Accessing reservation recommendations

If you enable Cost Explorer, you automatically get Amazon EC2, Amazon RDS, ElastiCache, OpenSearch Service, Amazon Redshift, Amazon MemoryDB, and Amazon DynamoDB purchase recommendations that could help reduce your costs. Reservations provide a discounted hourly rate (up to 75%) compared to On-Demand or provisioned capacity pricing. Cost Explorer generates your reservation recommendations using the following process:

• Identifies your On-Demand instance or provisioned capacity usage for a service during a specific time period

• Collects your usage into categories that are eligible for a reservation

• Simulates every combination of reservation in each category of usage

• Identifies the best number of each type of reservation to purchase to maximize your estimated savings

For example, Cost Explorer automatically aggregates your Amazon EC2 Linux, shared tenancy, and c4 family usage in the US West (Oregon) Region and recommends that you buy size-flexible regional RIs to apply to the c4 family usage. Cost Explorer recommends the smallest size instance in an instance family. This makes it easier to purchase a size-flexible RI. Cost Explorer also shows the equal number of normalized units so that you can purchase any instance size that you want. For this example, your RI recommendation would be for c4.large because that is the smallest size instance in the c4 instance family.

Cost Explorer recommendations are based on a single account or organization usage of the past seven, 30, or 60 days. Cost Explorer uses On-Demand instance usage during the selected look-back period to generate recommendations. All other usage in the look-back period that are covered by features such as RI, SPOT, and Savings Plans aren't included. Amazon EC2, ElastiCache, OpenSearch Service, Amazon Redshift, Amazon MemoryDB, and Amazon DynamoDB recommendations are for reservations scoped to Region, not Availability Zones, and your estimated savings reflects the application of those reservations to your usage. Amazon RDS recommendations are scoped to either Single-AZ or Multi-AZ RIs. Cost Explorer updates your recommendations at least once every 24 hours.

Note

Cost Explorer doesn't forecast your usage or take forecasts into account when recommending reservations. Instead, Cost Explorer assumes that your historical usage reflects your future usage when determining which reservations to recommend.

Linked accounts can only see recommendations if they have the relevant permissions. Linked accounts need permissions to view Cost Explorer and permissions to view recommendations. For more information, see Viewing reservation recommendations.

RI recommendations for size-flexible RIs

Cost Explorer also considers the benefits of size-flexible regional RIs when generating your RI purchase recommendations. Size-flexible regional RIs help maximize your estimated savings across eligible instance families in your recommendations. AWS uses the concept of normalized units to compare the various sizes within an instance family. Cost Explorer uses the smallest normalization factor to represent the instance type that it recommends. For more information, see Instance size flexibility in the Amazon Elastic Compute Cloud User Guide.

For example, let’s say you own an EC2 RI for a c4.8xlarge. This RI applies to any usage of a Linux/Unix c4 instance with shared tenancy in the same region as the RI, such as the following instances:

• One c4.8xlarge instance

• Two c4.4xlarge instances

• Four c4.2xlarge instances

• Sixteen c4.large instances

It also includes combinations of EC2 usage, such as one c4.4xlarge and eight c4.large instances.

If you own an RI that is smaller than the instance that you're running, you are charged the prorated, On-Demand price for the excess. This means that you could buy an RI for a c4.4xlarge, use a c4.4xlarge instance most of the time, but occasionally scale up to a c4.8xlarge instance. Some of your c4.8xlarge usage is covered by the purchased RI, and the rest is charged at On-Demand prices. For more information, see How Reserved Instance discounts are applied in the Amazon Elastic Compute Cloud User Guide.

Viewing reservation recommendations

Linked accounts need the following permissions to view recommendations:

• ViewBilling

• ViewAccount

For more information, see Using identity-based policies (IAM policies) for AWS Cost Management.

To view your reservation recommendations

1. Sign in to the AWS Management Console and open the AWS Cost Management console at https://console.aws.amazon.com/cost-management/home.

2. In the navigation pane, under Reservations, choose Recommendations.

3. On the Recommendations page, under Recommendation parameters, choose the Service that you want recommendations for.

Understanding reservation recommendations

The Reservations Recommendations page shows you your estimated potential savings, your reservation purchase recommendations, and the parameters that Cost Explorer used to create your recommendations. You can change the parameters to get recommendations that might match your use case more closely.

The Recommendations page shows you the following three numbers:

• Total purchase recommendations – The number of different reservation purchase options Cost Explorer has found for you.

• Estimated monthly savings – How much Cost Explorer calculates you could save by purchasing the recommended reservations.

• Estimated savings vs. On-Demand rates – Your estimated savings as a percentage of your current costs.

These numbers provide you with a rough estimate of how much you could potentially save by buying more reservations. You can recalculate these numbers for a different use case using the following Recommendation parameters:

• Term – The duration for which you want recommendations.

• Offering class – Whether you want recommendations for a standard or convertible reservation.

• Payment option – Whether you want to pay for recommendations upfront.

