PCNE Configuring Network Services Practice Question
A network engineer configures a Global external HTTP(S) Load Balancer with a serverless NEG backend pointing to Cloud Run. The load balancer returns 502 Bad Gateway errors. What is the most 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 Cloud Run service has ingress set to 'internal'
Serverless NEG for Cloud Run requires that the Cloud Run service is publicly accessible or that the ingress is set to allow all traffic. Additionally, the load balancer's health checks must pass. A common cause is that the Cloud Run service has ingress restricted to internal traffic only.
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 URL map is misconfigured
Why it's wrong here
While possible, the most likely cause is ingress restriction.
- ✗
The SSL certificate is expired
Why it's wrong here
An expired SSL certificate would cause client-side errors, not 502 from the LB.
- ✗
The serverless NEG is not supported for Cloud Run
Why it's wrong here
Serverless NEGs are supported for Cloud Run.
- ✓
The Cloud Run service has ingress set to 'internal'
Why this is correct
If ingress is set to internal, the load balancer (external) cannot reach the service. It must be set to 'all' or use a VPC connector.
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.