Remove unused Elastic IP addresses
AWS Resource Type:
AWS Elastic IP
Elastic IP addresses are static IPv4 addresses designed for dynamic cloud computing. They are free to use when attached to a running EC2 instance or network device. To promote efficient use of the static IPs, AWS charges for each EIP that is not in use. To save these costs, we release unused EIPs allocated to your accounts.
Criteria for identifying the opportunity:
The Finder selects Elastic IPs that have been unattached for over 7 days, are not associated with a Route 53 hosted zone, and have no reverse DNS record.
Potential savings (range in % on annual basis):
We have found that normally 66% of Elastic IP addresses are unused and can be released.
What happens when the Fixer is executed?
The Fixer gets the current Elastic IP details using the DescribeAddress API and saves the details in an S3 Bucket named `cloudfix-fixer-executions<AccountId>`, with a key of `UnusedElasticIps/<AllocationId>`, where `AccountId` is the AWS Account Id, and `AllocationId` is the Elastic IP’s allocation ID. The IP address is then released using the ReleaseAddress API.
Is it possible to rollback once CloudFix implements the fixer?
No, as once an Elastic IP address is released, it may not be reused. See AWS Documentation. The only option is to assign a new Elastic IP address and update referencing application(s) as appropriate. As mentioned in the previous section, the prior Elastic IP details are saved in an S3 bucket.
Can CloudFix implement the fix automatically once I accept the recommendation?
Does this fix require downtime?
No. CloudFix checks that the Elastic IP is unused before releasing it.