• Based on the past – The number of days of previous usage that you want your recommendations to take into account.

At the bottom of the page are tabs with some of your savings estimates. The All accounts tab enables you to see the recommendations based on the combined usage across your entire organization, and the Individual accounts tab enables you to see recommendations that Cost Explorer generated on a per-linked-account basis. The table on each tab shows the different purchase recommendations and details about the recommendations. If you want to see the usage that Cost Explorer based a recommendation on, choose the View associated usage link in the recommendation details. This takes you to a report that shows the exact parameters that Cost Explorer used to generate your recommendation. The report also shows your costs and associated usage grouped by Purchase option, so that you can view the On-Demand Instance usage that your recommendation is based on.

Note

Recommendations that Cost Explorer bases on an individual linked account consider all usage by that linked account, including any RIs used by that linked account. This includes RIs shared by another linked account. The recommendations don't assume that an RI will be shared with the linked account in the future.

You can sort your recommendations by Monthly estimated savings, Upfront RI cost, Purchase recommendation, or Instance type.

Modifying reservation recommendations

You can change the information that Cost Explorer uses when it creates your recommendations, and you can also change the types of recommendations that you want. This allows you to see recommendations for the reservations that work best for you, such as All upfront reservations with a one-year term, based on your last 30 days of usage.

Note

Instead of forecasting your future usage, Cost Explorer assumes that your future usage is the same as your previous usage. Cost Explorer also assumes that you are renewing any expiring reservations.

To modify your reservation recommendations

1. Sign in to the AWS Management Console and open the AWS Cost Management console at https://console.aws.amazon.com/cost-management/home.

2. In the navigation pane, under Reservations, choose Recommendations.

3. On the Recommendations page, under Recommendation parameters, choose the Service that you want recommendations for.

4. Choose the relevant Term.

5. Choose the relevant Offering class.

6. Choose the relevant Payment option.

7. For Based on the past, select how many days of usage that you want your reservation recommendations to be based on.

8. Choose either All accounts or Individual accounts to see recommendations based either on your organization-wide usage or on all of your linked accounts based on their individual account usage.

Saving reservation recommendations

You can save reservation recommendations as a CSV file.

To save your reservation recommendations

1. On the Reservations Recommendations page, under Recommendation parameters, choose the Service that you want recommendations for and update any parameters you want to change.

2. Under Recommended actions, choose Download CSV.

The CSV file contains the following columns.

