What Is an Immutable Linux Distro, and Should You Use One?

Linux but more secure.

KEY TAKEAWAYS
 

• Immutable Linux distributions are read-only operating systems that don't allow writing to the root file system.

•  These distros are more secure, reliable, and stable than ordinary Linux distros but also more complex to use.

•  Servers, container environments, and handheld devices benefit from immutable operating systems.

The Linux world is always evolving. There's one recent concept that's causing quite a stir: immutable distros. Imagine a Linux distribution that's unchangeable. Sounds like a limitation? What if that brings actual benefits for you as a Linux user?

Let's delve deeper into the world of immutable operating systems and discuss whether they're the right choice for you.

What Is an Immutable Linux Distribution?

An immutable Linux distribution is an operating system (OS) that is read-only at its core. That means you can't easily modify the OS. This includes the file system, directories, applications, and even configurations. Even as an administrator, you can't make any modifications to the distribution.

If something gets changed in an immutable distro, it's only temporary and reverts when you reboot. That's why these OSes are called "immutable."

What Are the Advantages of Immutable Distros?

Why should someone consider an immutable Linux distribution over regular ones? That's because these distros come with some extra perks due to their immutable nature. Let's discover some of them.

1. Enhanced Security

One of the reasons many regular users prefer Linux to other operating systems is due to its security. But that doesn't mean your Linux system is immune to vulnerability (especially if you're not following the best security practices).

Immutable Linux distributions offer an additional layer of security by preventing unauthorized modifications to the system, making them more resistant to attacks.

Suppose the wrong person gets administrative privileges on your system. Now they can tamper with it as much as they want, if it's a normal Linux system. But in immutable distros, even the administrator can't modify the system files.

This reduces the attack surface for malicious people since they can't install malware or compromise the system. Your computer becomes more secure and resists unauthorized changes.

2. Easier Maintenance

Immutable distros are easier to manage and deploy. You don't need to take care of complex upgrade processes, dependency issues, or managing system state.

Updates don't work on the live system and only work after you reboot. This reduces the chance of messing something up during an update, which is a common occurrence.

3. Atomic Updates

These distributions follow a different approach when updating the OS. Instead of treating the updates package-wise, updates are done throughout the whole OS. In other words, the entire OS is treated as a single indivisible unit. If there is any kind of failure during the update, the system rolls back to the previous state.

Another interesting aspect is the image-based upgrade process. During the update, the system creates a new image in a separate partition. All the updates take place in that new image while you're using the existing image. In the next boot, you're booted into the new and updated image instead of the old one.

4. Improved Reliability

You or others can't modify the file system. So unlike a normal Linux distribution, you can't permanently break these operating systems easily. Even if you accidentally or purposefully break something, it gets fixed in the next reboot. Third-party programs can't tweak anything behind your back or erase any important system element that could make your system unstable.

This also means that you can't run any dangerous Linux commands, such as the sudo rm rf /* command, that would harm your system. Overall, immutable distros are way more reliable.

How Does Software Installation and Updates Work on Immutable Distros?

If immutable distros are read-only, how do you install applications or update them? Most, if not all, immutable distros use Flatpak, AppImages, or Snaps for managing software, which are self-contained package systems. You can install and run these packages without modifying the file system.

These universal package formats come packed with all the necessary dependencies and libraries so that they don't have to rely on system libraries. They are also isolated from your operating system.

Some immutable distributions use a technique known as "layering" to install packages. In this method, you install applications on a dedicated layer on top of the read-only base system.

This means you have access to the distro's package repositories to install the packages. But instead of using traditional package managers like APT or DNF, you use specialized tools to manage packages within the layering system. These layered packages are kept when you update your system and then get added to the updated image after you reboot.

Another option on some operating systems is installing apps through containers such as Distrobox. You install your software in the container on top of the main distro. This allows you to install and use programs not available in the official repositories.

Best Use Cases for Immutable Distros

Immutable distros are not as rare as you might expect. In fact, Steam Deck uses an immutable Arch Linux-based distribution called SteamOS. Likewise, a lot of handheld devices make use of immutable distros due to atomic updates.

