Google PCA Practice Question: Managing Implementation and Ensuring Solution and Operations Reliability
You need to automatically roll back a GKE deployment if a new version causes a spike in 5xx errors. The deployment uses a canary strategy with Istio traffic splitting. What should you do?
⚠ Common exam trap
PCA often tests the misconception that Kubernetes auto-repair or Istio retries provide application-level rollback — candidates pick them because they sound like resilience features, but neither changes traffic routing based on error rates.
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
✓
Use Cloud Monitoring to watch the canary's error rate and trigger a Cloud Function that updates the Istio VirtualService to route all traffic back to the stable version.
The correct pattern is to monitor the canary's error rate with Cloud Monitoring (using Istio's telemetry metrics like istio_requests_total filtered by response_code=5xx and destination_version=canary), then use an alerting policy to trigger a Cloud Function (or Cloud Run) that patches the Istio VirtualService to shift 100% of traffic back to the stable version. This closes the loop between observability and traffic control, which is exactly what automated canary rollback requires.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Use Cloud Monitoring to watch the canary's error rate and trigger a Cloud Function that updates the Istio VirtualService to route all traffic back to the stable version.
Why this is correct
Cloud Monitoring detects the canary's elevated 5xx rate, and the triggered Cloud Function rewrites the Istio VirtualService weights, shifting all traffic back to the stable version. This satisfies the automatic rollback requirement without redeploying, since Istio controls routing independently of the GKE workload.
- ✗
Set the canary's traffic weight to 0 in the Istio VirtualService if errors exceed threshold using a Kubernetes Job.
Why it's wrong here
Zeroing the canary weight stops new traffic but leaves the faulty ReplicaSet running, so no rollback of the deployment revision happens and the bad image remains live. Manual weight edits suit gradual canary promotion, not automated revision rollback.
- ✗
Use GKE's built-in auto-repair feature to replace unhealthy pods.
Why it's wrong here
Auto-repair restarts pods that fail health checks; it cannot detect 5xx error spikes, which pods report as healthy, and it never reverts to the previous image. Auto-repair suits node or container failures, not application-level regression rollback.
- ✗
Configure an Istio VirtualService with a retry policy that automatically redirects traffic on errors.
Why it's wrong here
Retries re-send failed requests to the same canary pods, masking rather than removing the faulty version, so 5xx errors persist and no rollback occurs. Retry policies suit transient network faults, not version-level regressions needing traffic reversal.
Visual reference
Go deeper
Related to this question
Learn chapter
Deployment Manager and Infrastructure as Code
Key term
Cloud Monitoring
Cloud monitoring is the process of observing, measuring, and managing an organization's cloud infrastructure and applications to ensure performance, availability, and security.
Key term
Cloud Run
Cloud Run is a fully managed compute platform from Google Cloud that lets you run containerized applications in a serverless environment, automatically scaling from zero to thousands of requests.
About these practice questions
Courseiva writes every PCA question from scratch — 807 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Google Cloud exam blueprint
This PCA 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 PCA exam.