PCD Practice Test 2 — 25 Questions

Question 1

A company is running a global application on Cloud Spanner. They notice high write latency on a specific table because a frequently updated row is being accessed by many clients simultaneously. Which design pattern should they implement to distribute writes across multiple nodes and reduce contention?

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

Accepted Answer

Add a hash suffix to the primary key of the hot row to split it into multiple rows.. Adding a hash suffix to the primary key of the hot row splits the single heavily contended row into multiple logical rows, each with a different primary key. This distributes the write load across multiple Cloud Spanner splits and nodes, reducing lock contention and write latency. Cloud Spanner uses a distributed, synchronous replication architecture where a single row is managed by a single split; splitting the hot row into multiple rows allows parallel writes to different splits.

Answer

Increase the number of nodes in the Cloud Spanner instance.

Answer

Use interleaved tables to co-locate related data.

Answer

Migrate the table to Cloud Bigtable which handles hotspots better.

Question 2

A company is migrating a MySQL 5.7 database to Cloud SQL for MySQL 8.0. They use MyISAM tables and utf8 charset. What changes must they make during migration?

Accepted Answer

Convert MyISAM tables to InnoDB and change charset from utf8 to utf8mb4.. Cloud SQL for MySQL 8.0 does not support the MyISAM storage engine, so tables must be converted to InnoDB. Additionally, MySQL 8.0 defaults to utf8mb4 and deprecates the legacy utf8 (which is actually utf8mb3, limited to 3 bytes), so the charset must be migrated to utf8mb4 to support full Unicode including emoji and supplementary characters. Both changes are mandatory.

Answer

Convert MyISAM to InnoDB only; utf8 is fine in MySQL 8.0.

Answer

No changes needed; Cloud SQL automatically converts MyISAM to InnoDB and utf8 to utf8mb4.

Answer

Change charset to utf8mb4 only; MyISAM is supported in Cloud SQL.

Question 3

A company is migrating an on-premises MySQL 5.7 database to Cloud SQL for MySQL 8.0. The database includes MyISAM tables. What is the required action for these tables?

Accepted Answer

Convert MyISAM tables to InnoDB. Cloud SQL for MySQL 8.0 does not support the MyISAM storage engine; it only supports InnoDB. Therefore, before migrating, MyISAM tables must be converted to InnoDB. This conversion is required for compatibility and to leverage Cloud SQL's features such as automated backups, replication, and point-in-time recovery.

Answer

Use a MySQL 5.7 compatible Cloud SQL instance

Answer

Keep MyISAM tables as is

Answer

Migrate to Cloud Spanner instead

Question 4

Drag and drop the steps to configure a Cloud CDN with a Cloud Load Balancer in the correct order.

Accepted Answer

Create a Cloud Storage bucket, then create an external HTTP(S) load balancer with the bucket as a backend, then enable Cloud CDN on the backend bucket, then update DNS records to point to the load balancer's IP.. Cloud CDN is enabled on a backend bucket of a load balancer, then DNS is configured.

Answer

Create a Cloud Storage bucket, then enable Cloud CDN on the bucket, then create an external HTTP(S) load balancer with the bucket as a backend, then update DNS records.

Answer

Create an external HTTP(S) load balancer, then create a Cloud Storage bucket, then enable Cloud CDN on the bucket, then update DNS records.

Answer

Enable Cloud CDN on a bucket, then create an external HTTP(S) load balancer, then add the bucket as a backend, then update DNS records.

Question 5

Which three are valid ways to authenticate a service account when using the Google Cloud client libraries? (Choose three.)

Accepted Answer

Attaching a service account to a Compute Engine instance and letting the metadata server provide credentials.. Options A, B, and D are correct. These are standard methods for Application Default Credentials (ADC). Attaching a service account to a Compute Engine instance allows the metadata server to provide credentials (A). Setting the GOOGLE_APPLICATION_CREDENTIALS environment variable to point to a service account key file is another valid method (B). Using the gcloud CLI default application credentials is also a valid approach (D). Option C is incorrect because OAuth 2.0 client IDs for web applications are used for user authentication, not service account authentication. Option E is incorrect because API keys are not used for service account authentication; they are used for simple API access without a service account.

