hqhq / docker-busybox

Busybox for Stackbrew

Jpetazzo's Busybox Image Builders

A.k.a. "The Little Containers That Could!"

This repository contains:

• a rootfs.tar archive suitable to build a minimal Docker image, based on Busybox;
• a Dockerfile referencing this tarball, suitable for inclusion into Stackbrew;
• multiple subdirectories providing Dockerfiles to build this tarball.

The goal of the latter is to solve a difficult question, id est "who builds the builders?".

Those meta-builders are called "tarmakers". They obey the following "API":

• they are built with a Dockerfile themselves;
• the Dockerfile doesn't use any local content (no ADD of local file);
• they generate rootfs.tar in their root directory.

The script mkrootfs.sh is a helper to build rootfs.tar. It requires as first and only argument the name of a subdirectory containing a tarmaker.

The following tarmakers are available:

• buildroot: uses the Buildroot toolchain to compile everything from scratch (WARNING: THIS IS SLOW, it takes half an hour on my quad-core laptop with badass SSDs, so it will probably take a few hours in a typical VM!)
• ubuntu: installs the busybox-static Ubuntu package and use it as the base for the newly built image. This is very fast but the resulting image is a bit bigger, because we have to slap a few fat greasy libraries on top of it. Would you like some fries with that?

To rebuild a busybox image using one tarmaker or the other...

# Use buildroot or ubuntu
TARMAKER=ubuntu
./mkrootfs.sh tarmaker-ubuntu
docker build -t busybox .
docker run -t -i busybox