Buildah vs Jib

Buildah is a free command-line tool for building OCI container images on Linux. It can create images from working containers, Dockerfiles, or Containerfiles, and can also build through commands and scripts without a build file. Output can use OCI format or the traditional upstream Docker image format. Builds can run without root privileges, and Buildah follows a fork-exec model rather than running as a daemon. Its commands create, mount, unmount, delete, and rename working containers, as well as create or delete images; users can also pull images from a specified location and push local images elsewhere. Buildah is based on a Go API that other tools can vendor, and Podman uses it for Dockerfile builds while remaining independently installable. Buildah requires a kernel with OverlayFS or fuse-overlayfs support; RHEL or CentOS requires version 7.4 or later. Installation guidance warns that short image names can be spoofed and recommends fully qualified names from trusted registries or pulling by digest. The project points users to tutorials, releases, and a mailing list for questions.

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.