meta-digi/meta-digi-containers

meta-digi-containers

Yocto layer for Digi container-focused image generation and packaging.

This layer provides:

• dey-image-container to generate container artifacts
• dey-image-container-manager to run and manage Podman/LXC containers on target

dey-image-container-manager installs dedicated lxc-trimmed and podman-trimmed recipes, so it does not require DISTROOVERRIDES changes in local.conf and does not affect other DEY images built in the same environment.

The layer explicitly depends on meta-virtualization, and dey-image-container-manager requires DISTRO_FEATURES:append = " virtualization" in local.conf.

The dey-image-container workflow produces:

• A base rootfs (tar.xz)
• An OCI image output
• A Podman archive (*.tar)
• An LXC bundle (*.tar.gz)
• Final container artifacts (*.tar.gz) with:
  • manifest.json
  • payload/
  • checksums/sha256sums.txt
  • optional metadata/

Note: Podman archive generation requires an OCI image output as intermediate input. The recipe keeps oci in IMAGE_FSTYPES because do_image_podman_archive converts that OCI artifact into a docker-archive tar using skopeo.

External Digi Container Package (DCP) generation

Use the following Python script to generate a DCP out of Yocto workspace:

• meta-digi-containers/scripts/generate-dcp.py

This script requires:

• manifest.json
• payload artifact, which may be one of:
  • Podman: image.tar
  • LXC: a Yocto-style LXC bundle (.tar.gz) containing rootfs/ and config

Usage:

python3 meta-digi-containers/scripts/generate-dcp.py \
  --manifest /path/to/manifest.json \
  --payload /path/to/payload \
  [--output-dir /path/to/outdir] \
  [--readme /path/to/README.txt] \
  [--changelog /path/to/changelog.txt]

and generates a final DCP bundle with the same layout used today by the Yocto recipe:

• manifest.json
• payload/
• checksums/sha256sums.txt
• metadata/README.txt
• metadata/changelog.txt

The script generates exactly one runtime artifact per execution.

Notes:

• --output-dir is optional. If omitted, the script writes the DCP to the current directory.
• The output file name is always derived from manifest fields as:
  • <package_id>_artifact_<runtime>_<device_types[0]>.tar.gz
• For Podman payloads, the final internal payload name is always payload/image.tar
• For LXC payloads, the generator requires a Yocto-style .tar.gz bundle, validates its layout, and stores it inside the DCP using the original file name and format without re-packaging it.

Example manifests are provided at:

• meta-digi-containers/examples/manifest-lxc.json
• meta-digi-containers/examples/manifest-podman.json

Example:

python3 meta-digi-containers/scripts/generate-dcp.py \
  --manifest meta-digi-containers/examples/manifest-podman.json \
  --payload /tmp/image.tar

This generates:

• ./flutter-demo_artifact_podman_ccmp25-dvk.tar.gz

Layer Scope

Main recipes:

• recipes-core/images/dey-image-container.bb
• recipes-core/images/dey-image-container-manager.bb

Recipe includes:

• dey-image-container-fragments.inc
• dey-image-container-lxc.inc
• dey-image-container-podman.inc
• dey-image-container-artifact.inc

Container support files:

• containers/<profile>/configs_lxc/ (profile LXC config fragments)
• containers/<profile>/rootfs_files/ (profile rootfs overlays)
• containers/<profile>/artifact/ (optional artifact metadata template)

Container runtime recipes:

• recipes-containers/lxc/lxc-trimmed_git.bb
• recipes-containers/podman/podman-trimmed_git.bb

Add The Layer

In your build environment:

bitbake-layers add-layer /path/to/sources/meta-digi/meta-digi-containers
bitbake-layers add-layer /path/to/sources/meta-virtualization
bitbake-layers add-layer /path/to/sources/meta-openembedded/meta-filesystems

Or add it manually to conf/bblayers.conf.

Basic Usage

Set profile and naming in conf/local.conf:

DISTRO_FEATURES:append = " virtualization"
CONTAINER_TYPE = "webkit"         # or: lvgl, flutter, base, custom profile
CONTAINER_NAME = "webkit-example"
# PODMAN_TAG defaults to "${CONTAINER_NAME}-tag"

Build:

bitbake dey-image-container

Outputs are generated in:

• tmp/deploy/images/${MACHINE}/

Final outputs:

• ${CONTAINER_PACKAGE_ID}_artifact_podman_<device_types[0]>.tar.gz
• ${CONTAINER_PACKAGE_ID}_artifact_lxc_<device_types[0]>.tar.gz

Notes:

• The generator script makes the DCP filename using package_id, runtime, and device_types[0] fields from the manifest file.
• In Yocto builds, CONTAINER_PACKAGE_ID defaults to ${CONTAINER_NAME}

Intermediate outputs generated during the build (LXC bundle, Podman archive, OCI/rootfs files) are removed automatically at the end of artifact creation.

