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AWS Compute Optimizer recommendations do not change resources by themselves. A separate feature, Compute Optimizer Automation, can apply certain eligible actions—currently documented for specific EBS volume tasks—either after an operator reviews and confirms them or through configured rules. It does not automatically carry out every recommendation the service generates.
How recommendations differ from implemented changes
Compute Optimizer analyzes supported AWS resources and their configuration and utilization metrics, then provides recommendations intended to help assess cost and performance trade-offs. A recommendation is advice, not evidence that AWS has modified the resource. A change occurs only when an action is eligible and is applied through an available workflow.
Automation is a separate feature. AWS documents two ways to use it: apply selected recommended actions directly after review and confirmation, or configure rules that apply matching actions on a recurring schedule. The available action types are limited; the feature should not be treated as an automatic executor for every Compute Optimizer recommendation. See AWS’s Automation overview and its list of recommended actions.
Which actions can Automation apply?
AWS currently documents Automation actions for particular EBS volume recommendations:
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- Create a snapshot of an unattached EBS volume and delete that volume.
- Upgrade an EBS volume type.
These are specific EBS actions, not a promise that Automation can implement recommendations for EC2 instance types, databases, Lambda, or other resource categories. Check the action shown for the individual recommendation and whether it is eligible for Automation before planning a change.
Direct application or scheduled rules?
| Consideration | Apply selected actions directly | Use Automation rules |
|---|---|---|
| How it works | An operator selects recommended actions and reviews and confirms the application. | AWS applies matching eligible actions according to configured rule criteria and schedule. |
| Targeting | Selection is made from the recommended actions available for application. | Rules can use criteria such as Region and resource tags to determine which actions match. |
| Timing | Applied when the operator confirms the action. | Rules can be scheduled daily, weekly, or monthly. |
| Batch limit | AWS documents selecting and applying up to 10 recommended actions in one batch. | No comparable batch limit is stated in the cited rules documentation. |
For the direct workflow, AWS describes selecting actions, reviewing them, and confirming application in Apply recommended actions. Rules are a different control path: they can reduce repeated manual selection, but their configured matching criteria and schedule determine when and where eligible actions are applied. See AWS’s Automation rules documentation.
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What enabling Automation authorizes
Enabling the feature grants Compute Optimizer authority to manage resources in the account for supported automation actions. AWS specifically describes permissions that can include creating EBS snapshots, deleting EBS volumes, and modifying EBS volumes. Because deletion and modification are consequential, confirm the account permissions and intended scope before enabling it. AWS explains the enablement process and permissions in Enabling Automation.
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EC2 instance-type recommendations
For EC2 instance recommendations, AWS says the operator must decide whether to act. These recommendations use historical usage, which may not capture upcoming demand or a workload change. Before changing an instance type, evaluate future resource needs, compatibility, and potential performance risk, and test the workload before and after the change. This guidance applies specifically to EC2 instance-type recommendations; risks and recovery options can differ for other actions. AWS sets out these considerations in Get EC2 instance recommendations from Compute Optimizer.
Recommendation eligibility
AWS must support the resource category, and the resource must meet its type-specific requirements and provide enough metrics. For example, AWS says EC2 instances and Auto Scaling groups generally need at least 30 hours of CloudWatch metrics during the previous 14 days to receive recommendations. This is a recommendation-coverage threshold, not a guarantee of savings or a measure of optimization performance. See Resource requirements for the relevant conditions.
Compute Optimizer covers multiple resource categories, including EC2 instances, Auto Scaling groups, EBS volumes, Lambda functions, ECS services on Fargate, databases, and other AWS services. Coverage depends on the resource’s requirements and available metrics; a service category being supported does not mean every resource in it will have a recommendation or an automatable action. AWS describes the service and its coverage in What is AWS Compute Optimizer?
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How to verify an automatic change
- Check the recommendation and action type. Confirm the affected resource, the proposed action, and whether AWS lists that action as available through Automation.
- Choose the application path. For direct application, inspect and confirm selected actions. For recurring application, review rule criteria—including Region and tags—and the schedule.
- Confirm authorization and scope. Ensure Automation is enabled with permissions appropriate to the actions and resources it may manage.
- Review recorded events. Track Automation events to determine whether an action was applied and to which resource.
- Check recovery options for that action. AWS documents controls to reverse actions through Compute Optimizer, but the right recovery step depends on the action. Verify the specific action’s behavior rather than assuming every change has an identical rollback.
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