Exam Professional Cloud Developer topic 1 question 89 discussion

Let's analyze why the other options are less suitable: B. Broadcast message to users: This approach is not a reliable way to initiate a graceful shutdown. It relies on user interaction and might not be effective if users are not actively using the application. C. Write a file for polling: This approach is less efficient and introduces a delay. The application needs to poll the file every five minutes, which can introduce latency and might not be timely enough for a graceful shutdown. D. Publish a message to the Pub/Sub topic: This approach is not ideal because it introduces additional complexity and relies on the application's ability to process messages from the same topic it's subscribing to. It also might not be a reliable way to ensure a timely shutdown.

Shutdown Script: Write a shutdown script that is executed when the instance is being preempted. Publish a Message to Pub/Sub: In the shutdown script, publish a message to the Pub/Sub topic, indicating that a shutdown is in progress. This message serves as a notification to the application. Application Subscription: The application subscribes to the Pub/Sub topic and continuously listens for incoming messages

Graceful Shutdown: When the application receives the shutdown message from Pub/Sub, it initiates a graceful shutdown, including disconnecting from the database.

You have only one topic, so if there are multiple messages in the queue before the one announcing the disconnect, then a lot of time can pass before the retrival of the message

Option B, broadcasting a message to signed-in users and instructing them to save current work and sign out, is not relevant to the shutdown process of the application. Option C, writing a file in a location that is being polled by the application, is not a reliable method for initiating a graceful shutdown because the application may not read the file in a timely manner. Option D, publishing a message to the Pub/Sub topic announcing that a shutdown is in progress, is not a reliable method for initiating a graceful shutdown because the application may not read the message in a timely manner.

Because for preemptible instances the script should run within 30 seconds of the instance being shutdown or restarted, in this case a pub sub trigger would be faster to perform.

The issue with option D is that we have a SINGLE PubSub topic that is used to send the rows to be inserted; sending a completely different message seems wrong.