Question #1066
A company requires guaranteed Amazon EC2 capacity in three distinct Availability Zones within a specific AWS Region for a marketing campaign lasting 7 days. What should the company do to ensure the EC2 capacity is reserved for the campaign?
Purchase Reserved Instances specifying only the target AWS Region.
Create an On-Demand Capacity Reservation specifying only the target AWS Region.
Purchase Reserved Instances specifying both the target AWS Region and the three Availability Zones.
Create an On-Demand Capacity Reservation specifying both the target AWS Region and the three Availability Zones.
Explanation
Answer D is correct because:
1. On-Demand Capacity Reservations allow reserving capacity in specific AZs, ensuring instances can be launched when needed. This is critical for time-sensitive campaigns.
2. Reserved Instances (RIs) (Options A/C) provide billing discounts but do not guarantee capacity. RIs are designed for long-term usage (1-3 years), not short-term needs like a 7-day campaign.
3. Capacity Reservations must be created per AZ (Option D), while RIs with AZ scope (Option C) still do not reserve capacity.
4. Option B is invalid because Capacity Reservations cannot be created at the Region level; they are AZ-specific.
Key Points:
- Use On-Demand Capacity Reservations for short-term, guaranteed capacity in specific AZs.
- RIs are cost-saving tools, not capacity guarantees.
- Always specify AZs when creating Capacity Reservations for zonal redundancy.
Answer
The correct answer is: D