PCD Practice Test 31 — 15 Questions

Question 1

A company deploys a microservices application on Google Kubernetes Engine (GKE). The operations team needs to monitor API latency between services. Which Google Cloud service should they use to trace requests across services?

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

Accepted Answer

Cloud Trace. Cloud Trace is the correct choice because it is a distributed tracing system designed to capture latency data as requests propagate through microservices. It provides end-to-end visibility by collecting trace spans from each service, allowing the operations team to identify bottlenecks and measure API latency between services in a GKE environment.

Answer

Error Reporting

Answer

Cloud Logging

Answer

Cloud Monitoring

Question 2

You need a caching layer for a web application that handles high read traffic. The cache must support pub/sub messaging for cache invalidation across multiple servers. Which service should you use?

Accepted Answer

Memorystore for Redis. Memorystore for Redis is the correct choice because Redis natively supports pub/sub messaging, which enables cache invalidation notifications across multiple application servers. This allows each server to subscribe to channels and receive real-time invalidation messages, ensuring cache consistency in a distributed environment. Memcached, in contrast, lacks pub/sub capabilities, making it unsuitable for this requirement.

Answer

Cloud Bigtable

Answer

Memorystore for Memcached

Answer

Firestore

Question 3

A company needs to run AlloyDB on-premises to maintain data sovereignty while leveraging the same management APIs as in Google Cloud. Which AlloyDB offering should they use?

Accepted Answer

AlloyDB Omni. AlloyDB Omni is designed for on-premises deployment with the same AlloyDB engine, managed via Google Cloud’s APIs or CLI. AlloyDB clusters are cloud-only. Cloud SQL is a different service. Bigtable Omni is for Bigtable, not AlloyDB.

Answer

Cloud SQL for PostgreSQL with HA

Answer

Bigtable Omni

Answer

AlloyDB cluster with cross-region replication

Question 4

An engineer is deploying a Cloud SQL for SQL Server instance and wants to automatically increase storage when the disk usage reaches a threshold. Which flag should they set?

Accepted Answer

Enable 'automatic storage increase'. Cloud SQL supports the 'storage auto-increase' flag. When enabled, Cloud SQL automatically increases storage size in small increments when free space is low. This is set at instance creation or update.

Answer

Set 'disk size' to unlimited

Answer

Configure 'storage tier' to auto-scale

Answer

Use 'persistent disk auto-resize'

Question 5

A company's Firestore security rules are too permissive, allowing all users to read and write any document. They need to restrict access so that only authenticated users can read and write their own data. Which rule structure should they use?

Accepted Answer

Allow read/write if request.auth.uid == resource.data.user_id;. Firestore security rules can use `request.auth.uid` to verify the authenticated user's identity and `resource.data.user_id` to check ownership. The correct rule ensures that the authenticated user's UID matches the `user_id` field in the document.

Answer

Allow read/write if request.auth != null;

Answer

Allow read/write if request.auth != null && request.auth.uid == resource.id;

Answer

Allow read/write if request.auth.token.email == resource.data.email;

Question 6

A company uses Cloud Bigtable for time-series data. They want to enable disaster recovery with the ability to fail over to another region in minutes. What feature should they enable?

Accepted Answer

Enable Bigtable replication across regions.. Bigtable replication allows you to have multiple clusters in different regions, with automatic replication of data. You can fail over by redirecting traffic to the other cluster. This meets the RTO of minutes.

Answer

Export tables to Cloud Storage and import into another Bigtable instance.

Answer

Configure Bigtable backups and restore in another region.

Answer

Use BigQuery federated queries to access Bigtable data from another region.

Question 7

An organization is migrating an on-premises PostgreSQL database to Cloud SQL. They need minimal downtime and want to use Database Migration Service (DMS) with continuous change data capture (CDC). What is the correct sequence of steps?

Accepted Answer

Create connection profile → start migration job with full dump → CDC phase → promote replica. DMS first creates a connection profile, then starts a migration job performing a full dump, then transitions to CDC, and finally promotes the replica to complete the cutover.

Answer

Create connection profile → start full dump → promote to primary

Answer

Start CDC directly without full dump → promote replica

Answer

Promote replica immediately after creating connection profile

Question 8

An organization needs a globally distributed relational database with strong consistency across regions and the ability to scale horizontally without manual sharding. Which Google Cloud database should they choose?

Accepted Answer

Cloud Spanner. Cloud Spanner is a globally distributed, strongly consistent relational database that scales horizontally. It supports multiple regional configurations and auto-scaling. Bigtable is not relational, Cloud SQL does not scale horizontally, and Firestore is not relational.

