PCDE Practice Exam 53 — 20 Questions

Question 1

Your team has an alerting policy that fires frequently but the on-call engineer has difficulty understanding the impact. You want to add contextual information such as a runbook URL and severity label. What should you do?

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

Accepted Answer

Edit the alert policy documentation field to include a runbook URL and labels. In Google Cloud Monitoring, the alert policy's documentation field is specifically designed to carry human-readable context such as a runbook URL, playbook link, or severity label that appears in the incident/notification payload. Editing this field attaches the context directly to the alert so the on-call engineer sees the runbook and severity when the policy fires. This is the intended mechanism for enriching alert notifications without changing the underlying metric or condition.

Answer

Set a description on the notification channel

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Create a separate alert policy for each severity level

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Add labels to the metric descriptor used in the condition

Question 2

A DevOps engineer wants to implement a GitOps workflow for a GKE cluster using a tool that automatically syncs the cluster state with a Git repository. Which Google Cloud service is designed for this purpose?

Accepted Answer

Config Sync. Config Sync is the Google Cloud service specifically designed to implement a GitOps workflow for GKE clusters. It automatically synchronizes the cluster's desired state (as defined in a Git repository) with the actual cluster state, ensuring continuous reconciliation without manual intervention.

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Cloud Run

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Config Connector

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Cloud Deploy

Question 3

A Cloud Spanner application experiences high write latency on a table with a monotonically increasing primary key. Which schema change will most effectively reduce latency?

Accepted Answer

Modify the primary key to include a hash of the original key as a leading column. Cloud Spanner partitions data by primary key ranges, and a monotonically increasing key (e.g., timestamp or auto-increment) causes all writes to go to the last partition, creating a hotspot. By adding a hash of the original key as a leading column, writes are distributed across multiple partitions, significantly reducing write latency. This is a standard best practice for avoiding hotspots in Spanner.

Answer

Convert the table to an interleaved table

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Add a secondary index on the existing key

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Increase the number of nodes in the instance

Question 4

Your company is deploying a new application on Google Cloud and needs to choose a database solution. The application requires strong transactional consistency, complex SQL queries, and the ability to scale horizontally for read-heavy workloads. Which database service should you recommend?

Accepted Answer

Cloud Spanner. Cloud Spanner is the correct choice because it provides strong transactional consistency (ACID) across globally distributed nodes, supports complex SQL queries with standard SQL syntax, and offers horizontal scaling for read-heavy workloads through automatic sharding and read replicas. Unlike other options, Spanner uniquely combines these three requirements—strong consistency, SQL, and horizontal scaling—in a single managed service.

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BigQuery

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Cloud SQL

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Cloud Firestore

Question 5

A global e-commerce platform uses Cloud Spanner multi-region configuration. The compliance team mandates that all write transactions must be committed in a specific geographic region to comply with data sovereignty laws. Which Spanner feature should be used to enforce this requirement?

Accepted Answer

Set the default leader region to the required region. Setting the default leader region to the required region ensures that all write transactions are committed in that region, satisfying data sovereignty requirements. In a multi-region Spanner instance, the leader region handles writes, while other regions serve reads.

Answer

Enable customer-managed encryption keys (CMEK)

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Use read-only replicas in the required region

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Deploy a regional instance in the required region

Question 6

An SRE wants to measure latency SLI for a web service. Which metric is the BEST indicator of user-perceived performance?

Accepted Answer

Proportion of requests served in under 200ms.. An SLI should measure the user's experience directly. The proportion of requests served under a threshold (e.g., 200ms) is a distribution-based indicator that captures the fraction of users getting an acceptable experience, which aligns with how SREs define latency SLIs in the Google SRE workbook. It is directly actionable and reflects user-perceived performance better than averages or single-point extremes.

Answer

Maximum latency observed in the last 5 minutes.

Answer

Average latency over the last hour.

Answer

99th percentile latency.

Question 7

You are responsible for a Cloud Spanner instance that serves a global user base. A new feature requires adding an index on a column of an existing table that contains millions of rows. The table is actively used by production traffic. What is the recommended approach to add the index with minimal impact?

Accepted Answer

Use the gcloud command 'gcloud spanner databases ddl update' with a CREATE INDEX statement. The operation will be non-blocking and will not impact production traffic.. Cloud Spanner supports online schema changes, including CREATE INDEX, which run asynchronously in the background without locking the table or blocking production traffic. The recommended approach is to issue the DDL via 'gcloud spanner databases ddl update' with a CREATE INDEX statement; Spanner backfills the index while serving reads and writes normally. This is the standard, low-impact method for adding indexes to large, actively used tables.

Answer

Create a second table with the index already defined, then copy the data using batch writes and switch traffic. This avoids any impact to the original table.

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Take a full database backup to Cloud Storage, restore it to a new instance, create the index on the restored instance, and then fail over to the new instance.

Answer

Use the gcloud command 'gcloud spanner databases ddl update' with an ALTER TABLE statement to add the index. This will lock the table briefly but is acceptable.

