meta-digi/meta-digi-containers

meta-digi-containers

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

This layer provides:

• dey-image-dcp: generates Digi Container Package (DCP) artifacts
• dey-image-containers: generates a minimal root file system with the Container Manager and everything it requires to run and manage containers

cc-container-mng depends on the container runtime packages listed in CONTAINERS_BACKEND_TOOLS, which defaults to podman lxc. Override it to select different runtimes or a single engine, for example:

CONTAINERS_BACKEND_TOOLS = "podman-trimmed lxc-trimmed"
CONTAINERS_BACKEND_TOOLS = "podman-trimmed"
CONTAINERS_BACKEND_TOOLS = "lxc"

dey-image-containers overrides CONTAINERS_BACKEND_TOOLS to install the trimmed runtime packages to keep the image smaller.

The layer explicitly depends on meta-virtualization. dey-image-dcp anddey-image-containers requires DISTRO_FEATURES:append = " virtualization" in local.conf.

The dey-image-dcp 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.
• If the input manifest omits package_id, the generator derives the final package_id from name and appends a unique suffix using the created_at timestamp encoded in base36 milliseconds.
• If the input manifest provides package_id, that value is kept unchanged.
• The output file name is always derived from the generated package ID and manifest fields as:
  • <generated_package_id>-<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 a bundle named like:

• ./flutter-demo-<base36_created_at_ms>-podman-ccmp25-dvk.tar.gz

In those manifests:

• name is the stable logical container name stored on the target.
• friendly_name is the user-facing label shown by the manager output when available.
• the final package_id is generated automatically from name unless the input manifest provides an explicit package_id
• registration_defaults is limited to local manager policy such as autostart, monitor, and restart; this release does not generate DRM-specific defaults

dey-image-containers also overrides the manager persistent base path through CC_CONTAINER_PATH, which defaults to ${ROOT_HOME}/cc-container in the Digi platform defaults. This makes the effective target paths live under /root/cc-container in DEY images, while the upstream cc-container-mng project keeps /opt/cc-container as its built-in default.

Layer Scope

Main recipes:

• recipes-core/images/dey-image-dcp.bb
• recipes-core/images/dey-image-containers.bb

Recipe includes:

• dey-image-dcp-fragments.inc
• dey-image-dcp-lxc.inc
• dey-image-dcp-podman.inc
• dey-image-dcp-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"
DCP_NAME = "webkit-demo"          # or: lvgl-demo, chromium-demo, flutter-demo
# PODMAN_TAG defaults to "${DCP_NAME}-tag"

If DCP_NAME is not set, dey-image-dcp now defaults to lvgl-demo.

Build:

bitbake dey-image-dcp

Outputs are generated in:

• tmp/deploy/images/${MACHINE}/

Final outputs:

• ${DCP_NAME}-<base36_created_at_ms>-podman-<device_types[0]>.tar.gz
• ${DCP_NAME}-<base36_created_at_ms>-lxc-<device_types[0]>.tar.gz

Notes:

• The generator script derives package_id from the input name only when the manifest does not provide one explicitly. In that default case it appends a base36-encoded millisecond timestamp suffix, stores the generated package_id in the final manifest.json, and uses it in the DCP file name.
• In Yocto builds, dey-image-dcp keeps that unique-name behavior and removes older DCP artifacts with the same ${DCP_NAME} prefix before generating the new one, so the deploy directory does not keep accumulating previous builds of the same container/runtime.

Intermediate rootfs and OCI outputs are kept available for incremental rebuilds. The LXC bundle and Podman archive are generated as temporary payloads while creating the final DCP artifacts, then removed at the end of artifact creation.

Profiles

Profile-specific behavior is controlled with:

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

Current built-in profile examples:

• container-lvgl-demo
• container-flutter-demo
• container-webkit-demo
• container-chromium-demo

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

To define your own profile, use:

DCP_NAME = "myprofile"
PODMAN_TAG = "myprofile-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/${DCP_NAME}/rootfs_files exists, it is used automatically.

LXC Fragment Configuration

LXC fragments are loaded from:

• containers/${DCP_NAME}/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@
• @DCP_NAME@
• @CONTAINER_INIT_MANAGER@
• @CONTAINER_INIT_SCRIPT@

Artifact Manifest Fields

The artifact manifest is generated automatically and includes:

• package_id
• name [stable logical container name]
• friendly_name [optional user-facing display name]
• 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:

• DCP_NAME
• CONTAINER_FRIENDLY_NAME
• 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/${DCP_NAME}/artifact exists, it is used automatically.

Container Folder Layout

Each profile is self-contained under containers/:

containers/
  lvgl-demo/
    rootfs_files/
    configs_lxc/
    artifact/
  chromium-demo/
    rootfs_files/
    configs_lxc/
    artifact/
  flutter-demo/
    rootfs_files/
    configs_lxc/
    artifact/
  webkit-demo/
    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 DCP_NAME = "<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-dcp or dey-image-containers is not found, verify the layer is present in BBLAYERS and DISTRO_FEATURES:append = " virtualization" is defined in local.conf.