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A fast and lightweight fully featured OCI runtime and C library for running containers
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giuseppe tag new release
Signed-off-by: Giuseppe Scrivano <>
Latest commit d098caf Aug 19, 2019
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build-aux make: add infrastructure for make syntax-check Sep 13, 2017
contrib tests: drop sonarcloud tests Aug 12, 2019
libocispec @ f6c15f2 libocispec: sync from upstream Jul 20, 2019
m4 initial commit Aug 30, 2017
python python: fix build errors May 31, 2019
src cgroup: write correctly blkio throttling Aug 19, 2019
tests utils: fix file existence check Aug 19, 2019
.gitmodules gitmodules: use containers/libocispec.git repository Aug 12, 2019
.travis.yml tests: drop sonarcloud tests Aug 12, 2019
COPYING COPYING: new file Aug 31, 2017
COPYING.libcrun libcrun: change license to LGPL3+ Sep 10, 2017
Dockerfile Dockerfile: compile with -O3 Jul 29, 2019
GNUmakefile make: add infrastructure for make syntax-check Sep 13, 2017 update libocispec repository Aug 12, 2019 fix links Aug 12, 2019 linux: resolve symlinks for bind mounts Apr 19, 2019 tag new release Aug 19, 2019 cgroups2: use io.bfq.weight instead of io.weight Aug 13, 2019 make: add infrastructure for make syntax-check Sep 13, 2017


Build Status Coverity Status Total alerts Language grade: C/C++

A fast and low-memory footprint OCI Container Runtime fully written in C.

crun conforms to the OCI Container Runtime specifications (


The user documentation is available here.

Static build

If you are looking for a static build, take a look at the instructions here.

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 a lower level tool like a container runtime. runc, the most used implementation of the OCI runtime specs written in Go, re-execs itself and use a module written in C for setting up the environment before the container process starts.

crun aims to be also usable as a library that can be easily included in programs without requiring an external process for managing OCI containers.


crun is faster than runc and has a much lower memory footprint.

This is the elapsed time on my machine for running sequentially 100 containers, the containers run /bin/true:

crun runc %
100 /bin/true (no network namespace) 0:05.70 0:10.95 -47.9%
100 /bin/true (new network namespace) 0:06.16 0:11.17 -44.8%


On Fedora these dependencies are required for the build:

dnf install -y make python git gcc automake autoconf libcap-devel \
    systemd-devel yajl-devel libseccomp-devel libselinux-devel \
    go-md2man glibc-static python3-libmount libtool

On Ubuntu:

apt-get install -y make git gcc build-essential pkgconf libtool \
   libsystemd-dev libcap-dev libseccomp-dev libyajl-dev libselinux1-dev \
   go-md2man libtool autoconf python3

Unless you are also building the Python bindings, Python is needed only by libocispec to generate the C parser at build time, it won't be used afterwards.

Once all the dependencies are installed:

./ && ./configure
sudo make install
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