Question 8

You are designing a database schema for Cloud SQL (MySQL) for an OLTP application. Which normal form is typically recommended to avoid update anomalies?

Accepted Answer

Third Normal Form (3NF). Third Normal Form (3NF) is the standard for OLTP databases to reduce redundancy and avoid update, insert, and delete anomalies.

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Denormalized form

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Second Normal Form (2NF)

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First Normal Form (1NF)

Question 9

A company runs a BigQuery data warehouse. They notice that query performance has degraded over time. The data is loaded daily from Cloud Storage using batch loads. Which action is most likely to improve query performance?

Accepted Answer

Partition and cluster tables based on common query filters.. Partitioning and clustering tables based on common query filters directly reduces the amount of data scanned per query by organizing data into physical segments. In BigQuery, this allows the query engine to prune entire partitions and clusters, significantly lowering I/O and improving performance without additional cost or complexity.

Answer

Increase the number of slots in the reservation.

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Create materialized views for all frequent queries.

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Migrate the data to Cloud SQL for better performance.

Question 10

An organization uses Binary Authorization with Container Analysis to enforce that only images that have passed vulnerability scanning and have been signed by an approved authority can be deployed to GKE. A DevOps engineer notices that an unsigned image is still being deployed. What is the most likely cause?

Accepted Answer

The Binary Authorization admission controller is not enabled on the GKE cluster.. Binary Authorization enforcement requires the admission controller to be enabled on the GKE cluster. Without the admission controller, the cluster will not intercept pod creation requests to verify image attestations, so unsigned images can be deployed regardless of the Binary Authorization policy configuration.

Answer

The Build service account does not have the signer role.

Answer

The image is stored in a different project than the one where Binary Authorization is configured.

Answer

The Container Analysis API is not enabled in the project.

Question 11

A DevOps engineer wants to monitor the CPU utilization of a Compute Engine instance and receive an alert if it exceeds 80% for more than 5 minutes. Which type of metric should be used in the alerting condition?

Accepted Answer

GAUGE. A GAUGE metric represents a value that can go up or down over time, such as CPU utilization, memory usage, or temperature. Alerting on CPU > 80% for 5 minutes requires evaluating the instantaneous value of CPU utilization over a time window, which is exactly what a gauge metric provides. Cloud Monitoring's alerting policies use gauge metrics with a threshold condition and a duration.

Answer

CUMULATIVE

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DELTA

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COUNT

Question 12

An application is emitting custom metrics using OpenTelemetry. You want to collect and export these metrics to Cloud Monitoring. Which TWO components are required? (Select 2)

Accepted Answer

OpenTelemetry SDK in the application. Option D (OpenTelemetry SDK in the application) is correct because the application must be instrumented with the OpenTelemetry SDK to create and emit custom metrics in the OpenTelemetry data model. Option E (OpenTelemetry Collector) is correct because it receives the OTLP metrics from the SDK and exports them to Cloud Monitoring via the Google Cloud exporter, acting as the required collection and export pipeline. Option A (Cloud Logging Agent) is incorrect because it handles log ingestion, not OpenTelemetry metrics. Option B (Cloud Monitoring Agent) is incorrect because the legacy Monitoring agent collects system metrics, not custom OpenTelemetry metrics. Option C (Pub/Sub topic) is incorrect because Pub/Sub is not part of the standard OpenTelemetry-to-Cloud Monitoring metrics path.

Answer

Cloud Logging Agent

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Cloud Monitoring Agent

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Pub/Sub topic

Question 13

A company wants to enforce that only container images signed by their CI/CD pipeline can be deployed to GKE. Which two services should they use together?

Accepted Answer

Binary Authorization and Container Analysis. Binary Authorization enforces that only container images signed by trusted authorities (like a CI/CD pipeline) can be deployed to GKE. Container Analysis (now part of Artifact Analysis) scans images for vulnerabilities and stores attestations, which Binary Authorization uses to verify signatures before allowing deployment. Together, they provide a complete enforcement chain: signing during CI/CD and verification at deploy time.

Answer

Cloud Build and Artifact Registry

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Security Command Center and Artifact Registry

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Cloud Deploy and Cloud Run

Question 14

A Cloud Run service needs to handle background tasks after responding to a client. Which CPU configuration is required to ensure background tasks complete?

Accepted Answer

CPU always-on: true. CPU always-on must be enabled for Cloud Run to run background tasks; otherwise, CPU is throttled after the request is handled.

Answer

Set concurrency to 1

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CPU always-on: false (default)

Answer

Set execution environment to gen1

Question 15

Which TWO best practices should be followed when modeling data for a Looker BI dashboard to optimize query performance?

Accepted Answer

Use persistent derived tables (PDTs) to materialize intermediate results. Persistent Derived Tables (PDTs) materialize intermediate query results into physical tables in the underlying database (e.g., BigQuery). This avoids re-executing complex logic on every user interaction, drastically reducing query latency and cost. PDTs are a core Looker optimization for repeated, heavy transformations.