But these aren't the only use cases for these distros. Organizations requiring high security and reliability often opt for immutable distros. Especially in server environments where you need to ensure that the server configurations remain stable and secure, these distros can help you achieve that.

Developers can make great use of these systems to create isolated and reproducible testing environments. DevOps engineers can also deploy software in a consistent environment, reducing overheads in continuous integration/continuous deployment (CI/CD) pipelines.

Immutable Linux distros are often used for containerized environments (like Docker and Kubernetes) to make sure you can maintain and scale applications in a predictable and consistent container runtime environment.

Drawbacks of Immutable Linux Distros

Okay, maybe you're convinced about using immutable distros, or maybe you aren't. You've only seen the good so far. Let's see some of the complexity issues that come up with these operating systems.

The first thing is, of course, the learning curve. Learning Linux can be a bit difficult on its own. Even if you're already experienced with Linux systems, you still need to learn about things that immutable distros do differently. You'll also need to refine some of your workflow, which can be a bit time-consuming at the beginning. And if you're coming from Windows or macOS? That can be a daunting experience.

Updates not taking place on your active system and only applying after a reboot can be reliable. But that also means you must reboot the system to get the updated packages. However, some distros do allow you to apply the updates to your live running system. Another problem you face is juggling between several systems since these distros create a separate bootable system for updates.

Installing software also doesn't work the same as using traditional package managers. If you want to install apps not available as Flatpaks or other universal formats, you need to install a whole new distro in a container just to use a single app. That doesn't sound so good.

In addition, you can't write anything to the system. That includes editing the configuration files. But what if that's a necessity for you? You still can't do that. Some distros allow writing to the /etc directory, but that's about it.

4 Immutable Linux Distributions to Get You Started

If you'd like to get your hands on an immutable Linux distribution to test the waters yourself, here are four you can try right now:

1. NixOS

NixOS is a completely reproducible immutable Linux distro. You use a configuration file that includes all the services, options, packages, partition layout, and other stuff you need to build your system. You can then use this config file to create as many NixOS systems as you like, replicating your choices every time.

2. Vanilla OS

What if you could run multiple Linux distros on a single system? That's Vanilla OS for you. You can access different subsystems like Arch, Fedora, openSUSE, or Alpine to install specific software available in those distros. For that, you use the container for the particular distro. Every time you launch the software, the system runs the container and opens the app.

3. Fedora Silverblue

This is Fedora Workstation's immutable spin. Most of the experience is identical to the regular Fedora version. With every new Fedora release, you also get a new release for Silverblue. This version is more suited for testing and development in a container-based OS.

4. blendOS

blendOS is an Arch-based distro that supports multiple package managers, such as APT, Pacman, DNF, YUM, and Yay. You can either use its own package manager, blend, or the other ones you're familiar with using container systems.

Is an Immutable Distro Right for You?

So should you use an immutable distro? That depends on whether you actually need it or not.

For scenarios that require high security, reliability, and stability, such as cloud infrastructures, containerized environments, and servers, these make a lot of sense. Systems not meant for customization and tweaking (appliances, for example) can benefit from these distros.

But for regular desktop use, immutable distros may not be a good choice. Some of the simple stuff like installing software is much more complex than in a regular distro. You need special workarounds since you can't access the root file system.

Some of the advantages that immutable distros come with are also available in regular Linux distros. You can use Btrfs to roll back to the previous state of a package or even the whole operating system. Installing universal package formats on any Linux flavor is also possible. While more secure in certain ways, these distros are still vulnerable to cyberattacks and malware.

Considering all the pros and cons, you might as well try one of the immutable Linux versions for yourself in a virtual machine to see if you like them.

More Security and Reliability but With More Responsibility

Are immutable Linux distributions the future of Linux? Not likely. They aren't going to replace regular Linux systems any time soon. Not for regular users at least. But with numerous advantages, these are definitely suited for certain niche users and IT organizations.

If you're a Windows user interested in Linux, it's easy to try Linux without actually leaving Windows.

Source