In a lengthy technical article, Ikey doherty (known for leading projects such as Solus and contributing to Clear Linux) outlines the philosophy and architecture of AerynOS, this new project that seeks to rethink how an operating system should behave in the era of infrastructure as code.
And far from being just another distribution in the Linux ecosystem, AerynOS presents itself as a profound reimagining of the modern operating system.
From distribution to infrastructure
AerynOS is born from a question provocative: "What if the operating system behaved like a modern infrastructure?"The answer is a platform built from the ground up, without dragging the legacy conventions of traditional distributions and instead of mutating existing systems, AerynOS starts from a clean foundation, leveraging previous experiences and making radical architectural decisions to ensure consistency, reversibility, and structural simplicity.
Ikey Doherty mentions in his article that One of the most striking decisions is the adoption of the LLVM toolchain instead of the traditional GNU version, using libc++ and compiler-rt by default. This choice is not just due to stylistic preferences, but a strategic for superior diagnostics and greater portabilityDespite this upgrade, AerynOS remains committed to using glibc as its standard library, choosing it over musl for its superior performance under multithreaded loads and demanding applications.
In addition to this, it is mentioned that one One of the core concepts of AerynOS is “statelessness”: No package can install files outside of /usr. This strict demarcation separates user space (/etc, /var) from the system space, eliminating merge conflicts and facilitating clean upgrades. This idea, which dates back to Clear Linux, seeks to enforce sensible defaults and avoid the unnecessary complexity that more flexible systems often introduce.
Atomic and reversible updates
AerynOS uses a completely new package management system, called Moss, that performs atomic transactions. Each update creates a new /usr tree using hard links from a deduplicated store, and it is atomically swapped with the current tree using renameat2(). This mechanism ensures that updates either complete completely or are not applied at all, avoiding intermediate states.
Boot management also breaks with tradition. Thanks to tools like blsforme and disks-rs, AerynOS dynamically generates the kernel command line by directly reading superblocks of the file system, eliminating the need for a root= file. In addition, each kernel is tied to its specific transaction, facilitating system rollbacks from the boot menu and allowing the boot environment to be rebuilt from scratch in the event of ESP loss.
The .stone format: a new way to package software
Another key component is the .stone format, a modern binary package Designed to be version-independent and highly efficient. Each .stone file contains:
- Deduplicated content of package files
- A hash index (XXH128, with plans to migrate to Blake3)
- A map of the target file system
- Typed metadata such as name, version, capabilities, etc.
Instead of installing files directly, .stone are stored in a Content Addressable Store (CAS) and are compiled as part of a transaction. This approach not only improves performance but also allows any changes to be easily reverted.
The package management system does not follow the traditional imperative model. Developers believe that direct installation commands "introduce more bugs than they solve." Instead, each transaction creates a new system graph, paving the way for a future declarative model similar to Nix or Gentoo, where the desired system state is described rather than executing change commands.
Is AerynOS immutable?
Although it is often described as an immutable system, the creators themselves clarify that this is not strictly true. The system does not block read-only access, and while transactions replace the /usr tree, Complete immutability has not yet been implemented. The long-term goal is to achieve this without a reboot, leveraging technologies such as overlayfs and erofs.
Despite being in alpha phase, AerynOS already has ISOs available, support for GNOME, compatibility with Steam, NVIDIA, Flatpak, and real users who praise its stability and performance. The system already works well enough to be tested in real-world scenarios, although it is still evolving.
Source: https://aerynos.com