Answer

Use derived tables for all complex logic

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Use native derived tables to leverage BigQuery's UDFs

Answer

Use materialized views in the underlying database

Question 16

A company is migrating a stateful web application from on-premises to Google Kubernetes Engine (GKE). The application has variable traffic patterns, with occasional spikes. The team wants to optimize performance and availability while minimizing cost during spikes. The application is not fault-tolerant to instance restarts. Which TWO strategies should the team implement? (Choose TWO)

Accepted Answer

Configure pod disruption budgets to ensure a minimum number of pods remain available during node scaling. Option B is correct because a PodDisruptionBudget (PDB) guarantees that a minimum number of pods for the stateful application remain running during voluntary disruptions such as node draining triggered by cluster scaling, which preserves availability for an application that is not fault-tolerant to instance restarts. Option D is correct because the GKE cluster autoscaler automatically adds nodes to the node pool when pods cannot be scheduled due to high utilization, allowing the cluster to absorb traffic spikes while keeping costs lower during idle periods by scaling back down. Option A is incorrect because preemptible (Spot) VMs can be reclaimed at any time, causing abrupt instance restarts that this non-fault-tolerant stateful application cannot tolerate. Option C is incorrect because Vertical Pod Autoscaler in Auto mode evicts and restarts pods to apply new resource requests, which conflicts with the requirement that the application not be restarted. Option E is incorrect because setting the cluster autoscaler scale-down delay to 0 causes overly aggressive node removal, risking disruption to stateful workloads and defeating the availability goal.

Answer

Use preemptible VMs to reduce cost during spikes

Answer

Use Vertical Pod Autoscaler in Auto mode to automatically adjust pod resources without restarts

Answer

Set cluster autoscaler scale-down delay to 0 for immediate cost savings

Question 17

A team is migrating an on-premises PostgreSQL database to Cloud SQL using DMS. They want the migration job to continuously replicate changes after the initial dump. Which type of migration job should they create?

Accepted Answer

Continuous migration job. A continuous migration job in Database Migration Service (DMS) performs an initial full dump and then continuously replicates ongoing changes (via change data capture) from the source to the destination until the job is promoted. This is exactly what the team needs to keep the Cloud SQL target in sync after the initial load. One-time jobs stop after the initial dump and do not replicate subsequent changes.

Answer

One-time migration job

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Scheduled export job

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Bulk load job

Question 18

A startup uses Cloud SQL (MySQL) for a blogging platform. The schema has a table 'posts' with columns: post_id (auto-increment PK), title, content, author_id, created_at. The application frequently runs a query to display the latest 10 posts from a specific author: SELECT * FROM posts WHERE author_id = ? ORDER BY created_at DESC LIMIT 10. This query is slow when an author has thousands of posts. The team wants to optimize this query without changing the application code. What schema change will be most effective?

Accepted Answer

Add a composite index on (author_id, created_at DESC).. A composite index on (author_id, created_at DESC) directly supports the query's WHERE clause on author_id and its ORDER BY created_at DESC, allowing MySQL to seek to the author's rows and read them in already-sorted order without a filesort. This is the most effective schema change because it requires no application code changes and addresses the exact access pattern. Cloud SQL for MySQL supports descending indexes, so the DESC direction is honored.

Answer

Partition the table by author_id using range partitioning.

Answer

Increase the query cache size in Cloud SQL.

Answer

Migrate the posts table to Cloud Spanner and use interleaved indexes.

Question 19

Your team uses Cloud Monitoring to set up an alerting policy for high CPU utilization. You want the policy to trigger only if CPU usage exceeds 80% for at least 5 minutes. Which condition configuration should you use?

Accepted Answer

Set the duration field to 300 seconds. The duration field in a Cloud Monitoring alerting policy condition specifies how long the condition must be met before the alert fires. Setting it to 300 seconds means CPU usage must exceed 80% continuously for 5 minutes before triggering. This is the correct configuration for sustained threshold alerting.

Answer

Set the alignment period to 300 seconds

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Set the forecast horizon to 300 seconds

Answer

Set the retest window to 300 seconds

Question 20

A financial services company uses Cloud Bigtable for real-time fraud detection. They have a cluster with 10 nodes using HDD storage and are experiencing high latency due to disk throughput bottlenecks. They need to improve performance with minimal downtime. What should they do?

Accepted Answer

Create a new cluster with SSD storage, replicate data, then update the application to point to the new cluster. Cloud Bigtable does not support in-place conversion of storage from HDD to SSD. The only way to migrate to SSD storage is to create a new cluster with SSD, replicate data using Bigtable replication, and then update the application connection string to point to the new cluster. This approach minimizes downtime by allowing the old cluster to serve reads during replication.

Answer

Modify the existing cluster's storage type to SSD via the Cloud Console

Answer

Use Cloud Bigtable's hot tablet detection to rebalance the data

Answer

Increase the number of nodes in the existing cluster