DataCoral, a fintech startup, runs sensitive model training on SageMaker using custom Docker containers that must never access the public internet. Their security policy requires blocking all outbound internet traffic from training containers while still allowing access to S3 training data via VPC endpoints. Which configuration change will meet the requirement when launching a SageMaker training job?

Setting EnableNetworkIsolation to true on CreateTrainingJob ensures that the SageMaker training container cannot make any outbound network calls except to SageMaker dependencies, effectively blocking public internet access. To allow access to S3 for training data, a VPC gateway endpoint for S3 (com.amazonaws.<region.s3) is necessary, as it provides private connectivity to S3 without traversing the internet. The execution role must have appropriate S3 and VPC endpoint permissions. Omitting EnableNetworkIsolation is insufficient because SageMaker containers can still access the internet by default, even in private subnets, unless explicitly isolated. Enabling a NAT Gateway would grant internet access, which violates the requirement. Configuring a public subnet with an Internet Gateway, even with restrictive security groups, still exposes the container to potential internet access paths, which is less secure than network isolation.