Jib vs ko

Jib builds Docker and OCI images for Java applications without a Docker daemon. It can be used as a Maven or Gradle plugin, a Java library, or a command-line interface, and runs on Linux, macOS, and Windows. Jib divides application contents into layers, allowing code changes to be rebuilt without rebuilding the whole image. It can push images to a container registry of the user's choice, uses an OpenJDK base image by default, and accepts a custom base image. The project says that rebuilding an image from the same contents produces the same image. It supports local build caches and multi-architecture builds, and the project says it works well with Google Cloud Build. Examples cover Spring Boot, Micronaut, multi-module projects, and Spark Java with a Java Agent. Jib is free and open source under Apache License, Version 2.0. The project is not an officially supported Google product; it directs usage questions to Stack Overflow and also links to GitHub issues and a FAQ.

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.