A developer wants to deploy a containerized web application that receives HTTP requests and can scale to zero when not in use. The application is stateless and has a startup time of less than 2 seconds. Which Google Cloud compute option is the most cost-effective?
Cloud Run executes stateless containers on a fully managed platform, where each instance only receives compute billing while actually processing a request and the service can scale down to zero when no traffic arrives. It automatically provisions instances based on concurrency and can start many instances to handle bursts, with optional min instances for latency-sensitive workloads. A containerized web application is an ideal fit because Cloud Run accepts any container image that listens on a port, and integrates directly with Cloud Build and Artifact Registry.
Why this answer
Cloud Run is a fully managed serverless platform that runs stateless containers and automatically scales to zero when there is no traffic, meaning you pay nothing when idle. It natively handles HTTP requests and supports rapid scaling based on incoming requests, making it ideal for a stateless web app with sub-2-second startup. The other options either do not scale to zero or require manual scaling configuration, leading to higher costs for sporadic workloads.
Exam trap
ACE often tests the misconception that any autoscaling solution can scale to zero, but only serverless platforms like Cloud Run and App Engine Standard (with automatic scaling) truly scale to zero; managed instance groups and GKE Standard always maintain a minimum capacity.
How to eliminate wrong answers
Option A is wrong because Compute Engine with a managed instance group and autoscaling does not scale to zero; at least one VM instance must always be running, incurring continuous costs even when idle. Option B is wrong because GKE Standard charges for the control plane (unless on Autopilot, but even then nodes may persist) and typically does not scale to zero by default; it requires managing node pools and cluster infrastructure, adding cost and complexity. Option C is wrong because App Engine Standard with manual scaling requires you to specify the number of instances, which means you cannot scale to zero automatically and will pay for idle instances.