Which Docker network driver is essential for enabling communication between containers that are spread across different hosts in a Docker Swarm cluster?

The Docker `overlay` network driver is essential for enabling communication between containers that are spread across different hosts in a Docker Swarm cluster. An `overlay` network creates a distributed network layer that spans multiple Docker daemon hosts. This allows containers attached to the same `overlay` network to communicate with each other regardless of which physical or virtual host they are running on, as if they were on the same local network segment. A Docker Swarm cluster is a native clustering solution for Docker that turns a pool of Docker hosts into a single, virtual Docker host. Within a Swarm, services are deployed, which define the desired state of tasks (containers)....