Alpine Linux - User contributions [en]

Bootstrapping Alpine Linux

2020-06-10T10:48:44Z

Meehow: simplify with `arch` command

= VPS =
This section is to provide a means to bootstrap Alpine Linux on any VPS.

== Process ==

=== Prepare ===
<ol>
<li>Download apk-tools-static for your architecture.</li>
<pre>wget http://dl-cdn.alpinelinux.org/alpine/v3.12/main/$(arch)/apk-tools-static-2.10.5-r1.apk</pre>

<li>Unpack .apk</li>
<pre>tar zxf apk-tools-static-*.apk</pre>

</ol>

=== Install ===
<code>sudo ./sbin/apk.static --arch $(arch) -X http://dl-cdn.alpinelinux.org/alpine/latest-stable/main/ -U --allow-untrusted --root /tmp/target --initdb add alpine-base</code>

=== Bootloader ===

== References ==
* [https://www.linode.com/docs/tools-reference/custom-kernels-distros/running-a-custom-linux-distro-on-a-linode-vps Running a Custom Linux Distribution on a Linode]
* [https://www.linode.com/docs/tools-reference/custom-kernels-distros/run-a-custom-compiled-kernel-with-pvgrub Run a Custom Compiled Kernel with PV-GRUB]
* [[Replacing non-Alpine Linux with Alpine remotely]]
* [[Install Alpine on Amazon EC2]]
* [[Install Alpine on coLinux]]
* [[Install Alpine on Rackspace]]
* [[Alpine setup scripts]]
* [http://serverfault.com/questions/98950/how-do-i-chain-boot-from-grub-to-syslinux How do I chain boot from grub to syslinux?]
* [http://uggedal.com/journal/alpine-linux-on-linode/ Alpine Linux on Linode]
* [[Installing Alpine Linux in a chroot]]

[[Category:Installation]]
[[Category:Virtualization]]

Bootstrapping Alpine Linux

2020-06-10T10:45:00Z

Meehow: bootstrap using apk-tools-static

= VPS =
This section is to provide a means to bootstrap Alpine Linux on any VPS.

== Process ==

=== Prepare ===
<ol>
<li>Check which architecture you are using.</li>
<pre>arch=$(uname -m)</pre>

<li>Download apk-tools-static for your architecture.</li>
<pre>wget http://dl-cdn.alpinelinux.org/alpine/v3.12/main/${arch}/apk-tools-static-2.10.5-r1.apk</pre>

<li>Unpack .apk</li>
<pre>tar zxf apk-tools-static-*.apk</pre>

</ol>

=== Install ===
<code>sudo ./sbin/apk.static --arch ${arch} -X http://dl-cdn.alpinelinux.org/alpine/latest-stable/main/ -U --allow-untrusted --root /tmp/target --initdb add alpine-base</code>

=== Bootloader ===

== References ==
* [https://www.linode.com/docs/tools-reference/custom-kernels-distros/running-a-custom-linux-distro-on-a-linode-vps Running a Custom Linux Distribution on a Linode]
* [https://www.linode.com/docs/tools-reference/custom-kernels-distros/run-a-custom-compiled-kernel-with-pvgrub Run a Custom Compiled Kernel with PV-GRUB]
* [[Replacing non-Alpine Linux with Alpine remotely]]
* [[Install Alpine on Amazon EC2]]
* [[Install Alpine on coLinux]]
* [[Install Alpine on Rackspace]]
* [[Alpine setup scripts]]
* [http://serverfault.com/questions/98950/how-do-i-chain-boot-from-grub-to-syslinux How do I chain boot from grub to syslinux?]
* [http://uggedal.com/journal/alpine-linux-on-linode/ Alpine Linux on Linode]
* [[Installing Alpine Linux in a chroot]]

[[Category:Installation]]
[[Category:Virtualization]]

Alpine Linux in a chroot

2020-06-02T11:14:50Z

Meehow: there is no bash by default

{{TOC right}}

Inside the chroot environment, you can build, debug, and run alpine packages or develop things. It's the most known way to do so if one wants not to trash their main Alpine system.

