Available Layers | Moonforge
View page source
Edit this page
Create child page
Create documentation issue
Create project issue
Available Layers
A guide to the available Moonforge layers and how to compose them into an OS image.
Moonforge layers are the building blocks of your OS image. Each layer encapsulates a
single, well-defined feature. Layers are designed to be combined freely, you include
only what your product needs, and the result is an image that contains nothing more.
How layers work
Every layer ships a kas YAML fragment alongside its BitBake recipes. The fragment
declares:
Which external repositories the layer depends on.
Which BitBake layers within those repositories must be activated.
Default
local.conf
values the layer requires (overridable in your own fragment).
When you include a layer’s kas fragment in your configuration, all of its dependencies
are resolved automatically. You do not need to manually manage
bblayers.conf
or
hunt down transitive dependencies.
Layer overview
Layer
Category
What it adds
meta-moonforge-distro
Base
Read-only rootfs, overlayfs-etc, CVE reports.
Required.
meta-moonforge-qemu
BSP
QEMU x86-64 target support
meta-moonforge-raspberrypi
BSP
Raspberry Pi 4 and 5 support
meta-moonforge-docker
Feature
Docker engine and docker-compose
meta-moonforge-podman
Feature
Podman and container registry access
meta-moonforge-graphics
Feature
Weston compositor for kiosk displays
meta-moonforge-wpe
Feature
WPE WebKit browser in fullscreen kiosk mode
meta-moonforge-rauc
Feature
RAUC A/B OTA updates with bundle signing
meta-moonforge-rauc-update
Feature
Automated RAUC update client on a timer
Composing layers
A typical kas configuration file looks like this:
header
version
16
includes
# Base layer - always required
repo
meta-moonforge
file
kas/include/layer/meta-moonforge-distro.yml
# BSP layer - choose one for your target hardware
repo
meta-moonforge
file
kas/include/layer/meta-moonforge-raspberrypi.yml
# Feature layers - include as many as you need
repo
meta-moonforge
file
kas/include/layer/meta-moonforge-docker.yml
repo
meta-moonforge
file
kas/include/layer/meta-moonforge-rauc.yml
local_conf_header
20_meta-moonforge-distro
OVERLAYFS_ETC_DEVICE = "/dev/mmcblk0p3"
30_meta-moonforge-raspberrypi
WKS_FILE = "moonforge-image-base-raspberrypi.wks.in"
repos
meta-moonforge
url
commit
42b1aeefb1327785c48925e62719fa13d55c8e13
branch
main
machine
raspberrypi5
The numbered prefixes on
local_conf_header
keys (e.g.,
20_
30_
) control the
order in which configuration snippets are written to
local.conf
. Higher numbers take
precedence. Use a value higher than any upstream layer when you need a downstream
override to win.
Layer dependencies
Some layers depend on others:
meta-moonforge-wpe
requires
meta-moonforge-graphics
(Weston must be present for
WPE to render into a Wayland surface).
meta-moonforge-rauc-update
requires
meta-moonforge-rauc
(the update client drives
the RAUC daemon).
Each layer’s documentation page lists its requirement, and the layer kas fragments encode these
dependencies.
Writing your own layers
When the existing feature layers do not cover your needs, the recommended approach is to
create a downstream layer in your own repository. See
Customize a Moonforge OS
for a step-by-step walkthrough,
including how to add packages, extend recipes with
.bbappend
files, and define a
custom distro configuration.
meta-moonforge-distro
The mandatory base layer that establishes the Moonforge distribution identity, the default partition scheme, and read-only root filesystem.
meta-moonforge-qemu
Adds QEMU x86-64 target support to Moonforge, enabling OS images to be built and tested in a virtual machine without physical hardware.
meta-moonforge-raspberrypi
Adds board support for the Raspberry Pi 4 and Raspberry Pi 5.
meta-moonforge-docker
Adds Docker engine and docker-compose to a Moonforge image, with container storage configured on the persistent data partition.
meta-moonforge-podman
Adds Podman to a Moonforge image, with container storage configured on the persistent data partition and public registry access enabled out of the box.
meta-moonforge-rauc
Adds RAUC A/B over-the-air update support, including bundle signing and demo certificates for local development.
meta-moonforge-rauc-update
Adds an automated RAUC update client that polls a remote URL for new bundles on a configurable timer.
meta-moonforge-graphics
Adds the Weston Wayland compositor, configured for kiosk and single-application display environments.
meta-moonforge-wpe
Adds WPE WebKit to display a configurable URL in a fullscreen kiosk window via the Cog browser.