What happens if the DNS hostname is an EC2 default?

The reasoning behind selecting that specific answer centers around how Datadog recognizes and prioritizes hostnames within the monitoring environment.

When the DNS hostname is an EC2 default, it indicates that this hostname does not carry unique or meaningful identification for the resource it represents. In this context, the system is designed to prioritize meaningful or user-provided hostnames over default DNS names that may not adequately represent the instance or resource's purpose.

As a result, the default DNS hostname is effectively disregarded during the hostname selection process by Datadog. This ensures that the monitoring solution delivers more relevant and actionable insights based on unique identities, helping to facilitate better management and understanding of the monitored infrastructure.

In contrast, the other options imply that the default hostname holds some significance, which is not the case. For instance, it does not become the primary hostname or carry weight in hostname counting or prioritization—since what is vital is ensuring that the resource can be easily identified and understood, minimizing potential confusion when monitoring.