PCDOE Managing service incidents Practice Question
This PCDOE practice question tests your understanding of managing service incidents. 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 manage a production environment with a web service deployed on Compute Engine instances behind a HTTP(S) Load Balancer. The service has a health check configured on the load balancer, probing a health endpoint every 10 seconds. After a recent configuration change, you observe that all instances are marked as unhealthy and traffic is failing. The health check response is 200 OK from the instances, but the load balancer still marks them unhealthy. The health check configuration: protocol: HTTP, port: 80, request path: /health, interval: 10s, timeout: 5s, unhealthy threshold: 2. The instances are running a custom web server. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
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.
The load balancer is misconfigured with an incorrect protocol (HTTPS instead of HTTP).
Why wrong: If protocol mismatch, health check would not get 200.
B
The health check port is incorrectly configured as 80 but the service is listening on 8080.
Why wrong: The question states the service is on port 80.
C
The health check response is coming from a different server (e.g., a reverse proxy) that returns 200 but does not represent the actual service health.
If the response is from a different process, the load balancer may mark the instance unhealthy because the health check's interpretation of health is not satisfied.
D
The health check timeout is greater than the interval, causing overlapping probes.
Why wrong: Timeout 5s, interval 10s, so no overlap.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The health check response is coming from a different server (e.g., a reverse proxy) that returns 200 but does not represent the actual service health.
Option C is correct because the health check is receiving a 200 OK response from a reverse proxy or intermediary that is not the actual web server, so the load balancer's health check does not reflect the true health of the application. Even though the response is successful, the load balancer marks instances unhealthy because the health check is likely failing to reach the intended health endpoint on the custom web server, or the response is not coming from the service itself. This scenario often occurs when a reverse proxy (e.g., nginx) returns a static 200 for /health without forwarding the request to the backend service, causing the load balancer to see a healthy response but the service to be actually unhealthy.
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 misconfigured with an incorrect protocol (HTTPS instead of HTTP).
Why it's wrong here
If protocol mismatch, health check would not get 200.
✗
The health check port is incorrectly configured as 80 but the service is listening on 8080.
Why it's wrong here
The question states the service is on port 80.
✓
The health check response is coming from a different server (e.g., a reverse proxy) that returns 200 but does not represent the actual service health.
Why this is correct
If the response is from a different process, the load balancer may mark the instance unhealthy because the health check's interpretation of health is not satisfied.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The health check timeout is greater than the interval, causing overlapping probes.
Why it's wrong here
Timeout 5s, interval 10s, so no overlap.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Google Cloud often tests the misconception that a 200 OK response always indicates a healthy service, but the trap here is that the health check may be hitting a different server or proxy that does not reflect the actual application state.
Detailed technical explanation
How to think about this question
HTTP(S) Load Balancer health checks in Google Cloud use a separate health check system that sends probes directly to the instance IP and port specified. If a reverse proxy like nginx or Apache is configured to respond to /health with a static 200 without checking the backend service, the load balancer will see a successful response even if the actual web server is down or misconfigured. This is a common pitfall where the health check endpoint is served by a different layer than the application, leading to false positives in health status.
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
An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.
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.
Managing service incidents — This question tests Managing service incidents — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The health check response is coming from a different server (e.g., a reverse proxy) that returns 200 but does not represent the actual service health. — Option C is correct because the health check is receiving a 200 OK response from a reverse proxy or intermediary that is not the actual web server, so the load balancer's health check does not reflect the true health of the application. Even though the response is successful, the load balancer marks instances unhealthy because the health check is likely failing to reach the intended health endpoint on the custom web server, or the response is not coming from the service itself. This scenario often occurs when a reverse proxy (e.g., nginx) returns a static 200 for /health without forwarding the request to the backend service, causing the load balancer to see a healthy response but the service to be actually unhealthy.
What should I do if I get this PCDOE 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: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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 →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This PCDOE 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 PCDOE exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.