]
 +
[[zh-tw:Install from existing Linux]]
 +
{{Related articles start}}
 +
{{Related|Install from SSH}}
 +
{{Related articles end}}
  
This guide is intended for anybody who wants to install Arch Linux from any other running Linux -- be it off a LiveCD or a pre-existing install of a different distro.
+
This document describes the bootstrapping process required to install Arch Linux from a running Linux host system.
 +
After bootstrapping, the installation proceeds as described in the [[Installation guide]].
  
This is useful for building up new Arch Linux systems from scratch from another distro's LiveCD or existing installation. It is also useful for creating new chroot environments on a "host" system, maintaining a "golden-master" for development & distribution, or other fun topics like [[Diskless_network_boot_NFS_root|rootfs-over-NFS for diskless machines]].
+
Installing Arch Linux from a running Linux is useful for:
  
This guide requires that the existing host system be able to execute the new target Arch Linux architecture programs. In the case of an x86_64 host, it is possible to use i686-pacman to build a 32-bit chroot environment.  See [[Arch64 Install bundled 32bit system]]. However it is not so easy to build a 64-bit environment when the host only supports running 32-bit programs.
+
* remotely installing Arch Linux, e.g. a (virtual) root server
 +
* replacing an existing Linux without a LiveCD (see [[#Replacing the existing system without a LiveCD]])
 +
* creating a new Linux distribution or LiveCD based on Arch Linux
 +
* creating an Arch Linux chroot environment, e.g. for a Docker base container
 +
* [[Diskless_network_boot_NFS_root|rootfs-over-NFS for diskless machines]]
  
If you are already using Arch, instead of following this guide, just install {{Pkg|arch-install-scripts}} from the [[Official Repositories|official repositories]] and follow the [[Installation Guide]].
+
The goal of the bootstrapping procedure is to setup an environment from which the scripts from {{Pkg|arch-install-scripts}} (such as {{ic|pacstrap}} and {{ic|arch-chroot}}) can be run.
  
'''This guide provides additional steps to the [[Installation Guide]]. The steps of that guide must still be followed as needed.'''
+
If the host system runs Arch Linux, this can be achieved by simply installing {{Pkg|arch-install-scripts}}. If the host system runs another Linux distribution, you will first need to set up an Arch Linux-based chroot.
  
==Prepare the system==
+
{{Note|This guide requires that the existing host system be able to execute the new target Arch Linux architecture programs. In the case of an x86_64 host, it is possible to use i686-pacman to build a 32-bit chroot environment. See [[Arch64 Install bundled 32bit system]]. However it is not so easy to build a 64-bit environment when the host only supports running 32-bit programs.}}
  
Follow the [[Installation Guide]] steps, until you have your partitions, keyboard and internet connection ready.
+
{{Warning|Please make sure you understand each step before proceeding. It is easy to destroy your system or to lose critical data, and your service provider will likely charge a lot to help you recover. }}
  
==Setup the enviroment for the arch install scripts==
+
==Backup and Preparation==
 +
Backup all your data including mails, webservers, etc. Have all information at your fingertips. Preserve all your server configurations, hostnames, etc.
  
You need to create an enviroment where pacman and the arch install scripts can run on your current linux distro. In addition you will need a list of pacman mirror sites which are going to be used to download data on available packages as well as the packages themselves.
+
Here is a list of data you will likely need:
 +
* IP address
 +
* hostname(s), (note: rootserver are mostly also part of the providers domain, check or save your {{ic|/etc/hosts}} before you delete)
 +
* DNS server (check {{ic|/etc/resolv.conf}})
 +
* SSH keys (if other people work on your server, they will have to accept new keys otherwise. This includes keys from your Apache, your mail servers, your SSH server and others.)
 +
* Hardware info (network card, etc. Refer to your pre-installed {{ic|/etc/modules.conf}} )
 +
* Grub configuration files.
  
Here a different methods to prepare that enviroment:
+
In general, it is a good idea to have a local copy of your original {{ic|/etc}} directory on your local hard drive.
  
===Method: Installing pacman and other packages directly under your current distro===
+
== From a host running Arch Linux ==
{{Out of date|Needs to be updated for pacman 4, use another method instead}}
+
====Introduction====
+
  
You need to get the required packages for your host Linux environment. The examples given here assume you are using an i686 environment. '''If you are running on a 64-bit Linux instead you should replace each occurrence of "i686" with "x86_64".'''
+
Install the {{Pkg|arch-install-scripts}} package.
  
All version numbers given here may change. Please check the version numbers the packages are at first and note them down. The version numbers can be found at:
+
Follow [[Installation guide#Mount the partitions]]. If you already use the {{ic|/mnt}} directory for something else, just create another directory such as {{ic|/mnt/install}}, and use that instead.
* {{pkg|pacman}}
+
* {{pkg|pacman-mirrorlist}}
+
  
Once you are sure of the version numbers, download the required packages (change the value of ARCH to either x86_64 or i686, see above):
+
Then follow [[Installation guide#Installation]]. You can skip [[Installation guide#Select the mirrors]], since the host should already have a correct mirrorlist.
  
ARCH=i686
+
{{Tip|In order to avoid redownloading all the packages, consider following [[Pacman/Tips and tricks#Network shared pacman cache]] or using ''pacstrap'''s {{ic|-c}} option.}}
base_chroot=/tmp
+
mkdir ${base_chroot}/archlinux
+
cd ${base_chroot}/archlinux
+
  
====Download pacman's binaries and shared libraries====
+
{{Merge|Moving_an_existing_install_into_(or_out_of)_a_virtual_machine#Moving_into_a_VM|Same approach.}}
  
You want to install pacman in order to be able to install software in your new base directory. We first download the binaries for [[pacman]], the Arch package manager.
+
{{Note|If you only want to create an exact copy of an existing Arch installation, it is also possible to just copy the filesystem to the new partition. With this method, you will still need to
* pacman: https://www.archlinux.org/packages/core/$ARCH/pacman/download/ . Change $ARCH according to your system.
+
* pacman-mirrorlist: https://www.archlinux.org/packages/core/any/pacman-mirrorlist/download/
+
  
