Linux

Immutable, doesn't mean extreme secure. It's a false sense of security.
It could be more secure.
But during a runtime, it is possible to overwrite operational memory, mask some syscalls, etc.

That's my 3 cents.

Immutable distros are great for applications where you want uniformity for users and protections against users who are a little too curious for their own good.

SteamOS is a perfect use case. You don't want users easily running scripts on their Steam Decks to install god knows what and potentially wreck their systems, then come to Valve looking for a fix.

Immutable distros solve that issue. Patches and updates for the OS roll out onto effectively identical systems, and if something does break, the update will fail instead of the system. So users will still have a fully functional Steam Deck.

If you're not very technical, or you aren't a power user and packaged apps like Flatpaks are available for all your software, then go for it. I prefer to tinker under the hood with my computers, but I also understand and except the risk that creates.

Immutable distros are a valuable part of a larger, vibrant Linux ecosystem IMO.

Since the idea is that the "root partition" is immutable, serious question:

How do you fix a hardware config issue or a distro packaging / provision issue in an immutable distro?

Several times in my Linux history I've found that, for example, I need to remove package-provided files from the ALSA files in /usr/share/alsa in order for the setup to work with my particular chipset (which has a hardware bug). Other times, I've found that even if I set up a custom .XCompose file in my $HOME, some applications insist on reading the Compose files in /usr/share/X11/locale instead, which means I need to be able to edit or remove those files. In order to add custom themes, I need to be able to add them to /usr/share/{icons,themes}, since replicating those themes for each $HOME in the system is a notorious waste of space and not all applications seem to respect /usr/local/share. Etc.

Unless I'm mistaken on how immutable systems work, I'm not sure immutable systems are really useful to someone who actually wants to or needs to power user Linux, or customize past the "branding locking" that environments like Gnome have been aiming for for like a decade.

It's definitely great for the mainstream. Think of Linus Sebastian who has somehow broken every OS except for SteamOS.

It's not great for me who uses Arch Linux btw with the expectation that if the system doesn't break on its own, then I will break it myself.

what does the community think of it?

Everyone has their own opinion, personally I think they're a great idea and have lots of great applications. But just like rolling vs non-rolling release it's a personal and application dependant choice.

Do the downsides outweigh the benefits or vice versa?

Again, depends, for my personal computer I wouldn't use it because I think it could get complicated to get specific things to work, but for closed hardware like the Deck or even a fairly stable desktop used as a gaming system it's perfect.

Could this help Linux reach more mainstream audiences?

It could, it can also hamper it because people might start to try solutions that only work until next boot and not understanding why, or having problems getting some special hardware to work (more than it would be a mutable distro). But there is a great counter to this which is that once it's running it will be very difficult to break by user error.

At the end of the day I think it's a cool technology but that people should know what they're getting into, just like when choosing rolling vs non-rolling distro, it's not about what's better, but what suits your needs best.

I heard both flatpak and immutability are obstacles to developers. How bad is it really?

I've had NixOS absolutely refuse to run some compiler toolchain I depended upon that should've been dead simple on other distros, I'm really hesitant to try anything that tries to be too different anymore.

Then you have NixOS, which is declarative, and fairly immutable.

You don't have to reboot to make changes, but you can't just run unlinked binaries either.

You can't do things like edit your hosts table or modify the FS for cron jobs. The application store is unwritable, but you can sync new apps into it .

You have to make changes to the config file and run a rebuild as root.

From an advertising perspective, it's important to think about who you're targeting. Who are your likely customers? Certainly there are some based on the strengths that you raised.

However, some people are definitely not a good target audience, and some people is actually a very large group of people. There are a lot of current and potential users who essentially want the standard major applications to work, and they're not going to touch the root partition, and they want things to be very simple. For people like that, Debian or Ubuntu or Fedora already do what they want. And these major operating systems have been around for so long that people will naturally be more confident using them, because they were their friends have experience, or because they think the organization has more stability because of its experience.

Of course a lot of things depend on how you define words, but to me the above paragraph describes the mainstream audience, and I don't think you're going to have much luck reaching them, because I don't think the thing you're trying to sell gives them extra value. In other words, it's not solving a problem for them, so why should they care.

Immutable vs Mutable

weird        normal

NixOS is kinda the best of both worlds, because it does everything in a way that is compatible with an immutable fs, but it doesn’t force you into abiding by immutability yourself.

You can always opt into immutability by using Impermanence, but I’ve never seen any reason to.

Edit: That said, the syntax has a steep learning curve and there are tons of annoying edge cases that spawn out of the measures it takes to properly isolate things. It can be a lot to micromanage, so if you’d rather just use your system more than tinker with it, it may not be a good fit.

I am a huge fan of immutable distributions, not for my personal daily driver but for secondary systems like my living room/home theater PC.

I don't mind flatpaks in a pinch, but having to use them for literally every app on my computer is an unreasonable amount of bloat.

I personally vastly prefer mutable distros for my own system, but I understand the appeal for those who like them. As long as mutable distros remain an option I don't mind immutable distros.

Immutable ≠ atomic

Bazzite is atomic (not immutable), same with Silverblue and other Fedora variants (they're all atomic, even on their main page it says atomic). It's kinda misleading ngl

• You can still apply updates live, e.g. on Bazzite (Fedora Atomic) with the --apply-live tag (or however it's spelled).
• The root partition isn't read only per se, but you have to change the upstream image itself instead of the one booted right now. You can use the uBlue-Builder for example to make your own custom Bazzite spin just for you if you want.
• Both aren't inherently secure or insecure. It's harder to brick your system, yeah, for sure, but you can still fuck up some partitions or get malware. It's just better because everything is transparently identifiable (ostree works like git), saved (fallback images), containerised and reproducible.
• And you can still install system software, e.g. by layering it via rpm-ostree. Or use rootful containers in Distrobox and keep using apt or Pacman in there.

Secure != stable Immutable distros aren't always more secure but rather more stable and hard to break Also btw nixos can apply updates without rebooting