Over-provisioned ECS instances have a high cost and may not need the amount of resources provisioned to run the workload. You can rightsize (reduce CPU/RAM) without breaking normal usage.
Rightsizing means changing the instance type to meet actual needs. For example, you could downgrade from a 4xlarge to an xlarge instance.
Switching to the latest instance technologies, such as AWS Graviton, can also reduce costs, though you may need to ensure compatibility.
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ECS Launch Types
EC2:
You manage the underlying EC2 Instances in your ECS Cluster.
Rightsize your instance types and sizes based on CPU, memory, network performance, and storage needs.
Fargate:
AWS handles the provisioning and scaling of the compute resources.
You pay for the exact amount of vCPU and memory resources that your containerized applications use.
You can rightsize your task definitions.
To determine your launch type:
Navigate to ECS, select a cluster, and go to the Tasks section. Look at the Launch type column.
Fargate Deployment
By default, ECS uses a rolling update deployment strategy.
It replaces one task at a time, waiting for the new task to become healthy before replacing the next one.
to compare your current vCPU and Memory with other classes.
How to identify?
You can identify over-provisioned ECS instances using the following methods:
From our Cost Optimizations Report , check at ECS_Rightsize section.
In AWS Console:
Go to the ECS service. Click on a service and check the Health section to determine if it is over-provisioned.
Check your instance type or class, then refer to Cloud Compute Instances – Amazon EC2 Instance Types – AWS to compare your current vCPU and Memory with other classes.
Ensure that the network won’t be impacted when rightsized. If necessary, review your database’s network metrics.
Navigate to the AWS Compute Optimizer service, then select the EC2 Instances section for tailored recommendations.
Go to Cost Optimization Hub and filter savings opportunities by Resource type = ECS service and Recommended action = Rightsize.
Note: Estimated monthly savings may show as 0% / $0 if covered by Compute Savings Plans. You will still save money by rightsizing, as those savings plans will cover other services.
- To estimate savings, go to AWS Pricing Calculator, Select ECS Service and compare generation prices. For example, rightsizing an EC2 Instance c6a.8xlarge to r6g.2xlarge could save $602 per month (67% reduction).
How to fix?
For Launch Type = EC2, go to Rightsize EC2.
For Launch Type = Fargate:
In AWS Console, go to the ECS service, then select the Task definitions section.
Choose a task, then click Create new revision.
Modify the launch type, OS/Architecture, CPU, and memory sizes of the task.
By default, there is no downtime.
If the resource is provisioned automatically via IaC (such as CloudFormation or Terraform), update the corresponding code to reflect the changes.