==== Using wget to download ====
+
* Create [[Installation guide#Fstab|{{ic|/etc/fstab}}]] and edit {{ic|/etc/hostname}}
wget  https://www.archlinux.org/packages/core/$ARCH/pacman/download/ --no-check-certificate --trust-server-names
+
* Delete {{ic|/etc/machine-id}} so that a new, unique, one will be regenerated on boot
wget https://www.archlinux.org/packages/core/any/pacman-mirrorlist/download/ --no-check-certificate --trust-server-names
+
* Make any other changes appropriate to the installation medium
 +
* Install the bootloader
  
or this direct way (give attention to the date string in the file name, as it may need changing) :
+
When copying the filesystem root, use something like {{ic|cp -ax}} or {{ic|rsync -axX}}. This avoids copying contents of mountpoints ({{ic|-x}}), and preserves the [[capabilities]] attributes of some system binaries ({{ic|rsync -X}}).
{{bc|wget http://mirrors.kernel.org/archlinux/core/os/i686/pacman-mirrorlist-20120626-1-any.pkg.tar.xz}}
+
}}
  
See [http://pwet.fr/man/linux/commandes/wget the man page] and the [http://www.gnu.org/software/wget/manual/wget.html official manual] of wget for further details.
+
== From a host running another Linux distribution ==
  
==== Using lftp to download ====
+
There are multiple tools which automate a large part of the steps described in the following subsections. See their respective homepages for detailed instructions.
If you have issues with downloading '''pacman-mirrorlist''' use this direct way with lftp :
+
{{bc|1=link_name=http://mirrors.kernel.org/archlinux/core/os/i686/
+
lftp -e "mget pacman-mirrorlist-*.tar.xz" "${link_name}"}}
+
  
==== Additional libraries====
+
* [https://github.com/tokland/arch-bootstrap arch-bootstrap] (Bash)
You may need additional libraries to make pacman work, for newer distributions:
+
* [https://github.com/hartwork/image-bootstrap image-bootstrap] (Python)
 +
* [https://github.com/drizzt/vps2arch vps2arch] (Bash)
 +
* [https://github.com/m4rienf/ArchCX archcx] (Bash, from Hetzner CX Rescue System)
  
for software_name in libarchive openssl xz expat ; do wget https://www.archlinux.org/packages/core/$ARCH/${software_name}/download/ --no-check-certificate --trust-server-names ; done
+
The manual way is presented in the following subsections. The idea is to run an Arch system inside the host system, with the actual installation being executed from the Arch system. The nested system is contained inside a chroot.
  
When using an older distribution to bootstrap, a few more libraries may be needed for it to work, for example :
+
=== Creating the chroot ===
{{bc|for software_name in glibc gcc-libs binutils libssh2 curl gcc libarchive openssl xz expat ; do wget https://www.archlinux.org/packages/core/$ARCH/${software_name}/download/ --no-check-certificate --trust-server-names ; done}}
+
Also note that below when you set LD_LIBRARY_PATH you have to add /lib and /lib64:
+
{{bc|1=export LD_LIBRARY_PATH=${base_chroot}/archlinux/usr/lib:${base_chroot}/archlinux/lib:${base_chroot}/archlinux/usr/lib64:$LD_LIBRARY_PATH}}
+
  
Unpack all needed packages:
+
Two methods to setup and enter the chroot are presented below, from the easiest to the most complicated. Select only one of the two methods. Then, continue at [[#Using the chroot environment]].
for f in *.pkg.tar*; do tar xvf $f; done
+
  
To prepare for using pacman, do not forget to edit {{Ic|/tmp/archlinux/etc/pacman.conf}} to point to {{Ic|/tmp/archlinux/etc/pacman.d/mirrorlist}} and select your favorite mirror. For easier use (assuming you are using {{Ic|bash}} or {{Ic|zsh}}), you may set up an environment:
+
==== Method A: Using the bootstrap image (recommended) ====
export PATH=${base_chroot}/archlinux/usr/bin:$PATH
+
export LD_LIBRARY_PATH=${base_chroot}/archlinux/usr/lib:$LD_LIBRARY_PATH
+
alias pacman="pacman --config ${base_chroot}/archlinux/etc/pacman.conf"
+
  
====Install pacman on the host system====
+
Download the bootstrap image from a [https://www.archlinux.org/download mirror]:
{{Note|('''Issues while running pacman on 64-bit host''') If while running pacman you end up with {{ic|/tmp/archlinux/usr/bin/pacman: No such file or directory}} please symlink ld-linux-x86-64.so.2: {{ic|ln -s /lib64/ld-linux-x86-64.so.2 /lib/}}}}
+
# cd /tmp
 +
# curl -O https://mirrors.kernel.org/archlinux/iso/2016.08.01/archlinux-bootstrap-2016.08.01-x86_64.tar.gz
  
 +
You can also download the signature (same URL with {{ic|.sig}} added) and [[GnuPG#Verify_a_signature|verify it with GnuPG]].
  
If you do not mind littering your install host, you can extract all the downloaded tar balls into your root directory by running as root:
+
Extract the tarball:
{{Note|However, keep in mind that this operation could erase some of your files, and break your system.}}
+
  # tar xzf <path-to-bootstrap-image>/archlinux-bootstrap-2016.08.01-x86_64.tar.gz
  cd /
+
for f in /tmp/archlinux/pacman-*pkg.tar.gz ; do
+
  tar xzf $f
+
done
+
  
<ol>
+
Select a repository server by editing {{ic|/tmp/root.x86_64/etc/pacman.d/mirrorlist}}.
<li><div>If installing from Ubuntu 9.10's LiveCD (perhaps other versions), you will need more than just the pacman files (shared libs) to use pacman at all.  Use Lucky's script described in [[https://bbs.archlinux.org/viewtopic.php?pid=759166 this thread]] to get/install them for you!
+
  
