The Alpine Package Keeper (apk) was originally developed for Alpine Linux but is now used by a variety of other distributions as well.
What is Alpine Linux APK?
With Alpine Linux, you get access to an image that is only 5 MB in size and has access to a more complete package repository than BusyBox-based images. The image is based on musl libc and BusyBox and is designed for utilities as well as production applications. Alpine Linux's mantra fits right at home with Docker images, so read more about it here.
