PCDE Practice Test 20 — 15 Questions

Question 1

You are designing a schema for Cloud Spanner and need to avoid write hotspots. Which primary key design strategy is recommended?

Accepted Answer

Use a UUID or hash prefix as the first part of the primary key. Using a UUID or a hash prefix as the first part of the primary key ensures that writes are distributed across nodes, avoiding hotspots. Monotonically increasing keys like timestamps cause all writes to hit the same tablet, creating a hotspot.

Answer

Use the most frequently queried column as the primary key

Answer

Use a composite key with the leading column being a timestamp

Answer

Use a monotonically increasing timestamp as the primary key

Question 2

A company uses BigQuery materialized views to pre-aggregate sales data for a BI dashboard. The dashboard requires near-real-time data, but the materialized view currently reflects data up to 30 minutes old. What is the most effective way to reduce the refresh interval without significantly increasing costs?

Accepted Answer

Reduce the max_staleness parameter of the materialized view.. Reducing the `max_staleness` parameter directly controls the maximum acceptable age of the data in a BigQuery materialized view. By lowering this value, you force the view to refresh more frequently, achieving near-real-time data without incurring the cost of a full manual refresh or additional streaming infrastructure. This parameter is designed to balance freshness against cost, making it the most effective and efficient solution.

Answer

Disable automatic refresh and schedule a manual refresh every minute.

Answer

Use a streaming buffer with the base table to reduce latency.

Answer

Create additional materialized views with overlapping time windows.

Question 3

A company uses Cloud SQL for MySQL with automated backups enabled. They want to ensure they can recover their database in the event of a regional outage. Which TWO actions should they take? (Choose two.)

Accepted Answer

Create a cross-region read replica.. Option B is correct because a cross-region read replica keeps a continuously replicated copy of the primary instance in a different region, so if the primary region fails, the replica can be promoted to become the new primary and restore service. Option C is correct because cross-region backup replicas copy automated backups to a different region, allowing restoration of the instance even if the original region's backups are unavailable during a regional outage. Option A is wrong because extending backup retention to 30 days only keeps backups longer within the same region and does not provide cross-region resilience. Option D is wrong because point-in-time recovery with 7-day retention still relies on backups stored in the instance's region and does not protect against a regional failure. Option E is wrong because more frequent on-demand backups remain region-bound and do not address regional outage recovery.

Answer

Increase the backup retention period to 30 days.

Answer

Enable point-in-time recovery with a 7-day retention.

Answer

Schedule more frequent on-demand backups.

Question 4

A company is migrating their on-premises Oracle database to Cloud SQL for PostgreSQL. They want to test the converted stored procedures using unit tests. Which framework should they use?

Accepted Answer

pgTAP. pgTAP is a unit testing framework for PostgreSQL that can test stored procedures and functions.

Answer

pgAdmin

Answer

SQL Developer

Answer

Ora2Pg

Question 5

Which THREE metrics should you set up alerts for to proactively monitor the health of a Cloud SQL for MySQL instance? (Choose 3)

Accepted Answer

Replication lag (for instances with replicas). Option A (Replication lag for instances with replicas) is correct because Cloud SQL for MySQL exposes the mysql.replication.seconds_behind_master (or replication_lag) metric, and a growing lag indicates the replica is falling behind the primary, threatening read consistency and failover readiness. Option C (CPU utilization > 80%) is correct because Cloud SQL publishes the database/cpu/utilization metric, and sustained high CPU on the instance can signal query contention, missing indexes, or undersized tier, making it a key proactive health alert. Option E (Disk usage) is correct because Cloud SQL reports database/disk/bytes_used versus the instance's storage capacity, and running out of disk space causes write failures and instance outages, so alerting before the threshold is essential. Option B (Number of queries per second) is not a health indicator by itself since QPS varies with normal workload and has no universal threshold for alerting. Option D (Network throughput) is likewise workload-dependent and does not directly reflect instance health problems, so it is not one of the three recommended alert metrics.

Answer

Number of queries per second

Answer

Network throughput

Question 6

A company uses Cloud Build to build a container image with Kaniko. They want to speed up builds by caching the base image layers. Which configuration should they add to their cloudbuild.yaml?

Accepted Answer

Add '--cache=true' and '--cache-repo=us-central1-docker.pkg.dev/$PROJECT_ID/cache' to the Kaniko builder arguments.. Kaniko does not rely on the Docker daemon, so it cannot use Docker's native layer caching. Instead, Kaniko supports remote caching by pushing cached layers to a container registry. Adding `--cache=true` enables layer caching, and `--cache-repo` specifies the registry repository where cached base image layers are stored, allowing subsequent builds to reuse them and significantly reduce build time.

Answer

Add a 'docker pull' step before the Kaniko step to pre-pull the base image.

Answer

Use Docker's --layer-cache flag in the build step.

Answer

Configure Cloud Build to use a private pool with SSD persistent disks.

Question 7

A team is using Helm charts to deploy to GKE. They want to manage environment-specific values (dev, staging, prod) while keeping a single chart. Which approach is recommended?

