mirror of
https://github.com/containers/youki
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288 lines
10 KiB
Markdown
288 lines
10 KiB
Markdown
# youki: A container runtime in Rust
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[](https://discord.gg/zHnyXKSQFD)
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[](https://github.com/containers/youki/graphs/contributors)
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[](https://github.com/containers/youki/actions)
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[](https://codecov.io/gh/containers/youki)
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<p align="center">
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<img src="docs/youki.png" width="450">
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</p>
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**youki** is an implementation of the [OCI runtime-spec](https://github.com/opencontainers/runtime-spec) in Rust, similar to [runc](https://github.com/opencontainers/runc).
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Your ideas are welcome [here](https://github.com/containers/youki/issues/10).
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# 🏷️ About the name
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youki is pronounced as /joʊki/ or yoh-key.
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youki is named after the Japanese word 'youki', which means 'a container'. In Japanese language, youki also means 'cheerful', 'merry', or 'hilarious'.
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# 🚀 Quick Start
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> [!TIP]
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> You can immediately set up your environment with youki on GitHub Codespaces and try it out.
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>
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> [](https://codespaces.new/containers/youki?quickstart=1)
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> ```console
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> $ just build
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> $ docker run --runtime youki hello-world
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> $ sudo podman run --cgroup-manager=cgroupfs --runtime /workspaces/youki/youki hello-world
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> ```
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[User Documentation](https://containers.github.io/youki/user/basic_setup.html#quick-install)
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# 🎯 Motivation
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Here is why we are writing a new container runtime in Rust.
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- 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 tricky (e.g. _namespaces(7)_, _fork(2)_); with Rust too, but 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.
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- 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.
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| Runtime | Time (mean ± σ) | Range (min … max) | vs youki(mean) | Version |
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| -------- | -------- | -------- | -------- | -------- |
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| youki | 111.5 ms ± 11.6 ms | 84.0 ms ± 142.5 ms | 100% | 0.3.3 |
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| runc | 224.6 ms ± 12.0 ms | 190.5 ms ± 255.4 ms | 200% | 1.1.7 |
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| crun | 47.3 ms ± 2.8 ms | 42.4 ms ± 56.2 ms | 42% | 1.15 |
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<details>
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<summary>Details about the benchmark</summary>
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- A command used for the benchmark
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```bash
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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'
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```
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- Environment
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```console
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$ ./youki info
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Version 0.3.3
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Commit 4f3c8307
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Kernel-Release 6.5.0-35-generic
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Kernel-Version #35~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Tue May 7 09:00:52 UTC 2
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Architecture x86_64
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Operating System Ubuntu 22.04.4 LTS
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Cores 16
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Total Memory 63870
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Cgroup setup unified
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Cgroup mounts
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Namespaces enabled
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mount enabled
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uts enabled
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ipc enabled
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user enabled
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pid enabled
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network enabled
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cgroup enabled
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Capabilities
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CAP_BPF available
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CAP_PERFMON available
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CAP_CHECKPOINT_RESTORE available
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```
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</details>
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- I have fun implementing this. In fact, this may be the most important.
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# 📍 Status of youki
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**youki** has aced real-world use cases, including containerd's e2e test, and is now adopted by several production environments.
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We have [our roadmap](https://github.com/orgs/containers/projects/15).
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# 🔗 Related project
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- [containers/oci-spec-rs](https://github.com/containers/oci-spec-rs) - OCI Runtime and Image Spec in Rust
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# 🎨 Design and implementation of youki
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The User and Developer Documentation for youki is hosted at [https://containers.github.io/youki/](https://containers.github.io/youki/)
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# 🎬 Getting Started
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Local build is only supported on Linux.
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For other platforms, please use the [Vagrantfile](#setting-up-vagrant) that we have prepared. You can also spin up a fully preconfigured development environment in the cloud with [GitHub Codespaces](https://docs.github.com/en/codespaces/getting-started/quickstart).
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## Requires
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- Rust(See [here](https://www.rust-lang.org/tools/install)), edition 2021
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- linux kernel ≥ 5.3
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## Dependencies
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To install `just`, follow the instruction [here](https://github.com/casey/just#installation).
