Google PCA Ensure solution and operations reliability Practice Test 5 — 15 Questions

Question 1

A media company runs a batch video-transcoding pipeline on Google Cloud. A Cloud Logging-based log-based alert fires whenever a transcoder VM stops unexpectedly, but the on-call engineer frequently misses these alerts during off-hours. The team wants the transcoding jobs to recover automatically without human intervention when a VM is terminated. What should they implement?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Create a managed instance group (MIG) with an instance template and enable autohealing with a health check on the transcoding service port.. A managed instance group with autohealing is Google Cloud's native mechanism for keeping a fixed set of VMs running. It recreates terminated instances automatically and uses health checks to replace instances whose application has failed, so transcoding resumes without any on-call action. Notification-based or polling approaches still require human or custom-code intervention and add recovery latency.

Answer

Configure a Cloud Scheduler job that runs a script every five minutes to check for stopped transcoder VMs and restart them.

Answer

Attach a Cloud Logging log-based alert that triggers a Cloud Function to send an email and page the on-call engineer immediately.

Answer

Increase the VM's restart policy to always restart the instance after termination using the gcloud compute instances set-scheduling command.

Question 2

A healthcare provider stores patient documents in a Cloud Storage bucket. Auditors require that every object is retained for at least seven years and that no user, including project owners, can delete or overwrite objects before that period ends. The security team also wants to be alerted if anyone attempts to shorten the retention period. Which configuration should the architect implement?

Accepted Answer

Apply a bucket retention policy with a seven-year retention period, then lock the retention policy.. The requirement is enforced immutability for seven years against all users, including project owners, plus alerting on attempts to shorten retention. A bucket retention policy blocks deletion and replacement until the period expires, and locking the policy makes it permanent and impossible to remove or reduce. Versioning, IAM restrictions, and audit logging provide recoverability, access control, or visibility, but none of them prevent a privileged user from removing data early.

Answer

Assign the roles/storage.objectViewer role to all users and remove the storage.objects.delete permission from custom roles.

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Enable Object Versioning and create a lifecycle rule that deletes noncurrent versions after 2555 days.

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Enable Uniform bucket-level access and configure a Cloud Audit Logs sink to alert on storage.objects.delete events.

Question 3

A company has a web application running on a single Compute Engine instance. The application is not mission-critical, but the company wants to ensure that it remains available even if the instance fails. They want a simple, cost-effective solution with minimal configuration. What should they do?

Accepted Answer

Create an instance template and a managed instance group with a minimum of two instances, and configure an HTTP(S) load balancer.. A managed instance group with multiple instances and a load balancer is the simplest way to achieve high availability on Compute Engine. It automatically replaces failed instances and distributes traffic, requiring minimal configuration. This approach is cost-effective and suitable for non-mission-critical applications.

Answer

Use a single instance with a regional persistent disk and enable automatic restart.

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Deploy the application on Cloud Run with a minimum instance count of 1.

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Set up a Cloud DNS failover routing policy to point to a standby instance in another zone.

Question 4

A financial services firm runs a latency-sensitive trading dashboard on a regional external Application Load Balancer backed by a managed instance group in a single region. Regulators require the dashboard to survive a full zone outage without manual intervention and without exceeding a 30-second recovery objective. Which TWO changes should the architect make? (Choose two.)

Accepted Answer

Distribute the managed instance group across at least three zones in the region and set the target distribution shape to BALANCED.. Zonal resilience for a regional Application Load Balancer comes from having healthy backend capacity in more than one zone. Spreading the managed instance group across three zones with a balanced distribution, or attaching zonal instance groups from different zones to the same backend service, keeps the load balancer serving traffic automatically when a zone is lost, meeting the short recovery objective.

Answer

Configure the backend service to use a single-zone network endpoint group for deterministic routing.

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Increase the load balancer's global forwarding rule to use Premium Tier network service tier.

Answer

Enable Cloud CDN with cache mode set to CACHE_ALL_STATIC on the backend service.

Question 5

You are designing a disaster recovery (DR) plan for a stateful application running on Compute Engine. The application uses a regional persistent disk (PD) for data storage. You need to ensure that the application can be recovered in another region with minimal data loss and downtime. Which TWO actions should you take? (Choose two.)

Accepted Answer

Set up a managed instance group in the DR region with an instance template that references the replicated disk.. To recover a stateful application using a regional persistent disk in another region, you need to replicate the data. Snapshot schedules with cross-region replication ensure data is available. Then, a managed instance group in the DR region can create instances from an instance template that uses the replicated disk. This combination provides minimal data loss and downtime. Other options do not address data replication or are not suitable for block storage.

