Your company runs a microservices app on an Amazon EKS cluster and expects a large spike in requests next month. To avoid outages and minimize operational effort, which approach should you use to automatically scale the application?

The Kubernetes Horizontal Pod Autoscaler (HPA) is the most suitable solution for automatically scaling the application to handle a large spike in requests. HPA automatically adjusts the number of pod replicas in a deployment or replica set based on observed CPU utilization or other select metrics. This ensures the application can handle increased load without manual intervention, minimizing operational effort and preventing outages. Distributing traffic across two EKS clusters would increase operational overhead and cost without necessarily providing automatic scaling for the application itself within each cluster. Moving the application to EC2 instances and then back to EKS is a complex, time-consuming, and disruptive process that doesn't provide automatic scaling and is not practical for a temporary spike. The Kubernetes Vertical Pod Autoscaler (VPA) adjusts resource requests and limits for individual pods, which optimizes resource utilization but does not scale the number of pods to handle increased demand.