Google Cloud's asynchronous messaging service for decoupling systems at scale. Producers publish messages to topics and consumers receive them via subscriptions. Guarantees at-least-once delivery.
In CDL it's the equivalent of AWS SNS+SQS or Azure Service Bus. Used in real-time data pipelines and event-driven architectures. Question: real-time data ingestion on GCP → Pub/Sub + Dataflow.
Cloud Pub/Sub is a concept that can show up on the exam. Check the full guide to see it in context.