Answer

Using OAuth 2.0 client IDs for web applications.

Answer

Using an API key in the client library initialization.

Question 6

You are deploying a Node.js application on Cloud Run. The container image is stored in Artifact Registry. After deploying with gcloud run deploy, the revision fails with 'Container failed to start. Failed to start and then listen on the port defined by the PORT environment variable.' The application listens on port 8080 by default. The Dockerfile uses EXPOSE 8080. The Cloud Run service is configured with container port 8080. You have verified that the container starts locally using docker run -p 8080:8080. What is the most likely cause of the startup failure?

Accepted Answer

The application is hardcoded to listen on port 8080 but the Cloud Run environment variable PORT may override it to a different value.. Cloud Run injects a PORT environment variable that the container must listen on; the application is hardcoded to 8080, so if Cloud Run sets PORT to a different value (e.g., 8081), the app listens on the wrong port and fails the health check. The error message explicitly references the PORT environment variable, indicating the app ignored it. Since the container works locally with port 8080, the issue is the mismatch between the hardcoded port and the dynamically assigned PORT.

Answer

The application is trying to bind to a privileged port.

Answer

The Cloud Run service is configured with container port 443 by default.

Answer

The container does not have a proper HEALTHCHECK instruction.

Question 7

A team is deploying a microservice on Cloud Run that requires environment variables with sensitive information, such as database passwords. What is the recommended way to provide these secrets?

Accepted Answer

Use Secret Manager to store the secrets and refer to them in the Cloud Run service.. Secret Manager is Google Cloud's dedicated service for securely storing and managing sensitive data like API keys and database passwords. Cloud Run natively integrates with Secret Manager, allowing you to reference secret versions by name in your service configuration without exposing the secret value in plaintext. This approach ensures secrets are encrypted at rest and in transit, and access can be tightly controlled via IAM permissions.

Answer

Inject them directly in the Cloud Run YAML configuration.

Answer

Embed them in the container image as environment variables.

Answer

Store them in a Cloud Storage bucket and mount as a volume.

Question 8

Which THREE are valid approaches for automating testing in a Cloud Build CI pipeline?

Accepted Answer

Use Cloud Build triggers to run tests on every push to a branch.. Option B is correct because Cloud Build triggers (e.g., a push trigger on a branch) can automatically start a build that executes test steps whenever code is pushed, which is a standard CI testing approach. Option D is correct because Cloud Build supports multiple steps in a build config, and steps run in parallel by default unless you declare waitFor dependencies, so tests can be distributed across parallel steps for faster feedback. Option E is correct because a build step can use a custom builder image (referenced via the 'name' field in cloudbuild.yaml) that contains your test framework and commands, allowing arbitrary test execution inside the pipeline. Option A is not a valid testing approach because Cloud Monitoring is for metrics, dashboards, and alerting, not for shipping or executing test results as part of CI. Option C is not a valid Cloud Build testing approach because Cloud Build does not natively gate steps on manual approval; approvals are handled by external systems or release pipelines, not as a built-in Cloud Build test mechanism.

Answer

Use Cloud Build to ship test results to Cloud Monitoring.

Answer

Use Cloud Build to run tests only after manual approval.

Question 9

A company wants to run hybrid transactional/analytical processing (HTAP) workloads on a PostgreSQL-compatible database with built-in columnar engine for faster analytical queries. Which Google Cloud database should they choose?

Accepted Answer

AlloyDB. AlloyDB is a PostgreSQL-compatible database service with a built-in columnar engine that accelerates analytical queries by storing data in columns rather than rows, enabling HTAP workloads without needing to move data between separate transactional and analytical systems. Its architecture decouples compute from storage and uses a columnar cache to deliver up to 100x faster analytical queries than standard PostgreSQL, making it the correct choice for HTAP on Google Cloud.

Answer

Cloud SQL for PostgreSQL

Answer

Cloud Spanner

Answer

BigQuery

Question 10

A developer wants to automatically detect and capture application errors in a production environment on Google Cloud. Which two Google Cloud services should be enabled? (Choose two.)

