PCDE Practice Test 13 — 15 Questions

Question 1

Match each Cloud Spanner replication type to its purpose.

Accepted Answer

Read-write replica: Can serve reads and writes and participates in voting.. Cloud Spanner supports read-write, read-only, and witness replicas. Read-write replicas handle all operations and vote; read-only replicas scale reads without voting; witness replicas provide quorum without storing data. Common confusions include swapping the roles of read-only and witness replicas.

Answer

Read-write replica: Serves reads only and does not vote.

Answer

Read-only replica: Does not store data but participates in voting.

Question 2

A team is using Cloud Build to build Docker images and push them to Artifact Registry. They want to speed up builds by caching the Docker layers. Which approach is recommended for caching in Cloud Build?

Accepted Answer

Configure Cloud Build to use Kaniko cache with a destination in Artifact Registry. Cloud Build's recommended approach for Docker layer caching is to enable Kaniko cache, which stores intermediate layers in a specified Artifact Registry repository and reuses them across builds. Kaniko executes Dockerfile instructions without a Docker daemon and can push cached layers to a registry, dramatically reducing rebuild times. Configuring the cache destination in Artifact Registry integrates natively with Cloud Build and GCP IAM.

Answer

Use Google Cloud Storage as a layer cache for Docker builds

Answer

Use 'gcloud builds submit --cache-from' with a local cache

Answer

Set up a Docker registry proxy in Compute Engine to cache images

Question 3

A team wants to adopt GitOps for a GKE cluster. They need a solution that automatically syncs their Kubernetes manifests from a Git repository to the cluster and ensures the cluster state matches the repo. Which Google Cloud service should they use?

Accepted Answer

Config Sync. Config Sync is the correct choice because it is the native GitOps agent within Google Cloud's Anthos platform, designed specifically to continuously reconcile the state of a GKE cluster with Kubernetes manifests stored in a Git repository. It automatically detects changes in the configured source of truth and applies them to the cluster, ensuring drift is corrected without manual intervention.

Answer

Config Connector

Answer

Cloud Deploy

Answer

Argo CD on GKE

Question 4

An organization wants to implement a blameless postmortem culture after incidents. Which of the following is a key practice in blameless postmortems?

Accepted Answer

Identifying contributing factors using techniques like the 5 Whys. Blameless postmortems focus on identifying contributing factors and systemic issues, not individual blame. The 5 Whys technique helps uncover root causes.

Answer

Firing the responsible engineer to prevent recurrence

Answer

Assigning blame to the engineer who made the mistake

Answer

Immediately implementing a fix without documentation

Question 5

An engineer is migrating from on-premises PostgreSQL to Cloud SQL for PostgreSQL using pg_dump. Which flags should be used to avoid errors related to roles and privileges when importing into Cloud SQL?

Accepted Answer

--no-owner --no-acl. The --no-owner and --no-acl flags tell pg_dump to omit ownership and access privilege (GRANT/REVOKE) commands from the dump. Cloud SQL for PostgreSQL does not allow superuser-level role creation or arbitrary ownership assignments, so importing a dump that includes ALTER ... OWNER TO or GRANT statements for roles that do not exist in Cloud SQL will fail. Stripping these with --no-owner --no-acl produces a dump that imports cleanly.

Answer

--schema-only --no-data

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--clean --if-exists

Answer

--inserts --column-inserts

Question 6

A Cloud SQL for PostgreSQL instance needs to achieve a recovery point objective (RPO) of less than 1 minute and a recovery time objective (RTO) of less than 2 minutes in the event of a zone failure. Which disaster recovery strategy should be used?

Accepted Answer

Configure Cloud SQL HA (high availability) with a standby in a different zone.. Cloud SQL High Availability (HA) maintains a synchronous standby replica in a different zone within the same region. Because replication is synchronous, the standby is always up-to-date, giving an RPO near zero (well under 1 minute). On zone failure, automatic failover promotes the standby in under 2 minutes, satisfying the RTO. This is the only option that meets both the sub-1-minute RPO and sub-2-minute RTO requirements.

Answer

Perform regular backups to Cloud Storage and restore in a different zone.

Answer

Enable cross-region replication using a read replica.

Answer

Enable point-in-time recovery (PITR) with transaction log backups.

Question 7

A team is migrating an on-premises PostgreSQL database to Cloud SQL for PostgreSQL. The existing schema uses a large number of foreign key constraints and triggers for data validation. The team wants to minimize migration effort and maintain data integrity. Which schema design approach is most appropriate for Cloud SQL?

Accepted Answer

Keep the existing foreign keys and triggers as-is in Cloud SQL for PostgreSQL. Cloud SQL for PostgreSQL is fully compatible with the PostgreSQL engine, meaning foreign key constraints and triggers operate identically to on-premises PostgreSQL. This approach minimizes migration effort by preserving the existing schema logic and maintaining referential integrity without requiring application changes or data validation rewrites.

Answer

Migrate to Cloud Spanner and use interleaved tables to simulate foreign keys

Answer

Remove all foreign keys and triggers and implement validation in the application layer

Answer

Convert the schema to use Firestore in Datastore mode with composite indexes

Question 8

An application running on GKE emits custom metrics via OpenTelemetry. The metrics need to be ingested into Cloud Monitoring and visualized in a dashboard. Which approach should the engineer use?

Accepted Answer

Install the OTel Collector as a DaemonSet and configure the Google Cloud Monitoring exporter.. The OpenTelemetry (OTel) Collector is the standard way to receive OTLP metrics and export them to Cloud Monitoring. Deploying it as a DaemonSet ensures every node has a collector instance to receive metrics from local pods. The Google Cloud Monitoring exporter translates OTLP metrics into the Cloud Monitoring API format, enabling ingestion and dashboard visualization.

