Apptainer: Application Containers for Linux

I agree with Havoc, the message is unclear: Is Apptainer a replacement for Flatpack on the desktop, or is it targeting the server?

Server - but this is kind of a wrong question. Apptainer is for running cli applications in immutable, rootless containers. The closest tool I can think of is Fedora Toolbx [1]. Apptainer is primarily used to distributing and reusing scientific computing tools b/c it doesn't allow root, doesn't allow for changes to the rootfs in each container, automatically mounts the working directory and works well with GPUs (that last point I can't personally attest to).

[1]: https://docs.fedoraproject.org/en-US/fedora-silverblue/toolb...

> Apptainer is for running cli applications in immutable, rootless containers.

What's the appeal of using this over unshare + chroot to a mounted tarball with a tmpfs union mount where needed? Saner default configuration? Saner interface to cgroups?