KIWI NG vs rules_oci

KIWI NG is a free, daemonless command-line image builder for Linux. It turns versioned image descriptions and package repositories into bootable, reproducible artifacts. A prepared root tree can produce disk images, ISO files, or containers for virtual machines, cloud platforms, removable media, and specialized targets. Descriptions define metadata, repositories, packages, users, storage, target configuration, and image types, using config.xml or a .kiwi file. Overlays, archives, and scripts add customization. Documented package managers include apk, apt, dnf4, dnf5, microdnf, pacman, and zypper. Supported distributions include Fedora, CentOS Stream, openSUSE, Ubuntu, Debian, and Arch Linux. Builds support multiple architectures and a local cache backend. Installation is available through distribution packages, Open Build Service, or pip. A recent Linux host, Python 3.9 or newer, Git, and at least 15 GB recommended free disk space are required. QEMU can optionally boot and inspect outputs; GPL-3.0 governs the source.

rules_oci has no write-up on Specifiction yet; its figures are above.