# EC2 Spot Pool Selection Checklist (July 2026)

## ASG / fleet defaults

- [ ] **SpotAllocationStrategy = `price-capacity-optimized`** (default recommendation for most workloads)
- [ ] Attribute-based instance requirements (vCPU, memory, arch) — not a single hard-coded type
- [ ] ≥4–6 instance families across ≥2 AZs
- [ ] On-Demand base capacity for write/consensus roles; Spot for interruptible capacity

## Score before you chase cheapest

| Signal | Prefer |
| --- | --- |
| Low avg price + high interruption variance | Skip for jobs > ~4h |
| Slightly higher price + stable interruptions | Prefer for long batch / services |
| Newest generation thin capacity | Weight recent 7d over 90d history |

## Interruption hygiene

- [ ] Handle 2-minute Spot interruption notice (IMDS / EventBridge)
- [ ] Checkpoint or drain before terminate
- [ ] Diversify; never one pool for the whole fleet

## Do not put on Spot

Primary DB writers, Kafka/ZooKeeper quorum, OpenSearch master-eligible, anything without a failover path.