Container Networking Interface
Container Networking Interface (CNI) is a specification and library for configuring network interfaces in Linux containers, primarily used in container orchestration systems like Kubernetes. It defines a plugin-based architecture where network plugins implement the CNI specification to set up networking for containers, handling tasks such as IP address assignment, routing, and network namespace configuration. CNI provides a standardized way to manage container networking, enabling interoperability between different container runtimes and network solutions.
Developers should learn CNI when working with containerized environments, especially in Kubernetes clusters, as it is the default networking interface for managing pod networking. It is essential for implementing custom network policies, integrating with software-defined networking (SDN) solutions like Calico or Flannel, and ensuring secure and scalable communication between containers. Use cases include setting up multi-host container networks, enabling service discovery, and configuring network isolation in microservices architectures.