Setting up a build environment for Alpine 1.9

This docuemtn explains how to set up an Alpine build environment in a chroot in a "normal" Linux distro as Ubuntu, Fedora, Gentoo or Arch linux. In this build environment you will be able to build and run alpine packages.

Introduction

The Build Environment will be called BE from now on.
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 BE 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:

Lets start by geting the latest apk static binary:

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

We are setting up a basic chroot:

mkdir ${build_dir}
sudo ./apk.static --repo ${mirror}/v1.9/packages/core --root $PWD/${build_dir} add --initdb build-base git abuild
mkdir -p ./${build_dir}/proc
sudo mount --bind /proc ./${build_dir}/proc

Lets setup our needed devices:

sudo mknod -m 666 ./${build_dir}/dev/full c 1 7
sudo mknod -m 777 ./${build_dir}/dev/null c 1 3
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

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:

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

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

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