</div></li>
+
{{Note|If bootstrapping an i686 image from an x86_64 host system, also edit {{Ic|/tmp/root.i686/etc/pacman.conf}} and explicitly define {{Ic|1=Architecture = i686}} in order for pacman to pull the proper i686 packages.}}
<li><div>Alternatively, you can instead turn these tarballs into packages for your distribution with the [http://kitenet.net/~joey/code/alien/ alien] tool. See the man page of the tool for instructions. The packages created that way may be installed into your host distribution using the usual package management tools available there. This approach offers the best integration into the host Linux environment. For a Debian package based system this is done with the following commands:
+
cd /tmp/archlinux
+
alien -d pacman-*-i686.pkg.tar.xz
+
alien -d pacman-mirrorlist-20120626-1-any.pkg.tar.xz
+
  
RPM based systems will need to replace the parameter "-d" with "-r".
+
Enter the chroot
  
These distribution packages can then get installed using the normal package management tools of the host Linux environment.
+
* If bash 4 or later is installed, and unshare supports the --fork and --pid options:
</div></li>
+
# /tmp/root.x86_64/bin/arch-chroot /tmp/root.x86_64/
<li><div>
+
* Otherwise, run the following commands:
Under Fedora 12, I was not able to install pacman with any of the other methods, but with the nice script at https://bbs.archlinux.org/viewtopic.php?pid=734336#p734336 it will download and install it for you. Worked wonderfully for me.
+
# mount --bind /tmp/root.x86_64 /tmp/root.x86_64
</div></li>
+
# cd /tmp/root.x86_64
<li><div>On [http://gentoo.org/ Gentoo]: Just unmask pacman by adding {{Ic|sys-apps/pacman}} to {{Ic|/etc/portage/package.keywords}}. Now just run {{Ic|emerge -av pacman}}.
+
# cp /etc/resolv.conf etc
There is also a [http://ohnopub.net/~ohnobinki/gentoo/arch/ more detailed tutorial].
+
# mount -t proc /proc proc
</div></li>
+
# mount --rbind /sys sys
</ol>
+
# mount --rbind /dev dev
 +
# mount --rbind /run run    # (assuming /run exists on the system)
 +
# chroot /tmp/root.x86_64 /bin/bash
  
=== Method: Use the alternate easier method ===
+
==== Method B: Using the LiveCD image ====
{{Out of date|Needs to be updated for the new install scripts}}
+
  
This method is verified to be working as of 1-4-12.
+
It is possible to mount the root image of the latest Arch Linux installation media and then chroot into it. This method has the advantage of providing a working Arch Linux installation right within the host system without the need to prepare it by installing specific packages.
This works best if you are in a LiveCD environment (or, in the case of servers, a GNU/Linux-based rescue environment). Firstly, you need to mount the disk you want to use for the Archlinux installation at /mnt. In this example, /dev/sda1 is used.
+
mnt /dev/sda1 /mnt
+
cd ~
+
wget http://tokland.googlecode.com/svn/trunk/archlinux/arch-bootstrap.sh && chmod +x arch-bootstrap.sh
+
  
If you are wanting to install a 32-bit system:
+
{{Note|Before proceeding, make sure the latest version of [http://squashfs.sourceforge.net/ squashfs] is installed on the host system. Otherwise, errors like the following are to be expected: {{ic|FATAL ERROR aborting: uncompress_inode_table: failed to read block}}.}}
./arch-bootstrap.sh -a i686 -r "ftp://ftp.hosteurope.de/mirror/ftp.archlinux.org" /mnt/
+
Or a 64-bit system:
+
./arch-bootstrap.sh -a x86_64 -r "ftp://ftp.hosteurope.de/mirror/ftp.archlinux.org" /mnt/
+
  
The bootstrapping will take 2-5 minutes depending on the speed of your system.
+
* The root image can be found on one of the [https://www.archlinux.org/download mirrors] under either arch/x86_64/ or arch/i686/, depending on the desired architecture. The squashfs format is not editable, so we unsquash the root image and mount it.
  
mount -t proc none /mnt/proc
+
*To unsquash the root image, run
mount -t sysfs none /mnt/sys
+
{{bc|# unsquashfs airootfs.sfs}}
mount -o bind /dev /mnt/dev
+
  
Mounting these is essential for the installation of a bootloader later on.
+
* Before [[Change root|chrooting]] to it, we need to set up some mount points and copy the resolv.conf for networking.
 +
{{bc|
 +
# mount --bind squashfs-root squashfs-root
 +
# mount -t proc none squashfs-root/proc
 +
# mount -t sysfs none squashfs-root/sys
 +
# mount -o bind /dev squashfs-root/dev
 +
# mount -o bind /dev/pts squashfs-root/dev/pts  ## important for pacman (for signature check)
 +
# cp -L /etc/resolv.conf squashfs-root/etc  ## this is needed to use networking within the chroot
 +
}}
  
If you have switched between architectures, ''pacman'' auto-detection might not work, in this case you need to edit /etc/pacman.conf to:
+
* Now, everything is prepared to chroot into the newly installed Arch environment
 +
{{bc|# chroot squashfs-root bash}}
  
From 64-bit to a 32-bit system:
+
=== Using the chroot environment ===
Architecture = i686
+
Or from 32-bit to a 64-bit system:
+
Architecture = x86_64
+
  
Now for the fun part, chroot into your newly installed Arch installation:
+
The bootstrap environment is really barebones (no {{ic|nano}}, no {{ic|ping}}, no {{ic|cryptsetup}}, no {{ic|lvm}}). Therefore, we need to set up [[pacman]] in order to download the rest of the {{ic|base}} and, if needed, {{ic|base-devel}}.
chroot /mnt bash
+
pacman -Sy base
+
mkinitcpio -p linux
+
  
Choose a bootloader. You can find the installation instructions on their own dedicated pages. ([[Syslinux]], [[Grub]], [[Grub2]], etc.).
+
==== Initializing pacman keyring ====
  
'''Remember:''' You will still need to do any final configuration touches as you would in a normal Arch install.
+
Before starting the installation, pacman keys need to be setup. Before running the following two commands, read [[pacman-key#Initializing the keyring]] to understand the entropy requirements:
 +
{{bc|
 +
# pacman-key --init
 +
# pacman-key --populate archlinux
 +
}}
  
''Credits to the Turkish site [http://raptiye.org/blog/2011/3/27/hetznerde-arch-linux-kurulumu/ Raptiye] for the original guide.''
+
{{Tip|Installing and running {{Pkg|haveged}} must be done on the host system, since it is not possible to install packages before initializing pacman keyring and because ''systemd'' will detect it is running in a chroot and [https://superuser.com/questions/688733/start-a-systemd-service-inside-chroot ignore activation request].
  
