Spot Instances — Technology Wiki

Overview

Direct Answer

Spot instances are unused cloud computing capacity that providers offer at discounts typically 70–90% below on-demand rates, with the trade-off that the provider can terminate the instance with minimal notice when capacity is needed elsewhere. This model allows organisations to access compute resources opportunistically rather than maintaining guaranteed availability.

How It Works

Cloud providers maintain spare infrastructure capacity across data centres. When demand for standard reserved or on-demand instances declines, they release this surplus capacity as interruptible compute at auction-like pricing. Customers specify a maximum price they will pay; if the provider's available capacity falls below that threshold, instances are reclaimed, typically with a two-minute termination warning.

Why It Matters

The cost reduction is substantial for non-time-critical workloads, enabling organisations to run larger-scale batch processing, machine learning training, and analytics without proportional budget increases. This elasticity supports innovation and testing in resource-constrained enterprises whilst allowing providers to optimise utilisation of their infrastructure.

Common Applications

Batch data processing, long-running machine learning model training, distributed rendering, genomic sequencing analysis, and retrospective log analysis benefit significantly from spot capacity. Development and testing environments also leverage spot instances to reduce infrastructure costs without affecting production systems.

Key Considerations

Interruption risk makes spot instances unsuitable for stateful, long-running services or time-sensitive workloads unless paired with automatic failover and fault-tolerance mechanisms. Practitioners must architect applications with graceful termination handling and implement checkpointing for iterative workloads.

Cross-References(1)

Cloud Computing

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