This document explains how to set up an [[Alpine_newbie#Developer|Alpine build environment]] in a chroot under a host Linux distro, can also be used to install Alpine Linux from a non-Alpine Linux livecd.

== Requirements ==

* Working Linux instalation where to perform all the process
* Linux kernel 2.6.22, with <code>wget</code> and <code>chroot</code> installed
* target media with at least 100M, 900MB for more complete solution as minimum
* internet connection

== Prerequisites ==

The variables below:

*'''${chroot_dir}''' = Should point to the chroot directory where you
*'''${mirror}''' = Should be replaced with [http://nl.alpinelinux.org/alpine/MIRRORS.txt one of the available Alpine Linux mirrors].
*'''${arch}''' = Should be the cpu architecture like x86 (i386) or amd64(x86_64)..

== Set up APK ==

Download the latest apk static package (replace <tt>${version}</tt> with actual version):

{{Cmd|wget ${mirror}/latest-stable/main/${arch}/apk-tools-static-${version}.apk}}

.apk packages are just gzipped tarballs, unpack using:
{{Cmd|tar -xzf apk-tools-static-*.apk}}

== Install the alpine base installation onto the chroot ==

{{Cmd|./sbin/apk.static -X ${mirror}/latest-stable/main -U --allow-untrusted --root ${chroot_dir} --initdb add alpine-base}}

== Set up the chroot ==

Before made and enter into the chrooted system must be prepared with device nodes and tempfs :

===== Method 1.A fast way: using bind mount =====

{{Note|Mounts with bind, can mount in read-only the /dev at the alpine chroot so due limited will not touch the access time of the host system}}

{{Cmd|mount /dev/ ${chroot_dir}/dev/ --bind
mount -o remount,ro,bind ${chroot_dir}/dev
}}

If you need SCSI or R/W access only do the first command, mounting with "ro" makes more secure your chroot.

===== Method 1.B manual way: creating need nodes =====

{{Warning|Manually creating devices will only provide those representation that you have created.. for auto availability use bind mounts}}

{{Cmd|mknod -m 666 ${chroot_dir}/dev/full c 1 7
mknod -m 666 ${chroot_dir}/dev/ptmx c 5 2
mknod -m 644 ${chroot_dir}/dev/random c 1 8
mknod -m 644 ${chroot_dir}/dev/urandom c 1 9
mknod -m 666 ${chroot_dir}/dev/zero c 1 5
mknod -m 666 ${chroot_dir}/dev/tty c 5 0}}

If you need SCSI disc access:

{{Cmd|mknod -m 666 ${chroot_dir}/dev/sda b 8 0
mknod -m 666 ${chroot_dir}/dev/sda1 b 8 1
mknod -m 666 ${chroot_dir}/dev/sda2 b 8 2
mknod -m 666 ${chroot_dir}/dev/sda3 b 8 3
mknod -m 666 ${chroot_dir}/dev/sda4 b 8 4
mknod -m 666 ${chroot_dir}/dev/sda5 b 8 5
mknod -m 666 ${chroot_dir}/dev/sda6 b 8 6
mknod -m 666 ${chroot_dir}/dev/sdb b 8 16
mknod -m 666 ${chroot_dir}/dev/sdb1 b 8 17
mknod -m 666 ${chroot_dir}/dev/sdb2 b 8 18
mknod -m 666 ${chroot_dir}/dev/sdb3 b 8 19
mknod -m 666 ${chroot_dir}/dev/sdb4 b 8 20
mknod -m 666 ${chroot_dir}/dev/sdb5 b 8 21
mknod -m 666 ${chroot_dir}/dev/sdb6 b 8 22}}

==== Made available proc and sys fs ====

{{Cmd|mount -t proc none ${chroot_dir}/proc
mount -o bind /sys ${chroot_dir}/sys}}

==== Make networking resolution access ====

A resolv.conf is needed for name resolution:

