redjack/centos32 repository overview

⁠CentOS 5 i386

Docker Hub doesn't publish 32-bit CentOS builds, but this should let us publish our own.

Based off Docker's mkimage-yum.sh⁠ and toopher/toopher-docker⁠.

⁠Using

Internally, we use the setarch package to provide the ability to run commands in a 32-bit environment, even though the Docker daemon will be running on a 64-bit system. For one-off commands (e.g. docker run ...), you don't have to do anything, the linux32 ENTRYPOINT will handle this for you.

However, if you inherit from this image in another Dockerfile, make sure to preface architecture dependant commands (e.g. yum install ..., compilers, etc.) with linux32 $CMD, e.g.:

FROM redjack/centos32:5
RUN linux32 yum install -y git

⁠Building

Building is easy, despite the magic within:

$ docker build -t redjack/centos32:5 .

⁠Refreshing the tarball

To build the tarball referenced in the Dockerfile, we use Vagrant to build a VM that we can use to create a minimal CentOS 5 image:

$ vagrant up --provider=virtualbox
$ vagrant destroy -t

The provisioning step should create the new tarball, and then commit and push to trigger a rebuild on Docker hub.