Google PCA Ensure solution and operations reliability Practice Test 3 — 15 Questions

Question 1

A company uses the above IAM policy on a Cloud Storage bucket. They find that Bob can view objects in the bucket. Which statement explains this?

Accepted Answer

Bob is a member of the group viewers@example.com.. The IAM policy shown includes a binding that grants the `roles/storage.objectViewer` role to the group `viewers@example.com`. If Bob is a member of that group, he inherits the permissions to view objects in the bucket. The policy explicitly lists this group as a principal, so Bob's ability to view objects is directly explained by his group membership.

Answer

There is a higher-level policy that grants Bob viewer access.

Answer

The etag is mismatched causing policy override.

Answer

The bucket has uniform bucket-level access disabled.

Answer

The objectCreator role implicitly includes read access.

Question 2

You are using Cloud SQL for PostgreSQL. You want to ensure that data can be recovered to any point within the last 7 days. What should you enable?

Accepted Answer

Enable automated backups and set the backup configuration to enable binary logging (point-in-time recovery).. Enabling automated backups with binary logging (also known as write-ahead logging or WAL archiving) in Cloud SQL for PostgreSQL allows point-in-time recovery (PITR). This lets you restore your database to any specific timestamp within the retention window, which you can set to 7 days. Automated backups alone only provide daily snapshot restores, not the granularity needed for recovery to any point in time.

Answer

Export the database daily to Cloud Storage.

Answer

Create a cross-region read replica.

Answer

Enable automated backups with a 7-day retention period.

Question 3

You are designing a Dataflow streaming pipeline for real-time event processing. The pipeline must be cost-effective while tolerating worker failures without data loss. Which configuration should you use?

Accepted Answer

Use a Dataflow streaming job with Streaming Engine, autoscaling, and non-preemptible workers.. A standard Dataflow streaming job (non-FlexRS) with non-preemptible workers and Streaming Engine enabled provides failure tolerance without data loss. Non-preemptible workers are not subject to termination, reducing failure frequency, and Streaming Engine's durable state checkpointing preserves progress across any worker failures. While preemptible workers are cheaper, they introduce higher failure risk; FlexRS is batch-only and cannot be used for streaming pipelines. Therefore, option D is the correct choice for a cost-effective (via autoscaling) and reliable streaming pipeline.

Answer

Use a batch Dataflow job with preemptible workers.

Answer

Use high-memory machine types for all workers to avoid preemption.

Answer

Use FlexRS with preemptible workers and enable streaming engine.

Question 4

You are deploying a stateless web application on Compute Engine. Which TWO actions improve availability? (Choose 2)

Accepted Answer

Use a regional managed instance group.. A regional managed instance group (MIG) distributes instances across multiple zones within a region, ensuring that if one zone fails, traffic is automatically routed to healthy instances in other zones. This provides high availability by eliminating a single zone of failure, which is critical for stateless web applications that can serve requests from any instance.

Answer

Enable Cloud CDN for the static content.

Answer

Purchase 1-year committed use contracts for the instances.

Answer

Use preemptible VMs to reduce cost.

Question 5

An application running on Compute Engine instances behind a load balancer experiences intermittent failures. Health checks show instances passing, but some users get errors. What should be the first troubleshooting step?

Accepted Answer

Review the application logs for errors.. The correct first step is to review the application logs (Option B) because the issue is intermittent failures despite healthy load balancer health checks. Since health checks confirm the instances are reachable and responding correctly at the health check endpoint, the problem likely lies within the application itself—such as request handling errors, timeouts, or resource contention. Application logs provide the most direct evidence of what is happening when users encounter errors, enabling targeted debugging before modifying infrastructure.

Answer

Increase instance size.

Answer

Enable HTTP health checks.

Answer

Check the load balancer's backend service configuration for session affinity.

Question 6

A company has a microservices architecture on GKE. One service is failing due to resource exhaustion. How can they proactively prevent this?

Accepted Answer

Configure a horizontal pod autoscaler with custom metrics.. A Horizontal Pod Autoscaler (HPA) with custom metrics scales the number of pod replicas based on application-specific signals (e.g., queue depth, request rate) rather than just CPU, which proactively prevents resource exhaustion for a service with non-CPU-bound bottlenecks. Custom metrics allow scaling before the service saturates, addressing the root cause. This is the most proactive and workload-appropriate solution.

Answer

Use vertical pod autoscaling.

Answer

Set up autoscaling based on CPU utilization.

Answer

Implement a cluster autoscaler.

Question 7

An organization needs to meet a RTO of 1 hour for a critical application running on GCE with persistent disks. What is the most cost-effective approach?

Accepted Answer

Use regional persistent disks.. Regional persistent disks (PD) provide synchronous replication of data between two zones in the same region, enabling automatic failover for a GCE instance without manual intervention. This meets the 1-hour RTO by allowing the instance to be recreated or failed over to the secondary zone quickly, and it is more cost-effective than maintaining a full replica instance because you only pay for the disk storage and replication, not for an idle compute instance.

Answer

Replica of compute instance in another zone.

Answer

Frequent disk image exports.

Answer

Regular snapshots to a regional bucket.

Question 8

A company has a Spanner instance for global transactions. They need to ensure reliability during a regional outage. What is the best approach?

Accepted Answer

Enable multi-region configuration with read-only replicas.. Spanner multi-region configurations with read-only replicas provide automatic failover. In the event of a regional outage, Spanner can promote a read-only replica to read-write to maintain availability, ensuring strong consistency and global transaction support. This is the best approach for reliability during a regional outage.

Answer

Spanner is already resilient across zones; use backup/restore for regions.