Accepted Answer

Use --values flags with environment-specific value files. The recommended Helm pattern for managing environment-specific values with a single chart is to keep a base values.yaml and supply environment-specific overrides via '--values' (or '-f') flags pointing to files like values-dev.yaml, values-staging.yaml, and values-prod.yaml. This preserves one chart (single source of truth for templates) while cleanly separating environment configuration.

Answer

Store all environment values in a single values.yaml and use --set to override

Answer

Use Kustomize overlays to manage Helm values

Answer

Create separate Helm charts for each environment

Question 8

A company is running a MySQL database on Cloud SQL and needs to optimize for high random read/write performance. Which storage type should they choose?

Accepted Answer

SSD persistent disk. SSD persistent disk provides consistent low-latency performance for random read/write operations, which is critical for MySQL databases on Cloud SQL. It offers higher IOPS and throughput compared to HDD or balanced persistent disks, making it the optimal choice for high random read/write workloads.

Answer

Local SSD

Answer

Balanced persistent disk

Answer

HDD persistent disk

Question 9

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.

Question 10

A company plans to migrate an on-premises PostgreSQL database to Cloud SQL. The database is 2 TB in size and requires minimal downtime. Which migration approach should they use?

Accepted Answer

Use Database Migration Service with a continuous migration job.. Database Migration Service (DMS) with a continuous migration job is the correct approach because it supports minimal-downtime migrations from on-premises PostgreSQL to Cloud SQL. DMS uses logical replication (via PostgreSQL's pgoutput plugin) to continuously sync changes from the source to the target, allowing a short cutover window. For a 2 TB database, this avoids the lengthy downtime required by a full dump-and-load method.

Answer

Export the database using pg_dump and import into Cloud SQL using psql.

Answer

Use Datastream to stream data into Cloud SQL.

Answer

Copy the data files to Cloud Storage and use gcloud to load into Bigtable.

Question 11

An organization uses Cloud Deploy to promote releases across dev, staging, and prod. They want to automatically run integration tests after a deployment to a Cloud Run target, before proceeding to the next stage. How should they implement this?

Accepted Answer

Configure a postDeploy hook on the staging target that runs a Cloud Run Job for integration tests. Cloud Deploy supports postDeploy hooks that run after a deployment to a target completes, and these hooks can execute a Cloud Run Job to perform integration tests. If the job fails, the rollout is marked as failed and promotion to the next stage is blocked, giving you automated gating between dev, staging, and prod.

Answer

Create a separate Cloud Build trigger that runs tests after detecting the deployment

Answer

Use a preDeploy hook on the staging target to run tests

Answer

Add an approval gate after staging that requires manual test results

Question 12

During an incident, the incident commander decides to escalate to a higher severity level. Which of the following best describes the incident commander's primary responsibility?

Accepted Answer

Managing the incident response process and communications. The incident commander owns the overall response: coordinating responders, setting priorities, making severity and escalation decisions, and managing communications with stakeholders. They do not personally debug, fix, or write the postmortem — those are delegated to subject-matter experts and scribes so the IC can maintain situational awareness.

Answer

Debugging the root cause of the incident

Answer

Writing the postmortem document

Answer

Implementing the fix

Question 13

A team is automating toil reduction and needs to identify tasks that qualify as toil. Which of the following is a defining characteristic of toil according to SRE principles?

Accepted Answer

Work that has no enduring value. Toil is defined in SRE as work that is manual, repetitive, automatable, tactical, devoid of enduring value, and scales linearly with service growth. The defining characteristic most commonly tested is that toil has no enduring value — completing it does not leave the service in a permanently improved state. This distinguishes it from engineering work that produces lasting improvements.

Answer

Work that requires deep domain expertise

Answer

Work that is performed by junior engineers only

Answer

Work that is critical to business operations

Question 14

A team uses GitOps with Config Sync to manage multiple GKE clusters. They want to ensure that if a configuration change is applied to the git repository, it is automatically synced to all clusters within minutes. What must be configured?

Accepted Answer

Configure Config Sync with a webhook from Cloud Source Repositories or GitHub to trigger re-sync. Config Sync relies on a polling mechanism by default, which can introduce delays. Configuring a webhook from Cloud Source Repositories or GitHub triggers an immediate re-sync when changes are pushed to the repository, ensuring that configurations are applied to all GKE clusters within minutes without waiting for the next polling interval.

Answer

Use Anthos Service Mesh to distribute configurations

Answer

Set the `syncWait` parameter in the Config Sync operator to 1 second

Answer

Set up a Cloud Build trigger that runs `gcloud container clusters update` on each cluster

Question 15

A company is migrating their on-premises MySQL database to Cloud SQL. The database is 500 GB and they have a 1 Gbps network connection. They want to minimize downtime. Which THREE steps should they take?

Accepted Answer

Perform a test migration to validate the process.. Performing a test migration validates the entire process, including schema compatibility, data integrity, and application connectivity, before the actual cutover. This reduces the risk of unexpected failures during the production migration, which is critical for minimizing downtime. A test migration also helps estimate the time required for the final cutover and allows for tuning of the Database Migration Service settings.

Answer

Export the database to a SQL file and import after the cutover.

Answer

Schedule a maintenance window for the cutover.