Reservation recommendations CSV columns

Column name	Service	Column explanation
Account ID	Amazon EC2, RDS, Redshift, ElastiCache, OpenSearch Service, MemoryDB, DynamoDB	The account associated with your recommendation.
Availability zone	Amazon RDS	The availability zone of the instances used to generate a recommendation.
Average hourly normalized unit usage in historical period	Amazon EC2, RDS, MemoryDB	The average number of normalized units used per hour over the period chosen for generating recommendations.
Average hourly usage in historical period	Amazon EC2, RDS, Redshift, ElastiCache, OpenSearch Service, MemoryDB	The average number of instance hours used per hour over the period chosen for generating recommendations.
Average number of capacity units used per hour in the selected historical period	Amazon DynamoDB	The average number of provisioned capacity units used per hour over the period chosen for generating recommendations.
Break even months	Amazon EC2, RDS, Redshift, ElastiCache, OpenSearch Service, MemoryDB, DynamoDB	The estimated length of time before you recoup your upfront costs for this set of recommended reservations.
Cache engine	Amazon ElastiCache	The kind of engine that the recommended ElastiCache reserved node runs, such as Redis or Memcheched.
Capacity unit type	Amazon DynamoDB	The type of capacity unit for the recommendation. Read capacity units are used for operations that retrieve data from a table. Write capacity units are used for operations that insert, update, or delete data in a table.
Database edition	Amazon RDS	The edition of the database engine that the recommended RDS reserved instance runs.
Database engine	Amazon RDS	The kind of engine that the recommended RDS reserved instance runs, such as Aurora MySQL or MariaDB.
Deployment option	Amazon RDS	Whether your reserved instance is for an RDS instance in a single Availability Zone or an RDS instance with a backup in another Availability Zone.
Estimated savings	Amazon EC2, RDS, Redshift, ElastiCache, OpenSearch Service, MemoryDB, DynamoDB	The estimated savings of the recommended reservations.
Expected utilization	Amazon EC2, RDS, Redshift, ElastiCache, OpenSearch Service, MemoryDB, DynamoDB	How much of the recommended reservations Cost Explorer estimates you will use.
Instance type	Amazon EC2, RDS, OpenSearch Service	The type of instance that the recommendation is generated for (for example, m4.large or t2.nano). For size-flexible recommendations, Cost Explorer aggregates all usage in a organization (for example, the m4 family) and shows a recommendation for the smallest reserved instance type that is available for purchase (for example, m4.large).
Max hourly normalized unit usage in historical period	Amazon EC2, RDS, MemoryDB	The maximum number of normalized units used in an hour over the period chosen for generating recommendations.
Max hourly usage in historical period	Amazon EC2, RDS, Redshift, ElastiCache, OpenSearch Service, MemoryDB	The maximum number of instance hours used in an hour over the period chosen for generating recommendations.
Maximum number of capacity units used per hour in the selected historical period	Amazon DynamoDB	The maximum number of provisioned capacity units used in an hour over the period chosen for generating recommendations.
Min hourly normalized unit usage in historical period	Amazon EC2, RDS, MemoryDB	The minimum number of normalized units used in an hour over the period chosen for generating recommendations.
Min hourly usage in historical period	Amazon EC2, RDS, Redshift, ElastiCache, OpenSearch Service, MemoryDB	The minimum number of instance hours used in an hour over the period chosen for generating recommendations.
Minimum number of capacity units used per hour in the selected historical period	Amazon DynamoDB	The minimum number of provisioned capacity units used in an hour over the period chosen for generating recommendations.
Node type	Amazon ElastiCache, Redshift, MemoryDB	The type of node that the recommendation is generated for, such as ds2.xlarge.
Normalized hours to purchase	Amazon EC2, RDS, MemoryDB	How many normalized units that Cost Explorer recommends that you buy.
Number of instances to purchase	Amazon EC2, RDS, Redshift, ElastiCache, OpenSearch Service, MemoryDB	How many reservations Cost Explorer recommends that you buy.
Offering class	Amazon EC2	The offering class associated with the recommendation.
Payment option	Amazon EC2, RDS, Redshift, ElastiCache, OpenSearch Service, MemoryDB, DynamoDB	The recommended payment option for the recommendation.
Platform	Amazon EC2	The operating system and license model for the recommended reserved instance type.
Recommended number of capacity units to purchase	Amazon DynamoDB	How many reserved capacity units Cost Explorer recommends that you buy.
Recommendation date	Amazon EC2, RDS, Redshift, ElastiCache, OpenSearch Service, MemoryDB, DynamoDB	The date that Cost Explorer generated your recommendation.
Recurring monthly cost	Amazon EC2, RDS, Redshift, ElastiCache, OpenSearch Service, MemoryDB, DynamoDB	The recurring monthly cost of the recommended reservations.
Region	Amazon EC2, RDS, Redshift, ElastiCache, OpenSearch Service, MemoryDB, DynamoDB	The Region used to generate a recommendation. You must purchase the recommended reservations in the recommended Region to see potential savings.
Size flexible	Amazon EC2, RDS, MemoryDB	Whether a recommended reservation is size-flexible.
Tenancy	Amazon EC2	The tenancy for the recommendation. Valid values are shared or dedicated.
Term	Amazon EC2, RDS, Redshift, ElastiCache, OpenSearch Service, MemoryDB, DynamoDB	The recommended term length for the recommendation.
Upfront cost	Amazon EC2, RDS, Redshift, ElastiCache, OpenSearch Service, MemoryDB, DynamoDB	The upfront cost associated with the recommendation.

Using reservation recommendations

To purchase the recommended reservations, go to the purchase page in a service console. You can also save a CSV file of your recommendations and purchase the reservations at a later date.

To use Amazon Elastic Compute Cloud recommendations

1. On the Reserved Instance Recommendations page, choose Amazon EC2 RI Purchase Console.

2. Purchase your RIs by following the instructions at Buy Reserved Instances for Amazon EC2 in the Amazon Elastic Compute Cloud User Guide.

To use Amazon Relational Database Service recommendations

1. On the Reserved instances page in the Amazon RDS console, choose Purchase Reserved DB Instance.

2. Purchase your reservations by following the instructions at Purchasing reserved DB instances for Amazon RDS in the Amazon RDS User Guide.

To use Amazon Redshift recommendations

1. On the Reserved nodes page in the Amazon Redshift console, choose Purchase reserved nodes.

2. Purchase your reservations by following the instructions at Purchasing a reserved node in the Amazon Redshift Management Guide.

To use Amazon OpenSearch Service recommendations

1. On the Reserved Instance Leases page in the OpenSearch Service console, choose Order Reserved Instance.

2. Purchase your reservations by following the instructions at Reserved Instances in Amazon OpenSearch Service in the Amazon OpenSearch Service Developer Guide.

To use Amazon ElastiCache recommendations

1. On the Reserved Nodes page in the ElastiCache console, choose Purchase reserved nodes.

2. Purchase your reservations by following the instructions at Purchasing a reserved node in the Amazon ElastiCache User Guide.

To use Amazon MemoryDB recommendations

1. On the Reserved nodes page in the MemoryDB console, choose Purchase reserved nodes.

2. Purchase your reservations by following the instructions at Working with reserved nodes in the Amazon MemoryDB Developer Guide.

To use Amazon DynamoDB recommendations

1. On the Reserved capacity page in the DynamoDB console, choose Purchase reserved capacity.

2. Purchase your reserved capacity by following the instructions at Reserved capacity in the Amazon DynamoDB Developer Guide.