Automate Deletion of EC2 instances after agreed period

Question

We are looking for a solution that can do the following:
1. Identify EC2 instances that have not been used for more that 3 weeks and that do not have an agreed "permanent" or equivalent tag.
2. Notify the owner using the email address in the value of the 'owner' tag on the  EC2 instance. 
3. Automatically power down and/or terminate the instance after 4 weeks.

We would like to use this across many AWS accounts within an organization, but cannot find a solution to do this. We can either run this on an admin instance, but would like to use a native solution.

Any help is appreciated - let me know if you need further information.

Harshavardhan Gowda · Answer

Hello,

There is no native solution as such but, there is a solution that is published by AWS for a similar scenario. You might want to take a look at Instance scheduler:\
[+] https://aws.amazon.com/solutions/implementations/instance-scheduler-on-aws/

However, it also depends on what you mean by "have not been used". I have a set up in my account that uses AWS Lambda, Boto3 SDK and DynamoDB. The workflow is as follows:
1. A lambda function runs through the account and collects details about all active resources on the account every 1 hour except that have a special tag to exclude them.
2. This information is stored in DynamoDB table
3. Another lambda function reviews the data in the DDB table and evaluates against pre-defined rules. For example, all EC2 instances that have an average CPU utilization of less than 1% over 24 data points stored in the DDB table to be stopped.
4. Another lambda function evaluates the DDB items and performs necessary action such as stop/delete the resource.

kentrad · Answer

AWS Trusted Advisor has a check, [Low Utilization Amazon EC2 Instances](https://docs.aws.amazon.com/awssupport/latest/user/cost-optimization-checks.html#low-utilization-amazon-ec2-instances), under Cost Optimizations, that will alert when:
```
An instance had 10% or less daily average CPU utilization and 5 MB or less network 
I/O on at least 4 of the previous 14 days.
```
These events are sent to Amazon EventBridge and you can [create a rule to trigger an action](https://docs.aws.amazon.com/awssupport/latest/user/cloudwatch-events-ta.html), like an email from an SNS topic or a invoke a lambda function.

You can also turn on an [Organization view of Trusted Advisor](https://docs.aws.amazon.com/awssupport/latest/user/organizational-view.html).

Automate Deletion of EC2 instances after agreed period

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