Answer

Configure the application to write to a multi-region Cloud Storage bucket.

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Use a regional persistent disk in the DR region and set up asynchronous replication using a tool like rsync.

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Create a custom image of the instance and copy it to the DR region.

Question 6

A company runs a batch processing job on Google Kubernetes Engine (GKE) that processes large datasets. The job is long-running and can tolerate interruptions, but the company wants to minimize cost. They are using a regional cluster with nodes in three zones. They want to ensure that the job completes even if some nodes are preempted. What should they do?

Accepted Answer

Use preemptible VMs for the node pool and configure the job as a Kubernetes Job with a restartPolicy of OnFailure.. Using preemptible VMs minimizes cost for interruptible batch jobs. Configuring the job as a Kubernetes Job with restartPolicy OnFailure ensures that the job controller recreates pods if they are preempted, allowing the job to complete. This combination is cost-effective and reliable for batch processing.

Answer

Use committed use discounts for standard VMs and configure a PodDisruptionBudget.

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Use standard VMs and enable cluster autoscaler to add nodes when needed.

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Use preemptible VMs and deploy the job as a Deployment with multiple replicas.

Question 7

An online retailer runs its order-processing service on Cloud Run. The service depends on a Cloud SQL for PostgreSQL instance. During a regional outage of the Cloud SQL primary, the service returns errors for several minutes while operators manually promote a replica. The team wants the database to fail over automatically with minimal application changes. What should they do?

Accepted Answer

Migrate to Cloud SQL Enterprise Plus with a cross-region replica and configure the instance for automatic failover to the replica during a regional outage.. Cloud SQL Enterprise Plus supports cross-region replica configurations with automatic failover, so the primary can be replaced without operator intervention when a region is lost. Because the connection endpoint stays consistent, the Cloud Run service needs little or no change. This satisfies both the automatic failover and minimal-application-change requirements.

Answer

Enable Cloud SQL high availability by configuring a cross-region replica and promoting it automatically using a Cloud Function triggered by a Cloud Monitoring alert.

Answer

Add a read replica in a second region and update the application connection string to point to the replica when the primary is unavailable.

Answer

Migrate the database to Cloud SQL with a regional configuration, which provisions a standby in a different zone and performs automatic failover.

Question 8

An online ticketing platform runs its checkout service on GKE Autopilot. During a flash sale, the team observes that pods are being terminated and rescheduled repeatedly, and checkout requests fail intermittently. Logs show the containers exceed their configured memory limit under peak load. The team wants the service to degrade gracefully instead of being killed. Which action should the architect take first?

Accepted Answer

Increase the container's memory limit, set a memory request below the limit for scheduling headroom, and add a Horizontal Pod Autoscaler based on CPU or a custom metric.. The pods are being terminated because containers exceed their memory limit, so the fix is to give the workload more memory headroom and scale out horizontally as demand rises. Raising the limit and adding a Horizontal Pod Autoscaler keeps individual containers below the limit while spreading load, allowing the checkout service to serve requests during the flash sale instead of crash-looping.

Answer

Configure a PodDisruptionBudget with maxUnavailable set to zero for the checkout deployment.

Answer

Enable GKE Autopilot's cluster autoscaler to add nodes when pods are pending, and set the deployment's update strategy to Recreate.

Answer

Set the container's memory request equal to its limit and add a Vertical Pod Autoscaler in Off mode to gather recommendations.

Question 9

A company runs a critical application on Compute Engine instances in a managed instance group (MIG) with autoscaling. During a traffic spike, some instances become unhealthy but are not automatically replaced. What is the most likely cause?

Accepted Answer

The autohealing health check is misconfigured.. The most likely cause is that the autohealing health check is misconfigured. In a managed instance group, autohealing relies on a health check to detect unhealthy instances and trigger replacement. If the health check is misconfigured (e.g., wrong port, path, or protocol), the MIG will not recognize instances as unhealthy and will not automatically replace them, even during a traffic spike.

Answer

The MIG is regional and one zone failed.

Answer

The instance template has a startup script error.

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The HTTP load balancer's health check is failing.

Question 10

A company uses Cloud Spanner for a global financial application. They experience increased latency and transaction aborts during peak hours. Which measure should they take first to improve reliability?

Accepted Answer

Optimize transactions to reduce lock contention.. Transaction aborts and latency in Cloud Spanner are most commonly caused by lock contention during peak hours. By optimizing transactions—such as reducing their scope, using read-only transactions where possible, and avoiding hot-spot writes—you directly address the root cause of contention without incurring additional cost or schema changes. This aligns with Google's best practices for Spanner reliability.