{{Cmd|cp -L /etc/resolv.conf ${chroot_dir}/etc/
mkdir -p ${chroot_dir}/root}}

If you don't want to copy the resolv.conf from the local machine, you can create a new one using OpenDNS servers (or any other):
{{Cmd|echo -e 'nameserver 8.8.8.8\nnameserver 2620:0:ccc::2' > ${chroot_dir}/etc/resolv.conf}}

==== prepare the apk sources software ====

Set up APK mirror (replace <tt>${branch}</tt> with the latest stable branch name, e.g. v3.3):

{{Cmd|mkdir -p ${chroot_dir}/etc/apk
echo "${mirror}/${branch}/main" > ${chroot_dir}/etc/apk/repositories}}

== Mastering your chroot ==

The chroot methods are commonly used to have alpine in a portion of a already made directory, not forced to be a entire partion, that means Alpine can be in a very minimal directory indise the same partition of a Debian installed linux inclusively, so that why the chroot process does not included the boot method.

So then the following commands will described the need procedures only if the chroot instalation was made to a dedicated partition for and not to a directory inside another linux installed.

{{Warning|so then by the explained reasons, at this point, Alpine has been succesfully installed onto the chroot directory '''but still not able to boot it'''. }}

==== Entering your chroot ====

Take in consideration that the chroot command are only running as root, no stupid sudo tools are recommended for that.

{{Cmd|chroot ${chroot_dir} ash -l}}

==== Perform init process ====

Need to add some minimal initscripts to appropriate runlevels:

{{Cmd|rc-update add devfs sysinit
rc-update add dmesg sysinit
rc-update add mdev sysinit

rc-update add hwclock boot
rc-update add modules boot
rc-update add sysctl boot
rc-update add hostname boot
rc-update add bootmisc boot
rc-update add syslog boot

rc-update add mount-ro shutdown
rc-update add killprocs shutdown
rc-update add savecache shutdown}}

==== Make bootable the install ====

WIP:

{{Warning|Run only this if Alpine was installed to a dedicated partiton mounted at the <nowiki>${chroot_dir}</nowiki> directory, becose at this point, Alpine has been succesfully installed onto the chroot directory '''but still not able to boot it'''. }}

{{Cmd|<nowiki>dd if=/usr/share/syslinux/mbr.bin of=/dev/sda</nowiki>}}

Be care of that /dev/sda are the same disk where destination partition was mounted to <nowiki>${chroot_dir}</nowiki>.

= Troubleshooting =

== hardened kernels or alpine as chroot host ==

If you are using Alpine as a Native build system you will have to make sure that chroot can run chmod. Add following to <code>/etc/sysctl.conf</code>

<code>kernel.grsecurity.chroot_deny_chmod = 0</code>

Then run the following command

<code>sysctl -p</code>

== chroot: cannot run command ' ... Exec format error ==

This usually indicates that you booted with one architecture (e.g. armf) and are trying to chroot into another (e.g. x86_64). If you plans to make chroot into another installation must use same arch for both host and hosted chrooted!

Note that with '''one exception you can run 32 bit x86 chroot in x86_64, but not viceversa'''!

== WARNING: Ignoring APKINDEX.xxxx.tar.gz ==

Make sure <code>${chroot_dir}/etc/apk/repositories</code> is valid and inside the chroot run:

<code>apk update</code>

= External links =

* You can also use script [https://github.com/alpinelinux/alpine-chroot-install/ alpine-chroot-install]
* https://web.archive.org/web/20190808203313/https://isc.sans.edu/forums/diary/Forensic+use+of+mount+bind/22854/
* Alpine Linux in a chroot on Fedora : http://git.alpinelinux.org/cgit/user/fab/scripts/tree/alpine-chroot.sh script
* Alpine Linux aarch64 in a chroot on AWS Linux : https://gist.github.com/emolitor/0567e51c0ce04f4b025fc78d2cf0b4f1 script

[[Category:Installation]]
[[category: System Administration]]

Alpine Linux in a chroot

2020-06-02T11:13:18Z

Meehow: follow the resolv.conf symlink

{{TOC right}}

Inside the chroot environment, you can build, debug, and run alpine packages or develop things. It's the most known way to do so if one wants not to trash their main Alpine system.

