PCNE Configuring Network Services Practice Question
A global HTTPS load balancer is configured with a backend service that points to a serverless NEG for Cloud Run services. Some requests are failing with 502 errors. What is a likely cause?
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
✓
The serverless NEG is in a different region than the load balancer's forwarding rule.
Serverless NEGs require the load balancer to be in the same region as the Cloud Run service, or use a global external load balancer with serverless NEGs in multiple regions. A 502 error often indicates connectivity issues, such as the load balancer not being able to reach the backend due to missing network endpoint group or incorrect region.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The SSL certificate is expired.
Why it's wrong here
An expired SSL certificate would cause client-side errors, not 502s from the backend.
- ✗
The Cloud Run service requires IAP authentication.
Why it's wrong here
IAP is not related to 502 errors; it would cause 401/403.
- ✗
The health check is misconfigured for serverless NEGs.
Why it's wrong here
Serverless NEGs do not require health checks; the load balancer uses a default health check.
- ✓
The serverless NEG is in a different region than the load balancer's forwarding rule.
Why this is correct
For a global load balancer, the serverless NEG must be in a supported region and the load balancer must be configured to route to that region.
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 |
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PCNE practice question is part of Courseiva's free Google Cloud certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PCNE exam.