Answer

Use multiple instances in different regions.

Answer

Enable leader placement option.

Question 9

A team is using Cloud Functions and wants to ensure retries on failure. What is the best practice?

Accepted Answer

Configure maximum retries and set dead-letter topic.. Cloud Functions (2nd gen) and Cloud Run allow configuring maximum retry attempts and a dead-letter topic to handle messages that repeatedly fail processing. This ensures that transient failures are retried automatically, while persistent failures are captured in a dead-letter queue for later analysis, preventing message loss and enabling reliable event-driven processing.

Answer

Increase function timeout.

Answer

Use background functions with Pub/Sub.

Answer

Use synchronous invocation.

Question 10

A company is designing a highly available application on GCE. Which TWO steps should they take to ensure reliability?

Accepted Answer

Use a managed instance group with autohealing.. A managed instance group (MIG) with autohealing automatically replaces unhealthy VM instances based on health check results, ensuring the application remains available even if individual instances fail. This is a core reliability pattern for stateless applications on Compute Engine, as it provides self-healing infrastructure without manual intervention.

Answer

Use a global external HTTP(S) load balancer.

Answer

Use persistent disks without snapshots.

Answer

Deploy instances in a single zone to avoid latency.

Question 11

A company is migrating a critical database to Cloud SQL for MySQL. Which TWO actions ensure high availability?

Accepted Answer

Enable automatic backups.. Enabling automatic backups in Cloud SQL for MySQL ensures that point-in-time recovery (PITR) and daily backups are automatically taken, which is a fundamental requirement for high availability. While backups alone do not provide instant failover, they are essential for data durability and recovery in case of a disaster, and the question asks for actions that 'ensure high availability'—backups are a core component of a high-availability strategy by enabling recovery from data loss or corruption.

Answer

Use read replicas in multiple zones.

Answer

Configure a failover replica with a different IP.

Answer

Enable multi-region failover.

Question 12

A user reports that an application running on instance-1 is unreliable and often restarts. What is the most likely cause?

Accepted Answer

The instance is preemptible and can be terminated at any time.. Preemptible instances (now called 'spot instances' in Google Cloud) can be terminated by Google Compute Engine at any time due to resource demands, with only 30 seconds of warning. This makes them unsuitable for applications that require reliability and continuous uptime, as the instance can be stopped abruptly, causing the application to restart or become unavailable.

Answer

The instance is in a single zone without redundancy.

Answer

The machine type is too small.

Answer

The instance is using an outdated image.

Question 13

Company A runs a containerized application on Google Kubernetes Engine (GKE) with 3 node pools: one for frontend, one for backend, and one for stateful databases. The backend services experience periodic latency spikes. After investigation, they found that the spikes correlate with the node pool autoscaler scaling down nodes. The backend services are deployed as Deployments with resource requests and limits set to 100m CPU and 200Mi memory each. The node pool uses n1-standard-2 machine types. The cluster autoscaler is enabled. What should they do to prevent the latency spikes?

Accepted Answer

Configure a PodDisruptionBudget for the backend Deployment with minAvailable set to a high value.. The latency spikes occur because the cluster autoscaler is terminating nodes that host backend Pods, causing those Pods to be rescheduled and disrupting traffic. A PodDisruptionBudget (PDB) with a high minAvailable value ensures that a minimum number of backend Pods remain available during voluntary disruptions like node scale-down, preventing the sudden loss of capacity that leads to latency spikes. This directly addresses the root cause without disabling autoscaling or misconfiguring scheduling.

Answer

Disable cluster autoscaler for the backend node pool.

Answer

Use node taints and tolerations to isolate the backend services.

Answer

Increase the resource requests for the backend services to ensure they are scheduled on dedicated nodes.

Question 14

Company B uses Cloud Endpoints to expose their API. Recently, they started seeing 503 errors during periods of high traffic. They have enabled Cloud Endpoints with a moderate quota. The backend is running on Cloud Run. The Cloud Run service is configured with min instances = 0 and max instances = 100. The container concurrency is set to 80. The average request latency is 200ms. What is the most likely cause and what should they do?

Accepted Answer

Cloud Run is scaling too slowly; set min instances to a higher value.. The 503 errors during high traffic are most likely caused by Cloud Run's scaling latency. With min instances = 0, new requests must wait for a container to start (cold start), and during traffic spikes, the scaling algorithm may not provision instances quickly enough, leading to request timeouts and 503s. Setting a higher min instances value ensures a warm pool of containers is always ready to handle traffic bursts, reducing cold start delays.

Answer

The container concurrency is too low; increase it to 200.

Answer

The backend is experiencing cold starts; set a higher CPU limit.

Answer

The Cloud Endpoints quota is being exhausted; increase the quota.

Question 15

A company uses Cloud Spanner for a global financial application. They need to ensure that a regional outage does not cause data loss. The application requires strong consistency and low latency reads and writes across multiple regions. Which configuration meets the reliability requirements?

Accepted Answer

Use a multi-region Spanner instance with a primary region and two witness regions. A multi-region Spanner instance with a primary region and two witness regions uses Google's synchronous replication across three regions, ensuring strong consistency and no data loss during a regional outage. Witness regions participate in the Paxos quorum without serving read traffic, guaranteeing that writes are committed in at least two regions before acknowledgment, which meets the requirement for zero data loss and low latency reads and writes.

Answer

Use a multi-region Spanner instance with read replicas in two other regions

Answer

Use a single-region Spanner instance and schedule backups to Cloud Storage

Answer

Use a single-region Spanner instance with point-in-time recovery (PITR) enabled