Answer

Firestore

Answer

Cloud SQL for MySQL

Answer

Cloud Bigtable

Question 9

Which Google Cloud database service should be used to implement a low-latency session store for a web application that requires pub/sub capabilities and rate limiting?

Accepted Answer

Memorystore for Redis. Memorystore for Redis provides low-latency in-memory data storage with support for pub/sub and rate limiting patterns. It is ideal for session stores.

Answer

Firestore

Answer

Cloud Spanner

Answer

Memorystore for Memcached

Question 10

A company runs a stateless application on Compute Engine behind a load balancer. They want to monitor the number of active requests per instance without adding custom instrumentation. What is the most straightforward approach?

Accepted Answer

Use the load balancer's built-in 'request_count' metric.. The load balancer's built-in 'request_count' metric directly provides the number of active requests per instance without requiring any additional instrumentation or agents. This metric is automatically collected by Cloud Monitoring for Google Cloud HTTP(S) load balancers, making it the most straightforward approach for a stateless application on Compute Engine.

Answer

Configure the Cloud Monitoring agent to collect request metrics.

Answer

Install the Cloud Logging agent and parse access logs.

Answer

Deploy Prometheus and instrument the application.

Question 11

An organization wants to cache frequently accessed session data for a web application to reduce database load. They require sub-millisecond latency and support for pub/sub messaging. Which Google Cloud service should they use?

Accepted Answer

Memorystore for Redis. Memorystore for Redis is the correct choice because it provides an in-memory data store with sub-millisecond latency, ideal for caching frequently accessed session data. It also natively supports pub/sub messaging via Redis's built-in PUBLISH/SUBSCRIBE commands, meeting both requirements precisely.

Answer

Cloud SQL

Answer

Cloud Bigtable

Answer

Firestore

Question 12

You are troubleshooting a performance issue in a microservices application. Which TWO tools from Google Cloud's operations suite would you use to trace a request across services and identify the slowest component?

Accepted Answer

Cloud Monitoring. Cloud Trace is the dedicated Google Cloud service for distributed tracing, capturing latency data as requests propagate through microservices. Cloud Monitoring provides the dashboards and alerting to visualize trace data and pinpoint the slowest component. Together, they enable end-to-end request tracing and performance bottleneck identification.

Answer

Error Reporting

Answer

Cloud Profiler

Answer

Cloud Logging

Question 13

A company needs to run a PostgreSQL-compatible database with 4x faster OLTP performance than standard PostgreSQL, and also wants to run analytical queries on the same data without extracting to a separate system. Which Google Cloud database should they choose?

Accepted Answer

AlloyDB. AlloyDB is a PostgreSQL-compatible database that delivers up to 4x faster OLTP performance than standard PostgreSQL through a combination of a columnar engine, adaptive indexing, and a disaggregated storage architecture. It also supports running analytical queries on the same data without extraction, using its built-in columnar engine for fast analytics on transactional data.

Answer

Cloud Spanner

Answer

Cloud SQL for PostgreSQL

Answer

BigQuery

Question 14

You are designing a global e-commerce application with a product catalog that must be strongly consistent across continents and have 99.999% availability. Transactions must span multiple items and maintain ACID guarantees. Which Google Cloud database should you choose?

Accepted Answer

Cloud Spanner. Cloud Spanner is the only Google Cloud database that offers globally distributed ACID transactions, strong consistency across regions, and a 99.999% SLA. Cloud SQL is regional only, Firestore is eventually consistent across regions, and Bigtable is eventually consistent across clusters.

Answer

Cloud Bigtable

Answer

Cloud SQL for PostgreSQL

Answer

Firestore Native mode

Question 15

Your application running on Google Kubernetes Engine (GKE) is experiencing intermittent latency spikes. You have enabled Cloud Monitoring and Cloud Logging. Which approach would be MOST effective to identify the root cause?

Accepted Answer

Use Cloud Trace to analyze distributed tracing data for slow requests.. Cloud Trace is the most effective tool for identifying intermittent latency spikes because it provides end-to-end distributed tracing, allowing you to pinpoint which specific service or request path is causing the delay. Unlike aggregate metrics or logs, Cloud Trace captures individual request spans and can reveal high-latency operations, such as slow database queries or external API calls, that occur only under certain conditions.

Answer

Increase the number of replicas or switch to a larger machine type.

Answer

Examine CPU and memory utilization metrics in Cloud Monitoring for the GKE cluster.

Answer

Review recent Cloud Logging entries for error messages.