PCDE Practice Exam 53 — 20 Questions

Question 1

A DevOps engineer is using Cloud Deploy to promote a release from staging to production. They want to require a manual approval before the release is deployed to production. What should they configure in the delivery pipeline?

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

Accepted Answer

Configure the production target with requireApproval: true.. Cloud Deploy natively supports manual approval gates at the target level. Setting `requireApproval: true` on the production target in the delivery pipeline configuration ensures that a release must receive explicit approval via the Cloud Deploy console or API before it can proceed to that target. This is the intended mechanism for adding a manual approval step without external services or hooks.

Answer

Use a Cloud Build trigger with a manual approval step.

Answer

Add a preDeploy hook to the production target that runs a Cloud Run Job to send a notification.

Answer

Add a postDeploy hook that checks for approval.

Question 2

Which TWO actions can help reduce the number of read replicas needed for a Cloud SQL for PostgreSQL instance that serves a read-heavy workload?

Accepted Answer

Implement connection pooling to reuse database connections.. Connection pooling reduces the overhead of establishing new database connections, which can consume significant CPU and memory resources on the primary instance. By reusing existing connections, the primary instance can handle more read requests without needing additional read replicas to offload the connection management load. This directly reduces the number of replicas required for a read-heavy workload.

Answer

Enable synchronous replication on all read replicas.

Answer

Use smaller machine types for read replicas.

Answer

Increase the max_connections parameter on the primary instance.

Question 3

A data engineering team wants to monitor BigQuery query performance and slot utilization. Which TWO tools or features should they use? (Choose two.)

Accepted Answer

INFORMATION_SCHEMA tables (e.g., JOBS_BY_PROJECT). INFORMATION_SCHEMA tables like `JOBS_BY_PROJECT` provide detailed metadata about query execution, including slot usage, job timing, and user-level performance metrics. This allows the team to analyze historical query performance and identify inefficiencies directly within BigQuery without external tools.

Answer

Cloud Logging (audit logs)

Answer

bq command-line tool with the '--format=prettyjson' flag

Answer

Cloud Profiler

Question 4

A team is migrating from Cloud Deployment Manager to Terraform. They need to manage state for multiple environments (dev, staging, prod) using a single Terraform configuration. Which Terraform feature should they use to achieve this?

Accepted Answer

Use Terraform workspaces, with each workspace mapping to an environment and storing state in the same GCS bucket with workspace-specific prefixes.. Terraform workspaces allow you to manage multiple distinct state files from a single configuration. By mapping each workspace to an environment (dev, staging, prod) and configuring a single GCS backend with workspace-specific prefixes (e.g., `prefix = "terraform/state"`), Terraform automatically stores each workspace's state in a separate path within the same bucket. This enables isolated state management without duplicating configuration code.

Answer

Use Terraform data sources to switch between environments.

Answer

Use Terraform modules with different variable files for each environment.

Answer

Create separate Terraform configurations in separate directories.

Question 5

An SRE team wants to implement error budget burn rate alerts for a service with SLO 99.9% over 30 days. They need to be notified both when the error budget is being consumed rapidly (full consumption in ~2 days) and when it is being consumed slowly (full consumption in ~6 days). Which two alert configurations should they use? (Choose 2)

Accepted Answer

Burn rate threshold: 14, lookback window: 1 hour. The correct choices are B (burn rate 14, window 1 hour) and C (burn rate 5, window 6 hours). These are the standard Google SRE recommended alert configurations for fast and slow error budget burn rate alerts. Option B: With a burn rate of 14 over a 1-hour window, the error budget would be exhausted in approximately 2.14 days (30 days / 14), matching the requirement for rapid consumption (~2 days). Option C: A burn rate of 5 over a 6-hour window exhausts the budget in 6 days (30 days / 5), matching the 'slow' consumption requirement of ~6 days. Option A (2/1) would exhaust in 15 days, too slow for rapid. Option D (10/1) exhausts in 3 days, not fast enough. Option E (14/6) exhausts in 2.14 days but with a longer window, making it less suitable for rapid detection. Therefore, B and C are the correct pair.

Answer

Burn rate threshold: 2, lookback window: 1 hour

Answer

Burn rate threshold: 10, lookback window: 1 hour

Answer

Burn rate threshold: 14, lookback window: 6 hours

Question 6

During an incident, the incident commander notices that multiple teams are working on the same issue without coordination. Which structure should be implemented to improve incident response?

Accepted Answer

Assign a single incident commander to coordinate all teams. An incident command system (ICS) establishes a clear hierarchy with an incident commander who coordinates teams, assigns roles (e.g., operations lead, communications lead), and ensures focused response.

Answer

Use a chatbot to broadcast updates without a commander

Answer

Have each team work independently and report after resolution

Answer

Escalate to the VP of Engineering to make decisions

Question 7

You notice that your Cloud SQL for MySQL instance's storage is filling up quickly. You have enabled automatic storage increase, but you want to manually increase the storage size by 50 GB to avoid any risk of reaching the limit. The current disk size is 200 GB. What is the correct gcloud command to resize the disk?

