Unable to delete an ENI that is being used by a Lambda function (none). Lambda 함수(없음)가 사용하고 있는 ENI를 삭제할 수 없습니다.

After deleting the EKS (deployed with EKSCTL) cluster, I checked later and found that the EKS-related security groups were still there. eks(eksctl로 배포) 클러스터 삭제 후 나중에 확인해보니 eks 관련 보안그룹이 남아 있었습니다.

When I tried to delete that security group, it was impossible to delete because there were 4 ENIs connected to it. Therefore, when I tried to find the ENI and delete it, it was not deleted because it was connected to Lambda. 해당 보안 그룹을 삭제하려고하니 연결된 ENI 4개가 있어서 삭제가 불가능 했습니다. 따라서 ENI를 찾아 삭제 하려고 하니 Lambda에 연결되어 있다고 삭제가 되지 않았습니다.

For reference, there is never a Lambda function currently running, and when I tried to detach and force the ENI to detach, it was impossible. 참고로 현재 실행 중인 Lambda 함수는 절대로 없으며, ENI 분리 및 강제 분리 하려고 해도 불가능 했습니다.

https://repost.aws/knowledge-center/lambda-eni-find-delete Below is the result of using the support tool to find the ENI being used by the lambda following the guide above. 아래는 위 가이드에 따라 lambda가 사용하고 있는 eni를 찾는 서포트 도구를 이용해 확인한 결과입니다.

./findEniAssociations --eni eni-0393d9cd99c705410 --region ap-northeast-2
This script is for determining why an ENI that is managed by AWS Lambda has not been deleted.

Found eni-0393d9cd99c705410 with "subnet-b9dc2ae6" using Security Groups "sg-068b2832a64f71b13"
Searching for Lambda function versions using "subnet-b9dc2ae6" and Security Groups "sg-068b2832a64f71b13"...

No Lambda functions or versions found that were using the same subnet as this ENI.
If this ENI is not deleted automatically in the next 24 hours then it may be 'stuck'. If the ENI will not allow you to delete it manually after 24 hours then please contact AWS support and send them the output of this script.

./findEniAssociations --eni eni-09799395b59ca56e5 --region ap-northeast-2
This script is for determining why an ENI that is managed by AWS Lambda has not been deleted.

Found eni-09799395b59ca56e5 with "subnet-ca7f9a85" using Security Groups "sg-068b2832a64f71b13"
Searching for Lambda function versions using "subnet-ca7f9a85" and Security Groups "sg-068b2832a64f71b13"...

No Lambda functions or versions found that were using the same subnet as this ENI.
If this ENI is not deleted automatically in the next 24 hours then it may be 'stuck'. If the ENI will not allow you to delete it manually after 24 hours then please contact AWS support and send them the output of this script.

This script is for determining why an ENI that is managed by AWS Lambda has not been deleted.

Found eni-009e78e3d1f4ef141 with "subnet-129efc69" using Security Groups "sg-068b2832a64f71b13"
Searching for Lambda function versions using "subnet-129efc69" and Security Groups "sg-068b2832a64f71b13"...

No Lambda functions or versions found that were using the same subnet as this ENI.
If this ENI is not deleted automatically in the next 24 hours then it may be 'stuck'. If the ENI will not allow you to delete it manually after 24 hours then please contact AWS support and send them the output of this script.

This script is for determining why an ENI that is managed by AWS Lambda has not been deleted.

Found eni-0b6876313b65688ee with "subnet-942392ff" using Security Groups "sg-068b2832a64f71b13"
Searching for Lambda function versions using "subnet-942392ff" and Security Groups "sg-068b2832a64f71b13"...

No Lambda functions or versions found that were using the same subnet as this ENI.
If this ENI is not deleted automatically in the next 24 hours then it may be 'stuck'. If the ENI will not allow you to delete it manually after 24 hours then please contact AWS support and send them the output of this script.

The current time (2024.03.14) is obviously well past 24 hours (at least a couple weeks). 현재(2024.03.14)는 당연히 24시간(최소 몇 주 지남)은 충분히 지난 시점 입니다.