This container aggregates various tools used to build Fedora CoreOS style systems, including:

• mantle
• rpm-ostree
• libvirt

Getting started - prerequisites

You can use podman or docker. These examples use podman. Note the container must be privileged, as the build process uses container functionality itself - we're using recursive containers.

Secondly, in order to build VM images, the container must have access to /dev/kvm. If you're running this in a VM, you must enable nested virt. See also GCE nested virt.

Setup

Here we store data in /srv/coreos on our host system. You can choose any directory you like.

$ mkdir /srv/coreos
$ cd /srv/coreos
$ alias coreos-assembler='podman run --rm --net=host -ti --privileged -v $(pwd):/srv --workdir /srv quay.io/cgwalters/coreos-assembler:testing'

Initializing

You only need to do this once; it will create various directories and also download an installer image (used to make VMs).

$ coreos-assembler init

One thing to note is you'll have a /srv/coreos/src/config directory. By default, this is a clone of https://github.com/cgwalters/fedora-coreos-config If you're doing something custom, you likely want to fork it and edit. Just replace the src/config directory with your git clone.

Performing a build

$ coreos-assembler build

Each build will write an ostree commit into /srv/coreos/repo as well as generate VM images in /srv/coreos/builds/$datestamp.

Development

The container image is built in OpenShift CI.