railcar - rust implementation of the oci-runtime spec
What is railcar?
railcar is a rust implementation of the opencontainers
initiative's runtime
spec. It is similar to the
reference implementation runc, but it is implemented completely in rust for
memory safety without needing the overhead of a garbage collector or multiple
threads. For more information on the development of railcar, check out
Building a Container Runtime in
Rust
Building railcar
Install rust:
curl https://sh.rustup.rs -sSf, sh
cargo install cargo-when
rustup toolchain install stable-x86_64-unknown-linux-gnu
rustup default stable-x86_64-unknown-linux-gnu # for stable
rustup target install x86_64-unknown-linux-musl # for stable
rustup toolchain install nightly-x86_64-unknown-linux-gnu
rustup default nightly-x86_64-unknown-linux-gnu # for nightly
rustup target install x86_64-unknown-linux-musl # for nightly
Building can be done via build.sh:
build.sh
By default, build.sh builds a dynamic binary using gnu. To build a static
binary, set TARGET to x86_64-unknown-linux-musl:
TARGET=x86_64-unknown-linux-musl ./build.sh
Build requirements for TARGET=x86_64-unknown-linux-gnu:
libseccomp-devel
Build requirements for TARGET=x86_64-unknown-linux-musl:
git submodule update --init
autotools
make
gcc
musl-gcc
To build a release version:
build.sh --release
If you build using stable instead of nightly, the set_name feature will be
disabled and the init process inside the container will not be named rc-init
when viewed via ps or /proc/$pid/cmdline.
Using railcar
./railcar run
You can specify a different bundle directory where your config.json is
located with -b:
./railcar -b /some/other/directory run
Using railcar with docker
railcar can be used as a backend for docker. To use it, start the docker
daemon with an additional backend:
dockerd ... --experimental --add-runtime "rc=/path/to/railcar"
Then you can use railcar by specifying the rc backend:
docker run -it --rm --runtime rc hello
Note that you should start the daemon with a terminal (the -t option) so that
docker can properly collect stdout and stderr from railcar. If you want to
daemonize the container, just use:
docker run -dt --rm --runtime rc hello
Differences from runc
In general, railcar is very similar to runc, but some of the runc
commands are not supported. Currently, railcar does not support the following
commands:
checkpoint
events
exec
init
list
pause
restore
resume
spec
Also, railcar always runs an init process separately from the container
process.
Contributing
railcar is an open source project. See CONTRIBUTING for
details.
Oracle gratefully acknowledges the contributions to railcar that have been made
by the community.
Getting in touch
The best way to get in touch is Slack.
Click here to join the the Oracle Container Tools workspace.
Then join the Railcar channel.
License
Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
railcar is dual licensed under the Universal Permissive License 1.0 and the
Apache License 2.0.
See LICENSE for more details.