This document explains how to set up an [[Alpine_newbie#Developer|Alpine build environment]] in a chroot under a host Linux distro, can also be used to install Alpine Linux from a non-Alpine Linux livecd.

== Requirements ==

* Working Linux instalation where to perform all the process
* Linux kernel 2.6.22, with <code>wget</code> and <code>chroot</code> installed
* target media with at least 100M, 900MB for more complete solution as minimum
* internet connection

== Prerequisites ==

The variables below:

*'''${chroot_dir}''' = Should point to the chroot directory where you
*'''${mirror}''' = Should be replaced with [http://nl.alpinelinux.org/alpine/MIRRORS.txt one of the available Alpine Linux mirrors].
*'''${arch}''' = Should be the cpu architecture like x86 (i386) or amd64(x86_64)..

== Set up APK ==

Download the latest apk static package (replace <tt>${version}</tt> with actual version):

{{Cmd|wget ${mirror}/latest-stable/main/${arch}/apk-tools-static-${version}.apk}}

.apk packages are just gzipped tarballs, unpack using:
{{Cmd|tar -xzf apk-tools-static-*.apk}}

== Install the alpine base installation onto the chroot ==

{{Cmd|./sbin/apk.static -X ${mirror}/latest-stable/main -U --allow-untrusted --root ${chroot_dir} --initdb add alpine-base}}

== Set up the chroot ==

Before made and enter into the chrooted system must be prepared with device nodes and tempfs :

===== Method 1.A fast way: using bind mount =====

{{Note|Mounts with bind, can mount in read-only the /dev at the alpine chroot so due limited will not touch the access time of the host system}}

{{Cmd|mount /dev/ ${chroot_dir}/dev/ --bind
mount -o remount,ro,bind ${chroot_dir}/dev
}}

If you need SCSI or R/W access only do the first command, mounting with "ro" makes more secure your chroot.

===== Method 1.B manual way: creating need nodes =====

{{Warning|Manually creating devices will only provide those representation that you have created.. for auto availability use bind mounts}}

{{Cmd|mknod -m 666 ${chroot_dir}/dev/full c 1 7
mknod -m 666 ${chroot_dir}/dev/ptmx c 5 2
mknod -m 644 ${chroot_dir}/dev/random c 1 8
mknod -m 644 ${chroot_dir}/dev/urandom c 1 9
mknod -m 666 ${chroot_dir}/dev/zero c 1 5
mknod -m 666 ${chroot_dir}/dev/tty c 5 0}}

If you need SCSI disc access:

{{Cmd|mknod -m 666 ${chroot_dir}/dev/sda b 8 0
mknod -m 666 ${chroot_dir}/dev/sda1 b 8 1
mknod -m 666 ${chroot_dir}/dev/sda2 b 8 2
mknod -m 666 ${chroot_dir}/dev/sda3 b 8 3
mknod -m 666 ${chroot_dir}/dev/sda4 b 8 4
mknod -m 666 ${chroot_dir}/dev/sda5 b 8 5
mknod -m 666 ${chroot_dir}/dev/sda6 b 8 6
mknod -m 666 ${chroot_dir}/dev/sdb b 8 16
mknod -m 666 ${chroot_dir}/dev/sdb1 b 8 17
mknod -m 666 ${chroot_dir}/dev/sdb2 b 8 18
mknod -m 666 ${chroot_dir}/dev/sdb3 b 8 19
mknod -m 666 ${chroot_dir}/dev/sdb4 b 8 20
mknod -m 666 ${chroot_dir}/dev/sdb5 b 8 21
mknod -m 666 ${chroot_dir}/dev/sdb6 b 8 22}}

==== Made available proc and sys fs ====

{{Cmd|mount -t proc none ${chroot_dir}/proc
mount -o bind /sys ${chroot_dir}/sys}}