 +
If you go with doing {{ic|ls -Ra /}} in another console (TTY, terminal, SSH session...), do not be afraid of running it in a loop a few times: five or six runs from the host proved sufficient to generate enough entropy on a remote headless server.}}
  
===Method: Chroot into the Arch Linux LiveCD===
+
==== Selecting a mirror and downloading basic tools ====
  
Alternatively, you can mount the root image of the latest archlinux installation media and then chroot into it. This method has the advantage of providing you with a working Arch Linux installation right within your host system without the need to prepare it by installing specific packages.
+
After [[Mirrors#Enabling_a_specific_mirror|selecting a mirror]], [[Mirrors#Force_pacman_to_refresh_the_package_lists|refresh the package lists]] and [[install]] what you need: {{Grp|base}}, {{Grp|base-devel}}, {{Pkg|parted}} etc.
  
====Unsquash the root image====
+
=== Installation tips ===
  
The root image exists in squashfs format on the Live CD. The squashfs format is not editable as such. Hence, we unsquash the root image and then mount it.
+
You can now proceed to [[Installation_guide#Partition_the_disks]] and follow the rest of the [[Installation guide]].
  
To unsquash the root image, run
+
Some host systems or configurations may require certain extra steps. See the sections below for tips.
unsquashfs -d /squashfs-root root-image.fs.sfs
+
  
====Mount root file system====
+
===== Debian-based host =====
  
Then, mount the unsquashed root file system to a suitable mount point. We shall mount it to /arch. You can mount it wherever you want.
+
====== /dev/shm ======
livecd_arch=/arch
+
mount -B /squashfs-root ${livecd_arch}
+
  
====Chroot into the Live CD root file system====
+
On some Debian-based host systems, {{ic|pacstrap}} may produce the following error:
  
Mount various file systems into the Live CD root file system:
+
{{hc|# pacstrap /mnt base|
mount -t proc /proc ${livecd_arch}/proc
+
==> Creating install root at /mnt
mount -t sysfs /sys ${livecd_arch}/sys
+
mount: mount point /mnt/dev/shm is a symbolic link to nowhere
mount -B /dev ${livecd_arch}/dev
+
==> ERROR: failed to setup API filesystems in new root
mount -t devpts /dev/pts ${livecd_arch}/dev/pts
+
}}
  
Then, chroot into the Live CD root file system:
+
This is because in some versions of Debian, {{ic|/dev/shm}} points to {{ic|/run/shm}} while in the Arch-based chroot, {{ic|/run/shm}} does not exist and the link is broken. To correct this error, create a directory {{ic|/run/shm}}:
  chroot ${livecd_arch} /bin/bash
+
  # mkdir /run/shm
  
This chroot is able to execute the arch install scripts. The destination partitions should be mounted under the {{ic|/mnt}} directory from this chroot.
+
====== /dev/pts ======
  
===Method: Script to bootstrap the arch install scripts===
+
While installing {{ic|archlinux-2015.07.01-x86_64}} from a Debian 7 host, the following error prevented both [https://projects.archlinux.org/arch-install-scripts.git/tree/pacstrap.in pacstrap] and [[Change_root#Using_arch-chroot|arch-chroot]] from working:
  
You can run the following script to automatically download the minimum packages required to run pacman and the arch install scripts.
+
{{hc|# pacstrap -i /mnt|
Your current linux enviroment require bash, wget, sed, xz, chroot and tar installed.
+
mount: mount point /mnt/dev/pts does not exist
====Script====
+
==> ERROR: failed to setup chroot /mnt
Create a file called archinstall-bootstrap.sh and put the following content:
+
}}
  
{{hc|archinstall-bootstrap.sh|<nowiki>
+
Apparently, this is because these two scripts use a common function. {{ic|chroot_setup()}}[https://projects.archlinux.org/arch-install-scripts.git/tree/common#n76] relies on newer features of {{Pkg|util-linux}}, which are incompatible with Debian 7 userland (see {{Bug|45737}}).
#!/bin/bash
+
# This script is inspired on the archbootstrap script.
+
  
PACKAGES=(acl attr bzip2 curl expat glibc gpgme libarchive libassuan libgpg-error libssh2 openssl pacman xz zlib pacman-mirrorlist coreutils bash grep gawk file tar ncurses readline libcap util-linux pcre arch-install-scripts)
+
The solution for ''pacstrap'' is to manually execute its [https://projects.archlinux.org/arch-install-scripts.git/tree/pacstrap.in#n77 various tasks], but use the [[Change_root#Using_chroot|regular procedure]] to mount the kernel filesystems on the target directory ({{ic|"$newroot"}}):
# Change the mirror as necessary
+
MIRROR='http://mirrors.kernel.org/archlinux'
+
# You can set the ARCH variable to i686 or x86_64
+
ARCH=`uname -m`
+
LIST=`mktemp`
+
CHROOT_DIR=archinstall-chroot
+
DIR=archinstall-pkg
+
mkdir -p "$DIR"
+
mkdir -p "$CHROOT_DIR"
+
# Create a list with urls for the arch packages
+
for REPO in core community extra; do 
+
        wget -q -O- "$MIRROR/$REPO/os/$ARCH/" |sed  -n "s|.*href=\"\\([^\"]*\\).*|$MIRROR\\/$REPO\\/os\\/$ARCH\\/\\1|p"|grep -v 'sig$'|uniq >> $LIST 
+
done
+
# Download and extract each package.
+
for PACKAGE in ${PACKAGES[*]}; do
+
        URL=`grep "$PACKAGE-[0-9]" $LIST|head -n1`
+
        FILE=`echo $URL|sed 's/.*\/\([^\/][^\/]*\)$/\1/'`
+
        wget "$URL" -c -O "$DIR/$FILE"
+
        xz -dc "$DIR/$FILE" | tar x -k -C "$CHROOT_DIR"
+
done
+
# Create mount points
+
mkdir -p "$CHROOT_DIR/dev" "$CHROOT_DIR/proc" "$CHROOT_DIR/sys" "$CHROOT_DIR/mnt"
+
mount -t proc proc "$CHROOT_DIR/proc/"
+
mount -t sysfs sys "$CHROOT_DIR/sys/"
+
mount -o bind /dev "$CHROOT_DIR/dev/"
+
mkdir -p "$CHROOT_DIR/dev/pts"
+
mount -t devpts pts "$CHROOT_DIR/dev/pts/"
+
  