Accepted Answer

Cloud Error Reporting. Cloud Error Reporting aggregates and displays application errors in real time, allowing developers to automatically detect and capture errors in production. Cloud Logging stores all application logs, which Error Reporting uses as a source to identify and analyze error events. Together, they provide a complete solution for error detection and capture without manual intervention.

Answer

Cloud Trace

Answer

Cloud Profiler

Answer

Cloud Debugger

Question 11

A developer notices that a Cloud Function is timing out after 60 seconds. The function makes an external API call that occasionally takes longer than the timeout. What is the best practice to handle this?

Accepted Answer

Increase the timeout for the specific Cloud Function to a higher value. Cloud Functions have a configurable timeout per function (up to 540 seconds for HTTP functions). Increasing the timeout for the specific function that makes the slow external API call directly addresses the timeout issue without affecting other functions or introducing unnecessary retry overhead. This is the most targeted and efficient solution.

Answer

Implement retry logic without changing the timeout

Answer

Increase the timeout for all Cloud Functions in the project

Answer

Decrease the timeout to fail fast and implement retry logic

Question 12

A company is migrating a monolithic Java application to microservices on Google Kubernetes Engine (GKE). The application uses a shared MySQL database. The team wants to adopt a testing strategy that validates service interactions without deploying to a full cluster. Which testing approach is most appropriate?

Accepted Answer

Consumer-driven contract testing with tools like Spring Cloud Contract.. Consumer-driven contract testing (CDC) with tools like Spring Cloud Contract validates the interactions between microservices by defining and verifying API contracts (e.g., request/response formats, headers, status codes) without requiring a full GKE cluster. This approach is ideal for a migration from a monolithic Java application because it ensures that each service adheres to its expected behavior when communicating over HTTP or messaging, catching integration issues early in the development cycle. It does not require deploying to a cluster, making it faster and more lightweight than end-to-end testing.

Answer

Load testing to simulate production traffic.

Answer

Unit testing with mocked dependencies.

Answer

End-to-end testing in a staging environment.

Question 13

A company is using Cloud Run for a stateless API. They want to ensure that the service can handle sudden traffic spikes. Which two features should they configure?

Accepted Answer

Enable container concurrency.. Enabling container concurrency allows a single Cloud Run container instance to handle multiple requests simultaneously, up to the configured concurrency limit (default 80, max 1000). This improves throughput and resource utilization during traffic spikes without requiring additional instances. Option D is correct because setting max instances to a high value ensures the service can scale out to handle sudden load by creating more container instances, up to the configured maximum, preventing cold starts and request queuing.

Answer

Use Cloud Load Balancing.

Answer

Enable CPU always on allocation.

Answer

Set min instances to zero to save cost.

Question 14

You want to identify performance bottlenecks in your application's code, such as functions consuming excessive CPU. Which Google Cloud tool should you use?

Accepted Answer

Cloud Profiler. Cloud Profiler is the correct tool because it continuously gathers CPU and memory usage data from your application's functions and methods, presenting a flame graph or call graph that pinpoints which code paths consume the most resources. This allows you to identify performance bottlenecks like functions consuming excessive CPU without adding significant overhead to your production environment.

Answer

Cloud Monitoring

Answer

Cloud Trace

Answer

Cloud Logging

Question 15

A company is migrating a 500 GB MySQL database to Cloud SQL for MySQL 8.0. They want to test the migration with minimal risk before the final cutover. Which TWO testing approaches should they use?

Accepted Answer

Set up shadow writes to dual-write to both source and target databases.. Option A is correct because shadow writes (dual-writing to both the source and the Cloud SQL target) let the team validate write-path compatibility, replication fidelity, and application behavior against MySQL 8.0 in production-like conditions without exposing users to the new database, which directly supports low-risk testing before cutover. Option C is correct because running comparison queries on a snapshot of data from both databases verifies data consistency and correctness (row counts, checksums, key business queries) after a test migration, catching transformation or replication discrepancies before the final cutover. Option B is not appropriate because synthetic-data load testing alone does not validate real data fidelity or application compatibility with the actual 500 GB dataset. Option D is not a testing approach for validating the migration; migrating only the schema with Database Migration Service tests connectivity and DDL compatibility but not data movement or application behavior. Option E is a prudent risk-management step, but a rollback plan is not a migration testing approach and does not itself validate the migration.

