The Container Network Interface
CNI (Container Network Interface), a Cloud Native Computing Foundation project, consists of a specification and libraries for writing plugins to configure network interfaces in Linux containers, along with a number of supported plugins. CNI concerns itself only with network connectivity of containers and removing allocated resources when the container is deleted. Because of this focus, CNI has a wide range of support and the specification is simple to implement.
As well as the specification , the CNI repository contains the Go source code of a library for integrating CNI into applications and an example command-line tool for executing CNI plugins. A separate repository contains reference plugins and a template for making new plugins.
The template code makes it straight-forward to create a CNI plugin for an existing container networking project. CNI also makes a good framework for creating a new container networking project from scratch.
Here are the recordings of two sessions that the CNI maintainers hosted at KubeCon/CloudNativeCon 2019: