What role does a load balancer play when using Docker, and what tasks does it solve?

The load balancer when using Docker acts as a distributor of incoming requests among multiple containers or services running in a cluster. Its tasks:

• Ensure even distribution of load so that no container is overwhelmed.
• Increase fault tolerance: if one container crashes, the load balancer redirects traffic to others.
• Provide scalability by allowing containers to be added or removed without interruption.

For example, in Docker Swarm, the built-in load balancer automatically distributes requests among service replicas.