created_at2019-10-06 14:04:22.220692
updated_at2021-12-09 22:06:05.950709
descriptionA Rust-based library operting system
Martin Kröning (mkroening)



RustyHermit: libhermit-rs

Documentation License Slack Status

libhermit-rs is the kernel of the RustyHermit unikernel project.

Building the kernel

Usually the kernel will be linked as static library to your applications.

  • Rust applications: Instructions can be found in the rusty-hermit repository.

  • For C/C++ applications: Instructions can be found in the hermit-playground repository.

Standalone static library build

If this does not fit your needs and you want to build the kernel as static library to link afterwards, you need the following:

The Rust nightly toolchain (official webpage), the source code of the Rust runtime, and llvm-tools:

rustup toolchain install nightly
rustup component add rust-src llvm-tools-preview

You can then build libhermit-rs with the following command

cargo build -Z build-std=core,alloc,panic_abort --target x86_64-unknown-none-hermitkernel

The resulting library then can be found in target/x86_64-unknown-none-hermitkernel/debug/libhermit.a

Control the kernel messages verbosity

libhermit-rs uses the lightweight logging crate log to print kernel messages. The environment variable HERMIT_LOG_LEVEL_FILTER controls the verbosity. You can change it by setting it at compile time to a string matching the name of a LevelFilter. If the variable is not set, or the name doesn't match, then LevelFilter::Info is used by default.

$ HERMIT_LOG_LEVEL_FILTER=Debug cargo build -Z build-std=core,alloc,panic_abort --target x86_64-unknown-none-hermitkernel


libhermit-rs is derived from following tutorials and software distributions:

  1. Philipp Oppermann's excellent series of blog posts.
  2. Erik Kidd's toyos-rs, which is an extension of Philipp Opermann's kernel.
  3. The Rust-based teaching operating system eduOS-rs.

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Licensed under either of

at your option.


Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

libhermit-rs is being developed on GitHub. Create your own fork, send us a pull request, and chat with us on Slack

Commit count: 1329

cargo fmt