==== Make networking resolution access ====

A resolv.conf is needed for name resolution:

{{Cmd|cp -L /etc/resolv.conf ${chroot_dir}/etc/
mkdir -p ${chroot_dir}/root}}

If you don't want to copy the resolv.conf from the local machine, you can create a new one using OpenDNS servers (or any other):
{{Cmd|echo -e 'nameserver 8.8.8.8\nnameserver 2620:0:ccc::2' > ${chroot_dir}/etc/resolv.conf}}

==== prepare the apk sources software ====

Set up APK mirror (replace <tt>${branch}</tt> with the latest stable branch name, e.g. v3.3):

{{Cmd|mkdir -p ${chroot_dir}/etc/apk
echo "${mirror}/${branch}/main" > ${chroot_dir}/etc/apk/repositories}}

== Mastering your chroot ==

The chroot methods are commonly used to have alpine in a portion of a already made directory, not forced to be a entire partion, that means Alpine can be in a very minimal directory indise the same partition of a Debian installed linux inclusively, so that why the chroot process does not included the boot method.

So then the following commands will described the need procedures only if the chroot instalation was made to a dedicated partition for and not to a directory inside another linux installed.

{{Warning|so then by the explained reasons, at this point, Alpine has been succesfully installed onto the chroot directory '''but still not able to boot it'''. }}

==== Entering your chroot ====

Take in consideration that the chroot command are only running as root, no stupid sudo tools are recommended for that.

{{Cmd|chroot ${chroot_dir} /bin/bash -l}}

==== Perform init process ====

Need to add some minimal initscripts to appropriate runlevels:

{{Cmd|rc-update add devfs sysinit
rc-update add dmesg sysinit
rc-update add mdev sysinit

rc-update add hwclock boot
rc-update add modules boot
rc-update add sysctl boot
rc-update add hostname boot
rc-update add bootmisc boot
rc-update add syslog boot

rc-update add mount-ro shutdown
rc-update add killprocs shutdown
rc-update add savecache shutdown}}

==== Make bootable the install ====

WIP:

{{Warning|Run only this if Alpine was installed to a dedicated partiton mounted at the <nowiki>${chroot_dir}</nowiki> directory, becose at this point, Alpine has been succesfully installed onto the chroot directory '''but still not able to boot it'''. }}

{{Cmd|<nowiki>dd if=/usr/share/syslinux/mbr.bin of=/dev/sda</nowiki>}}

Be care of that /dev/sda are the same disk where destination partition was mounted to <nowiki>${chroot_dir}</nowiki>.

= Troubleshooting =

== hardened kernels or alpine as chroot host ==

If you are using Alpine as a Native build system you will have to make sure that chroot can run chmod. Add following to <code>/etc/sysctl.conf</code>

<code>kernel.grsecurity.chroot_deny_chmod = 0</code>

Then run the following command

<code>sysctl -p</code>

== chroot: cannot run command ' ... Exec format error ==

This usually indicates that you booted with one architecture (e.g. armf) and are trying to chroot into another (e.g. x86_64). If you plans to make chroot into another installation must use same arch for both host and hosted chrooted!

Note that with '''one exception you can run 32 bit x86 chroot in x86_64, but not viceversa'''!

== WARNING: Ignoring APKINDEX.xxxx.tar.gz ==

Make sure <code>${chroot_dir}/etc/apk/repositories</code> is valid and inside the chroot run:

<code>apk update</code>

= External links =

* You can also use script [https://github.com/alpinelinux/alpine-chroot-install/ alpine-chroot-install]
* https://web.archive.org/web/20190808203313/https://isc.sans.edu/forums/diary/Forensic+use+of+mount+bind/22854/
* Alpine Linux in a chroot on Fedora : http://git.alpinelinux.org/cgit/user/fab/scripts/tree/alpine-chroot.sh script
* Alpine Linux aarch64 in a chroot on AWS Linux : https://gist.github.com/emolitor/0567e51c0ce04f4b025fc78d2cf0b4f1 script

[[Category:Installation]]
[[category: System Administration]]