Docker container auto-scaling can dynamically adjust the number of containers based on load. In Docker Swarm, use docker service scale service_name=replica_count for manual scaling, or combine with external monitoring tools for auto-scaling. Kubernetes provides Horizontal Pod Autoscaler (HPA) for automatic scaling based on CPU, memory, or custom metrics. Implementing auto-scaling requires: 1) configuring resource requests and limits; 2) setting scaling metrics and thresholds; 3) configuring minimum and maximum replica counts; 4) choosing appropriate scaling strategies (such as stabilization window, scaling ratio). Auto-scaling improves resource utilization, reduces costs, while ensuring service performance.