# Hash for empty password  Created by doing: openssl passwd -1 -salt ihlrowCo and entering an empty password (just press enter)
+
{{bc|1=
echo 'root:$1$ihlrowCo$sF0HjA9E8up9DYs258uDQ0:10063:0:99999:7:::' > "$CHROOT_DIR/etc/shadow"
+
# newroot=/mnt
echo "root:x:0:0:root:/root:/bin/bash" > "$CHROOT_DIR/etc/passwd"
+
# mkdir -m 0755 -p "$newroot"/var/{cache/pacman/pkg,lib/pacman,log} "$newroot"/{dev,run,etc}
touch "$CHROOT_DIR/etc/group"
+
# mkdir -m 1777 -p "$newroot"/tmp
echo "myhost" > "$CHROOT_DIR/etc/hostname"
+
# mkdir -m 0555 -p "$newroot"/{sys,proc}
test -e "$CHROOT_DIR/etc/mtab" || echo "rootfs / rootfs rw 0 0" > "$CHROOT_DIR/etc/mtab"
+
# mount --bind "$newroot" "$newroot"
[ -f "/etc/resolv.conf" ] && cp "/etc/resolv.conf" "$CHROOT_DIR/etc/"
+
# mount -t proc /proc "$newroot/proc"
sed -ni '/^[ \t]*CheckSpace/ !p' "$CHROOT_DIR/etc/pacman.conf"
+
# mount --rbind /sys "$newroot/sys"
sed -i "s/^[ \t]*SigLevel[ \t].*/SigLevel = Never/" "$CHROOT_DIR/etc/pacman.conf"
+
# mount --rbind /run "$newroot/run"
echo "Server = $MIRROR/\$repo/os/$ARCH" >> "$CHROOT_DIR/etc/pacman.d/mirrorlist"
+
# mount --rbind /dev "$newroot/dev"
 +
# pacman -r "$newroot" --cachedir="$newroot/var/cache/pacman/pkg" -Sy base base-devel ... ## add the packages you want
 +
# cp -a /etc/pacman.d/gnupg "$newroot/etc/pacman.d/"       ## copy keyring
 +
# cp -a /etc/pacman.d/mirrorlist "$newroot/etc/pacman.d/" ## copy mirrorlist
 +
}}
  
chroot $CHROOT_DIR /usr/bin/pacman -Sy
+
Instead of using {{ic|arch-chroot}} for [[Installation guide#Chroot]], simply use {{ic|chroot "$newroot"}}.
chroot $CHROOT_DIR /bin/bash
+
</nowiki>}}
+
  
Execute it as root:
+
====== lvmetad ======
# bash archinstall-bootstrap.sh
+
The script is going to create a directory called {{ic|archinstall-pkg}} and download the required packages there. Then, is going to extract them into the {{ic|archinstall-chroot}} directory.
+
  
After that, is going to prepare mount points, configure pacman and enter into a chroot.
+
Trying to create [[LVM]] [[LVM#Logical_volumes|logical volumes]] from an {{ic|archlinux-bootstrap-2015.07.01-x86_64}} environment on a Debian 7 host resulted in the following error:
  
This chroot is able to execute the arch install scripts. The destination partitions should be mounted under the {{ic|/mnt}} directory from this chroot.
+
{{hc|# lvcreate -L 20G lvm -n root|
 +
  /run/lvm/lvmetad.socket: connect failed: No such file or directory
 +
  WARNING: Failed to connect to lvmetad. Falling back to internal scanning.
 +
  /dev/lvm/root: not found: device not cleared
 +
  Aborting. Failed to wipe start of new LV.}}
  
==Setup the target system==
+
(Physical volume and volume group creation worked despite {{ic|/run/lvm/lvmetad.socket: connect failed: No such file or directory}} being displayed.)
  
At this point, follow the normal steps of [[Installation Guide]]. Remember to mount the destination partition under the {{ic|/mnt}} of the chroot.
+
This could be easily worked around by creating the logical volumes outside the chroot (from the Debian host). They are then available once chrooted again.
  
After you have done {{ic|pacstrap /mnt base base-devel}}, do also
+
{{Accuracy|This problem did not arise when installing from a Debian 7 host without lvmetad enabled. The recommended messaround with {{ic|/etc/lvm/lvm.conf}} looks rather error prone (2015-07-26).}}
pacstrap /mnt haveged
+
{{Style|Language and formatting are lacking, links to relevant articles in the wiki as well.}}
  
That is required later for fixing the pacman keyring.
+
Also, if the system you are using has lvm, you might have the following output:
  
===Edit the fstab file===
+
{{hc|1=# grub-install --target=i386-pc --recheck /dev/mapper/main-archroot|2=
 +
Installing for i386-pc platform.
 +
  /run/lvm/lvmetad.socket: connect failed: No such file or directory
 +
  WARNING: Failed to connect to lvmetad. Falling back to internal scanning.
 +
  /run/lvm/lvmetad.socket: connect failed: No such file or directory
 +
  WARNING: Failed to connect to lvmetad. Falling back to internal scanning.
 +
  /run/lvm/lvmetad.socket: connect failed: No such file or directory
 +
  WARNING: Failed to connect to lvmetad. Falling back to internal scanning.
 +
  /run/lvm/lvmetad.socket: connect failed: No such file or directory
 +
  WARNING: Failed to connect to lvmetad. Falling back to internal scanning.
 +
  /run/lvm/lvmetad.socket: connect failed: No such file or directory
 +
  WARNING: Failed to connect to lvmetad. Falling back to internal scanning.
 +
}}
  
