- A
The load balancer is configured with only one backend service. Solution: Create a separate backend service for each region.
Why wrong: A single backend service can have multiple backends; the issue is health checks.
- B
The load balancer backend lacks a health check that marks the backend as unhealthy when the cluster is down. Solution: Configure a health check on the backend service that points to a readiness endpoint on the GKE cluster.
Health checks are required for the load balancer to stop routing traffic to unhealthy backends.
- C
The Cloud Spanner instance is not configured with multi-region replication, causing write failures. Solution: Configure Cloud Spanner as a multi-region instance.
Why wrong: Cloud Spanner multi-region replication is for database availability, not load balancing traffic routing.
- D
The GKE clusters are not configured as network endpoint groups (NEGs). Solution: Create NEGs for each cluster and use them as backends.
Why wrong: NEGs are likely already in use; the issue is health checks, not NEGs.
Quick Answer
The answer is a missing or misconfigured health check on the load balancer backend service. The global HTTP(S) load balancer relies on health checks to determine which backend instances are healthy; without a health check probing a readiness endpoint like /healthz on the GKE cluster, the load balancer cannot detect when an entire regional cluster is down, so it continues routing traffic to the unhealthy region. This scenario directly tests your understanding of GKE multi-region high availability health check design, a frequent exam trap where candidates assume the load balancer automatically detects cluster failures. On the Google Professional Cloud Developer exam, this concept appears in questions about failover behavior and backend service configuration, often paired with Cloud Spanner and audit logging requirements to distract from the core networking issue. Remember the memory tip: "No health check, no failover"—if the load balancer doesn’t know a backend is dead, it will keep sending traffic there.
PCD Integrating Google Cloud services Practice Question
This PCD practice question tests your understanding of integrating google cloud services. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
You are a cloud architect at a financial services company. The company is deploying a new application on Google Kubernetes Engine (GKE) that processes sensitive financial transactions. The application must be highly available across two regions (us-central1 and europe-west1) and must fail over automatically if one region becomes unavailable. The application uses Cloud Spanner as its primary database. Additionally, the application needs to send audit logs to a centralized Cloud Storage bucket for compliance. The current design uses GKE clusters in each region with a global HTTP(S) load balancer. However, during a recent test, when the us-central1 cluster was deliberately taken down, the load balancer continued to send traffic to that region, causing errors. You need to troubleshoot and fix the issue. What is the most likely cause and the best solution?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"best"Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Clue:
"primary"Why it matters: Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
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 load balancer backend lacks a health check that marks the backend as unhealthy when the cluster is down. Solution: Configure a health check on the backend service that points to a readiness endpoint on the GKE cluster.
The issue is that the global HTTP(S) load balancer continues to send traffic to the us-central1 region because its backend service lacks a health check that can detect when the GKE cluster is down. By configuring a health check on the backend service that probes a readiness endpoint (e.g., /healthz) on the GKE cluster, the load balancer will automatically stop routing traffic to the unhealthy region and fail over to the healthy region. This ensures high availability across the two regions as required.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 load balancer is configured with only one backend service. Solution: Create a separate backend service for each region.
Why it's wrong here
A single backend service can have multiple backends; the issue is health checks.
- ✓
The load balancer backend lacks a health check that marks the backend as unhealthy when the cluster is down. Solution: Configure a health check on the backend service that points to a readiness endpoint on the GKE cluster.
Why this is correct
Health checks are required for the load balancer to stop routing traffic to unhealthy backends.
Clue confirmation
The clue words "best", "most likely", "primary" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
The Cloud Spanner instance is not configured with multi-region replication, causing write failures. Solution: Configure Cloud Spanner as a multi-region instance.
Why it's wrong here
Cloud Spanner multi-region replication is for database availability, not load balancing traffic routing.
- ✗
The GKE clusters are not configured as network endpoint groups (NEGs). Solution: Create NEGs for each cluster and use them as backends.
Why it's wrong here
NEGs are likely already in use; the issue is health checks, not NEGs.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse infrastructure-level health checks (e.g., instance group health) with application-level health checks, or assume that GKE's built-in ingress controller automatically configures health checks for regional failover, when in fact the load balancer backend service must have an explicit health check configured to detect a complete regional cluster outage.
Detailed technical explanation
How to think about this question
The global external HTTP(S) load balancer uses a backend service that references a health check; the health check must be configured with a protocol (e.g., HTTP or HTTPS), a port, and a request path (e.g., /healthz) that the GKE cluster's readiness probe exposes. Under the hood, the load balancer's health check probes are sent from Google's health checking system at a configurable interval (default 5 seconds) and if a backend fails a consecutive threshold (default 2 failures), it is marked unhealthy and traffic is diverted. In a real-world scenario, if the health check path is not implemented or returns a 200 OK even when the cluster is down (e.g., due to a static response from a reverse proxy), the failover will not occur.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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Integrating Google Cloud services — study guide chapter
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FAQ
Questions learners often ask
What does this PCD question test?
Integrating Google Cloud services — This question tests Integrating Google Cloud services — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The load balancer backend lacks a health check that marks the backend as unhealthy when the cluster is down. Solution: Configure a health check on the backend service that points to a readiness endpoint on the GKE cluster. — The issue is that the global HTTP(S) load balancer continues to send traffic to the us-central1 region because its backend service lacks a health check that can detect when the GKE cluster is down. By configuring a health check on the backend service that probes a readiness endpoint (e.g., /healthz) on the GKE cluster, the load balancer will automatically stop routing traffic to the unhealthy region and fail over to the healthy region. This ensures high availability across the two regions as required.
What should I do if I get this PCD question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "best", "most likely", "primary". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jun 11, 2026
This PCD 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 PCD exam.
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