youki is an implementation of the OCI runtime-spec in Rust, similar to runc.
Your ideas are welcome here.
youki is pronounced as /joʊki/ or yoh-key. youki is named after the Japanese word 'youki', which means 'a container'. In Japanese language, youki also means 'cheerful', 'merry', or 'hilarious'.
Here is why we are writing a new container runtime in Rust.
-
Rust is one of the best languages to implement the oci-runtime spec. Many very nice container tools are currently written in Go. However, the container runtime requires the use of system calls, which requires a bit of special handling when implemented in Go. This is too tricky (e.g. namespaces(7), fork(2)); with Rust, it's not that tricky. And, unlike in C, Rust provides the benefit of memory safety. While Rust is not yet a major player in the container field, it has the potential to contribute a lot: something this project attempts to exemplify.
-
youki has the potential to be faster and use less memory than runc, and therefore work in environments with tight memory usage requirements. Here is a simple benchmark of a container from creation to deletion.
Runtime Time (mean ± σ) Range (min … max) youki 198.4 ms ± 52.1 ms 97.2 ms … 296.1 ms runc 352.3 ms ± 53.3 ms 248.3 ms … 772.2 ms crun 153.5 ms ± 21.6 ms 80.9 ms … 196.6 ms Details about the benchmark
- A command used for the benchmark
$ hyperfine --prepare 'sudo sync; echo 3 | sudo tee /proc/sys/vm/drop_caches' --warmup 10 --min-runs 100 'sudo ./youki create -b tutorial a && sudo ./youki start a && sudo ./youki delete -f a'
- Environment
$ ./youki info Version 0.0.1 Kernel-Release 5.11.0-41-generic Kernel-Version #45-Ubuntu SMP Fri Nov 5 11:37:01 UTC 2021 Architecture x86_64 Operating System Ubuntu 21.04 Cores 12 Total Memory 32025 Cgroup setup hybrid Cgroup mounts blkio /sys/fs/cgroup/blkio cpu /sys/fs/cgroup/cpu,cpuacct cpuacct /sys/fs/cgroup/cpu,cpuacct cpuset /sys/fs/cgroup/cpuset devices /sys/fs/cgroup/devices freezer /sys/fs/cgroup/freezer hugetlb /sys/fs/cgroup/hugetlb memory /sys/fs/cgroup/memory net_cls /sys/fs/cgroup/net_cls,net_prio net_prio /sys/fs/cgroup/net_cls,net_prio perf_event /sys/fs/cgroup/perf_event pids /sys/fs/cgroup/pids unified /sys/fs/cgroup/unified CGroup v2 controllers cpu detached cpuset detached hugetlb detached io detached memory detached pids detached device attached Namespaces enabled mount enabled uts enabled ipc enabled user enabled pid enabled network enabled cgroup enabled $ ./youki --version youki version 0.0.1 commit: 0.0.1-0-0be33bf $ runc -v runc version 1.0.0-rc93 commit: 12644e614e25b05da6fd08a38ffa0cfe1903fdec spec: 1.0.2-dev go: go1.13.15 libseccomp: 2.5.1 $ crun --version crun version 0.19.1.45-4cc7 commit: 4cc7fa1124cce75dc26e12186d9cbeabded2b710 spec: 1.0.0 +SYSTEMD +SELINUX +APPARMOR +CAP +SECCOMP +EBPF +CRIU +YAJL
- A command used for the benchmark
-
The development of railcar has been suspended. This project was very nice but is no longer being developed. This project is inspired by it.
-
I have fun implementing this. In fact, this may be the most important.
- containers/oci-spec-rs - OCI Runtime and Image Spec in Rust
youki is not at the practical stage yet. However, it is getting closer to practical use, running with docker and passing all the default tests provided by opencontainers/runtime-tools.
Feature | Description | State |
---|---|---|
Docker | Running via Docker | ✅ |
Podman | Running via Podman | ✅ |
pivot_root | Change the root directory | ✅ |
Mounts | Mount files and directories to container | ✅ |
Namespaces | Isolation of various resources | ✅ |
Capabilities | Limiting root privileges | ✅ |
Cgroups v1 | Resource limitations, etc | ✅ |
Cgroups v2 | Improved version of v1 | Support is complete except for devices. WIP on #78 |
Systemd cgroup driver | Setting up a cgroup using systemd | ✅ |
Seccomp | Filtering system calls | ✅ |
Hooks | Add custom processing during container creation | ✅ |
Rootless | Running a container without root privileges | ✅ |
OCI Compliance | Compliance with OCI Runtime Spec | ✅ 50 out of 50 test cases passing |
The User and Developer Documentation for youki is hosted at https://containers.github.io/youki/
Local build is only supported on Linux. For other platforms, please use the Vagrantfile that we have prepared. You can also spin up a fully preconfigured development environment in the cloud with gitpod.