Probably the {{ic|genfstab}} script wont work. In that case, you'll need to edit the {{ic|/mnt/etc/fstab}} file by hand.
+
This is because debian does not use lvmetad by default. You need to edit {{ic|/etc/lvm/lvm.conf}} and set {{ic|use_lvmetad}} to {{ic|0}}:
You can use the content of {{ic|/etc/mtab}} as reference.
+
  
===Fix the Pacman Signature Keyring===
+
use_lvmetad = 0
  
After you have entered the {{ic|arch-chroot /mnt}}, is necessary to fix the pacman signature keyring.
+
This will trigger later an error on boot in the initrd stage. Therefore, you have to change it back after the grub generation. In a software RAID + LVM, steps would be the following:
This will fix it:
+
 
# /usr/sbin/haveged -w 1024 -v 1
+
* After installing all the system, when you have to do all the initramfs (mkinitcpio) and grub thing.
# pacman-key --init
+
* Change /etc/mdadm.conf to reflect your RAID config (if any)
# pacman -U /var/cache/pacman/pkg/archlinux-keyring*
+
* Change HOOKS and MODULES according to lvm and raid requirements: {{ic|1=MODULES="dm_mod" HOOKS="base udev '''mdadm_udev''' ... block '''lvm2''' filesystems ..."}}
===Finish the Installation===
+
* Generate initrd images with mkinitcpio
Now just do the rest of the steps normally.
+
* Change /etc/lvm/lvm.conf to put use_lvmetad = 0
==Tips and tricks==
+
* Generate grub config (grub-mkconfig)
* If you are using this method because you are trying to do a remote install, like a vps, and can't umount the root partition, and, assuming the system has a swap partition large enough (about 600mb or larger), one path is to delete that partition, create the partitions for arch in that area, and install arch there (only base, not base-devel). Once the system is installed, you can reboot to your new arch system, reformat the former partitions, and [[Full_System_Backup_with_rsync#With_a_single_command|rsync the entire system]] there. At that point, next step would be to reconfigure grub or syslinux.
+
* Change /etc/lvm/lvm.conf to put use_lvmetad = 1
 +
 
 +
===== Fedora-based host =====
 +
 
 +
On Fedora based hosts and live USBs you may encounter problems when using {{ic|genfstab}} to generate your [[fstab]]. Remove duplicate entries and the "seclabel" option where it appears, as this is Fedora-specific and will keep your system from booting normally.
 +
 
 +
== Things to check before you reboot==
 +
 
 +
Before rebooting, chroot into the newly-installed system.
 +
 
 +
Set a root password so that you can log in with ssh later:
 +
# passwd
 +
 
 +
Install [[ssh]] and [[enable]] it to start automatically at boot.
 +
 
 +
Configure the [[network]] connection to start automatically at boot.
 +
 
 +
Set up a [[boot loader]] and configure it to use the swap partition you appropriated earlier as the root partition. You might want to configure your bootloader to be able to boot into your old system; it is helpful to re-use the server's existing /boot partition in the new system for this purpose.
 +
 
 +
== Replacing the existing system without a LiveCD ==
 +
 
 +
Find ~700MB of free space somewhere on the disk, e.g. by partitioning a swap partition. You can disable the swap partition and set up your system there.
 +
 
 +
===Set old swap partition as new root partition===
 +
 
 +
Check {{ic|cfdisk}}, {{ic|/proc/swaps}} or {{ic|/etc/fstab}} to find your swap partition. Assuming your hard drive is located on sdaX (X will be a number).
 +
 
 +
Do the following:
 +
 
 +
Disable the swap space:
 +
# swapoff /dev/sdaX
 +
 
 +
Create a filesystem on it
 +
# fdisk /dev/sda
 +
(set /dev/sdaX ID field to "Linux" - Hex 83)
 +
# mke2fs -j /dev/sdaX
 +
 
 +
Create a directory to mount it in
 +
# mkdir /mnt/newsys
 +
 
 +
Finally, mount the new directory for installing the intermediate system.
 +
# mount -t ext4 /dev/sdaX /mnt/newsys
 +
 
 +
=== Installation ===
 +
If less than 700MB are available, examine the packages in the group base, and select only those required to get a system with internet connection up and running in the temporary partition. This will mean explicitly specifying individual packages to pacstrap, as well as passing it the -c option, to get packages downloaded to the host system to avoid filling up valuable space.
 +
 
 +
Once the new Arch Linux system is installed, reboot into the newly created system, and [[Full system backup with rsync#With_a_single_command|rsync the entire system]] to the primary partition.
 +
Fix the bootloader configuration before rebooting.

Latest revision as of 22:25, 26 August 2016

Related articles

This document describes the bootstrapping process required to install Arch Linux from a running Linux host system. After bootstrapping, the installation proceeds as described in the Installation guide.

Installing Arch Linux from a running Linux is useful for:

The goal of the bootstrapping procedure is to setup an environment from which the scripts from arch-install-scripts (such as pacstrap and arch-chroot) can be run.

If the host system runs Arch Linux, this can be achieved by simply installing arch-install-scripts. If the host system runs another Linux distribution, you will first need to set up an Arch Linux-based chroot.

Note: This guide requires that the existing host system be able to execute the new target Arch Linux architecture programs. In the case of an x86_64 host, it is possible to use i686-pacman to build a 32-bit chroot environment. See Arch64 Install bundled 32bit system. However it is not so easy to build a 64-bit environment when the host only supports running 32-bit programs.
Warning: Please make sure you understand each step before proceeding. It is easy to destroy your system or to lose critical data, and your service provider will likely charge a lot to help you recover.

Backup and Preparation

Backup all your data including mails, webservers, etc. Have all information at your fingertips. Preserve all your server configurations, hostnames, etc.

Here is a list of data you will likely need:

  • IP address
  • hostname(s), (note: rootserver are mostly also part of the providers domain, check or save your /etc/hosts before you delete)
  • DNS server (check /etc/resolv.conf)
  • SSH keys (if other people work on your server, they will have to accept new keys otherwise. This includes keys from your Apache, your mail servers, your SSH server and others.)
  • Hardware info (network card, etc. Refer to your pre-installed /etc/modules.conf )
  • Grub configuration files.

In general, it is a good idea to have a local copy of your original /etc directory on your local hard drive.

