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

Question 1

Drag and drop the steps to set up a Cloud VPN tunnel between Google Cloud and an on-premises network into the correct order.

Accepted Answer

1. Create a Cloud Router
2. Create a VPN gateway
3. Create a tunnel with the on-premises public IP and pre-shared key
4. Establish BGP sessions. Cloud Router is used for dynamic routing. The tunnel requires the on-premises public IP and pre-shared key.

Answer

1. Create a VPN gateway
2. Create a Cloud Router
3. Establish BGP sessions
4. Create a tunnel with the on-premises public IP and pre-shared key

Answer

1. Create a VPN gateway
2. Create a tunnel with the on-premises public IP and pre-shared key
3. Establish BGP sessions

Answer

1. Create a tunnel with the on-premises public IP and pre-shared key
2. Create a VPN gateway
3. Create a Cloud Router
4. Establish BGP sessions

Question 2

A company deploys a web application on Compute Engine behind an HTTP Load Balancer. They want to ensure only healthy instances receive traffic. What should they configure?

Accepted Answer

Configure an HTTP health check with a custom request path that returns a 200 status. An HTTP health check with a custom request path that returns a 200 status allows the HTTP Load Balancer to verify that the web application is actually serving requests correctly. This ensures that only instances passing the application-level health check are considered healthy and receive traffic, preventing requests from being routed to instances that may be running but not serving the expected content.

Answer

Configure the instance group autoscaling based on CPU utilization

Answer

Configure a TCP health check on port 80

Answer

Configure an SSL health check to verify TLS handshake

Question 3

An application uses Cloud Pub/Sub for asynchronous processing. Subscribers occasionally fail to acknowledge messages within the ack deadline, causing redelivery. How to improve reliability and prevent message buildup?

Accepted Answer

Implement exponential backoff in the subscriber retry logic. Implementing exponential backoff in the subscriber retry logic allows the subscriber to gradually increase the delay between retries when messages are not acknowledged, reducing the likelihood of overwhelming the system and preventing message buildup. This approach aligns with Cloud Pub/Sub's recommended practices for handling transient failures, as it gives the subscriber time to recover without exhausting the ack deadline or causing excessive redelivery.

Answer

Increase the ack deadline to the maximum value

Answer

Set max delivery attempts to 1 to avoid redelivery

Answer

Use a dead-letter topic to capture failed messages

Question 4

A global application uses Cloud Spanner with a multi-region configuration. During a regional outage, some transactions are failing. What is the recommended approach to maintain write availability?

Accepted Answer

Configure Spanner with leader-based replication and rely on automatic failover. Cloud Spanner's multi-region configuration uses leader-based replication, where each region has a leader for its read-write replicas. During a regional outage, Spanner automatically fails over the leader to another region, ensuring write availability without manual intervention. This is the recommended approach because it leverages Spanner's built-in synchronous replication and automatic failover to maintain consistency and availability.

Answer

Implement application-level retry with exponential backoff

Answer

Use a single-region Spanner instance with a standby in a different zone

Answer

Manually failover to a different region using a script

Question 5

A startup uses Cloud Functions for event-driven processing. They notice some functions are timing out. How to increase reliability without changing the business logic?

Accepted Answer

Enable retry on failure for the event-driven function. Enabling retry on failure for event-driven Cloud Functions allows the platform to automatically retry the invocation when a function times out or fails, without modifying the business logic. This leverages the built-in retry mechanism for background functions, which uses exponential backoff to handle transient failures and improve reliability.

Answer

Increase the function timeout to the maximum allowed

Answer

Use Cloud Tasks to decouple and retry synchronously

Answer

Refactor the function to reduce complexity

Question 6

An organization wants to define an SLO for their API hosted on Cloud Endpoints. Which metric should they use as a Service Level Indicator (SLI) for availability?

Accepted Answer

Ratio of HTTP 200 responses to total requests. For an availability SLO, the SLI must measure the proportion of successful requests. In Cloud Endpoints, availability is defined as the ratio of successful (HTTP 200) responses to total requests, as this directly reflects whether the API is functioning correctly. Option C is correct because it captures the fraction of requests that completed without error, which is the standard definition of availability in service-level monitoring.

Answer

Number of HTTP 5xx errors

Answer

Request latency at the 99th percentile

Answer

CPU utilization of backend instances

Question 7

A developer wants to monitor a custom application metric from their application running on GKE. What should they use?

Accepted Answer

Cloud Monitoring custom metrics API. Cloud Monitoring custom metrics API (option D) is the correct choice because it allows a developer to push custom application-specific metrics (e.g., request latency, queue depth) from a GKE pod using the `custom.googleapis.com` metric domain. This integrates directly with Cloud Monitoring for alerting and dashboards, whereas Cloud Logging is for log data, not metrics.

Answer

Cloud Logging

Answer

Cloud Trace

Answer

Cloud Debugger

Question 8

After a data corruption incident, a company needs to restore their Cloud SQL for PostgreSQL instance from a backup. What is the correct procedure to minimize downtime?

Accepted Answer

Restore the backup directly to the existing Cloud SQL instance. Restoring a backup directly to the existing Cloud SQL instance is the fastest method to minimize downtime because it overwrites the current data in-place without requiring DNS propagation, connection string changes, or reconfiguration of applications. Cloud SQL supports in-place restore from automated or on-demand backups, which typically completes within minutes for most instance sizes, as the operation leverages the underlying storage layer to apply the backup snapshot directly to the existing persistent disk.

