EMR serverless Natgateway charges for ETL in same region

It's possible that EMR serverless is using NAT Gateway over VPC endpoint due to certain configurations or limitations. Here are some possible reasons why this might be happening:

EMR serverless might be using a different network interface than the EC2 instance that you tested the VPC endpoint with. This could be due to the way that EMR serverless is designed to operate or how it interacts with the VPC.

It's also possible that there is a misconfiguration or an issue with the VPC endpoint setup that is causing EMR serverless to fallback to NAT Gateway.

To avoid NAT Gateway charges for processing data in S3, you can try the following:

• Ensure that your VPC endpoint is properly configured and working correctly. You can check the VPC endpoint's route table to make sure that it's properly configured to route S3 traffic to the VPC endpoint.

• If you have already confirmed that the VPC endpoint is properly configured, then you can try removing the NAT Gateway from your VPC. This will force EMR serverless to use the VPC endpoint for all S3 traffic.

• You can also try using VPC flow logs to identify the source of the NAT Gateway traffic. This may help you to identify any misconfigurations or issues that are causing EMR serverless to use the NAT Gateway instead of the VPC endpoint.