From a host running Arch Linux

Install the arch-install-scripts package.

Follow Installation guide#Mount the partitions. If you already use the /mnt directory for something else, just create another directory such as /mnt/install, and use that instead.

Then follow Installation guide#Installation. You can skip Installation guide#Select the mirrors, since the host should already have a correct mirrorlist.

Tip: In order to avoid redownloading all the packages, consider following Pacman/Tips and tricks#Network shared pacman cache or using pacstrap's -c option.

Merge-arrows-2.pngThis article or section is a candidate for merging with Moving_an_existing_install_into_(or_out_of)_a_virtual_machine#Moving_into_a_VM.Merge-arrows-2.png

Notes: Same approach. (Discuss in Talk:Install from existing Linux#)
Note: If you only want to create an exact copy of an existing Arch installation, it is also possible to just copy the filesystem to the new partition. With this method, you will still need to
  • Create /etc/fstab and edit /etc/hostname
  • Delete /etc/machine-id so that a new, unique, one will be regenerated on boot
  • Make any other changes appropriate to the installation medium
  • Install the bootloader

When copying the filesystem root, use something like cp -ax or rsync -axX. This avoids copying contents of mountpoints (-x), and preserves the capabilities attributes of some system binaries (rsync -X).

From a host running another Linux distribution

There are multiple tools which automate a large part of the steps described in the following subsections. See their respective homepages for detailed instructions.

The manual way is presented in the following subsections. The idea is to run an Arch system inside the host system, with the actual installation being executed from the Arch system. The nested system is contained inside a chroot.

Creating the chroot

Two methods to setup and enter the chroot are presented below, from the easiest to the most complicated. Select only one of the two methods. Then, continue at #Using the chroot environment.

Method A: Using the bootstrap image (recommended)

Download the bootstrap image from a mirror:

# cd /tmp
# curl -O https://mirrors.kernel.org/archlinux/iso/2016.08.01/archlinux-bootstrap-2016.08.01-x86_64.tar.gz

You can also download the signature (same URL with .sig added) and verify it with GnuPG.

Extract the tarball:

# tar xzf <path-to-bootstrap-image>/archlinux-bootstrap-2016.08.01-x86_64.tar.gz

Select a repository server by editing /tmp/root.x86_64/etc/pacman.d/mirrorlist.

Note: If bootstrapping an i686 image from an x86_64 host system, also edit /tmp/root.i686/etc/pacman.conf and explicitly define Architecture = i686 in order for pacman to pull the proper i686 packages.

Enter the chroot

  • If bash 4 or later is installed, and unshare supports the --fork and --pid options:
# /tmp/root.x86_64/bin/arch-chroot /tmp/root.x86_64/
  • Otherwise, run the following commands:
# mount --bind /tmp/root.x86_64 /tmp/root.x86_64
# cd /tmp/root.x86_64
# cp /etc/resolv.conf etc
# mount -t proc /proc proc
# mount --rbind /sys sys
# mount --rbind /dev dev
# mount --rbind /run run    # (assuming /run exists on the system)
# chroot /tmp/root.x86_64 /bin/bash

Method B: Using the LiveCD image

It is possible to mount the root image of the latest Arch Linux installation media and then chroot into it. This method has the advantage of providing a working Arch Linux installation right within the host system without the need to prepare it by installing specific packages.

Note: Before proceeding, make sure the latest version of squashfs is installed on the host system. Otherwise, errors like the following are to be expected: FATAL ERROR aborting: uncompress_inode_table: failed to read block.
  • The root image can be found on one of the mirrors under either arch/x86_64/ or arch/i686/, depending on the desired architecture. The squashfs format is not editable, so we unsquash the root image and mount it.
  • To unsquash the root image, run
# unsquashfs airootfs.sfs
  • Before chrooting to it, we need to set up some mount points and copy the resolv.conf for networking.
# mount --bind squashfs-root squashfs-root
# mount -t proc none squashfs-root/proc
# mount -t sysfs none squashfs-root/sys
# mount -o bind /dev squashfs-root/dev
# mount -o bind /dev/pts squashfs-root/dev/pts  ## important for pacman (for signature check)
# cp -L /etc/resolv.conf squashfs-root/etc  ## this is needed to use networking within the chroot
  • Now, everything is prepared to chroot into the newly installed Arch environment
# chroot squashfs-root bash

Using the chroot environment

The bootstrap environment is really barebones (no nano, no ping, no cryptsetup, no lvm). Therefore, we need to set up pacman in order to download the rest of the base and, if needed, base-devel.

Initializing pacman keyring

Before starting the installation, pacman keys need to be setup. Before running the following two commands, read pacman-key#Initializing the keyring to understand the entropy requirements:

# pacman-key --init
# pacman-key --populate archlinux
Tip: Installing and running haveged must be done on the host system, since it is not possible to install packages before initializing pacman keyring and because systemd will detect it is running in a chroot and ignore activation request. If you go with doing ls -Ra / in another console (TTY, terminal, SSH session...), do not be afraid of running it in a loop a few times: five or six runs from the host proved sufficient to generate enough entropy on a remote headless server.

Selecting a mirror and downloading basic tools

After selecting a mirror, refresh the package lists and install what you need: base, base-devel, parted etc.

Installation tips

You can now proceed to Installation_guide#Partition_the_disks and follow the rest of the Installation guide.

Some host systems or configurations may require certain extra steps. See the sections below for tips.

Debian-based host
/dev/shm

On some Debian-based host systems, pacstrap may produce the following error:

# pacstrap /mnt base
==> Creating install root at /mnt
mount: mount point /mnt/dev/shm is a symbolic link to nowhere
==> ERROR: failed to setup API filesystems in new root

This is because in some versions of Debian, /dev/shm points to /run/shm while in the Arch-based chroot, /run/shm does not exist and the link is broken. To correct this error, create a directory /run/shm:

# mkdir /run/shm
/dev/pts

While installing archlinux-2015.07.01-x86_64 from a Debian 7 host, the following error prevented both pacstrap and arch-chroot from working:

# pacstrap -i /mnt
mount: mount point /mnt/dev/pts does not exist
==> ERROR: failed to setup chroot /mnt

Apparently, this is because these two scripts use a common function. chroot_setup()[1] relies on newer features of util-linux, which are incompatible with Debian 7 userland (see FS#45737).