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### Debian, Ubuntu and related distributions
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```console
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$ sudo apt-get install \
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pkg-config \
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libsystemd-dev \
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build-essential \
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libelf-dev \
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libseccomp-dev \
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libclang-dev \
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glibc-static \
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libssl-dev
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```
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### Fedora, CentOS, RHEL and related distributions
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```console
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$ sudo dnf install \
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pkg-config \
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systemd-devel \
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elfutils-libelf-devel \
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libseccomp-devel \
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clang-devel \
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openssl-devel
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```
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## Build
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```bash
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git clone git@github.com:containers/youki.git
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cd youki
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just youki-dev # or youki-release
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./youki -h # you can get information about youki command
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```
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## Tutorial
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### Requires
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- Docker(See [here](https://docs.docker.com/engine/install))
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### Create and run a container
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Let's try to run a container that executes `sleep 30` with youki. This tutorial may need root permission.
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```bash
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git clone git@github.com:containers/youki.git
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cd youki
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just youki-dev # or youki-release
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mkdir -p tutorial/rootfs
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cd tutorial
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# use docker to export busybox into the rootfs directory
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docker export $(docker create busybox) | tar -C rootfs -xvf -
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```
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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.
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```bash
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../youki spec # will generate a spec file named config.json
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```
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We can edit the `config.json` to add customized behaviors for container. Here, we modify the `process` field to run `sleep 30`.
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```json
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"process": {
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...
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"args": [
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"sleep", "30"
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],
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...
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}
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```
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Then we can explore the lifecycle of a container:
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```bash
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cd .. # go back to the repository root
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sudo ./youki create -b tutorial tutorial_container # create a container with name `tutorial_container`
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sudo ./youki state tutorial_container # you can see the state the container is `created`
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sudo ./youki start tutorial_container # start the container
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sudo ./youki list # will show the list of containers, the container is `running`
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sudo ./youki delete tutorial_container # delete the container
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```
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Change the command to be executed in `config.json` and try something other than `sleep 30`.
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### Rootless container
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`youki` provides the ability to run containers as non-root user([rootless mode](https://docs.docker.com/engine/security/rootless/)). To run a container in rootless mode, we need to add some extra options in `config.json`, other steps are same with above:
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```bash
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$ mkdir -p tutorial/rootfs
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$ cd tutorial
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# use docker to export busybox into the rootfs directory
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$ docker export $(docker create busybox) | tar -C rootfs -xvf -
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$ ../youki spec --rootless # will generate a spec file named config.json with rootless mode
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## Modify the `args` field as you like
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$ ../youki run rootless-container # will create and run a container with rootless mode
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```
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## Usage
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Start the docker daemon.
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```bash
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dockerd --experimental --add-runtime="youki=$(pwd)/youki"
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```
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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).
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```console
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failed to start daemon: pid file found, ensure docker is not running or delete /var/run/docker.pid
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```
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Now repeat the command, which should start the docker daemon.
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You can use youki in a different terminal to start the container.
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```bash
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docker run -it --rm --runtime youki busybox
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```
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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:
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```bash
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systemctl start docker # might need root permission
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```
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### Integration Tests
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Go and node-tap are required to run integration tests. See the [opencontainers/runtime-tools](https://github.com/opencontainers/runtime-tools) README for details.
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```bash
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git submodule update --init --recursive
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just test-oci
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```
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### Setting up Vagrant
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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
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```bash
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git clone git@github.com:containers/youki.git
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cd youki
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# If you want to develop in rootless mode, and this is the default mode
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vagrant up
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vagrant ssh
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# or if you want to develop in rootful mode
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VAGRANT_VAGRANTFILE=Vagrantfile.root vagrant up
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VAGRANT_VAGRANTFILE=Vagrantfile.root vagrant ssh
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# in virtual machine
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cd youki
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just youki-dev # or youki-release
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```
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# 👥 Community and Contributing
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Please refer to [our community page](https://containers.github.io/youki/community/introduction.html).
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Thanks to all the people who already contributed!
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<a href="https://github.com/containers/youki/graphs/contributors">
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<img src="https://contributors-img.web.app/image?repo=containers/youki" />
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</a>
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