Understanding Immutable OSes

Yeah as far as I understand most folks pursuing an immutable Linux OS basically just want /etc, /var, and /home to be the only writable parts of the filesystem. Updating or changing the rest of the system requires some repackaging and redeployment of the OS (like using ostree or some other similar tool).

The article looks laser focused on Linux distros for running inside a container.

You don't want any data to actually change inside a container, since you want to be able to delete and create them at will. But I do agree that's a very bad name, since there are more to data immutability than the containerization practices, and there is more to mutability than filesystem data.

On the first point, there's already a reply about people wanting to edit /home and /etc. On a container that's something you really don't want to do. But on other applications of immutable filesystem data, that's what you want.

Sometimes yes, sometimes no.

A lot of things can get easier if you assume all local state is a transient cache, and master copy is somewhere else. Clearest examples are kiosks and digital billboards, which show a single webpage from remote server. A less common example are embedded devices - while there might be small local storage for settings, it is not managed by OS, and everything traditionally part of OS, like /home, /etc, /var and so on is nonpersistent.

> Here are some popular Immutable OS solutions, although this list is not exhaustive