The AWS cost of supporting previous-generation EC2 instances can be significantly higher compared to newer, more efficient, and cost-effective options. Previous-generation instances include older families and types that have been phased out:
t1, t2
m1, m2, m3, m4
c1, c2, c3, c4
r1, r2, r3, r4
i2
a1
d2
Previous Generation Instances Documentation
You can upgrade up to newer generations (e.g., t4g, m7, c7, r7 : See all instances types and should always consider Migrate To Graviton Instances in first opportunity.
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How to identify?
You can identify previous-generation instances using the following methods:
From our Cost Optimizations Report, check at EC2_Rightsize section.
In AWS Console, navigate to the EC2 service, then select the Instances section. Filter by Instance Type and compare with the list above.
In AWS Console, go to the Cost Optimization Hub and filter by EC2 Instance with the recommended action set to Upgrade:
In AWS Console, go to Billing and Cost Management, then select the Bills section. Click on Elastic Compute Cloud (EC2), followed by your region, then "Amazon Elastic Compute Cloud running [Instance Type]" and search for instance types to compare with the list.
To estimate savings, use the https://calculator.aws/. For example, upgrading 1 EC2 Instance (c4.4xlarge to c5.4xlarge in Oregon) can save you $85 per month, or 15%:
How to fix?
Upgrade your instances to newer generations. The process can be straightforward or complex, depending on compatibility with legacy code.
Stop the instance before changing its type. For production environments, consider using EC2 Auto Scaling or creating a new instance and migrating the data.
In AWS Console, go to the EC2 service, then select the Instances section. Choose a stopped instance, then click Actions > Instance Settings > Change Instance Type:
Note: If your EC2 instances are provisioned automatically (e.g., via CloudFormation or Terraform), update your infrastructure-as-code (IaC) to reflect the new instance type.