Chimera Linux

A Linux distribution based on FreeBSD userland and LLVM

GitHub organization

IRC: #chimera-linux @ OFTC



Chimera Linux

Chimera is a Linux distribution with the following goals:

For specific questions, read our FAQ.

The distribution is currently in heavy development and subject to breaking changes. It is capable of booting and building itself, but does not include a lot of software yet and packaging is not entirely set in stone.

Built with LLVM

Chimera uses LLVM and Clang as its system toolchain. This is used to build all core components of the system.

There is currently no GCC in the source repository. The compiler-rt component is used as the core runtime, and libc++ is used as the standard C++ library.

FreeBSD userland

The userland is based around FreeBSD components rather than GNU coreutils and related. There are few GNU components in main, and the only one that is strictly required for bootstrap and the build environment is GNU Make.

The musl libc is used as the standard C library in place of glibc.

Fast source package build system

Chimera has a completely new source packaging system that is not written in shell as is conventional, but rather in the Python scripting language. This reduces the build system overhead to a minimum, as well as making it introspectable and so on.

The builds are always containerized, with a minimal Chimera system being used as the build environment for every package. This system is sandboxed using bubblewrap and run completely unprivileged.

The binary packaging system used is apk-tools, originally from Alpine Linux. It was chosen because of its speed and ease of integration.


The system can build itself. You can use any musl based distribution as the initial system, as long as it has the few required components needed for the system build. It is also possible to bootstrap from a completely foreign system using our scripts.

After that, Chimera uses a 3-stage bootstrap path, with stage 0 building all components needed to assemble the build container, stage 1 rebuilding itself using components from stage 0, and stage 2 rebuilding itself using components from stage 1. This is done to ensure that the final system is not influenced by the initial host system.


Chimera can target a variety of CPU architectures, including ppc64le, aarch64, x86_64, riscv64 and ppc64. It is very easy to bring up a new architecture if necessary, as long as the required LLVM components support it - one simply needs to create a profile describing some basics of the target architecture. The build system has full support for cross-compiling (not only for bootstrap - all of it is cross-aware).