Accepted Answer

gcloud sql instances patch my-instance --storage-size 250. The `gcloud sql instances patch` command is used to modify an existing Cloud SQL instance, and the `--storage-size` flag expects the value in GB as an integer (without the 'GB' suffix). Specifying `250` correctly increases the storage from 200 GB to 250 GB.

Answer

gcloud sql instances patch my-instance --storage-size 250GB

Answer

gcloud sql instances update my-instance --storage-size 250

Answer

gcloud sql instances resize my-instance 250

Question 8

You are running a Memorystore for Redis instance with a high write volume. You notice that the eviction rate is high and the cache hit ratio has dropped significantly. Which configuration change would most directly reduce the eviction rate?

Accepted Answer

Change maxmemory-policy to allkeys-lru.. Setting `maxmemory-policy` to `allkeys-lru` tells Redis to evict the least recently used keys from the entire keyspace when memory is full. This directly reduces the eviction rate by ensuring that only the least accessed data is removed, preserving the most frequently accessed data and improving the cache hit ratio. In a high-write-volume scenario, this policy adapts to access patterns and minimizes unnecessary evictions of hot data.

Answer

Use many small keys instead of a few large keys.

Answer

Decrease the maxmemory setting to force earlier eviction.

Answer

Set maxmemory-policy to noeviction.

Question 9

A company runs a Spanner instance with a single region configuration. They are experiencing increased latency for writes when there is a network disruption between their application and the Spanner instance. The application is deployed in the same region. What should the database engineer do to minimize write latency during such disruptions?

Accepted Answer

Implement client-side retry logic.. Client-side retry logic is the correct approach because Spanner's built-in retry mechanisms (e.g., gRPC deadlines and backoff) can automatically re-send failed write requests when transient network disruptions occur. By implementing application-level retry with exponential backoff and jitter, the database engineer ensures that write operations are resilient to short-lived network blips without requiring infrastructure changes. This directly minimizes write latency during disruptions by avoiding manual intervention and leveraging Spanner's session-based retry capabilities.

Answer

Enable multi-region configuration.

Answer

Use a compute engine instance as a proxy.

Answer

Increase the number of nodes.

Question 10

A financial BI application stores monetary values such as revenue and tax amounts. Which BigQuery data type should be used to ensure accuracy in calculations?

Accepted Answer

Use NUMERIC or BIGNUMERIC. NUMERIC and BIGNUMERIC are exact numeric types with fixed precision and scale, designed to avoid floating-point rounding errors. In BigQuery, monetary calculations require exact decimal arithmetic, and these types provide up to 38 (NUMERIC) or 76 (BIGNUMERIC) digits of precision, ensuring accuracy for revenue and tax computations.

Answer

Use STRING and parse numbers as needed

Answer

Use INT64 and store amounts in cents

Answer

Use FLOAT64

Question 11

You need to monitor the disk usage of your Cloud SQL instances and receive an alert when disk usage exceeds 80%. Which GCP service should you use to set up this alert?

Accepted Answer

Cloud Monitoring. Cloud Monitoring (formerly Stackdriver) is the GCP service for monitoring metrics and setting up alerting policies. Cloud Logging is for logs, Cloud Audit Logs for audit trails, and Cloud Billing reports for cost tracking.

Answer

Cloud Audit Logs

Answer

Cloud Logging

Answer

Cloud Billing reports

Question 12

You want to automatically group and track similar errors in your application logs, and see trends over time. Which Google Cloud service should you use?

Accepted Answer

Error Reporting. Error Reporting automatically groups exceptions by similarity, provides trend analysis, and links to logs and traces. Cloud Monitoring is for metrics, Cloud Logging for logs, and Cloud Trace for tracing.

Answer

Cloud Monitoring

Answer

Cloud Logging

Answer

Cloud Trace

Question 13

A startup needs a database for a global user base with low-latency reads and writes, strong consistency, and the ability to scale horizontally without downtime. They anticipate variable traffic. Which Google Cloud database service meets these requirements?

Accepted Answer

Cloud Spanner. Cloud Spanner provides global distribution, strong consistency, horizontal scaling, and no downtime for schema changes or scaling. Cloud SQL is not global, Bigtable does not have strong consistency, and Firestore is not global with strong consistency for multi-region.

Answer

Cloud Bigtable

Answer

Cloud SQL

Answer

Firestore

Question 14

A DevOps engineer wants to test disaster recovery for a Cloud SQL for MySQL instance by simulating a zone failure without impacting production traffic. They need to ensure minimal data loss. Which approach should they take?

Accepted Answer

Promote a cross-region read replica in a test project to validate the failover process. Non-destructive tests are best done using read replicas. Promoting a read replica in a test environment avoids impacting production. Restoring a backup from Cloud Storage would not test the failover process. Using HA failover would affect production. Restoring to a new instance from PITR tests recovery but not failover.

