HermitCore is a unikernel targeting a scalable and predictable runtime for high-performance and cloud computing. Unikernel means, you bundle your application directly with the kernel library, so that it can run without any installed operating system. This reduces overhead, therfore, interesting applications include virtual machines and high-performance computing.
The RustyHermit can run Rust applications, as well as C/C++/Go/Fortran applications. A tutorial on how to use these programming languages on top of RustyHermit is published at https://github.com/hermitcore/hermit-playground.
HermitCore is a research project at RWTH-Aachen and was originally written in C (libhermit). We decided to develop a new version of HermitCore in Rust and name it RustyHermit. The ownership model of Rust guarantees memory/thread-safety and enables us to eliminate many classes of bugs at compile-time. Consequently, the use of Rust for kernel development promises less vulnerabilities in comparsion to common programming languages.
The kernel and the integration into the Rust runtime is entirely written in Rust and does not use any C/C++ Code. We extend the Rust toolchain so that the build process is similar to Rust's usual workflow. Rust applications that do not bypass the Rust runtime and directly use OS services are able to run on RustyHermit without modifications.
We provide a Docker container hermitcore-rs for easy compilation of Rust applications into a unikernel. Please pull the container and use cargo to cross compile the application. As an example, the following commands create the test application Hello World for RustyHermit.
sh
docker pull rwthos/hermitcore-rs
docker run -v $PWD:/volume -e USER=$USER --rm -t rwthos/hermitcore-rs cargo new hello_world --bin
cd hello_world
docker run -v $PWD:/volume -e USER=$USER --rm -t rwthos/hermitcore-rs cargo build --target x86_64-unknown-hermit
cd -
RustyHermit can run within our own hypervisor uhyve , which requires KVM to create a virtual machine. Please install the hypervisor as follows:
sh
cargo install uhyve
Afterwards, your are able to start RustyHermit applications within our hypervisor:
sh
uhyve target/x86_64-unknown-hermit/debug/hello_world
The maximum amount of memory can be configured via environment variables like in the following example
sh
HERMIT_CPUS=4 HERMIT_MEM=8G uhyve target/x86_64-unknown-hermit/debug/hello_world
The virtual machine is configured using the following environment variables
Variable | Default | Description
-----------------|-------------|--------------
HERMIT_CPUS | 1 | Number of cores the virtual machine may use
HERMIT_MEM | 512M | Memory size of the virtual machine. The suffixes M and G can be used to specify a value in megabytes or gigabytes
HERMIT_VERBOSE | 0 | Hypervisor prints kernel log messages stdout. ("1" enables log)
For instance, the following command starts the demo application in a virtual machine, which has 4 cores and 8GiB memory:
bash
$ HERMIT_CPUS=4 HERMIT_MEM=8G ./proxy ../../hello_world/target/x86_64-unknown-hermit/debug/hello_world
More details can be found in the uhyve README.
It is also possible to run RustHermit within Qemu. In this case, a loader is required to boot the application. This loader is part of the repository and can be build with xbuid as follows.
bash
$ cd loader
$ cargo xbuild --target x86_64-unknown-hermit-loader.json
Afterwards, the loader is stored in target/x86_64-unknown-hermit-loader/debug/ as hermit-loader.
Afterwards, the unikernel application app can be booted with following command:
bash
$ qemu-system-x86_64 -display none -smp 1 -m 64M -serial stdio -kernel path_to_loader/hermit-loader -initrd path_to_app/app -cpu qemu64,apic,fsgsbase,rdtscp,xsave,fxsr
It is important to enable the processor features fsgsbase and rdtscp because it is a prerequisite to boot RustyHermit.
This kernel can still be used with C/C++, Go, and Fortran applications. A tutorial on how to do this is available at https://github.com/hermitcore/hermit-playground.
RustyHermit is derived from following tutorials and software distributions:
HermitCore's Emoji is provided for free by EmojiOne.
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.
RustyHermit is being developed on GitHub. Create your own fork, send us a pull request, and chat with us on Slack