Google PCA Ensure solution and operations reliability Practice Question
A healthcare company runs a patient portal on Cloud Run services in the us-central1 region. The compliance team requires that the portal remain readable during a regional outage and that failover to a secondary region occur without changing the public hostname. The portal's data is stored in Cloud SQL for PostgreSQL. Which design should the architect recommend?
⚠ Common exam trap
The trap here is assuming Cloud SQL performs automatic cross-region failover like its within-region high availability mode, when cross-region recovery requires promoting a replica.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Deploy the Cloud Run services in us-central1 and us-east1 behind a global external Application Load Balancer with a serverless network endpoint group per region, and use a Cloud SQL cross-region replica promoted on failover.
A global external Application Load Balancer with serverless network endpoint groups in two regions gives a stable anycast hostname that keeps working when one region fails, and Cloud Run's multi-region deployment provides compute in both places. For the data tier, a Cloud SQL cross-region replica must be promoted during regional failover, since Cloud SQL does not automatically fail over across regions.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Deploy the Cloud Run services in both regions and use Cloud DNS geolocation routing with a 300-second TTL to direct users to the healthy region.
Why it's wrong here
Geolocation routing sends users based on where they appear to originate, not on backend health, and a 300-second TTL means clients can cache the stale record long after a region fails. Failover would not be automatic on outage detection, and the delay would likely breach the compliance expectation of continuous readability during a regional failure.
- ✗
Deploy the Cloud Run services in us-central1 only and front them with a regional external Application Load Balancer and a Cloud DNS failover routing policy pointing to a static IP.
Why it's wrong here
A regional load balancer and a single Cloud Run region keep all compute in one failure domain, so a us-central1 outage takes the portal down entirely. Cloud DNS failover routing changes the answer the resolver returns, which depends on client and resolver TTL caching, so it cannot deliver the near-instant, hostname-preserving failover the requirement implies.
- ✗
Deploy the Cloud Run services in both regions behind a global external Application Load Balancer, and rely on Cloud SQL's automatic regional failover of the primary instance.
Why it's wrong here
The multi-region load balancing half is sound, but Cloud SQL for PostgreSQL does not perform automatic cross-region failover of a primary instance; high availability configuration protects within a region across zones. Without a cross-region replica to promote, the data tier remains a single-region dependency and the portal cannot serve reads after a regional outage.
- ✓
Deploy the Cloud Run services in us-central1 and us-east1 behind a global external Application Load Balancer with a serverless network endpoint group per region, and use a Cloud SQL cross-region replica promoted on failover.
Why this is correct
A global external Application Load Balancer provides a single anycast hostname and can route to serverless network endpoint groups in multiple regions, so failover happens without DNS changes. A Cloud SQL cross-region replica keeps a warm copy of the data that can be promoted if the primary region fails, satisfying the readability requirement during a regional outage.
Quick reference
Cloud Service Model Comparison
| Model | You Manage | Provider Manages | Examples |
|---|---|---|---|
| IaaS | OS, runtime, apps, data | Hardware, hypervisor, networking | EC2, Azure VMs, GCP Compute Engine |
| PaaS | Apps and data | OS, runtime, middleware, hardware | Elastic Beanstalk, Azure App Service |
| SaaS | Data and settings only | Everything else | Microsoft 365, Salesforce, Workday |
| FaaS / Serverless | Function code only | Infra, scaling, runtime | Lambda, Azure Functions, Cloud Run |
| CaaS | Containers and apps | Kubernetes, OS, hardware | EKS, AKS, GKE |
Go deeper
Related to this question
Learn chapter
Deployment Manager and Infrastructure as Code
Key term
Cloud Run
Cloud Run is a fully managed compute platform from Google Cloud that lets you run containerized applications in a serverless environment, automatically scaling from zero to thousands of requests.
Key term
Load balancer
A load balancer is a device or software that distributes incoming network traffic across multiple servers so no single server gets overwhelmed.
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Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Google Cloud exam blueprint
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