Profiles

Profile-specific behavior is controlled with:

• CONTAINER_TYPE
• OVERRIDES:append = ":container-${CONTAINER_TYPE}" (handled in recipe)

Current built-in profile examples:

• container-lvgl
• container-flutter
• container-webkit

You can add new profiles by appending variables with :container-<name> overrides.

For customer-defined profiles, use:

CONTAINER_TYPE = "myprofile"
CONTAINER_NAME = "myprofile-demo"
PODMAN_TAG = "myprofile-demo-tag"

IMAGE_INSTALL:append:container-myprofile = " package-a package-b"
CONTAINER_INIT_MANAGER:container-myprofile = "/usr/bin/docker-init"
CONTAINER_INIT_SCRIPT:container-myprofile = "/usr/bin/my-app --foreground"

# Manifest-related overrides can also be profile-specific:
CONTAINER_ARTIFACT_VERSION:container-myprofile = "1.2.0"
CONTAINER_FIRMWARE_VERSIONS:container-myprofile = ">=25.01"
CONTAINER_DEVICE_TYPES_JSON:container-myprofile = "[\"ccmp25-dvk\"]"
CONTAINER_ARTIFACT_DESCRIPTION:container-myprofile = "My profile demo container"
CONTAINER_ARTIFACT_LABELS_JSON:container-myprofile = "{\"vendor\":\"digi\",\"component\":\"demo\"}"

Rootfs Overlay

Use the following variables to inject directories into the container rootfs:

CONTAINER_ROOTFS_OVERLAY_DIRS = "/absolute/path/to/overlay"
CONTAINER_ROOTFS_OVERLAY_TARBALLS = "/absolute/path/to/overlay.tar.gz"

Notes:

• Multiple entries are supported (space-separated).
• *.sh files copied from overlay directories are marked executable automatically.
• If CONTAINER_ROOTFS_OVERLAY_DIRS is not set and containers/${CONTAINER_TYPE}/rootfs_files exists, it is used automatically.

LXC Fragment Configuration

LXC fragments are loaded from:

• containers/${CONTAINER_TYPE}/configs_lxc/

Config file naming:

• config_lxc_<machine>

Example:

• config_lxc_ccmp25-dvk

<machine> matches the full MACHINE value.

Supported placeholders in LXC config fragments:

• @LXC_ARCH@
• @LXC_FOLDER@
• @CONTAINER_NAME@
• @CONTAINER_INIT_MANAGER@
• @CONTAINER_INIT_SCRIPT@

Artifact Manifest Fields

The artifact manifest is generated automatically and includes:

• package_id
• version
• runtime
• artifact_type
• create_args [optional] for Podman artifacts (only when non-empty)
• created_at
• digest
• device_types
• firmware_versions
• size_bytes
• build_id
• description
• labels

build_id behavior:

• Uses CONTAINER_ARTIFACT_BUILD_ID if explicitly set.
• Otherwise uses the current meta-digi git commit SHA (git rev-parse HEAD).

Relevant variables:

• CONTAINER_PACKAGE_ID
• CONTAINER_ARTIFACT_VERSION
• CONTAINER_CREATE_ARGS_PODMAN
• CONTAINER_FIRMWARE_VERSIONS
• CONTAINER_DEVICE_TYPES_JSON
• CONTAINER_ARTIFACT_DESCRIPTION
• CONTAINER_ARTIFACT_BUILD_ID
• CONTAINER_ARTIFACT_LABELS_JSON

Optional Artifact Metadata Template

If you set:

CONTAINER_ARTIFACT_TEMPLATE_DIR = "/path/to/artifact-template"

and the template contains metadata/, it is copied into final artifact bundles.

manifest.json, payload/*, and checksums/sha256sums.txt are always generated during build time and should not be pre-created in the template.

If CONTAINER_ARTIFACT_TEMPLATE_DIR is not set and containers/${CONTAINER_TYPE}/artifact exists, it is used automatically.

Container Folder Layout

Each profile is self-contained under containers/:

containers/
  lvgl/
    rootfs_files/
    configs_lxc/
    artifact/
  flutter/
    rootfs_files/
    configs_lxc/
    artifact/
  webkit/
    rootfs_files/
    configs_lxc/
    artifact/
  custom/
    rootfs_files/
    configs_lxc/
    artifact/

To create a new profile:

1. Create containers/<profile>/configs_lxc/config_lxc_<machine>.
2. Optionally add containers/<profile>/rootfs_files/ for rootfs content.
3. Set CONTAINER_TYPE = "<profile>" in local.conf.
4. Add profile packages with IMAGE_INSTALL:append:container-<profile> = " ... ".

Notes

• Intermediate container artifacts from the current build are removed at the end of the artifact task.
• If dey-image-container is not found, verify the layer is present in BBLAYERS.