Cloud Financial Management
EC2 purchasing options
High-level ways to pay for or reserve EC2 capacity, each addressing a different combination of flexibility, commitment, interruption tolerance, tenancy, or capacity assurance.
Key points
- On-Demand uses no long-term commitment; Spot uses spare capacity and can be interrupted.
- Reserved Instances provide billing discounts for eligible committed configurations; Savings Plans discount eligible usage in exchange for a spend commitment.
- Dedicated Hosts provide a physical server for one customer; Dedicated Instances run on single-tenant hardware without host-level allocation control.
- Capacity Reservations reserve EC2 capacity in an Availability Zone but do not inherently provide a billing discount.
Best-known use cases
- Use On-Demand for short or unpredictable workloads.
- Use Spot for interruption-tolerant work.
- Use commitments for steady eligible use.
- Use dedicated tenancy or a Capacity Reservation when that exact requirement is stated.
What candidates often confuse it with
- Savings Plans are spend commitments with broader usage flexibility; Reserved Instances are EC2 billing benefits tied to instance attributes and offering rules.
- Capacity Reservation assures capacity; it is not a discount by itself.
- Dedicated Host provides host visibility/control that Dedicated Instances do not.
Key Cloud Practitioner takeaway
Map the business requirement—flexibility, commitment discount, interruption tolerance, tenancy, or capacity—to the purchasing option.
Related services
- Amazon EC2
- AWS Organizations
Relevant exam tasks
- D4.1