Cloud Native Buildpacks Pack vs ko

Cloud Native Buildpacks Pack is a free command-line tool for building applications with buildpacks and rebasing the resulting application images. It is maintained by the Cloud Native Buildpacks project and is also available as a Go library. Buildpacks turn application source code into container images that can run on any cloud. Listed capabilities include caching, automatic source detection, modular buildpacks, support for multiple languages and processes, minimal images, reproducible builds and reuse of community buildpacks. Pack supports multi-architecture builds and multiple build-cache backends, and the project lists build-time software bills of materials in CycloneDX, SPDX and Syft JSON formats. The CLI runs on Linux, macOS and Windows; installation options include package managers, container images, scripts and manual installation. Builds need a containerized environment and a daemon such as Docker or Podman, and some setups may need the local Docker socket mounted. The project documents CircleCI, GitLab Auto DevOps and Tekton integrations, as well as kpack for Kubernetes-native builds and image updates. Pack is Apache-2.0 licensed.

ko is an open-source builder for container images of Go applications. It runs `go build` locally, so Docker does not need to be installed. The project positions it for a single Go application with few operating-system base-image dependencies, such as one without cgo or OS package requirements. Builds can target all platforms supported by the configured base image or selected platforms such as linux/amd64 and linux/arm64. For Kubernetes, `ko resolve` builds images for `ko://` references in YAML and replaces those references with image references; `ko apply` can apply the resolved configuration. ko reuses the normal Go build cache and avoids pushing image blobs already present in the remote registry. It generates and uploads SPDX-format SBOMs by default, with an option to disable this. Registry credentials can come from Docker configuration, with built-in environment credential support for Google, Amazon, Azure, and GitHub container registries. A Terraform provider supports Infrastructure-as-Code workflows. ko supports Go applications only and defaults to CGO_ENABLED=0. Windows container image support is experimental and requires a Windows base image.