Spare cloud computing capacity available at steep discounts (up to 90% off) but can be reclaimed with short notice. Like flying standby for much cheaper tickets, but you might get bumped.
A machine learning team uses spot instances to train models at 70% less cost, with checkpoints to resume if instances are interrupted.
All are discounted, interruptible VM capacity. AWS uses Spot pricing and interruption notices; Azure uses Spot VMs with eviction policies; GCP Spot VMs are fixed-discount, preemptible VMs; OCI Preemptible Instances can be reclaimed by Oracle with short notice.