Alpine Linux in a chroot: Difference between revisions

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If you don't want to copy the resolv.conf from the local machine, create this file with your DNS server entry.  
If you don't want to copy the resolv.conf from the local machine, create this file with your DNS server entry.  
{{Cmd|echo 'nameserver 8.8.8.8' >/etc/resolv.conf}}
{{Cmd|echo 'nameserver 8.8.8.8' > ./${build_dir}/etc/resolv.conf}}


We are setting up APK mirrors:  
We are setting up APK mirrors:  

Revision as of 18:49, 22 November 2012

This document explains how to set up an Alpine build environment in a chroot under a "normal" Linux distro, such as Arch, Debian, Fedora, Gentoo, or Ubuntu. Once inside the chroot environment, you can build, debug, and run alpine packages.

Requirements

You will need a few gigabytes of free disk space to have enough space for kernel compiling and storing all the binary packages.

Creating the installation

This example installation of Alpine Linux in a chroot will work with the lastest release. But it's also possible to make a chroot with edge or older releases of Alpine Linux to test backports.

Note: The variables below:

  • ${build_dir} = You can name it whatever you like.
  • ${mirror} = Should be replaced with one of the available Alpine Linux mirrors.

Choose a mirror from the mirror list.

Let's start by getting the latest apk static package:

Tip: In the command below, replace x86_64 with x86 if running on a 32 bit installation
Warning: You will need Kernel version 2.6.22 or later to use apk-tools-static


wget http://dl-3.alpinelinux.org/alpine/v2.4/main/x86_64/apk-tools-static-2.3.3-r0.apk

Unpack the tarball

tar -xzf apk-tools-static-2.3.3-r0.apk

We are setting up a basic chroot:

mkdir ${build_dir} sudo ./sbin/apk.static -X ${mirror}/v2.4/main -U --allow-untrusted --root ${build_dir} --initdb add alpine-base alpine-sdk mkdir -p ./${build_dir}/proc

Lets setup our needed devices:

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

seems as /dev/null is wrong

sudo rm -f ./${build_dir}/dev/null && sudo mknod -m 666 ./${build_dir}/dev/null c 1 3

We need a resolv.conf is needed for the DNS servers and the /root directory:

sudo cp /etc/resolv.conf ./${build_dir}/etc/ mkdir -p ./${build_dir}/root

If you don't want to copy the resolv.conf from the local machine, create this file with your DNS server entry.

echo 'nameserver 8.8.8.8' > ./${build_dir}/etc/resolv.conf

We are setting up APK mirrors:

sudo mkdir -p ./${build_dir}/etc/apk echo "${mirror}/v2.3/main" > ./${build_dir}/etc/apk/repositories

Entering your chroot

After the installation you should be able to enter your chroot:


sudo mount --bind /proc ./${build_dir}/proc sudo chroot ./${build_dir} /bin/sh -l

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

kernel.grsecurity.chroot_deny_chmod = 0

Then run the following command

sysctl -p

Alpine Linux in a chroot on Fedora

If you want to generate a chroot on a Fedora based system, you can use this script.

Note: Maybe you are able to use this script on other distribution but this is not tested.