Basics

This section has the general information and resources needed to work with any part of youki. As youki is written in Rust, you should know some basic Rust before. If you don't yet, some good resources for that can be found on the Rust's official site.

Youki

Youki is a low level container runtime, which deals with the creation and management of Linux containers. Some of other such low-level runtimes are runc and crun. These are usually used by a higher-level runtime such as Docker or Podman to actually create and manage containers, where the higher level runtime provides a much easier interface for users.

Before you start working on developing youki, you should go through the User documentation as it specifies the requirements and setup for running youki. For developing youki, you will need to install the dependencies and clone the repo, as specified in the Basic Setup and Basic Usage sections.

Testing while developing

While developing youki, you might need to compile and test the code from time to time, to make sure it is working and and something is not accidentally broken. Currently there are two ways to verify that:

  • Unit tests, which test individual components of youki
  • Integration tests, which test the complete functionality of youki commands from start to end.

As the steps to run these tests can be a bit tedious, a makefile in project the root provides an easy way to run these quickly. The makefile currently states three individual test :

  • test: The unit tests
  • oci-integration-test: The integration tests provided by OCI, these are the current standard to make sure youki is OCI compliant.
  • integration-test: This is the Rust port of the OCI runtime tests, as there are some issues in the OCI tests. See integration_test page.

All three can be run by using make test-all, or you can run the individual command to run specific tests.

Resources

OCI

Open containers initiative is project, which provides a standardization and standardized specification for operating-system-level virtualization. That way components that confirm to the specification provided by OCI spec, can interoperate with each other easily, and developing of new applications becomes easier. For example youki can be used inplace of runc in Docker, as all three : Docker, runc and youki are OCI compliant, and have a standard interface.

Their main GitHub page is at https://github.com/opencontainers, and more information about the runtime specifications can be found at https://github.com/opencontainers/runtime-spec/blob/master/runtime.md.

As youki needs to deal with a lot of low level programming interfaces of Linux Kernel, another good place know is the online man pages project, which can be found at https://man7.org/. Man pages provide detailed information about the programming interfaces of various features of Linux Kernel. You can simply search man <feature-name> using a search engine, or you can search at the site itself, at https://man7.org/linux/man-pages/index.html. These can be very helpful to know about the behavior and usage of and reasoning behind various kernel features used throughout youki.

Happy developing!!!