Which AWS EC2 Instance Purchasing option is right for me?

Rukmal Senavirathne
2 min readMar 5, 2023

On-Demand, Reserved, Saving Plans, Spot instances, Dedicated Hosts, and Capacity Reservations are AWS EC2 Purchasing options.

I have explained each purchasing option using a hotel resort example.

  1. On-Demand — They allow running instances On-Demand suitable for short-term and uninterrupted workloads. Pay for what you use.

Summary — coming and staying in a resort whenever we like, we pay the full price.

2. Reserved — Suitable for long workloads such as steady-state usage applications (database). Can change the instance type, instance family, OS, scope, and tenancy over time. Users can select a reservation period. Users can buy and sell their reserved instances in the AWS marketplace.

Summary — like planning ahead and if we plan to stay for a long time, we may get a good discount.

3. Saving Plans — Instead of using a committed specific instance type user committed to a specific amount of dollars ($10/hour for 1 or 3 years). Locked to specific instance family and AWS region (C4 in ap-south-1).

Summary — pay a certain amount per month and stay in any room type (King, Suite, or Sea view).

4. Spot Instance — suitable for short workloads and they are resilient to failure. An instance/instances can lose at any time if the user’s max price is less than the current spot price. The cheapest purchasing option.

Summary — The resort allows people to bid with high discounts for the empty rooms and the highest bidder keeps the rooms. Customers can kick out at any time.

5. Dedicated Hosts — The user can book the entire physical server and control instance placement. The most expensive option.

Summary — People book an entire building of the resort.

6. Capacity Reservations — The user allows reserving capacity in a specific AZ for any duration.

Summary — people book a room for a full-price period even if they do not stay in it.

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Rukmal Senavirathne

Graduated from the Department of Computer Science and Engineering at the University of Moratuwa.