Cost-Optimization

Overview Auto scaling and manual scaling both change how much compute capacity an application has, but they differ in who — or what — decides when that change happens. Auto scaling relies on an automated feedback loop that watches metrics and reacts on its own, while manual scaling depends on human intervention to notice load and issue the change. That difference in decision-maker drives everything else: reaction speed, cost efficiency, and how much ongoing attention the system needs. ...

Overview Both are ways to rent compute capacity from a cloud provider, but they trade cost against reliability in opposite directions. Spot Instances tap into unused capacity at steep discounts but can be reclaimed with almost no notice, while On-Demand Instances cost more per hour in exchange for a guaranteed, uninterrupted slot. Comparison Diagram Timeline of a running workloadOn-Demand InstanceReserved for you, no interruptionsRuns continuously until you stop itSpot InstanceRunning!2-min warningthen reclaimedResumes on new capacityUp to 90% cheaper, but availability is never guaranteed Comparison Table Aspect Spot Instances On-Demand Instances Request & provisioning Fulfilled only if provider has spare capacity at your bid price Fulfilled immediately from reserved capacity pools Capacity guarantee None — provider can reclaim the instance at any time Guaranteed for as long as you keep paying Pricing model Variable, set by real-time supply and demand for spare capacity Fixed hourly rate published by the provider Interruption behavior Reclaimed with a short warning (e.g. ~2 minutes on AWS) Never interrupted by the provider; you control shutdown Cost predictability Fluctuates; can spike or be revoked when demand rises Stable and predictable, easy to forecast in a budget Ideal workloads Fault-tolerant, stateless, or checkpointable batch jobs Stateful, latency-sensitive, or continuously running services Termination control Provider-initiated; your app must handle abrupt shutdown User-initiated; you decide exactly when it stops Key Differences Spot pricing floats with market demand and can be up to 90% cheaper than On-Demand rates Spot capacity is reclaimable at any time, typically with only a short warning window On-Demand gives a firm capacity guarantee that Spot never promises Workloads on Spot need to tolerate sudden termination or design for checkpointing On-Demand cost is fixed and predictable, while Spot cost is variable and market-driven When to Use Each Spot Instances ...