Answer

Perform load testing using synthetic data only.

Answer

Use Database Migration Service to migrate only the schema first.

Answer

Create a rollback plan before starting migration.

Question 16

A company is designing a microservices application. They want to ensure that if one service fails, it does not cascade to other services. Which pattern should they implement?

Accepted Answer

Circuit Breaker. The Circuit Breaker pattern is the correct choice because it prevents cascading failures by monitoring service calls and opening the circuit when failures exceed a threshold, allowing the system to fail fast and avoid resource exhaustion. This pattern directly addresses the requirement to isolate failures between microservices, ensuring that a failure in one service does not propagate to others.

Answer

Auto-scaling

Answer

Retry with exponential backoff

Answer

Load shedding

Question 17

Match each Cloud Storage class to its typical use case.

Accepted Answer

Standard: Frequently accessed data. Cloud Storage classes optimize cost based on access frequency. Standard is for hot data, Nearline for monthly, Coldline for quarterly, and Archive for yearly access. Common mistakes involve confusing the frequency thresholds.

Answer

Standard: Data accessed less than once a year

Answer

Nearline: Data accessed less than once a quarter

Question 18

Which THREE are best practices for building applications on GKE? (Choose three.)

Accepted Answer

Set resource requests and limits for CPU and memory. Option A is correct because setting CPU and memory requests lets the scheduler place pods on nodes with sufficient capacity, while limits prevent a single container from starving others and enable proper QoS classes and autoscaling decisions. Option C is correct because readiness probes ensure traffic only reaches containers that are ready to serve, and liveness probes let kubelet restart containers that are stuck or deadlocked, improving availability and reliability. Option E is correct because Google-managed SSL certificates integrate with GKE Ingress to automatically provision and renew TLS certificates for HTTPS, reducing operational overhead and avoiding expired-certificate outages. Option B is not a best practice because pinning pods to specific node instances via nodeSelector reduces scheduling flexibility and resilience, and performance consistency is better achieved with node affinity, taints/tolerations, or dedicated node pools. Option D is not a best practice because StatefulSets are intended for stateful workloads needing stable identities and persistent storage, while stateless applications should generally use Deployments for simpler scaling and rolling updates.

Answer

Use nodeSelector to pin pods to specific node instances for performance consistency

Answer

Use StatefulSets for all applications to preserve state across restarts

Question 19

A developer is writing a Cloud Function in Node.js that is triggered by HTTP. They want to test the function locally by sending an HTTP request. Which tool should they use?

Accepted Answer

The Functions Framework for Node.js.. The Functions Framework for Node.js allows developers to run HTTP-triggered Cloud Functions locally. It starts a local server that listens for HTTP requests and invokes the function, mimicking the production environment. This enables quick iteration and testing without deployment. Other options reference non-existent emulators or commands that require deployment, so they are not suitable for local testing.

Answer

The gcloud functions invoke command.

Answer

The Cloud Run emulator.

Answer

The Cloud Functions emulator.

Question 20

A developer is building a containerized application that will be deployed to Google Kubernetes Engine (GKE). They want to run unit tests for a Go package that interacts with the Kubernetes API. Which approach should they use to test the code without a running cluster?

Accepted Answer

Use the client-go library's fake clientset to simulate Kubernetes API interactions, and write tests that use the fake clientset to verify behavior.. The client-go library includes a fake clientset that implements the Kubernetes API interfaces. It allows you to simulate API operations, such as creating, updating, and deleting resources, without a real cluster. Tests can use the fake clientset to verify that the code interacts with the API correctly, including error handling. This approach is fast, reliable, and does not require external dependencies.

Answer

Use the kubectl proxy command to create a local proxy to a remote cluster, and point the tests to the proxy.

Answer

Start a local Kubernetes cluster using Minikube and run the tests against it, then tear it down after the tests complete.

Answer

Mock the HTTP calls to the Kubernetes API server using a library like httptest, and return predefined JSON responses.