GCP Professional Cloud Architect Practice Question

Your team is decomposing a monolithic payments platform into loosely coupled microservices. The microservices will be deployed on Cloud Run in two regions and must exchange business events (for example, PaymentSettled) asynchronously. Requirements: handle millions of events per day, allow new consumer services to be added without publisher changes, guarantee message delivery when consumers are temporarily offline, and minimize infrastructure management overhead. Which architecture best meets these goals?

Create a Cloud Tasks queue for events; for every event, enqueue a task that invokes the HTTP endpoint of each consumer microservice.
Publish each event to a Cloud Pub/Sub topic and let every consumer microservice create its own pull subscription, acknowledging messages after successful processing.
Use Memorystore for Redis streams; publishers append events to the stream and consumer services read them through Redis consumer groups.
Write event rows into a shared Cloud SQL table that consumer services poll at short intervals to discover and process new events.

Report Issue

Answer Description

Cloud Pub/Sub is a fully managed global messaging service that automatically scales to very high throughput while storing messages durably until each subscriber acknowledges them. Publishers write an event once to a topic; any number of consumers can create independent subscriptions, enabling fan-out without requiring changes to the publisher. Pull subscriptions allow Cloud Run services to fetch and acknowledge messages when they are ready, ensuring reliable delivery even if a service is temporarily unavailable.

Cloud Tasks targets a specific HTTP endpoint per task, so publishers must know every consumer and there is no built-in fan-out. Polling a Cloud SQL table introduces operational overhead and does not scale well to millions of events. Memorystore for Redis (including its Enterprise tier, which can replicate across regions) is primarily an in-memory data store; you must provision and manage capacity, messages are retained only as long as memory or configured stream limits allow, and there is no per-subscriber acknowledgment mechanism. Therefore, using Cloud Pub/Sub with per-service subscriptions best satisfies scalability, decoupling, durability, and low-ops requirements.

Ask Bash

Bash is our AI bot, trained to help you pass your exam. AI Generated Content may display inaccurate information, always double-check anything important.