Answer

Increase the number of nodes in the Spanner instance.

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Reduce the number of indexes on frequently updated columns.

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Use interleaved tables to co-locate related data.

Question 11

A company deploys a microservices application on Google Kubernetes Engine (GKE). Pods in one deployment are frequently OOMKilled. The team sets memory requests and limits, but pods still crash. What is the most likely remaining cause?

Accepted Answer

The application has a memory leak that eventually exceeds the limit.. OOMKilled errors occur when a container exceeds its memory limit. Setting memory requests and limits prevents unbounded usage, but if the application has a memory leak, it will continue to consume memory until it hits the configured limit, causing the kernel's Out-Of-Memory (OOM) killer to terminate the pod. The fact that pods still crash after setting limits indicates the application itself is the root cause, not resource configuration.

Answer

CPU requests are too low, causing throttling and eventual crash.

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The node pool is too small, causing memory pressure on the node.

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Memory limits are set higher than the node's allocatable memory.

Question 12

An organization uses Cloud Functions (2nd gen) for event-driven processing. They notice that some functions fail with 'memory limit exceeded' errors during peak load. The function processes messages from Pub/Sub and writes to Firestore. What should they do to improve reliability without sacrificing throughput?

Accepted Answer

Increase the memory allocated to the Cloud Function.. The 'memory limit exceeded' error indicates that the function's allocated memory is insufficient for the workload during peak load. Increasing the memory allocation (Option B) directly resolves this by providing more RAM for processing larger messages or concurrent operations, without altering the invocation pattern or throughput. Cloud Functions (2nd gen) allow memory to be set up to 32 GiB, and this change does not reduce the number of events processed per second.

Answer

Increase the maximum number of concurrent function instances.

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Enable Pub/Sub batching to reduce the number of function invocations.

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Split the function into multiple smaller functions, each handling a subset of the data.

Question 13

A company monitors their application with Cloud Monitoring. They set up an alerting policy to notify the on-call team when the 99th percentile latency exceeds 500 ms for 5 minutes. However, they receive false positive alerts due to short bursts. How should they refine the policy?

Accepted Answer

Increase the evaluation window to 10 minutes.. Increasing the evaluation window to 10 minutes smooths out short bursts of high latency, ensuring the alert triggers only when the 99th percentile latency exceeds 500 ms for a sustained period. Cloud Monitoring evaluates metrics over the specified window, so a longer window reduces false positives from transient spikes while still detecting genuine degradation.

Answer

Set up alerting on each data point individually.

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Decrease the threshold to 400 ms.

Answer

Change the metric to average latency instead of 99th percentile.

Question 14

A company runs a web application on Google Kubernetes Engine (GKE) with Cluster Autoscaler enabled. During a traffic spike, the application becomes slow and some requests timeout. The cluster has sufficient CPU and memory headroom. What is the most likely cause and solution?

Accepted Answer

Configure Horizontal Pod Autoscaler (HPA) based on CPU utilization or custom metrics.. The cluster has sufficient CPU and memory headroom, indicating that the issue is not about cluster capacity but about pod-level scaling. The Horizontal Pod Autoscaler (HPA) automatically scales the number of pod replicas based on observed CPU utilization or custom metrics, which directly addresses the application slowdown and timeouts during traffic spikes by distributing the load across more pods.

Answer

Increase the node pool's machine type to a larger size.

Answer

Enable Cluster Autoscaler to add more nodes.

Answer

Deploy the application in a regional cluster for higher availability.

Question 15

An organization is migrating a legacy monolithic application to Google Cloud. The application currently runs on a single server with an on-premises database. The application is stateful and requires low-latency access to the database. The migration must minimize downtime and ensure high availability. Which architecture should the company adopt?

Accepted Answer

Deploy on Compute Engine with a regional persistent disk and use Cloud SQL for PostgreSQL with regional high availability.. It combines Compute Engine with a regional persistent disk for synchronous replication across zones, ensuring high availability with minimal downtime during a zonal failure. Cloud SQL for PostgreSQL with regional high availability provides a managed, low-latency database with automatic failover, meeting the stateful application's need for low-latency access and high availability without the complexity of container orchestration.

Answer

Deploy on GKE with StatefulSets and use Cloud Spanner for global consistency.

Answer

Deploy on App Engine Standard Environment and use Cloud Firestore in Datastore mode.

Answer

Deploy on Cloud Run and use Cloud SQL with read replicas.