A company is using a NAT gateway to allow internet connectivity for private subnets in a VPC in the us-west-2 Region. After a security audit, the…

To allow the unified CloudWatch agent to function from a private subnet without a NAT gateway, private connectivity to the CloudWatch services must be established using Interface VPC endpoints.

The unified agent sends data to two distinct services: CloudWatch Logs and CloudWatch Monitoring. Therefore, two interface endpoints are required: com.amazonaws.us-west-2.logs and com.amazonaws.us-west-2.monitoring (Option D).

These endpoints are secured using a security group that must allow inbound HTTPS (TCP/443) traffic from the resources in the private subnets that are sending the data (Option C).

Finally, for the CloudWatch agent to seamlessly resolve the standard AWS service hostnames (e.g., logs.us-west-2.amazonaws.com) to the private IP addresses of the endpoint network interfaces, the VPC's private DNS settings (enableDnsHostnames and enableDnsSupport) must be enabled (Option A).

B. The destination 0.0.0.0/0 represents internet traffic. The purpose of using VPC endpoints is to avoid routing traffic over the internet, making this rule incorrect for this solution.

E. This option is incomplete. The unified agent sends both logs and metrics, requiring the logs and monitoring endpoints. The cloudwatch endpoint alone is insufficient for the agent's data plane operations.

F. Route table associations are used for Gateway VPC endpoints (for S3 and DynamoDB). Interface VPC endpoints, which are used for CloudWatch, function via DNS resolution and do not use route table entries.

1. Amazon CloudWatch User Guide: "Use CloudWatch with interface VPC endpoints". This document specifies the necessary endpoints for CloudWatch services. It states, "If you use the CloudWatch agent to send both logs and metrics from an Amazon EC2 instance, you must create both of the following interface endpoints: com.amazonaws.region.monitoring and com.amazonaws.region.logs." This supports the correctness of option D and the incompleteness of option E.

2. Amazon VPC User Guide: "Private DNS for interface endpoints". This guide clarifies the DNS requirement: "To use private DNS for your interface endpoints, you must set the following VPC attributes to true: enableDnsSupport and enableDnsHostnames." This supports the correctness of option A.

3. AWS PrivateLink Guide: "Control access to services using VPC endpoints". This document details security group configuration: "The security group rules for the endpoint network interface must allow inbound traffic from the resources in your VPC that will communicate with the service." This supports the correctness of option C.

4. Amazon VPC User Guide: "VPC endpoints". This page distinguishes between endpoint types, clarifying that route table modifications are specific to Gateway endpoints: "A gateway endpoint is a gateway that you specify as a target for a route in your route table..." This confirms that option F is incorrect for Interface endpoints.