Tier Your Apps, Cut Your Costs: A Practical Framework for Spot Instances in Production

Spot Instances offer the potential to reduce cloud computing costs by up to 90%, yet many teams hesitate to use them in production due to the risk of interruptions. By implementing Cast AI's Pod Mutations and tiering applications based on their criticality, teams can strategically balance cost savings with reliability. This approach involves creating a single node template that combines both On-Demand and Spot Instances, segregating applications into tiers of criticality, and setting appropriate Pod Mutations to ensure the right scheduling behavior. Critical applications can be assigned stable, On-Demand resources, while less critical workloads can benefit from cost-efficient Spot Instances. To mitigate risks, teams should implement guardrails like Pod Disruption Budgets, multi-replica deployments, and topology spread constraints to protect against disruptions. This methodology enables significant cost savings without compromising the availability and reliability of essential services, offering a practical solution for optimal cloud infrastructure management.