crun
An OCI Container Runtime written in C.
An implementation of the OCI specs (https://github.com/opencontainers/runtime-spec) written in C.
Why another implementation?
While most of the tools used in the Linux containers ecosystem are written in Go, I believe C is a better fit for such a lower level tool. runC, the most used implementation of the OCI runtime specs and that is written in Go, forks itself and use a module written in C for setting up the environment before the container process starts.
crun aims to be usable as a library, that can be easily included in programs without requiring an external process for managing OCI containers.
Performance
crun is slightly faster than runC.
On my machine, this is the (elapsed time) for running sequentially 100
containers that execs /bin/true:
| crun | runC | % | |
|---|---|---|---|
| 100 /bin/true (no network namespace) | 0m4.449s | 0m7.514s | 40.7% |
| 100 /bin/true (new network namespace) | 0m15.850s | 0m18.986s | 16.5% |
BUILD
On Fedora you will need these dependencies:
$ dnf install -y python git gcc automake autoconf libcap-devel systemd-devel yajl-devel libseccomp-devel libselinux-devel glibc-static python3-libmount
Python is needed by libocispec to generate the C parser, it won't be used afterwards.
At this point it is enough to run:
$ ./autogen.sh && ./configure
$ make