# COST 4 How do you decommission resources?
Implement change control and resource management from project inception to end-of-life. This ensures you shut down or terminate unused resources to reduce waste.
**Topics**
+ [COST04-BP01 Track resources over their lifetime](cost_decomissioning_resources_track.md)
+ [COST04-BP02 Implement a decommissioning process](cost_decomissioning_resources_implement_process.md)
+ [COST04-BP03 Decommission resources](cost_decomissioning_resources_decommission.md)
+ [COST04-BP04 Decommission resources automatically](cost_decomissioning_resources_decomm_automated.md)
# COST04-BP01 Track resources over their lifetime
Define and implement a method to track resources and their associations with systems over their lifetime. You can use tagging to identify the workload or function of the resource.
**Level of risk exposed if this best practice is not established:** High
## Implementation guidance
Decommission workload resources that are no longer required. A common example is resources used for testing, after testing has been completed, the resources can be removed. Tracking resources with tags (and running reports on those tags) will help you identify assets for decommission. Using tags is an effective way to track resources, by labeling the resource with its function, or a known date when it can be decommissioned. Reporting can then be run on these tags. Example values for feature tagging are `feature-X testing` to identify the purpose of the resource in terms of the workload lifecycle.
**Implementation steps**
+ ** Implement a tagging scheme: **Implement a tagging scheme that identifies the workload the resource belongs to, verifying that all resources within the workload are tagged accordingly.
+ ** Implement workload throughput or output monitoring: **Implement workload throughput monitoring or alarming, triggering on either input requests or output completions. Configure it to provide notifications when workload requests or outputs drop to zero, indicating the workload resources are no longer used. Incorporate a time factor if the workload periodically drops to zero under normal conditions.
## Resources
**Related documents:**
+ [AWS Auto Scaling](https://aws.amazon.com/autoscaling/)
+ [AWS Trusted Advisor](https://aws.amazon.com/premiumsupport/trustedadvisor/)
+ [Tagging AWS resources](https://docs.aws.amazon.com/general/latest/gr/aws_tagging.html)
+ [Publishing Custom Metrics](https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/publishingMetrics.html)
# COST04-BP02 Implement a decommissioning process
Implement a process to identify and decommission orphaned resources.
**Level of risk exposed if this best practice is not established:** High
## Implementation guidance
Implement a standardized process across your organization to identify and remove unused resources. The process should define the frequency searches are performed, and the processes to remove the resource to ensure that all organization requirements are met.
**Implementation steps**
+ **Create and implement a decommissioning process: **Working with the workload developers and owners, build a decommissioning process for the workload and its resources. The process should cover the method to verify if the workload is in use, and also if each of the workload resources are in use. The process should also cover the steps necessary to decommission the resource, removing them from service while ensuring compliance with any regulatory requirements. Any associated resources are also covered, such as licenses or attached storage. The process should provide notification to the workload owners that the decommissioning process has been executed.
## Resources
**Related documents:**
+ [AWS Auto Scaling](https://aws.amazon.com/autoscaling/)
+ [AWS Trusted Advisor](https://aws.amazon.com/premiumsupport/trustedadvisor/)
# COST04-BP03 Decommission resources
Decommission resources triggered by events such as periodic audits, or changes in usage. Decommissioning is typically performed periodically, and is manual or automated.
**Level of risk exposed if this best practice is not established:** Medium
## Implementation guidance
The frequency and effort to search for unused resources should reflect the potential savings, so an account with a small cost should be analyzed less frequently than an account with larger costs. Searches and decommission events can be triggered by state changes in the workload, such as a product going end of life or being replaced. Searches and decommission events may also be triggered by external events, such as changes in market conditions or product termination.
**Implementation steps**
+ **Decommission resources: **Using the decommissioning process, decommission each of the resources that have been identified as orphaned.
## Resources
**Related documents:**
+ [AWS Auto Scaling](https://aws.amazon.com/autoscaling/)
+ [AWS Trusted Advisor](https://aws.amazon.com/premiumsupport/trustedadvisor/)
# COST04-BP04 Decommission resources automatically
Design your workload to gracefully handle resource termination as you identify and decommission non-critical resources, resources that are not required, or resources with low utilization.
**Level of risk exposed if this best practice is not established:** Low
## Implementation guidance
Use automation to reduce or remove the associated costs of the decommissioning process. Designing your workload to perform automated decommissioning will reduce the overall workload costs during its lifetime. You can use [Amazon EC2 Auto Scaling](https://aws.amazon.com/ec2/autoscaling/) or [Application Auto Scaling](https://docs.aws.amazon.com/autoscaling/application/userguide) to perform the decommissioning process. You can also implement custom code using the [API or SDK](https://aws.amazon.com/developer/tools/) to decommission workload resources automatically.
**Implementation steps**
+ ** Implement Amazon EC2 Auto Scaling or Application Auto Scaling:** For resources that are supported, configure them with Amazon EC2 Auto Scaling or Application Auto Scaling.
+ ** Configure CloudWatch to terminate instances:** Instances can be configured to terminate using CloudWatch alarms. Using the metrics from the decommissioning process, implement an alarm with an Amazon Elastic Compute Cloud (Amazon EC2) action. Verify the operation in a non-production environment before rolling out.
+ **Implement code within the workload:** You can use the AWS SDK or AWS CLI to decommission workload resources. Implement code within the application that integrates with AWS and terminates or removes resources that are no longer used.
## Resources
**Related documents:**
+ [Amazon EC2 Auto Scaling](https://aws.amazon.com/ec2/autoscaling/)
+ [Getting Started with Amazon EC2 Auto Scaling](https://docs.aws.amazon.com/autoscaling/ec2/userguide/GettingStartedTutorial.html)
+ [Application Auto Scaling](https://docs.aws.amazon.com/autoscaling/application/userguide)
+ [AWS Trusted Advisor](https://aws.amazon.com/premiumsupport/trustedadvisor/)
+ [Create Alarms to Stop, Terminate, Reboot, or Recover an Instance](https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/UsingAlarmActions.html)