Container Network Interface (CNI)

CNI (Container Network Interface) is a CNCF-incubating project that defines a specification and libraries for configuring network interfaces in Linux containers. It provides a simple exec/stdin interface between the container runtime and network implementation plugins, enabling pluggable networking for Kubernetes and other container orchestrators. The CNI spec defines four operations (ADD, DEL, CHECK, VERSION), a network configuration document format, and a plugin Result document. CNI also publishes a collection of reference plugins (bridge, ipvlan, macvlan, host-device, ptp, loopback) and meta-plugins (portmap, bandwidth, firewall, sbr).