The solution for pacstrap is to manually execute its various tasks, but use the regular procedure to mount the kernel filesystems on the target directory ("$newroot"):

# newroot=/mnt
# mkdir -m 0755 -p "$newroot"/var/{cache/pacman/pkg,lib/pacman,log} "$newroot"/{dev,run,etc}
# mkdir -m 1777 -p "$newroot"/tmp
# mkdir -m 0555 -p "$newroot"/{sys,proc}
# mount --bind "$newroot" "$newroot"
# mount -t proc /proc "$newroot/proc"
# mount --rbind /sys "$newroot/sys"
# mount --rbind /run "$newroot/run"
# mount --rbind /dev "$newroot/dev"
# pacman -r "$newroot" --cachedir="$newroot/var/cache/pacman/pkg" -Sy base base-devel ... ## add the packages you want
# cp -a /etc/pacman.d/gnupg "$newroot/etc/pacman.d/"       ## copy keyring
# cp -a /etc/pacman.d/mirrorlist "$newroot/etc/pacman.d/"  ## copy mirrorlist

Instead of using arch-chroot for Installation guide#Chroot, simply use chroot "$newroot".

lvmetad

Trying to create LVM logical volumes from an archlinux-bootstrap-2015.07.01-x86_64 environment on a Debian 7 host resulted in the following error:

# lvcreate -L 20G lvm -n root
  /run/lvm/lvmetad.socket: connect failed: No such file or directory
  WARNING: Failed to connect to lvmetad. Falling back to internal scanning.
  /dev/lvm/root: not found: device not cleared
  Aborting. Failed to wipe start of new LV.

(Physical volume and volume group creation worked despite /run/lvm/lvmetad.socket: connect failed: No such file or directory being displayed.)

This could be easily worked around by creating the logical volumes outside the chroot (from the Debian host). They are then available once chrooted again.

Tango-inaccurate.pngThe factual accuracy of this article or section is disputed.Tango-inaccurate.png

Reason: This problem did not arise when installing from a Debian 7 host without lvmetad enabled. The recommended messaround with /etc/lvm/lvm.conf looks rather error prone (2015-07-26). (Discuss in Talk:Install from existing Linux#)

Tango-edit-clear.pngThis article or section needs language, wiki syntax or style improvements.Tango-edit-clear.png

Reason: Language and formatting are lacking, links to relevant articles in the wiki as well. (Discuss in Talk:Install from existing Linux#)

Also, if the system you are using has lvm, you might have the following output:

# grub-install --target=i386-pc --recheck /dev/mapper/main-archroot
Installing for i386-pc platform.
  /run/lvm/lvmetad.socket: connect failed: No such file or directory
  WARNING: Failed to connect to lvmetad. Falling back to internal scanning.
  /run/lvm/lvmetad.socket: connect failed: No such file or directory
  WARNING: Failed to connect to lvmetad. Falling back to internal scanning.
  /run/lvm/lvmetad.socket: connect failed: No such file or directory
  WARNING: Failed to connect to lvmetad. Falling back to internal scanning.
  /run/lvm/lvmetad.socket: connect failed: No such file or directory
  WARNING: Failed to connect to lvmetad. Falling back to internal scanning.
  /run/lvm/lvmetad.socket: connect failed: No such file or directory
  WARNING: Failed to connect to lvmetad. Falling back to internal scanning.

This is because debian does not use lvmetad by default. You need to edit /etc/lvm/lvm.conf and set use_lvmetad to 0:

use_lvmetad = 0

This will trigger later an error on boot in the initrd stage. Therefore, you have to change it back after the grub generation. In a software RAID + LVM, steps would be the following:

  • After installing all the system, when you have to do all the initramfs (mkinitcpio) and grub thing.
  • Change /etc/mdadm.conf to reflect your RAID config (if any)
  • Change HOOKS and MODULES according to lvm and raid requirements: MODULES="dm_mod" HOOKS="base udev mdadm_udev ... block lvm2 filesystems ..."
  • Generate initrd images with mkinitcpio
  • Change /etc/lvm/lvm.conf to put use_lvmetad = 0
  • Generate grub config (grub-mkconfig)
  • Change /etc/lvm/lvm.conf to put use_lvmetad = 1
Fedora-based host

On Fedora based hosts and live USBs you may encounter problems when using genfstab to generate your fstab. Remove duplicate entries and the "seclabel" option where it appears, as this is Fedora-specific and will keep your system from booting normally.

Things to check before you reboot

Before rebooting, chroot into the newly-installed system.

Set a root password so that you can log in with ssh later:

# passwd

Install ssh and enable it to start automatically at boot.

Configure the network connection to start automatically at boot.

Set up a boot loader and configure it to use the swap partition you appropriated earlier as the root partition. You might want to configure your bootloader to be able to boot into your old system; it is helpful to re-use the server's existing /boot partition in the new system for this purpose.

Replacing the existing system without a LiveCD

Find ~700MB of free space somewhere on the disk, e.g. by partitioning a swap partition. You can disable the swap partition and set up your system there.

Set old swap partition as new root partition

Check cfdisk, /proc/swaps or /etc/fstab to find your swap partition. Assuming your hard drive is located on sdaX (X will be a number).

Do the following:

Disable the swap space:

# swapoff /dev/sdaX

Create a filesystem on it

# fdisk /dev/sda
(set /dev/sdaX ID field to "Linux" - Hex 83)
# mke2fs -j /dev/sdaX

Create a directory to mount it in

# mkdir /mnt/newsys

Finally, mount the new directory for installing the intermediate system.

# mount -t ext4 /dev/sdaX /mnt/newsys

Installation

If less than 700MB are available, examine the packages in the group base, and select only those required to get a system with internet connection up and running in the temporary partition. This will mean explicitly specifying individual packages to pacstrap, as well as passing it the -c option, to get packages downloaded to the host system to avoid filling up valuable space.

Once the new Arch Linux system is installed, reboot into the newly created system, and rsync the entire system to the primary partition. Fix the bootloader configuration before rebooting.