kolla-containers

A central repository of build customizations for Kolla containers specific to Chameleon, and automated triggers for rebuilding pieces of Kolla's image tree when sources change.

Setup

Using the build utilities requires having Python 3 and the venv module installed:

# e.g., for Ubuntu/Debian
apt-get install python3-venv

Configuration sets

Each Kolla service requires at minimum either its own configuration set defined in the build_config.yaml, or being added to an existing configuration set. To add a service's images to the list of images that will be built for a given configuration set, update the regex in the [profiles] section of the kolla-build.conf; one or more configuration sets will reference one of these build profiles.

Configuration sets can also be used to override specific Kolla build flags, such as the target base distro, tag, or architecture/platform.

Adding support for a new service fork

By default all Kolla images build from tarballs published by OpenStack. Many of Chameleon's forks are by contrast built via local Git clones. When forking a service, add an entry for the service's base image in the kolla-build.conf and have it use Git as the source; there are several examples in the configuration already.

Additional notes:

• Kolla supports adding additions to images at build time, which can be a useful tool when trying to add in additional sources into a specific image (we do this to add a custom Horizon theme, for example.)

• The kolla-template-overrides.j2 Jinja file is used to override or customize the templating of the Dockerfile(s) written out by Kolla. See an example Dockerfile (horizon) in Kolla for more context in to how this works.

Building a container

The supported services can be build using the build.py script and passing the name of a configuration set and a profile name. The configuration sets are defined in the build_config.yaml file and set things like the platform/architecture and base distro for the build.

# Build container for Horizon
./run.sh python build.py --config-set x86_ubuntu --profile horizon

# Build containers for Nova
./run.sh python build.py --config-set x86_ubuntu --profile nova

Bypassing cache

If you wish to force a rebuild of all parent images, you can do so by passing in the --no-use-cache flag:

# Force a rebuild of all parent images
./run.sh python build.py --config-set horizon --no-use-cache

Automatically pushing images to a Docker Registry

The --push flag can be used to instruct Kolla to push the images up to a registry once they are built:

./run.sh python build.py --config-set x86_ubuntu --profile horizon --push

Cross-compiling

It is possible to cross-compile Docker images in order to, e.g., build an ARM image on an x86 machine. Docker BuildKit has support built-in for this, but docker-py does not yet have support for BuildKit. Fortunately, it is possible to configure Docker in a more general way for cross-compiling.

Ubuntu

# Install additional QEMU support packages
sudo apt-get install qemu binfmt-support qemu-user-static
docker run --rm --privileged multiarch/qemu-user-static --reset -p yes

RHEL

docker run --rm --privileged multiarch/qemu-user-static --reset -p yes

Once the above is complete, you can set the platform in a config set to the target platform, e.g.:

config_sets:
  base_aarch64:
    platform: linux/arm64

./run.sh python build.py --config-set base_aarch64