PCD Practice Test 48 — 15 Questions

Question 1

A company deploys a stateful application on GKE using a StatefulSet with PersistentVolumeClaims (PVCs). After a node failure, the pod is rescheduled to another node but the PVC remains in 'Pending' state. What is the most likely reason?

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

Accepted Answer

The PV's claimRef still points to the old PVC UID and is in Released state.. When a StatefulSet pod is rescheduled after a node failure, the original PersistentVolume (PV) may remain in a 'Released' state if its claimRef still points to the old PersistentVolumeClaim (PVC) UID. The PV cannot be re-bound to the new PVC (which has a different UID) until the claimRef is cleared, causing the PVC to remain 'Pending'. This is a known behavior in Kubernetes where PVs are not automatically recycled for reuse with a new PVC UID.

Answer

The PVC is bound to a PV that is still attached to the failed node.

Answer

The StorageClass has reclaimPolicy: Delete so the PV was deleted.

Answer

The StatefulSet's pod management policy prevents reattachment.

Question 2

During a deployment to App Engine flexible environment, the new version fails to start and the logs show 'Container failed to start: context deadline exceeded'. The previous version remains serving traffic. What is the most likely cause?

Accepted Answer

The container startup time exceeds the 10-minute timeout.. The error 'context deadline exceeded' in App Engine flexible environment indicates that the container did not start within the allowed startup timeout. The default timeout for container startup in App Engine flexible is 10 minutes, and if the application takes longer (e.g., due to slow initialization, large dependency downloads, or database migrations), the platform kills the container and logs this error. The previous version continues serving because the new version failed to become healthy.

Answer

The health check is misconfigured, causing the instance to be considered unhealthy.

Answer

The app requires an environment variable that is not set.

Answer

The Dockerfile has a syntax error that prevents the container from building.

Question 3

A developer is writing unit tests for a Python application that will run on Cloud Functions. The function makes HTTP requests to an external API. The developer wants to avoid making actual network calls during tests. What should the developer use?

Accepted Answer

Mock the HTTP requests using a library like unittest.mock.. `unittest.mock` allows the developer to replace the actual HTTP request calls (e.g., `requests.get`) with mock objects that return controlled responses, preventing any real network traffic. This is essential for unit testing Cloud Functions where external API calls must be isolated to ensure tests are fast, deterministic, and do not depend on external services.

Answer

Use a test double to replace the entire function.

Answer

Use dependency injection to pass a fallback URL.

Answer

Deploy the function to Cloud Functions and run integration tests.

Question 4

A company runs a microservices architecture on GKE with gRPC services. They want to implement traffic splitting for canary deployments. Which THREE components should they use?

Accepted Answer

Istio or Anthos Service Mesh. Istio or Anthos Service Mesh provides fine-grained traffic splitting capabilities for canary deployments in a GKE environment. It uses Envoy sidecar proxies to route a percentage of traffic to different service versions based on HTTP headers or weight, enabling controlled rollouts without modifying application code.

Answer

ClusterIP service

Answer

Headless service

Question 5

A developer is deploying a Python web application to App Engine Flexible Environment. The application requires a specific third-party binary that is not pre-installed on the runtime image. Which two steps should the developer take to ensure the binary is available? (Choose two.)

Accepted Answer

Use a startup script in the app.yaml to install the binary.. App Engine Flexible Environment supports a `startup_script` field in `app.yaml` that runs shell commands during instance initialization, allowing installation of third-party binaries. Option E is correct because using a custom runtime with a Dockerfile gives full control over the base image and dependencies, enabling the developer to install any required binary via `RUN` commands.

Answer

Configure a VM-level startup script in the Google Cloud Console.

Answer

Specify the binary as a dependency in the requirements.txt file.

Answer

Include the binary in the application's Git repository and reference it in the app.yaml.

Question 6

Your application writes structured logs to Cloud Logging. You want to create a metric that counts log entries with a specific severity level, then alert when the count exceeds a threshold. What should you do?

Accepted Answer

Create a log-based metric using the Logs Explorer, then set up an alerting policy.. Log-based metrics in Cloud Logging allow you to define a counter metric based on log entries matching a filter (e.g., severity=ERROR). Once the metric is created, you can set up an alerting policy in Cloud Monitoring to trigger when the count exceeds a threshold. This approach is native, serverless, and requires no custom code or external exports.

Answer

Use Cloud Monitoring's custom metrics API to write the count.

Answer

Export logs to BigQuery and analyze there.

Answer

Use Cloud Logging's metrics dashboard.

Question 7

A developer wants to deploy a Cloud Function that connects to a Cloud SQL database. What is the simplest way to securely inject database credentials?

Accepted Answer

Use Secret Manager to store and access the database password.. Secret Manager provides a secure, centralized service for storing sensitive data like database passwords, and the Cloud Function can access the secret at runtime via the Secret Manager API or by mounting it as a volume. This avoids hardcoding credentials in code or environment variables, which can be exposed in logs or source control. It is the simplest and most secure approach recommended by Google Cloud for injecting database credentials into Cloud Functions.

Answer

Store credentials in the Cloud Function code as environment variables.

Answer

Use Cloud Key Management Service to encrypt credentials and pass them via HTTP headers.

Answer

Embed credentials in the database connection string in the source code.

Question 8

You are designing a data pipeline that ingests streaming data from IoT devices using Cloud IoT Core, processes it with Dataflow, and stores results in BigQuery. The data volume is expected to be 10 GB per day with occasional spikes. You need to minimize processing latency and cost. Which configuration should you choose for the Dataflow pipeline?

