Creating a Cloud Pub/Sub topic called NewEmployee is essential because it acts as the communication channel for delivering notifications about new employees. By establishing this topic, you provide a central point through which all relevant information can be disseminated. When a new employee joins, the HRPublisher service can publish messages to this topic, ensuring that all intended subscribers are notified concurrently.
This design follows the publish-subscribe pattern, which is efficient for notifying multiple teams without direct dependencies between them. Consequently, teams such as Security, Facilities, and Training can have their dedicated subscriber services listening to the NewEmployee topic. This approach ensures that each team receives the necessary information about new employees in a timely manner while maintaining scalability and separation of concerns.
The other options focus on aspects of the implementation process, such as creating subscriber services or managing subscriptions, but they do not establish the initial framework necessary for notification. Without the topic itself, the communication to the different teams cannot effectively occur.