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Scaling with Google Cloud operations →hardMultiple ChoiceObjective-mapped

Quick Answer

The answer is a load balancer with health checks across multiple zones. Without this component, chaos engineering zone failure testing reveals that traffic cannot be automatically redirected because there is no mechanism to detect that an entire zone has gone down and reroute requests to healthy instances in surviving zones. A load balancer like Google Cloud’s HTTP(S) Load Balancer continuously monitors backend health via probes; when a zone fails, the health checks mark those instances as unhealthy, and the load balancer instantly stops sending traffic to them. On the Google Cloud Digital Leader exam, this scenario tests your understanding of how high availability relies on multi-zone architecture and health-check-aware traffic distribution—a common trap is assuming that instance groups or autoscaling alone handle failover. Remember the memory tip: “No health checks, no redirects—without a load balancer, a zone failure is a full outage.”

Cloud Digital Leader Scaling with Google Cloud operations Practice Question

This GCDL practice question tests your understanding of scaling with google cloud operations. 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.

An SRE team is practicing 'chaos engineering' by simulating a zone-level failure in their staging environment. They find that their application does not automatically recover — traffic is not redirected and the service remains down. What architectural component is most likely missing?

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.

Question 1hardmultiple choice

Full question →

A
The application needs more replicas in the failing zone to survive the failure
Why wrong: More replicas in the failing zone doesn't help when the zone itself is unavailable — all replicas in a failed zone are equally inaccessible. Replicas must be distributed across multiple zones.
B
A load balancer with health checks across multiple zones is most likely missing — without it, there is no mechanism to detect the zone failure and automatically redirect traffic to healthy instances in surviving zones
The load balancer is the key component. It must be configured with backend instances in multiple zones and health checks enabled. When the health check detects that zone A instances are unhealthy, it automatically removes them from the rotation and sends all traffic to healthy instances in zones B and C. Without the load balancer, clients connect directly to zone A and have no fallback.
C
The application needs a larger machine type to handle the full traffic load without the failed zone's capacity
Why wrong: Larger machines in the remaining zones may be needed to handle full traffic, but this is a capacity concern, not the mechanism for automatic traffic redirection. The load balancer is the missing routing and detection component.
D
Cloud Monitoring alerts need to be configured to notify the team when a zone fails, enabling manual traffic redirection
Why wrong: Manual intervention after an alert is too slow for production availability. Automatic failover through a load balancer with health checks provides the immediate, automated response needed during a zone failure.

Full breakdown with real-world context →

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

✓

A load balancer with health checks across multiple zones is most likely missing — without it, there is no mechanism to detect the zone failure and automatically redirect traffic to healthy instances in surviving zones

In a zone-level failure, traffic cannot be redirected to healthy instances in surviving zones without a load balancer that performs health checks across multiple zones. Google Cloud's external or internal load balancers (e.g., HTTP(S) Load Balancer, TCP/UDP Network Load Balancer) use health checks to detect unhealthy instances and automatically route traffic only to healthy backends. Without this component, the application has no mechanism to detect the zone failure and reroute traffic, leaving the service down.

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 application needs more replicas in the failing zone to survive the failure
Why it's wrong here
More replicas in the failing zone doesn't help when the zone itself is unavailable — all replicas in a failed zone are equally inaccessible. Replicas must be distributed across multiple zones.
✓
A load balancer with health checks across multiple zones is most likely missing — without it, there is no mechanism to detect the zone failure and automatically redirect traffic to healthy instances in surviving zones
Why this is correct
The load balancer is the key component. It must be configured with backend instances in multiple zones and health checks enabled. When the health check detects that zone A instances are unhealthy, it automatically removes them from the rotation and sends all traffic to healthy instances in zones B and C. Without the load balancer, clients connect directly to zone A and have no fallback.
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 application needs a larger machine type to handle the full traffic load without the failed zone's capacity
Why it's wrong here
Larger machines in the remaining zones may be needed to handle full traffic, but this is a capacity concern, not the mechanism for automatic traffic redirection. The load balancer is the missing routing and detection component.
✗
Cloud Monitoring alerts need to be configured to notify the team when a zone fails, enabling manual traffic redirection
Why it's wrong here
Manual intervention after an alert is too slow for production availability. Automatic failover through a load balancer with health checks provides the immediate, automated response needed during a zone failure.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates may confuse 'scaling up' (larger machine types or more replicas) with 'resilience through load balancing', failing to recognize that without a load balancer with health checks, no amount of capacity in surviving zones will automatically redirect traffic.

Detailed technical explanation

How to think about this question

Google Cloud's HTTP(S) Load Balancer uses a global anycast IP and performs health checks at the backend service level, with a configurable health check interval (e.g., 5 seconds) and unhealthy threshold (e.g., 2 failures). When a zone fails, the load balancer's health check probes fail, and it automatically removes the unhealthy instances from the backend service's load balancing pool, redirecting traffic to healthy instances in other zones. This behavior is governed by the load balancer's forwarding rules and backend service configuration, not by instance-level settings.

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 healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.

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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FAQ

Questions learners often ask

What does this GCDL question test?

Scaling with Google Cloud operations — This question tests Scaling with Google Cloud operations — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: A load balancer with health checks across multiple zones is most likely missing — without it, there is no mechanism to detect the zone failure and automatically redirect traffic to healthy instances in surviving zones — In a zone-level failure, traffic cannot be redirected to healthy instances in surviving zones without a load balancer that performs health checks across multiple zones. Google Cloud's external or internal load balancers (e.g., HTTP(S) Load Balancer, TCP/UDP Network Load Balancer) use health checks to detect unhealthy instances and automatically route traffic only to healthy backends. Without this component, the application has no mechanism to detect the zone failure and reroute traffic, leaving the service down.

What should I do if I get this GCDL 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.

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