The valid OKE cluster network configuration that meets the requirement of having the least attack surface while still allowing direct access to the deployed applications from the Internet is: Private subnets for nodes and the Kubernetes API endpoint; public subnets for load balancers. By placing the nodes and the Kubernetes API endpoint in private subnets, they are not directly accessible from the Internet, reducing the attack surface.
The load balancers, on the other hand, are placed in public subnets, allowing them to be accessed from the Internet and serve as the entry point for accessing the deployed applications. This configuration ensures that the critical components of the cluster, such as the nodes and the API endpoint, are protected within the private network, while still providing accessibility to the applications through the load balancers. It helps to enhance security by limiting direct access to the internal components of the cluster while maintaining the availability of the deployed applications.