Answer

Use the Cloud Monitoring API to directly ingest metrics from the application.

Answer

Configure the application to write logs in JSON format and create a log-based metric.

Answer

Use the Operations Agent on the node to scrape metrics from the application.

Question 9

A company is migrating a MySQL OLTP database to Bigtable for a time-series application. The current schema uses a relational model with normalized tables. Which two actions should the team take when designing the Bigtable schema? (Choose TWO.)

Accepted Answer

Denormalize the data into a single wide-column table.. Option A is correct because Bigtable is a wide-column NoSQL store with no joins, so the normalized relational model must be denormalized into a single wide-column table where related data is stored together for efficient reads. Option C is correct because Bigtable row keys are sorted lexicographically and writes to sequential keys (such as timestamps) create hotspots; salting the row key (e.g., prepending a hash or bucket prefix) distributes writes evenly across nodes. Option B is incorrect because Bigtable only supports single-row atomic operations, not multi-row ACID transactions like a relational database. Option D is incorrect because Bigtable does not support secondary indexes; query patterns must be served by row key design or by maintaining separate index tables. Option E is incorrect because normalizing to reduce duplication is a relational design practice that would require joins, which Bigtable cannot perform.

Answer

Maintain transactional integrity using Bigtable transactions.

Answer

Create secondary indexes on timestamp columns.

Answer

Normalize the schema to reduce data duplication.

Question 10

Your Cloud Bigtable instance is experiencing hot spots, causing performance degradation. You want to identify the specific row keys causing the hot spots. Which tool should you use?

Accepted Answer

Key Visualiser. The Key Visualiser is a tool provided by Google Cloud for Cloud Bigtable that analyzes row key distribution and identifies hot spots by visualizing the access patterns of row keys. It helps you understand which specific row keys are causing performance degradation due to uneven load. By using the Key Visualiser, you can pinpoint the problematic keys and then redesign your schema or application logic to distribute the load more evenly.

Answer

Cloud Monitoring dashboard

Answer

cbt command-line tool

Answer

Cloud Logging

Question 11

A team is migrating a relational database to Bigtable. The existing schema uses foreign keys to join orders, customers, and products. Which data model approach is most suitable for Bigtable?

Accepted Answer

Denormalize orders, customers, and products into a single table with a composite row key.. Bigtable is a wide-column NoSQL database optimized for high-throughput, low-latency access, and it does not support SQL-style joins or secondary indexes in the traditional relational sense. Denormalizing orders, customers, and products into a single table with a composite row key (e.g., customer_id#order_id#product_id) allows all related data to be co-located and retrieved with a single row scan, eliminating the need for joins and aligning with Bigtable's key-value access pattern.

Answer

Store each entity in a separate table and use secondary indexes.

Answer

Use Cloud SQL as a lookup table for joins.

Answer

Keep the normalized structure and use MapReduce to perform joins.

Question 12

A DevOps engineer is building a CI/CD pipeline and needs to securely pass a database password to a Cloud Build step. The password is stored in Secret Manager. What is the correct way to access it in cloudbuild.yaml?

Accepted Answer

Define the secret in 'availableSecrets' and reference it via 'secretEnv' in the step. The correct approach is to define the secret in the 'availableSecrets' section of cloudbuild.yaml and reference it via 'secretEnv' in the step. This method securely injects the secret as an environment variable without exposing it in logs or build artifacts. It leverages Cloud Build's native integration with Secret Manager, ensuring the secret is fetched at runtime and only accessible to the specified step.

Answer

Use 'gcloud secrets versions access' directly in a step's entrypoint

Answer

Store the password in a Cloud Storage bucket and download it during build

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Pass the password as a build substitution variable

Question 13

An organization is migrating a MySQL database to Cloud SQL using Database Migration Service (DMS). They need to ensure minimal downtime and continuous replication of changes from the source. Which type of migration job should they create?

Accepted Answer

Continuous migration job (CDC). Continuous (CDC) migration jobs replicate ongoing changes after the initial dump, allowing minimal downtime during cutover. One-time jobs only perform a full dump and import without ongoing replication.

Answer

Batch migration job

Answer

One-time migration job

Answer

Snapshots-only job

Question 14

A DevOps team is using Terraform to manage infrastructure. They have a module that creates a Cloud Storage bucket. They want to reference the bucket's URL in another part of the configuration without hardcoding. Which approach should they use?

Accepted Answer

Use Terraform outputs and a remote state data source to read the bucket URL from the state of the configuration that created it.. Terraform outputs expose values from a module or root configuration, and the terraform_remote_state data source reads those outputs from another configuration's state file, allowing the bucket URL to be referenced without hardcoding. This is the canonical pattern for sharing resource attributes across separate Terraform configurations or stacks. It decouples the producer and consumer while keeping a single source of truth.

Answer

Use a shared Terraform workspace to access the bucket across configurations.

Answer

Use a Terraform data source for the bucket, such as google_storage_bucket.

Answer

Store the bucket URL in a variable and pass it manually.

Question 15

You are troubleshooting a Cloud SQL read replica that is experiencing high replication lag. You check the 'replication_lag' metric and see it is consistently above 60 seconds. What is the most likely cause of this lag?

Accepted Answer

The primary instance has a heavy write workload.. High replication lag in Cloud SQL is most commonly caused by a heavy write workload on the primary instance. When the primary processes a large volume of write operations (e.g., INSERT, UPDATE, DELETE), the replica must replay those changes from the binary log, and if the rate of writes exceeds the replica's ability to apply them, lag accumulates. This is a fundamental behavior of MySQL asynchronous replication, where the replica is always slightly behind the primary under load.

Answer

The replica's automatic storage increase is disabled.

Answer

The replica has point-in-time recovery enabled.

Answer

The replica is using a different storage type than the primary.