Docker Swarm is a native clustering and orchestration solution for Docker. It allows you to create and manage a swarm of Docker nodes, turning them into a single, virtual Docker engine. This enables you to deploy and manage containerized applications at scale.

Here are some key concepts and features of Docker Swarm:

Node: A Docker node is an instance of the Docker engine participating in the swarm. Nodes can be physical machines or virtual machines.

Manager Node: In a Docker Swarm, there are one or more manager nodes that are responsible for managing the swarm and orchestrating the deployment of services. Manager nodes maintain the desired state of the swarm and respond to events.

Worker Node: Worker nodes are responsible for running the tasks that make up the services in the swarm. They receive instructions from manager nodes and execute the tasks.

Service: A service is the definition of the tasks to execute on the worker nodes. It includes information about which container image to use, how many replicas (instances) should be running, and various other settings.

Task: A task represents a running container on a worker node. The manager node schedules tasks based on the desired state defined in the service.

Overlay Networking: Docker Swarm uses overlay networking to facilitate communication between containers running on different nodes in the swarm. This enables multi-host networking for your services.

Load Balancing: Docker Swarm includes built-in load balancing for distributing incoming requests across the tasks in a service.