Getting Started with Reserved Instances

If you enroll in Trusted Advisor support, you can receive Reserved Instance purchase recommendations. For more information, visit the Cost Optimization Dashboard in the Amazon Trusted Advisor Console. Here are some guidelines to help you choose the right type and quantity of Reserved Instances.

Using the EC2 Usage Reports, group Amazon EC2 instance usage by instance type, platform description, Availability Zone (optional), and tenancy.

Since Reserved Instances provide optimal savings with “always-on” infrastructure, assess cost savings for groups of instances that are on more than 60% of the time. Compare the cost of running always-on On-Demand EC2 instances vs. Reserved Instances. Here are a few things to consider:

Determine the term length

What percentage of this group do I expect will be running 1 year from now? 3 years from now? Determine the number of instances you want to run and the term length (1-year or 3-years).
You can find Reserved Instances with shorter term lengths and lower pricing options sold by third-party sellers in the Reserved Instance Marketplace.

Select a payment option

AWS offers you three payment options: All Upfront, Partial Upfront, and No Upfront. The more you pay upfront, the more you save.

Select an offering class

Purchase Convertible Reserved Instances if you need flexibility to change the attributes of your Reserved Instances over the term.

Do you need a capacity reservation?

Reserved Instances provide a capacity reservation when they are assigned to a specific Availability Zone. If you need to reserve capacity, purchase Reserved Instances in the specific Availability Zones where your capacity is needed. If you do not specify an Availability Zone, the discounted rate of your Reserved Instance will apply to instance usage in any Availability Zone in the region that matches the other attributes.

The following is a helpful overview to understanding how to purchase and use a Reserved Instance from the AWS Management Console. Visit the AWS Documentation to learn how to purchase with the CLI or APIs.

1. Log in to the Amazon EC2 Console

Go to the Amazon EC2 Console and choose "Reserved Instances" in the left navigation pane. Then choose "Purchase Reserved Instances".

2. Search for Reserved Instances

Specify the instance and payment attributes.

3. Specify the quantity and check out

Select the Reserved Instance you’d like to purchase and specify the quantity. Reserved Instances are sold by AWS and by third-party sellers, who sometimes offer lower prices and shorter terms. Click here to learn more about the Reserved Instance Marketplace.

4. Reserved Instance cost savings are automatically applied

The discounted hourly rate is automatically applied to an on-demand instance (which matches the instance type, Availability Zone, platform, and tenancy of the Reserved Instance you've purchased) during a given hour.

For example, if you purchase two m3.xlarge Linux Reserved Instances, in us-east-1a, with default tenancy, then two On-Demand instances with the same attributes will benefit from the discounted hourly rate.

1. Modifying a Reserved Instance

You can request to move your Reserved Instance to another Availability Zone within the same region, change its network platform or, for Linux/UNIX Reserved Instances, modify the instance type size of your reservation to another size of the same instance type at no additional cost. (Certain conditions apply).

2. Sell Reserved Instances on the AWS Reserved Instance Marketplace

The Reserved Instance Marketplace provides you with the opportunity to sell Reserved Instances if your needs change (e.g., you want to move instances to a new AWS region, change to a new instance type, or sell capacity for projects that end before your Reserved Instance term expires).