Flannel
Flannel is a lightweight and flexible networking solution designed for containerized environments, particularly in orchestrators like Kubernetes. Introduced in 2014 by CoreOS, Flannel facilitates networking between containers across multiple hosts or nodes in a cluster. It operates by creating a virtual network overlay that abstracts the underlying network infrastructure, allowing containers to communicate seamlessly regardless of their physical location. Flannel uses various backend technologies, including VXLAN, host-gw, and UDP encapsulation, to establish network connectivity and route traffic efficiently. It dynamically assigns IP addresses to containers and manages routing tables to ensure optimal communication within the cluster. Flannel is widely adopted in Kubernetes deployments due to its simplicity, scalability, and compatibility with various network topologies and environments. More information about Flannel can be found at https://coreos.com/flannel/docs/latest/.