Answer

Create a new instance from the backup, then rename and delete the old instance

Answer

Use point-in-time recovery to restore to a time before corruption

Answer

Export the backup to Cloud Storage and import into the existing instance

Question 9

A company runs a stateful application on Compute Engine with persistent disks. They want to ensure data durability across a zone failure. What is the best approach?

Accepted Answer

Use regional persistent disks. Regional persistent disks (RPDs) synchronously replicate data between two zones in the same region, providing an RPO of zero and automatic failover without application-level changes. This ensures data durability across a zone failure while maintaining consistent performance and low latency.

Answer

Replicate data at application level to another instance in a different zone

Answer

Use Google Cloud NetApp Volumes with replication

Answer

Take regular snapshots of the persistent disks and store them in a multiregional bucket

Question 10

A company wants to improve the reliability of their microservices architecture on Google Cloud. Which TWO practices should they implement? (Choose 2)

Accepted Answer

Implement retry with exponential backoff. B is correct because implementing retry with exponential backoff allows transient failures (e.g., network timeouts, temporary service unavailability) to be handled gracefully by automatically retrying the request after increasing delays, reducing load on the recovering service. This pattern is essential in microservices on Google Cloud to improve reliability without overwhelming downstream dependencies.

Answer

Design with a single point of failure for simplicity

Answer

Use synchronous communication between all services

Answer

Disable health checks to reduce latency

Question 11

A team is designing a disaster recovery (DR) plan for a critical application. Which THREE components are essential for a robust DR plan? (Choose 3)

Accepted Answer

Failover procedures and runbooks. Failover procedures and runbooks (A) are essential because they provide step-by-step instructions for executing a controlled transition to the secondary site, ensuring minimal downtime and consistent recovery actions. Without documented runbooks, teams risk misconfigurations during a disaster, which can extend recovery time objectives (RTO) beyond acceptable limits.

Answer

A single-region deployment for consistency

Answer

Load testing to validate performance

Question 12

A company wants to monitor the health of their Cloud Run services. Which THREE metrics should they use to define a comprehensive health SLI? (Choose 3)

Accepted Answer

Latency (e.g., p99 response time). Latency (p99 response time) is a critical metric for Cloud Run because it measures the end-to-end request processing time, directly reflecting user experience. In a serverless environment, high latency can indicate cold starts, insufficient concurrency, or downstream service bottlenecks, making it essential for a comprehensive health SLI.

Answer

CPU utilization

Answer

Instance count

Question 13

A company is deploying a critical application on Compute Engine with an HTTP load balancer. They want to ensure that if an instance health check fails, traffic is automatically rerouted to healthy instances. Which configuration should they implement?

Accepted Answer

Use an HTTP(S) load balancer with a backend service configured with a health check and enable connection draining.. An HTTP(S) load balancer with a backend service configured with a health check automatically monitors instance health and reroutes traffic away from unhealthy instances. Enabling connection draining ensures that in-flight requests to an unhealthy instance are given time to complete before the instance is removed from the load balancing pool, preventing disruption to active sessions.

Answer

Use an internal load balancer with a backend service configured with a health check.

Answer

Use a network load balancer with a health check configured on the target pool.

Answer

Use an HTTP(S) load balancer with a backend service configured with a health check and enable session affinity.

Answer

Use a TCP proxy load balancer with a backend service configured with a health check.

Question 14

A financial services company runs a stateful backend service on Google Kubernetes Engine (GKE) using StatefulSets with Persistent Volumes. They observe that after a node failure, the pod is rescheduled on a different node but the Persistent Volume cannot be attached because it is still "released" and not "available". What is the most likely cause and solution?

Accepted Answer

The PersistentVolume has retain policy "Retain"; manually delete and recreate the volume.. When a PersistentVolume (PV) has a reclaim policy of 'Retain', after the PersistentVolumeClaim (PVC) is deleted, the PV enters a 'Released' state and is not automatically recycled for reuse. The underlying storage resource (e.g., a Compute Engine persistent disk) still exists but the PV cannot be re-attached until an administrator manually deletes the PV and recreates it, or edits the PV to remove the claim reference. This explains why the pod rescheduled on a new node cannot attach the volume.

Answer

The PersistentVolume has reclaim policy "Recycle"; it is not supported in GKE.

Answer

The PersistentVolumeClaim was not created with the correct storage class; recreate with reclaim policy "Delete".

Answer

The PersistentVolumeClaim's access mode is ReadWriteOnce, which prevents attachment to a new node; change to ReadWriteMany.

Answer

The PersistentVolume has reclaim policy "Retain" and the previous pod's volume attachment is not cleared; use a StatefulSet with volumeClaimTemplates and reclaim policy "Delete".

Question 15

A startup runs a web application on App Engine standard environment. They want to ensure the application can handle sudden traffic spikes without manual intervention. Which App Engine feature should they configure?

Accepted Answer

Automatic scaling with a maximum number of idle instances.. App Engine's automatic scaling with a maximum number of idle instances is designed to handle sudden traffic spikes by dynamically creating and removing instances based on request load. This configuration allows the application to scale up quickly when traffic increases, ensuring responsiveness without manual intervention, while the maximum idle instances setting prevents over-provisioning and controls costs.

Answer

Manual scaling with a fixed number of instances.

Answer

Basic scaling with automatic instance creation.

Answer

Resident instances with a minimum number of always-on instances.

Answer

Custom scaling based on CPU utilization.