Amazon EC2 Capacity Blocks for ML overview

Availability/mechanics facts: Capacity Blocks can be reserved up to 8 weeks in advance, for up to 6 months, in clusters of 1-64 instances (512 GPUs or 1024 Trainium chips), and can be shared across accounts. Every accelerated family AWS sells (P4d, P5, P5e, P5en, P6-B200, P6-B300, P6e-GB200, Trn1, Trn2) is Capacity-Block-eligible - this is AWS's official answer to the 'p5 capacity is scarce' problem: you cannot buy p5 on-demand with any reliability, you reserve a block.