jericop/cnb-lfx-buildkit-poc

cnb-lfx-buildkit-poc

This repo is an initial proof-of-concept for the following LFX mentorship project.

CNCF - Cloud Native Buildpacks: Proof of concept making multiarch images with buildkit (2024 Term 1)

It is heavliy inspired by the following article. While the article is invaluable for understanding how the lifecycle works, it requires a fair amount of manual steps, which must be repeated if any changes are made to buildpacks. For the sake of simplicity, I am using an inline buildpack and running pack build once in order to copy out the necessary files.

• https://medium.com/buildpacks/unpacking-cloud-native-buildpacks-ff51b5a767bf

Primary objective

The primary objective is to create a Dockerfile that has all of the lifecycle commands needed to build and push architecture-specific images to a registry. Dockerfile-example is an example of how it works. You can then combine the architecture-specific images into a manifest list (multi-arch) image.

pack-with-buildkit.sh

This script will do the following:

• Sets up a buildkit builder with host network access
• Starts a local registry on a random port
• Run pack build using the project.toml which has an inline buildpack that copies the files we need to /workspace
• Copies the files we need out of the container built with pack so we can use them in a new build (with buildkit)
• Generates a Dockerfile from Dockerfile-initial that will look like Dockerfile-example
• Runs docker buildx build --platform linux/amd64,linux/arm64 to execute the lifecycle commands through buildkit
  • This builds and publishes images to the local registry with amd64 and arm64 tags
  • There is some hackery that happens to fix the architecture (for now)
• Finally it creates a manifest list with the amd64 and arm64 tagged images

Requirements

• Multi-arch builders are required. I'm using ones that I build and publish.

Published image(s)

• ghcr.io/jericop/inline-app:latest