Google PCA Practice Question: Managing Implementation and Ensuring Solution and Operations Reliability
Your company runs a production application on Compute Engine instances behind a managed instance group (MIG). You need to perform a rolling update with canary testing, gradually shifting traffic to the new version only if performance metrics are healthy. Which approach should you use?
⚠ Common exam trap
The trap here is assuming that a MIG rolling update alone provides canary behavior; in reality, rolling updates replace instances without traffic-based verification, so candidates who pick the gcloud rolling-action option miss the automated canary requirement.
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 Deploy with a deployment strategy that includes a canary phase and automated verification
Cloud Deploy is Google Cloud's managed continuous delivery service that natively supports progressive rollout strategies including canary deployments with automated verification against SLOs or custom metrics. It integrates with Cloud Monitoring to pause or roll back a rollout if health checks fail, which directly satisfies the requirement of gradually shifting traffic only when performance metrics are healthy. This is the intended Google-recommended pattern for canary releases on GCE MIGs.
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 Deploy with a deployment strategy that includes a canary phase and automated verification
Why this is correct
Cloud Deploy orchestrates the progressive rollout across the MIG, defining a canary phase that shifts a percentage of traffic, then runs automated verification against your defined metrics before promoting or rolling back. This satisfies the requirement to advance only when performance stays healthy.
- ✗
Create a new MIG with the new template and use a Cloud Load Balancer's traffic splitting
Why it's wrong here
A separate MIG with load balancer splitting does shift traffic, but the MIG's own rolling update and health-gated progression are not used, so failed instances are not automatically reverted. It suits blue-green cutovers between two independently managed fleets.
- ✗
Manually update each instance by SSH'ing and running a script
Why it's wrong here
Manual SSH updates bypass the MIG's rolling-update mechanism entirely, so no automatic health gating or traffic shifting occurs. It is tempting because SSH scripting suits one-off patching of unmanaged instances outside an instance group, where no orchestrator exists to coordinate version rollout or rollback.
- ✗
Use gcloud compute instance-groups managed rolling-action start-update with a maxSurge of 0
Why it's wrong here
Setting maxSurge to 0 replaces instances in place, so no canary capacity exists to split traffic between old and new versions, and no metric-gated promotion occurs. Rolling-action start-update suits straightforward fleet-wide patching where all instances run identical code; canary testing instead requires a second versioned MIG behind a load balancer with traffic splitting.
Go deeper
Related to this question
Learn chapter
IAM Policies, Service Accounts, and Auditing
Key term
Instance group
An instance group is a collection of virtual machine instances that are managed as a single unit for scaling, load balancing, and lifecycle management in cloud computing.
Key term
Managed instance group
A managed instance group is a collection of identical virtual machine instances that are automatically managed as a single unit to ensure high availability and scalability.
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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.