Flannel
Flannel is a simple and lightweight network fabric for Kubernetes clusters that provides a virtual network layer to enable communication between containers across different nodes. It assigns each pod a unique IP address and handles the routing of traffic between pods, abstracting the underlying network infrastructure. Flannel supports various backends like VXLAN, host-gw, and UDP to implement this overlay network.
Developers should use Flannel when deploying Kubernetes clusters that require a straightforward and reliable networking solution for pod-to-pod communication, especially in on-premises or cloud environments where native Kubernetes networking is not available. It is ideal for small to medium-sized clusters due to its simplicity and ease of setup, making it a popular choice for getting started with Kubernetes networking without complex configurations.