$ sudo apt-get install \
pkg-config \
libsystemd-dev \
libdbus-glib-1-dev \
build-essential \
libelf-dev \
libseccomp-dev
$ sudo dnf install \
pkg-config \
systemd-devel \
dbus-devel \
elfutils-libelf-devel \
libseccomp-devel
$ git clone [email protected]:containers/youki.git
$ cd youki
$ ./build.sh
$ ./youki -h # you can get information about youki command
Let's try to run a container that executes sleep 30
with youki. This tutorial may need root permission.
$ git clone [email protected]:containers/youki.git
$ cd youki
$ ./build.sh
$ mkdir -p tutorial/rootfs
$ cd tutorial
# use docker to export busybox into the rootfs directory
$ docker export $(docker create busybox) | tar -C rootfs -xvf -
Then, we need to prepare a configuration file. This file contains metadata and specs for a container, such as the process to run, environment variables to inject, sandboxing features to use, etc.
$ ../youki spec # will generate a spec file named config.json
We can edit the config.json
to add customized behaviors for container. Here, we modify the process
field to run sleep 30
.
"process": {
...
"args": [
"sleep", "30"
],
...
}
Then we can explore the lifecycle of a container:
$ cd .. # go back to the repository root
$ sudo ./youki create -b tutorial tutorial_container # create a container with name `tutorial_container`
$ sudo ./youki state tutorial_container # you can see the state the container is `created`
$ sudo ./youki start tutorial_container # start the container
$ sudo ./youki list # will show the list of containers, the container is `running`
$ sudo ./youki delete tutorial_container # delete the container
Change the command to be executed in config.json
and try something other than sleep 30
.
youki
provides the ability to run containers as non-root user(rootless mode). To run a container in rootless mode, we need to add some extra options in config.json
, other steps are same with above:
$ mkdir -p tutorial/rootfs
$ cd tutorial
# use docker to export busybox into the rootfs directory
$ docker export $(docker create busybox) | tar -C rootfs -xvf -
$ ../youki spec --rootless # will generate a spec file named config.json with rootless mode
## Modify the `args` field as you like
$ ../youki run rootless-container # will create and run a container with rootless mode
Start the docker daemon.
$ dockerd --experimental --add-runtime="youki=$(pwd)/target/x86_64-unknown-linux-gnu/debug/youki"
If you get an error like the below, that means your normal Docker daemon is running, and it needs to be stopped. Do that with your init system (i.e., with systemd, run systemctl stop docker
, as root if necessary).
failed to start daemon: pid file found, ensure docker is not running or delete /var/run/docker.pid
Now repeat the command, which should start the docker daemon.
You can use youki in a different terminal to start the container.
$ docker run -it --rm --runtime youki busybox
Afterwards, you can close the docker daemon process in other the other terminal. To restart normal docker daemon (if you had stopped it before), run:
$ systemctl start docker # might need root permission
Go and node-tap are required to run integration tests. See the opencontainers/runtime-tools README for details.
$ git submodule update --init --recursive
$ ./integration_test.sh
# run specific test_cases with pattern
$ ./integration_test.sh linux_*
You can try youki on platforms other than Linux by using the Vagrantfile we have prepared. We have prepared two environments for vagrant, namely rootless mode and rootful mode
$ git clone [email protected]:containers/youki.git
$ cd youki
# If you want to develop in rootless mode, and this is the default mode
$ vagrant up
$ vagrant ssh
# or if you want to develop in rootful mode
$ VAGRANT_VAGRANTFILE=Vagrantfile.root vagrant up
$ VAGRANT_VAGRANTFILE=Vagrantfile.root vagrant ssh
# in virtual machine
$ cd youki
$ ./build.sh
We also have an active Discord if you'd like to come and chat with us.
This project welcomes your PR and issues. For example, refactoring, adding features, correcting English, etc. If you need any help, you can contact me on Twitter.
Thanks to all the people who already contributed!