beginnerDocker Networking: Bridge, Host, Overlay, DNS & Port Mapping
What is an overlay network and why does it matter for clustering?
An overlay network uses VXLAN encapsulation to create a virtual Layer 2 network spanning multiple physical or virtual hosts, so containers on different machines can communicate as if they were on the same LAN. This underlies Docker Swarm's multi-host service discovery and load balancing, and is conceptually the same problem that Kubernetes CNI plugins (Calico, Flannel, Cilium) solve for pod-to-pod networking across nodes.
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