What the exam asks
- Match a workload to On-Demand, Savings Plans, Reserved Instances, Spot, Capacity Reservations, Dedicated Instances or Dedicated Hosts.
- Choose between Compute Savings Plans and EC2 Instance Savings Plans, and between Standard and Convertible Reserved Instances.
- Design Spot-tolerant architectures: stateless tasks, checkpoints, diversified instance pools, the right allocation strategy and mixed-instance Auto Scaling groups.
- Separate capacity (Capacity Reservations, zonal RIs) from discount (Savings Plans, regional RIs).
- Use Dedicated Hosts for licenses tied to sockets or cores, and Dedicated Instances for simple single-tenant hardware.
Core ideas
The options side by side
| Option | Commitment | Relative price | Capacity guaranteed? | Best for |
|---|---|---|---|---|
| On-Demand | None (per-second billing for Linux) | Highest | No | Short-term, unpredictable or uninterruptible work; new workloads with unknown usage |
| Compute Savings Plan | 1 or 3 years of USD/hour spend | Up to 66% off | No | Steady spend that may change family, size, Region or OS, or move to Fargate or Lambda |
| EC2 Instance Savings Plan | 1 or 3 years, one instance family in one Region | Up to 72% off | No | Steady usage fixed on a family in a Region (size, OS and tenancy can change) |
| Standard RI | 1 or 3 years, specific instance attributes | Up to 72% off | Only with zonal scope | Steady, unchanging usage; can be sold on the RI Marketplace |