Alpine Linux in a chroot

Setting up a 'edge' build environment in a chroot

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.

Introduction

You will need a few Gigabytes to have enough pace for kernel compiling and storing all the binary packages and iso image.

Create a build environment

We are setting up our Build Environment in chroot.

Note: The variables below:

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

• http://dl-cdn.alpinelinux.org/alpine/
• http://nl.alpinelinux.org/alpine/
• http://dl-2.alpinelinux.org/alpine/
• http://dl-3.alpinelinux.org/alpine/
• http://dl-4.alpinelinux.org/alpine/
• http://dl-5.alpinelinux.org/alpine/
• http://dl-6.alpinelinux.org/alpine/
• http://dl-8.alpinelinux.org/alpine/
• http://distrib-coffee.ipsl.jussieu.fr/pub/linux/alpine/alpine/
• http://mirror.yandex.ru/mirrors/alpine/
• http://mirrors.gigenet.com/alpinelinux/
• http://mirror1.hs-esslingen.de/pub/Mirrors/alpine/
• http://liskamm.alpinelinux.uk/
• http://mirrors.2f30.org/alpine/
• http://mirror.leaseweb.com/alpine/
• http://repository.fit.cvut.cz/mirrors/alpine/
• http://alpine.mirror.far.fi/
• http://lasca.ic.unicamp.br/pub/alpine/
• http://alpinelinux.c3sl.ufpr.br/
• http://mirrors.cug.edu.cn/alpine/
• http://mirrors.cicku.me/alpine/

Lets start by geting the latest apk static binary:

wget ${mirror}/v1.9/apk.static ^^chmod +x ./apk.static

Verify you have apk-tools 2.0_rc1 or later:

./apk.static --version apk-tools 2.0_rc1

We are setting up a basic chroot:

mkdir ${build_dir} sudo ./apk.static -X ${mirror}/v1.9/packages/main -U --allow-untrusted --root ${build_dir} --initdb add alpine-base alpine-sdk mkdir -p ./${build_dir}/proc sudo mount --bind /proc ./${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 2sudo 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 or dns servers and root dir:

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

We are setting up apk mirrors:

sudo mkdir -p ./${build_dir}/etc/apk sudo su echo "${mirror}/v1.9/packages/main" > ./${build_dir}/etc/apk/repositories exit

At this point you should be able to enter your chroot:

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

Now you can move on to creating packages for Alpine.