Answer

Take an on-demand backup and restore it to a new Cloud SQL instance

Answer

Use the gcloud command to perform a point-in-time recovery on the same instance

Answer

Enable the HA configuration and trigger a failover by stopping the primary instance

Question 15

A company is designing a Cloud Firestore schema for a social media application. Users can follow other users, and the application needs to display a feed of posts from followed users ordered by timestamp. Which schema design is most cost-effective and performant for querying the feed?

Accepted Answer

Store a feed subcollection under each user document containing references to posts from followed users.. It uses a feed subcollection under each user document to store pre-computed references to posts from followed users. This design avoids expensive collection-group queries or multiple individual queries per followed user, ensuring that fetching the feed is a single, indexed read operation ordered by timestamp, which is both cost-effective and performant at scale.

Answer

Store all posts in a top-level collection and query for posts where user ID is in the list of followed users, ordered by timestamp.

Answer

Store all user posts in an array within a single document and use array-contains queries.

Answer

Store a 'follows' collection with documents containing follower and followed user IDs; then query posts for each followed user.

Question 16

A team is migrating an on-premises PostgreSQL database to Cloud SQL. The current schema uses a composite primary key on columns (customer_id, order_date) in the orders table. The migration team wants to reduce the cost of secondary indexes. Which schema design change should they consider?

Accepted Answer

Partition the table by customer_id to reduce the number of secondary indexes needed.. Partitioning the table by customer_id can reduce the need for secondary indexes on that column. When the table is partitioned, queries that filter by customer_id can use partition pruning instead of an index scan, allowing you to drop an index on customer_id and thus reduce secondary index storage costs. Creating a secondary index on the composite key (B) would add an index and increase cost. Replacing the composite primary key with a surrogate UUID (C) would require a unique constraint index on the original columns, resulting in two indexes (the PK on UUID and the unique index on the composite columns) instead of one, which increases index costs. Using the CLUSTER command (D) physically reorders table rows but does not reduce index sizes.

Answer

Create a secondary index on the composite key to keep the same query performance.

Answer

Replace the composite primary key with a surrogate UUID primary key and add unique constraints on the original columns.

Answer

Use the CLUSTER command to physically reorder the table based on the composite key.

Question 17

A team is deploying a new application on Google Kubernetes Engine (GKE) that uses Cloud Spanner. They want to minimize latency for read operations. Which Spanner configuration should they use?

Accepted Answer

Use a single-region instance and configure the leader preference to the application's zone.. Using a single-region Cloud Spanner instance with leader preference set to the zone where the application runs ensures that the leader replica is in the same zone as the application. Strongly consistent reads are served from the leader, so this configuration minimizes read latency by avoiding cross-zone network round trips. Option B is incorrect because a regional instance does not have separate 'read replicas'; all replicas in a regional instance are read-write, and the leader is already in the same region, but specifying 'read replicas' is misleading and not a valid Spanner configuration. Multi-region options (A and D) introduce cross-region latency for strongly consistent reads.

Answer

Use a multi-region configuration with default leader preference set to the region where the application runs.

Answer

Use a regional instance with read replicas in the same region.

Answer

Use a single-region instance and enable read-only replicas in multiple zones.

Question 18

A DevOps engineer wants to create a custom metric in Cloud Monitoring that represents the number of requests processed by a service, measured from the start of each request to its completion. The metric should increment by 1 for each request and must be queryable for the count in the last 24 hours. Which metric kind would best suit this requirement?

Accepted Answer

CUMULATIVE. A CUMULATIVE metric measures a value that increases over time, such as a count of requests. It is appropriate when you want to know the total count up to a point in time, which can be queried for any time range (e.g., last 24 hours) by subtracting the start value from the end value. GAUGE represents a snapshot value that can go up and down, DELTA represents a rate per time interval but does not accumulate.

Answer

DELTA

Answer

COUNT

Answer

GAUGE

Question 19

An organization is implementing Binary Authorization for GKE. They need to ensure that only container images signed by their CI system are deployed. Which service must be enabled and configured to enforce this?

Accepted Answer

Binary Authorization attestor and policy. Binary Authorization is a managed service that requires an attestor to verify signatures. The attestor is configured with a public key, and the CI system signs images with the private key.

Answer

Cloud Key Management Service (KMS)

Answer

Artifact Registry with Container Analysis

Answer

Cloud Build service account with 'iam.serviceAccountUser' role

Question 20

A developer wants to use a pre-existing Docker image from Artifact Registry in a Cloud Build step. How should they authenticate the build step to pull the image?

Accepted Answer

Use a Docker step with the image specified directly; Cloud Build automatically uses its service account.. Cloud Build's default service account is automatically granted the Artifact Registry Reader role (roles/artifactregistry.reader) when the Cloud Build API is enabled in a project. This means any build step that references an image from Artifact Registry can pull it without explicit authentication, as Cloud Build uses its own service account credentials to authenticate the pull request to the registry.

Answer

Run 'gcloud auth configure-docker' in a build step.

Answer

Set the environment variable 'ARTIFACT_REGISTRY_KEY' in the build step.

Answer

Store a service account key in Secret Manager and activate it in the build step.