Accepted Answer

Use streaming mode with streaming engine enabled and 2 workers.. Streaming mode with Streaming Engine is designed for low-latency, continuous data ingestion from IoT Core, and setting 2 workers minimizes cost while handling the expected 10 GB/day volume with occasional spikes through autoscaling. Streaming Engine offloads state management to the backend, reducing worker overhead and improving latency, making it ideal for this use case. Option B (Dataflow Prime) is not optimal because, although it supports both batch and streaming pipelines and offers automatic optimization, for a small, predictable workload like 10 GB/day, the overhead of Prime's automation may not justify the cost. Manual tuning with Streaming Engine and a small initial worker count is more cost-effective while still providing low latency. Autoscaling can handle spikes without over-provisioning, making C a better fit.

Answer

Use streaming mode with autoscaling and maximum workers set to 10.

Answer

Use Dataflow Prime for automatic optimization.

Answer

Use batch mode with a fixed number of workers to reduce cost.

Question 9

A financial services company runs a transaction processing microservice on Google Kubernetes Engine (GKE). The service uses Cloud Spanner as its database. After migrating from Cloud SQL to Spanner to improve scalability, the team notices that a small percentage of transactions fail with an 'ABORTED' error due to deadlock detection. The application currently performs no retries, and the failures cause customer-facing errors. The team also observes that under peak load, transaction latencies are around 500ms, which is acceptable but they want to ensure the system remains reliable. They need to implement a solution that minimizes failures while maintaining acceptable performance. Which course of action should they take?

Accepted Answer

Implement retry logic with exponential backoff and random jitter for aborted transactions.. In Cloud Spanner, 'ABORTED' errors due to deadlock detection are a normal part of the optimistic concurrency control mechanism. The correct solution is to implement retry logic with exponential backoff and random jitter, as recommended by Google's own documentation. This approach transparently handles transient deadlocks without requiring infrastructure changes or sacrificing consistency, and it maintains acceptable latency by spacing out retries.

Answer

Increase the number of Spanner nodes to reduce the probability of deadlocks.

Answer

Reduce the size of each transaction by splitting them into smaller ones.

Answer

Change the transaction isolation level to READ UNCOMMITTED to avoid deadlocks.

Question 10

You need a fully managed, relational OLTP database that is PostgreSQL-compatible and can run analytical queries on the same data without extract-transform-load (ETL). Which Google Cloud database should you use?

Accepted Answer

AlloyDB. AlloyDB is a fully managed, PostgreSQL-compatible database service designed for both transactional (OLTP) and analytical workloads on the same data without requiring ETL. It achieves this through its AlloyDB Columnar Engine, which automatically accelerates analytical queries by storing data in a columnar format while maintaining full PostgreSQL compatibility for OLTP operations.

Answer

Cloud Bigtable

Answer

Cloud SQL for PostgreSQL

Answer

Cloud Spanner

Question 11

An e-commerce company wants to use Cloud SQL for PostgreSQL with high availability (HA) in the same region. What is the RPO (Recovery Point Objective) of Cloud SQL HA configuration?

Accepted Answer

0 (zero). Cloud SQL uses synchronous replication to a standby instance in the same zone/region, ensuring zero data loss on failover.

Answer

Up to 1 hour

Answer

Up to 5 minutes

Answer

Depends on the database size

Question 12

A financial services company is building a global payment system that requires strong ACID transactions across multiple regions, with 99.999% availability and automatic failover. Which Google Cloud database should they choose?

Accepted Answer

Cloud Spanner. Cloud Spanner is the only Google Cloud database that provides strong ACID transactions across multiple regions with 99.999% availability and automatic failover. It uses a globally distributed architecture with synchronous replication and the TrueTime API to ensure external consistency, making it ideal for a global payment system that requires strict consistency and high availability.

Answer

AlloyDB with cross-region replicas

Answer

Cloud SQL with cross-region replicas

Answer

Firestore in Native mode

Question 13

Which TWO Google Cloud services can be used to build a data pipeline that transforms and moves data between different databases? (Select 2)

Accepted Answer

Dataflow. Dataflow is a serverless, fully managed service for executing Apache Beam pipelines, which can read from and write to various databases (e.g., Cloud Spanner, BigQuery, Cloud SQL) while performing transformations in a unified streaming or batch model. It is specifically designed for data movement and transformation between different data sources and sinks, making it a correct choice for building a data pipeline that transforms and moves data between databases.

Answer

Cloud Scheduler

Answer

Memorystore

Answer

Cloud SQL Proxy

Question 14

A development team is using Cloud Monitoring to set up an alerting policy for a Compute Engine instance. They want to be notified when the instance's CPU utilization exceeds 80% for at least 5 minutes. Which alerting policy configuration should they use?

Accepted Answer

Condition type: Metric Threshold, Trigger: For 5 minutes, Threshold: 80%. Cloud Monitoring alerting policies use a Metric Threshold condition type to evaluate a metric against a static threshold. Setting the trigger to 'For 5 minutes' ensures the condition is met only when the CPU utilization exceeds 80% consistently over the specified duration, preventing false alarms from transient spikes.

Answer

Condition type: Metric Threshold, Trigger: For most recent value, Threshold: 80%

Answer

Condition type: Change Rate, Trigger: For 5 minutes, Threshold: 80%

Answer

Condition type: Metric Absence, Duration: 5 minutes

Question 15

An e-commerce platform uses Cloud SQL for PostgreSQL for its inventory database. To meet a higher availability requirement, they decide to enable the HA configuration. What is the expected recovery point objective (RPO) with Cloud SQL HA?

Accepted Answer

0 (zero). Cloud SQL for PostgreSQL HA uses synchronous replication to a standby instance in a different zone within the same region. This ensures that every write transaction is committed on both the primary and standby before acknowledging the client, resulting in zero data loss upon failover. Therefore, the RPO is 0 (zero).

Answer

Depends on the replication lag

Answer

Up to 5 minutes

Answer

Up to 1 minute